Soil Weed Seed Bank Dynamics After Two-Year of On-Farm Trials Under Conservation Agriculture in Bangladesh

Introduction

While Conservation Agriculture (CA) has been recognized as an excellent method for boosting crop yields sustainably, weed management is often regarded as one of the most difficult aspects [1]. Due to the reduced tillage operation, the composition and dynamics of the weed seed bank in CA will vary as compared to conventional tillage. The soil weed seed bank is a repository for weed seeds that influences the species composition. The seed bank is the primary source of weeds, represents a critical stage in the weed life cycle, and the weed population is inextricably linked to its seed bank. Knowledge of the size and composition of the soil weed seed bank is critical for forecasting future weed infestations and management techniques, weed seed production after the cropping season, calculation of crop-weed competition and crop yield loss, as well as agricultural economics [2]. There are relatively few research that investigate the influence of CA principles on the dynamics of weed seed banks. These sorts of research are necessary to include weed management into cost-benefit assessments of CA adoption. In light of this, long-term CA studies were done to determine the influence of CA principles on the dynamics of weed seed banks.

Materials and Methods

We conducted green-house experiments at the Department of Agronomy, Bangladesh Agricultural University in Mymensingh, Bangladesh. Soil was taken from the site of long-term CA experiments in the Durbacahra village of Gouripur upazila in Bangladesh’s Mymensingh district. Under the Summer Rice– Mustard–Winter Rice cropping system, crops were cultivated using conventional tillage (CT) and strip tillage (ST), with 50% standing residues from previous harvests retained compared to no-residue. CT was performed using a two-wheeler tractor, whereas ST was performed using a Versatile Multi-Crop Planter machine [3]. Prior to the trials, five soil samples from each plot were obtained at depths of 0–5 cm, 5–10 cm, and 10–15 cm in a “W” pattern [4]. One kilogram of dirt from each plot was deposited in a 32 cm diameter plastic dish. To ensure adequate weed germination, the samples were maintained wet. During a one-year period, emerging seedlings were recognized, numbered, and destroyed at 30-day intervals. To help identification, seedlings of dubious identity were transplanted to another plate and nurtured to maturity. Following the removal of each batch of seedlings, the soils were carefully mixed and rewetted to allow for further emergence. This procedure was done a total of 12 times. The seedlings that were counted were translated to numbers per m2. Following the conclusion of the two-year field experiments in Gouripur, soil samples were gathered again using a similar approach, and the same experimental procedures were used in the green house.

Results and Discussion

Effect of CT, ST, No-Residue and 50% Residue Mulching on the Weed Abundance (Number Per M2): Effect of ST and retention of 50% crop residues was significant on the number of weed species. Before setting the long-term CA trials in 2013, there was no significant difference in the weed species for CT and ST. During this time, there was 59 species in CT and 62 species in ST indicating the homogeneity of weed seed bank in the field. After 6 field trials of two-year study, there was 20% higher weed species in CT (71 species) but 7% less species in ST (58 species) (Figure 1). Retention of 50% crop residue in the field caused to decrease the weed species by 9% after 2-year study compared to the before study (Figure 2).

Figure 1: Effect of CT and ST on the weed abundance (number per m2) after 2-year field trials of Conservation Agriculture (CT: Conventional Tillage, ST: Strip Tillage).

Figure 2: Effect of no-residue and 50% residue mulching on the weed abundance (number per m2) after 2-year filed trials of Conservation Agriculture.

Table 1: Effect of tillages and residues on weed density (number per m2) at different soil depths.

Note: CT: Conventional Tillage, ST: Strip Tillage, (+): increase (-): decrease.

Effect of CT, ST, No-Residue and 50% Residue Mulching on the Weed Abundance (Number Per M2) At Different Soil Depths: The highest weed density was recorded from 0–5 cm depth followed by 5–10 and 10–15 cm depth both in CT and ST during both of before and after field trials (Table 1). After 2-year crop cultivation CT increased the weed density by 13%. Data recorded from after 2-year study also reveals that, heavy pulverization in CT caused to increase density by 11% at 0–5 cm depth and 25% at 5–10 cm depth but decreases by 53% at 10–15 cm depth which might be attributed from continuous upward movement of weed seeds to the upper layer of soil. After 2-year cropping, ST reduced the seed bank size by 22%. It was also found that, ST reduced the weed seeds by 24% at 0–5 cm and 57% at 10–15 cm depth but increased by 25% at 5–10 cm depth. Minimal soil disturbance may cause to emerge the weeds from upper most layer leading to reduce seed bank size and deposition of seed to the middle layer leading to enrich seed bank. Soil compactness at the lowest layer may cause to increase seed dormancy and mortality and reduce seed bank size [5]. Two-year cropping with the retention of 50% residue reduced the seed bank by 11% and there was a decreasing trend in seed composition from upper to lower soil layer. Residue may cause to hinders the optimal atmosphere for weeds and favors the weeds seed predation by soil fauna and reduce seed bank status [6].

Conclusion

Results of the present on-farms study claimed that two years’ continuous practice Conservation Agriculture based on Strip Tillage with the retention of 50% anchored residues of previous crop may lead to reduce soil weed seed bank status. It is recommended to conduct long-term trials across the Agro-ecological Zones of Bangladesh to validate the results.

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A Brief Summary of the Global Status of the 2022 Monkeypox Outbreak in Non-Endemic Countries

Introduction

Since the second week of May 2022, a sudden outbreak of Human monkeypox cases has been observed in as many as 21 non-endemic countries [1-5]. The concerning aspect of this 2022 outbreak of Human monkeypox is that many of the diagnosed cases didn’t exhibit any direct travel history to any endemic country or region [6]. Monkeypox ICD-10 B04 [7,8] is an infection that is primarily seen in Central and West African countries that have tropical forests populated with animals which can act as hosts for this virus [3,6,9-12]. Human monkeypox refers to a virus-based zoonosis that is caused by the monkeypox virus. The monkeypox virus is a member of the Orthopoxvirus family that also includes the variola virus responsible for causing smallpox. Since it’s discovery, there have been found to be two genetically separate strains of the monkeypox virus namely the Congo Basin (Central African) strain and the West African strain. In the past, Human monkeypox infections caused by the West African strain have shown to be of low severity in comparison to the infections caused by the Congo Basin strain [1,2,11,12].

Facts known about the Ongoing Human Monkeypox Virus Infection

Human monkeypox is a viral infection which has been transmitted to human beings from animals (mainly monkeys) and the human version spreads through direct or close contact with an infected individual [4-8]. Thus, it is safe to say that human monkeypox is generally transmitted by both direct and indirect contact with the bodily fluids of an infected person like their blood, bodily fluids, their skin or mucosal lesions and their clothes or belongings that have some degree of infected bodily fluids on them [1,4,5,7,8,12]. Secondary or person-to-person spread may take place also in people who touch the infected respiratory secretions, the skin lesions or contaminated belongings of the infected individual [8,10]. In previous outbreaks, the main route of transmission was found to be close contact with infected respiratory droplets. Human monkeypox infections can also be transmitted through inoculation or via the transplacental route from mother to foetus (this is known as congenital monkeypox). Even though most of the initial cases of Human monkeypox have been diagnosed in sexual health care clinics amongst men who have sex with other men, the most probable route of infection was the close contact with skin lesions of the infected person [4,5,7-9,12].

The main symptoms of Human monkeypox infection are fever (>38.5℃), headache, joint and muscle pains with subsequent presentation of a skin rash that is generally localized to the patient’s face, palm section of the hands and the soles of their feet. Other symptoms include lymphadenopathy (this refers to the presence of swollen lymph nodes), profound myalgia (this means having severe muscle and body pains), pain in the back and presenting with asthenia (serious degree of weakness). The incubation period is usually 6 to 16 days but has been reported as ranging from 5 to 21 days [5-7]. The infected individuals remain contagious from the onset of the above mentioned symptoms till the skin lesions are completely cured [7]. A confirmed case of Human monkeypox is one in which the patient presents with symptoms and probable cause (direct contact with an infected person or a travel history to endemic regions) followed by laboratory confirmation of having the monkeypox virus (done using molecular protocols like the realtime PCR test as well as genetic sequencing where possible) [11,12].

Figure 1: The appearance and progression of the different types of skin lesions in the second stage of the Human monkeypox infection (Source: 1).

The Human monkeypox infection in a patient has two clear stages. The first stage is the period of incubation and invasion (generally lasts between 5-21 days). This first stage is the one in which the patient presents with fever, serious headaches, lymphadenopathy, acute pain within the lower back as well as serious asthenia. The second stage is the skin rash period (this occurs within three days after presenting with fever) and is characterized by the different phases of rash appearance. It usually affects the face first and then spreads to the rest of the body (see Figure 1 below) [1]. The most affected areas are the face (in 96% of cases), the palms of the hands and the soles of the feet (in 75% of cases). The progression of skin rashes from maculopapular (the flat-based type of lesions) to vesicles (the fluid-filled blister type of lesions), pustules, and the formation of crusts in the end takes place within a 10-12 day period. The drying and falling of the scabs may occur or continue for almost 21 days.

Status of the Present Ongoing Human Monkeypox Outbreak on a Global Scale

Human monkeypox which spreads via direct person-to-person contact has always been low, but the appearance of the present outbreaks in as many as 24 non-endemic nations poses a definite risk to the general public (see Table 1 below) [8,11,12].

Table 1: Status Report of the present Human monkeypox outbreak as of 30th May 2022 (Sources of data: 8, 11-15).

Potential Mitigation of Transmission, the Guidelines for Diagnosis and Existing Treatment Options

Monkeypox symptoms usually get resolved in the patient with only supporting management and treatment. Still, in the present outbreak, it is of vital importance to contain the outbreak by limiting contact with patients, contact tracing, swift information of contact status to the contacts and isolation of such contacts. The risk summary in the present 2022 Human monkeypox virus for various populations was carried out by the EDEC and is presented in Table 2 below [12]. Patients must be kept isolated till the skin rashes are totally cured and must limit or totally abstain from contact with immune-suppressed individuals (at high risk of contracting the Human monkeypox infection) persons and pets. There is also need to avoid sexual activity and close physical proximity until the skin lesions are healed. Most patients can be cared for at home with supportive care. Those who come in close contacts of Human monkeypox cases need to carry out self-monitoring for any presentation of the disease symptoms up to 21 days from the last exposure to the patient.

Table 2: Summary of risk assessment for contracting the Human monkeypox virus in various population groups as published by the EDEC [12].

Health care staff and certain populations are more susceptible to getting infected. Health care staff needs to wear appropriate PPE (personal protection equipment) like gloves, water-resistant gown, FFP2 respirator when in touch with suspected cases or providing care to diagnosed patients. Laboratory personnel that test for the Human monkeypox virus must take mandatory precautions to mitigate occupational exposure [12]. A summary of treatment and management guidance for Human monkeypox cases has been published by the EDEC and is shown in Table 3 below. This will be useful as a reference point for health care professionals [12].

Table 3: Summary of treatment and management strategy for those in close contact with a Human monkeypox patient as published by the EDEC [12].

The strict compliance with sanitary hygiene protocols (regularly disinfecting hands after contact with the patient) by care givers and all in contact with the patients is mandatory. The surveillance, case assessment, contact tracing, follow-up, laboratory diagnosis, assessment and management of the patients should follow the WHO guidelines [10,11] or the EDEC guidelines [12] as per the country’s health care policies [5-7,11,12].

The WHO, the EDEC and USA’s CDC (The Centre for Disease Control and Prevention) are responding to this event as a high priority to avoid further spread [6-15]. The WHO has also recommended safe sex as many of the present cases on a global scale seem to have been diagnosed in men who have sex with other men. Infected people and those in contact with them have to abstain from contact with pet or domestic animals to prevent the jumping of the monkeypox virus infection in these susceptible populations [5-7,11,12]. At present, there are no validated as well as licensed treatment protocols for human monkeypox. However, two orally used medicines namely brincidofovir and tecovirimat have been given approval by the FDA (Food and Drug Administration), USA for the treatment of smallpox as emergency strategies in the event of any future bioterrorism event. None of these two medications have been assessed properly in human clinical trials for effectiveness against other members of the Orthopoxvirus family including the Human monkeypox virus. There has been some compassionate usage of tecovirimat in the Central African Republic, where Human monkeypox outbreaks are common [1].

In terms of prevention through vaccination, there are a few vaccines available for preventing smallpox which give a certain degree of protection against the Human monkeypox virus. One of the more recent vaccines that was made for smallpox namely MVABN (also called Imvamune or Imvanex or Jynneos) has been given approval in the year 2019 for usage in prevention of the spread of the Human monkeypox infection. However the drawback is that this vaccine isn’t freely accessible globally at present. The WHO is presently working towards better availability by collaborating with the makers. It is of importance to know that individuals who are in the above 40 age group were vaccinated against smallpox as it had not been eradicated and this provides them some measure of protection against the Human monkeypox virus. The issue that is worrisome at present is that these original smallpox vaccines were withdrawn from public circulation after smallpox was eradicated. As such, people in the below 40 population were most probably not given smallpox vaccination after the year 1980. In some countries, some of the highly at risk health care staff might be given a more recent smallpox vaccine [15].

Conclusion

The UN and WHO are of the opinion that the present global outbreak of Human monkeypox in non-endemic countries is still a controllable public health situation. However, there is need for every country to carry out appropriate surveillance, reporting of cases, contact tracing, adequate management as well as the compliance with the prevention, management and treatment guidelines provided by WHO [10,11,15] as well as the EDEC guidelines [12] or the CDC [13,14], depending on the country’s health care policies. The general public can consult the WHO factsheet [15] and the EDEC or CDC websites for general awareness and information on the Human monkeypox infection.

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The Changes of Paradigm in the Gynecology of the 21st Century

Introduction

In general terms, we could define the specialty of Obstetrics and Gynecology (hereinafter G&O), as the field of medicine that specializes in the care of women during pregnancy and childbirth, and in the diagnosis and treatment of diseases of the organs. female reproductive. With this, it is intended that the women of the world reach the highest possible standards of health and physical, mental, reproductive, and sexual well-being throughout their lives [1]. As old as humanity, the care of women in a way specifically linked to the regarding pregnancy and childbirth, they have been constant in the different societies in which life has developed. Much more modernly, barely a century or a little more, the general care of women has been spreading to the extent that survival first, longevity later, made their way into our vital evolution. To all this, if anything, and even more closely in time, one could add in a similar sense, the alterations of the male reproductive system in relation (exclusively) to the search for fertility.

In this constant and changing evolution, like life itself, our specialty of G&O is today dynamically witnessing a continuous and perpetual “paradigm change” [2]. All this surely hand in hand with the multiple social changes (and even demographic), that women themselves have been leading, over the past 100 years (suffering many times, which of course must also be recognized), until completing a path that has caused a better and greater attention to health care over even other more “classic” functions. To speak, therefore, of the evolution of G&O is inevitably to refer to the evolution of the woman herself [3] and her role in the world, since ours is a specialty that, far from attending only to the disease, deals extensively and more intense each time, of health care and the evolution of a situation that is so physiological and essential for the future of humanity, such as gestation, its search when it does not arrive, and everything related to both situations and their complications and evolutions. The objective of this short clinical note is to succinctly review those circumstances of all kinds (medical and biological, but also social and cultural) that condition the paradigm changes that gynecology faces in this wellentered 21st century. Similarly, perhaps provide some guidelines for reflection on these changes in future direction.

Reflections for Paradigm Changes

Indeed, women have gradually changed their position in a radical way, occasionally in a more abrupt or intense way, but qualitatively and quantitatively definitively in the world (at least in the Western world), presenting very different needs, with an “empowerment” generalized and at all levels [4] With it, our specialty has been forced to assume cultural changes, with different beliefs and origins of the women themselves that forced, at different times in history, to modify protocols and diverse approaches for different pathologies. Barely half a century ago, various alternative forms of fertility [5] were described by gynecologists (among others), even designing new forms of maternity, thus offering an alternative fertility to the natural one of the past 400,000 years (with in vitro fertilization, fertility deferred or without a partner [6], the possibility of procreating even beyond menopause in “older” women [7], the cryopreservation of ovarian tissue before its definitive damage resulting from a necessary iatrogenesis, maternal surrogacy that even unfolds the (once) immutable role of the old “mother there is only one”..., etc, etc).

With the social changes came the modifications even of civil ethics, always under revision, permanently changing like life itself [8,9]. Trying to manage the past from the point of view provided by current thinking or the prevailing civil ethics today is not only a serious error, but also leads to permanent frustration due to the (wrong) value judgment that it would entail for people, attitudes and stories that because they are dead at least, they do not have the slightest opportunity not only to defend themselves but perhaps even to explain their positions of yesteryear [10]. In this context of permanent change, our specialty today has taken as its commitment to the identification and report to the police of violence against women in any of its states and links. Thus, the gynecologist assumes a role that goes beyond health care itself for diseases and conditions of the female genital tract and transcends care and empathy with women (not sick), insofar as they are different and susceptible to receiving verbal damage. psychological or physical.

Finally, at least for now, while our specialty is the true queen and pioneer of minimally invasive and endoscopic surgery at all levels (abdominal, perineal, even breast...) [11], while witnessing the unstoppable development of surgery to distance and robotized [12], turns over time from a primitive and fundamentally surgical perspective, to increasingly less invasive, less surgical extremes, more on the side of internal medicine with the approach of healthy aging as a banner in a continuously older population that assumes regenerative medicine and repair of senility [13] in a classic medical-surgical specialty, less and less surgical and more and more medical. In this order of things, the gynecologist becomes a true “internist for women”, with new diseases for him such as climacteric care and aging with hormonal decline, osteoporosis or sarcopenia that cause so much disability in a world that honors even the puerile adoration of the increasingly immature youth, while socially despising the “sexalescence” [14] and the creativity of the (previously misnamed) “third age” and the “silver economy” [15], true engines of entrepreneurship beyond retirement. Thus, in this dynamic context, the gynecologist assumes to be more than “the woman’s family doctor”, to the point of mutating and being the “caregiver or healthprovider of women’s health throughout life”, the authentic alma mater of this blessed specialty that since assistance at the beginning of life, is obstinate in staying by her side while she lives her dreams of professional fulfillment in a changing environment and in permanent crisis.

Let’s toast to those paradigm shifts that history forces us to make every day and let’s hope that this very future grants us sufficient capacity to adapt to all of them and pilot them in an environment that will always be imbued with risk and uncertainty, such as biology. same of the woman; perhaps combating ignorance and empathy are the (only) keys to achieving it [16].

Final Comments

It is extraordinary to conclude anything concrete when constant change is the work dynamic not only of our specialty, but of biology and of life itself. In relation to the issue that concerns us today, there are surely more factors (than those briefly indicated in (Table 1)) and some even more important than those mentioned (such as the ambulatory use of various surgical procedures, the substantial change in the role of assistance to childbirth, the modeling of new assistance groups, even birth outpatient care [17], etc, etc), but between all of them they are transforming a specialty that was born timidly and quietly at the risk of intuitive assistance at birth as a need of social populations in anywhere in the world and that today assumes a change of roles driven by paradigm shifts that, like life itself, never cease throughout not only the previous century but those to come.

Table 1: Main paradigm changes assumed by gynecology in the 21st century. If it were a matter of systematizing the milestones of the supposed paradigm shift that G&O has been leading in this first quarter of the new century, apart from other more general conditions for all health care, we could point out a few items that we try to systematize below one by one.

Therefore, welcome are all those changes that allow us to enjoy life itself, in which everything and always is mutation, because otherwise it would not even be Life.

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Nano-Bio Applications in Photo-Bio Processes and Photochemical Devices

Introduction

It is expected that photovoltaic processes or devices will have a strong impact on both wastewater treatment and air purification processes, as well as energy storage devices. Where mechanical or chemical methods can be used in the application of effective filtration methods. One class of filtration methods is based on the use of membranes with appropriate pore sizes, allowing the liquid to be compressed across the membrane. Nanoporous membranes are suitable for mechanical filtration with micropores of less than 10 nm (“nanofiltration”) which may consist of membrane nanotubes. Nanofiltration is mainly used in the process of removing ions or separating different liquids. On a larger scale, membrane filtration methods are called nanofiltration, and they work between sizes of 10 to 100 nanometers [1-3]. Perhaps one of the important areas of nanofiltration applications is medical purposes, including the dialysis process. Magnetic nanoparticles provide a reliable and efficient way to remove heavy metal pollutants from wastewater by utilizing magnetic separation methods. Nanoparticles increase the efficiency of the ability to absorb pollutants, in addition, compared to traditional filtration and filtration methods, they are inexpensive. Some of the devices used to treat water using nanotechnology are now presented on the market, but more of them are in the process of being developed and developed. A recent study has demonstrated that low-cost nanomembrane separation methods are effective in producing potable water [4-6].

Electro-Optical Devices

The fabrication of devices that take advantage of the properties of low-dimensional elements such as nanoparticles is a promising field due to the possibility of applying a number of electrophysical, optical and magnetic properties to change the sizes of nanoparticles, which can be controlled during the manufacturing process. For example, in the case of nanopolymers, we can use the properties of turbulent, unstable systems. Here, some of the recent developments in the field of nanopolymers and some of their applications were reviewed. Although there are not enough opportunities for use in this field, there are many limitations as well. For example, the release of drugs using nanofibers cannot be controlled independently and often the mode is an explosive release, when a linear release is required. Hence, let us consider the future features in that field and study them. There is also the possibility of constructing ordered arrays of nanoparticles in a polymer matrix. A range of possibilities are also available for fabricating nanocircuit boards [7-9]. There is even a very attractive way to use nano polymers in neutral network applications. Also promising areas for development are optoelectronics and optical computing. The nature of single-band highly permeable metalcontaining nanoparticles with superior paramagnetic behavior can be used to fabricate an optical-magnetic storage medium.

The crystal defects also affect the electrical properties of the nanotube in the electronic device. A common finding is a reduced ability to conduction across the defective area of the tube. A deformation of the Arechia-shaped nanotube (which has the ability to conduct electricity) may cause the surrounding region to become semiconducting rather than electrically conducting, and the single-atom gaps have magnetic properties [10-13]. The crystal deformations clearly and strongly affect the thermal properties of the tube. Such distortions may lead to phonon scattering, which in turn increases the relaxation rate of these phonons, thereby reducing the mean free path and reducing the thermal conductivity of carbon nanotube structures. Simulations of phonon transmission indicate that alternative defects such as nitrogen or boron primarily scatter high-frequency optical phonons. However, large distortions such as Stone Wells distortions cause the phonon to scatter over a wide range of frequencies, resulting in an even greater reduction in thermal conductivity [14-17].

Nano-Parts in Electrical Instruments

The non-linear response of smart polymers is what makes them unique and efficient in the field of manufacturing sensitive and electronically efficient nanoparticles in optical devices. A large change in structure and properties can be brought about by a very small stimulus. Once this change occurs, there is no further change, which means that a predictable all-or-nothing response occurs, with perfect uniformity throughout the polymer. Smart polymers may alter the deformation, adhesion, or water-retaining properties, due to small changes in pH, ionic strength, temperature, or other stimuli. Another factor in the effectiveness of smart polymers lies in the inherent nature of polymers in general. The strength of each molecule’s response to changes in stimuli is the composite of changes in individual monomer units, which alone would be weak. However, these weak responses, multiplied hundreds or thousands of times, create significant power to drive biological processes [18-20]. Electronic single-walled nanotubes represent an important variety of carbon nanotubes because they exhibit electrical properties that are not present in the multi-walled nanotube variants. In particular, their bandgap ranges from zero to about 2 eV, and their electrical conductivity shows their metallic or semiconducting properties, while multi-walled carbon nanotubes are zero-gap metals. This makes single-band carbon nanotubes a good candidate for miniaturizing electrons beyond the precise electromechanical scale currently used for electrons. Perhaps the most basic building block of these systems is the electric wire, which makes single-walled carbon nanotubes (SCNTs) an excellent conductor. One of the useful applications of single-walled nanotubes was the development of the first transistors affected by the intermolecular field [21-23].

The Practical Application of Nanotechnology in Optical- Electronic Devices

Many of the electronic applications of carbon nanotubes depend precisely on methods for the production of both semiconductor or optionally metallic carbon nanotubes, preferably having a certain hydrophobicity. Noting that many methods for separating SCTs are known, but most of them are still not suitable for largescale technical processes. The most efficient method is based on a density gradient ultracentrifugation process, which separates surface-coiled nanotubes by a small difference in their density. This difference in density often translates into a difference in the diameters of the nanotubes and their (semi)conducting properties. Another method of separation is the use of a sequence of freezing, thawing, and compression of single-walled carbon nanotubes (SCNTs), which are an integral part of the agarose gel [24-27]. This process yields a solution containing 70% SCNTs and leaves a gel containing 95% SCNTs semiconductor. The dilute solution separated by this method shows many colours. Furthermore, carbon nanotubes can be separated using column chromatography. We note that the output we get is in the form of 95% of the semiconductor single-walled carbon nanotubes and 90% of the metal-type single-walled carbon nanotubes. In addition to the separation of metallic and semiconductor single-walled carbon nanotubes, it is also possible to classify single-walled carbon nanotubes based on length, diameter, and cyclist.

Figure 1: Nano-Wireless for wave sensor.

The highest grading of the highest solution length [28-30], with a length variation of less than 10%, was achieved by size exclusion chromatography of scattered carbon nanotubes in the DNA. The SWCNT diameter separation was accomplished by density-gradient ultracentrifugation through the use of SWCNTs scattered in surfaceactivity factors, and by ion-exchange chromatography of SWCNTs Single-walled nucleic acid was also purified by ion exchange chromatography between single-walled carbon nanotubes and DNA. ion-exchange chromatography (IEC) for DNA-SWNT: Special short DNA oligomers can be used to isolate single-walled carbon nanotube ligands. Hence, 12 s.c. nanotubes have been isolated so far with purities ranging from 70% between (8.3) and (9.5) SWCNTs to 90% for SWCNTs (6.5), (7.5) and (10.5). Successful efforts have been made to integrate these purified nanotubes into devices such as the field transistor, for example. The development and development of selective growth of semiconductor or metallic carbon nanotubes is one alternative to the separation process. A new chemical vapor deposition (CVD) recipe was recently announced that includes a mixture of ethanol and methanol vapors as well as quartz substrates [31-45], all producing horizontally aligned bundles of 95-98% semiconductor carbon nanotubes (Figure 1).

Conclusion

The degree of efficiency of the internal combustion engine has reached between 30-40% at present. However, nanotechnology may improve the combustion rate by designing special catalysts with greater surface area. In 2005, scientists at the University of Toronto developed a sprayable nanoparticle material that, when sprayed onto a surface, instantly transforms it into a solar collector. Nanotubes often grow on nanoparticles of magnetized metals (iron and cobalt), which facilitate the production of electronic devices (based on spin). As the current tuning in such single tube nanotubes is achieved through the field transistor by magnetic field.

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Orofacial and Digit Force Dynamics in Neurotypical Children

Introduction

Biomechanical analyses of active force dynamics can be used for clinical assessment of muscle force control of single motor subsystems, including force control in the tongue, lips, jaw, and digits Barlow, et al. [1-3]. Custom designed force transducers with real time visuomotor tracking software can be used to measure muscle forces in individuals with neuromotor disorders such as Parkinson’s disease and cerebral palsy. The resulting data can be used to predict motor speech impairments and develop corresponding rehabilitative measures Barlow, et al. [1,4]. Furthermore, there is evidence that the sensitivity of strain gage force transducers can be used to precisely measure patterns of muscle force impairment that were not evident from a neurological evaluation, as well as to track changes in orofacial and limb muscle function across the lifespan during periods of recovery and assess the efficacy of motor rehabilitation Barlow, et al. [5-8].

This aim of the present study was to establish normative data regarding fine muscle force dynamics in the lower lip (lower lip compression) and thumb-index finger (pinch grip) of neurotypical children at 0.25, 0.50, 1.00, and 2.00 N (Newtons), which represent less than 20% of a maximum contractile force for these muscle systems typically used in skilled movements. Independent variables examined included target force level, muscle group, sex, and age. Dependent measures included maximum force, reaction time, maximum rate of force change, standard deviation, hold phase criterion percentage, mean force, and peak force. Hypotheses were formulated regarding the dependent variables. A sex effect was anticipated for maximum force measurements. It was expected that an age effect would be present for maximum forces based on increasing muscle mass with age, as well as in hold phase criterion percentage based on fine motor control development. Similarly, it was predicted that the standard deviation of active force would decrease with age due to increasing fine motor control with maturation. Based on results present in adults, a sex effect is not expected for reaction time and a positive relationship was expected between target force and maximum rate of force change Barlow, et al. [9].

Materials and Methods

Participants

Twenty-nine (29) neurotypical children (16F/13M, 9.82 [SD = 1.34] years old) were recruited for the study. These children were stratified into two age groups, including a younger age group (N=16, 7.6-9.9 years, 8.81 [SD = 0.72]) and an older age group (N=13, 10- 12.3 years, 11.07 [SD = 0.77]). Child assent and written informed parent/guardian consent were recorded following University of Nebraska Institutional Review Board approval. Inclusion criteria: no report of injury or illness affecting the nervous system. Exclusion criteria: traumatic injury to the hands or face resulting in sensorimotor impairment, and traumatic brain injury or neurologic disease resulting in sensorimotor impairment to the orofacial or hand movements.

Instrumentation

Research participants were assessed using the ForceWIN10 system, a biomechanics visuomotor tracking application that runs on a DELL XPS laptop PC (MS WIN10 x64) with a 15” HD touchscreen display to measure muscle force output for both diagnostic and therapeutic purposes Greenwood, et al. [8]. ForceWIN10 measures voluntary fine force muscle dynamics in both the lower face (tongue, lips, and jaw) and the hand (thumb-index finger pinch). The ForceWIN10 connects to our custom designed Bluetooth low-energy (BLE) strain gage sensors to measure active forces generated by the participant. There are separate transducers used to sample active force dynamics for orofacial and thumb-index finger muscle systems (Figure 1). The transducer for the thumbindex finger pinch is composed of a Cooper Instruments load cell (Model LKCP 410-25 lb; Warrenton, VA, USA) and a Li-ion battery. For the finger transducer, the load cell sensitivity is 1.17mV/V at 100% load (111N). The orofacial transducer is composed of a stainless steel jaw cantilever, lip cantilever, and titanium maxillary and mandibular dental trays. For the orofacial transducer, the lip cantilever sensitivity is 2.03 mV/V at 100% load (40N) Greenwood, et al. [8]. In this study, a pediatric-sized jaw tray set was attached to the transducer apparatus to measure muscle force output of the lower lip. A dental impression mold was created for both the maxillary and mandibular dental trays, so that users could bite down on the trays comfortably to keep the transducer stable in the mouth while testing the muscle groups of interest. The dental molds were made using a polyvinylsiloxane impression material (Kerr Extrude XP, Kerr Corporation, Romulus, MI, USA) Barlow, et al. [3].

Figure 1: Wireless Bluetooth orofacial and finger pinch force transducers.

Protocol

Participants completed a series of visuomotor isometric ‘rampand- hold’ muscle contractions to target forces of 0.25, 0.5, 1, and 2 N in a randomized block design while seated in front of a laptop display. Participants were prompted to contract their muscles ‘rapidly and accurately’ and hold the contraction for approximately 5 seconds before relaxing. Ten ramp-and-hold contractions were completed at each force level for a given structure. For each structure, following the ramp-and-hold trials, participants were asked to contract their muscles maximally for 2 seconds and subsequently relax (3 repetitions) to collect MVCF data. The protocol consisted of 43 trials per structure (lower lip, right thumbfinger pinch, and left thumb-finger pinch). Test order for structure was also randomized for all participants.

Force Signal Processing

A low-pass filter was applied for each ‘ramp-and-hold’ contraction (finite impulse response (FIR) filter at 40 Hz, with high stopband and flat passband attenuation). The terminal holdphase was divided into T1 (2.0-3.4s) and T2 (3.4-4.8s). Hold-phase criterion percentage was calculated using the data points in T1 or T2 that were in the range of ±5 % of the target force measure. Hold phase mean force was calculated for T1 and T2. Baseline force was calculated by finding the mean during the first 100ms of a force trial. The first derivative maxima (dF/dtmax) were used to compute the maximum rate of force change (N/s). During the recruitment phase, peak force was computed by finding the maximum force in the first 2 seconds of a trial. Lastly, reaction time was calculated by linearly interpolating a value when the force was γ standard deviations (SD) above the baseline.

Statistical Analysis

Linear mixed modeling was conducted for each dependent variable [peak force (N), dF/dt (N/s), reaction time (seconds), mean force for T1 and T2 (N), standard deviation for T1 and T2 (N), holdphase criterion for T1 and T2 (proportion within +/- 5% target), and maximum force (N)] to estimate overall difference between muscle groups (right thumb-index finger, left thumb-index finger, lower lip; i.e., muscle effect), change in the dependent variable as a linear or polynomial function of target force (0.25, 0.5, 1, and 2 N; i.e., force effect), and muscle group difference in this change (i.e., muscle-by-force interaction effect). The models accounted for participants’ sex and nesting of repeated measurements within participants, thereby providing unbiased estimates of the model effects. When the muscle and/or muscle-by-force interaction effect was significant, adjusted means were pairwise compared at a Bonferroni corrected alpha level while controlling for Type I error at the nominal level. A proper error covariance structure was determined for each dependent variable based on model fit (i.e., adjusted Akaike Information Criterion, Bayesian Information Criterion). All analyses were conducted using SAS 9.4 SAS Institute [10] and statistical significance was determined at .05 alSignificant improvements in the performance of active force dynamics were apparent for boys and girls between the younger and older age

Results

Table 1: Descriptive summary statistics for ‘ramp-and-hold’ isometric force dynamics in children stratified by age group among selected dependent measures [ ± SEM].

Significant improvements in the performance of active force dynamics were apparent for boys and girls between the younger and older age cohorts, and between the face and digits. An example of individual ramp-and-hold isometric force trials during the ForceWIN10 visuomotor tracking paradigm for the left finger, right finger, and lower lip are shown for two males, at age 8 and 12 years in Figure 2. Waterfall displays are shown at each of the four target force levels for each muscle system. A performance advantage is evident for the left and right thumb-index finger pinch force productions compared to the lower lip during compression. A notable improvement can also be seen between the 8 year-old and 12 year-old males performing similar tasks. Corresponding force heat maps are shown below each of the waterfall displays to highlight striking differences in force variability, baseline force control, and reaction time consistency. Similar trends are evident for girls as well as shown in Figure 3 which contrasts the isometric ramp-andhold force trials as produced by a 9 year-old and a 12 year-old child. The force heat maps also reveal greater variability in achieving the four discrete level target force productions for the three muscle systems. An analysis of the pooled results (N=29 children) is shown in Figure 4 to contrast target force accuracy (thick line at each force is the median) and variability (shaded regions correspond to the median of the standard deviation) of composite trials for each of the three muscle systems among younger and older child groups (left and right plot columns).Overall, the older children (10.0-12.3 years of age) manifest improved accuracy in force control with reduced variability compared to their younger cohort. Descriptive summary statistics are shown in Table 1 by dependent variable.

Estimated marginal means for force reaction time ranged from 535 to 760 milliseconds across all conditions and factors (Table 2a). The force reaction time (RT) variable showed significant main effects for age group (p < 0.01), force target (p < 0.01), and muscle group (p < 0.0001). Estimated marginal means for combined digits was 564.6 ms compared to 679.3 ms for the lower lip across the four target levels. The lower lip manifested significantly longer RTs (by 50 to 70 ms) compared to the right and left hand digits during pinch force recruitment. Sex was not significant (p = 0.712). The dF/ dtmax force variable, a measure of active force recruitment, showed significant main effects as a function of target force (p < 0.0001) and age group (p < 0.05) (Table 2a). The estimated marginal means of the force derivative ranged from 10.39 to 31.10 N/sec. The estimated marginal means for dF/dtmax increased as a function of target force (0.25N target = -16.63N/s, 0.5N target = -15.44N/s, 1.0N target = -11.79N/s, and 2.0N target = 0.0N/s (reference)), respectively. The factors muscle group (p = 0.1174) and sex (p = 0.4923) were not significant. Among the neurotypical children in the present cohort, the tendency was to overshoot the visuomotor target during the ‘rapid-and-accurate’ force recruitment task. The magnitude of force overshoot (percent increase re: target force), was greatest at the 0.25N target where estimated marginal means for the right index-thumb, left index-thumb, and lower lip were 0.53N, 0.46N, and 0.68N greater than the target force, respectively.

Figure 2: Upper panel (row 1) shows individual ramp-and–hold force trials sampled from an 8-year-old male at 0.25 [blue], 0.5 [red], 1.0 [green], and 2.0 N [magenta] target force levels in waterfall display format for the left finger, right finger, and lower lip. Upper panel (row 2) shows the distribution of individual force trials including onsets as a function of structure and target as a heat map (absolute force amplitude is coded by a color heat scale). Bottom panel shows similar individual isometric waveforms and heat map sampled from a 12-year-old male.

Figure 3: Upper panel (row 1) shows individual ramp-and–hold force trials sampled from an 9- year-old female at 0.25 [blue], 0.5 [red], 1.0 [green], and 2.0 N [magenta] target force levels in waterfall display format for the left finger, right finger, and lower lip. Upper panel (row 2) shows the distribution of individual force trials including onsets as a function of structure and target as a heat map (absolute force amplitude is coded by a color heat scale). Bottom panel shows similar individual isometric waveforms and heat map sampled from a 12-year-old female.

Figure 4: Pooled right thumb-index finger (row 1), left thumb-index finger (row 2), and lower lip compression (row 3) trials at 0.25 [blue], 0.5 [red], 1.0 [green], and 2.0 N [magenta] target force levels among boys and girls [age 7.6-9.9 years [N=16], and age 10.0-12.3 years [N=13]. The thick colored line at each target force level represents the median, and shaded regions correspond to median standard deviation for composite force trials.

A clear finger advantage was found at the 0.25N target level with peak forces ranging from 186.9% to 214.5% of the intended target, whereas the lower lip peak force was 274.6% of target. The degree of overshoot (expressed as a percentage of the target) decreased with increasing target force levels such that the marginal means resulted in peak forces for the right and left digits that were 37.8% and 38.9% greater than the intended 2N target, whereas peak force for the lower lip exceeded the 2N target by 45%. In absolute terms, the fingers showed the clear advantage with 0.46N to 0.53N of overshoot at 0.25N target, whereas the lower lip yielded the greatest error at 0.69N of overshoot at this target. Peak isometric force overshoot increased at each higher target force, culminating in the largest absolute force errors approaching 0.78N for the digits, and 0.90N for the lower lip at the 2N target force. For the LMM, the peak force dependent variable showed significant main effect as a function of muscle group (p = 0.001) and target force (p < 0.0001) (Table 2a). Age group was marginally significant (p = 0.0539). Sex was not significant (p = 0.617). Mean force during the T1 and T2 hold-phase periods showed a high degree of end-point accuracy in isometric force output, favoring the digits over the lower lip (Table 2a). The LMM revealed a significant interaction for force target by muscle group (T1 phase, p = 0.0013; T2 phase, p < 0.0001). Sex and age were not significant.

Isometric contraction stability, calculated as the standard deviation (SD) during the same T1 and T2 hold-phase periods showed a significant main effect as a linear function of the child’s age (SD T1, p < 0.01; SD T2, p <0.001). Sex was not significant (SD T1, p = 0.751; SD T2, p = 0.428). LMM for the SD of isometric force revealed a significant interaction between force target and muscle group during the T1 and T2 hold phases after controlling for child’s age and sex (T1 phase, F(6,3440) = 5.21, p < 0.0001; T2 phase, F(6,3440) = 5.92, p < 0.0001). Estimated marginal means for SD showed a significant advantage for the digits at each target force level compared to the lower lip (Table 2b). For example, the composite SD in isometric force output during the T1 period was 0.1233N for the right thumb-index finger, 0.1497N for the left thumb-index finger, and nearly double indicative of greater instability for the lower lip at 0.2659N. A similar pattern for SD in isometric force was found during the T2 period (SD=0.0995N for the right thumbindex finger; 0.1526N for the left thumb-index finger, and 0.2523N for the lower lip). Post-hoc pairwise comparisons confirmed this trend with lower lip isometric compression force SD significantly greater than the same measure for either the right- or left thumbindex finger pinch contractions at each of the four target forces (p < 0.0001, effects size (d) ranging from 0.205 to 0.611). The additional 1.4 seconds of afforded by the T2 period resulted in more stable isometric force output, especially for the dominant right handdigits and lower lip, with marginal means for SD reduced by 16.99 to 26.99% RF, and 1.25 to 12.72% for LL across the force targets 2N, 1N, 0.5N, and 0.25N, respectively.

Table 2a. Linear mixed modeling (LMM) by dependent variables.

Table 2b. Linear mixed modeling (LMM) by dependent variables.

The hold-phase criterion percentage achieved during both the T1 and T2 hold phase periods showed a linear significant main effect age (p = 0.004, and p = 0.0011, respectively). Sex was not a significant factor during T1 and T2 (p = 0.93, and p=0.97, respectively). Overall, the thumb-index fingers of either hand are significantly better at maintaining a target force criterion (within ±5% of target) compared to the lower lip. LMM for the criterion percentage of isometric force at target revealed a significant interaction between force target and muscle group during the T1 and T2 hold phases after controlling for child’s age and sex (T1 phase, F(6,3440) = 11.00, p < 0.0001; T2 phase, F(6,3440) = 13.29, p < 0.0001). Overall, the digits of the hand performed at approximately twice the efficiency of the lower lip in generating isometric force within the ±5% criterion at each of the four target levels. For example, the marginal means for criterion performance (within ±5% of target window) during the T1 phase were 13.98 and 15.74% for the right and left thumb-index finger digits at 0.25N target, whereas only 9.4% of the digitized lower lip isometric force record fell within the prescribed criterion target (Table 2b).

A similar pattern was found at the other target forces for the right- and left-hand, and lower lip (FT=0.5N: 27.24, 21.88, 14.10%; FT=1N: 31.09, 31.79, 17.23%; and FT=2N: 38.02, 30.67, and 14.33%, respectively). As isometric contractions advanced into the T2 phase, criterion performance improved even more favoring the digits of the right- and left hand compared to the lower lip (FT=0.25N: 18.51, 16.16, 9.21%; FT=0.5N: 31.96, 27.62, 15.97%; FT=1N: 38.88, 41.32, 19.51%; and FT=2N: 48.80, 40.67, 17.57%, respectively). Overall, criterion ‘on-target’ performance increased by 22.86% from the T1 to T2 hold phase. Post-hoc pairwise comparisons confirmed this trend with superior criterion level ‘ontarget’ performance exhibited by the thumb-index fingers of the hand compared to the lower lip at each force target (p < 0.0001, effects size (d) ranging from 0.316 to 0.848 among force targets 2N, 1N, and 0.5N; and p < 0.05, d = 0.189 to 0.253 at the 0.25N target force). The maximum voluntary compression force (MVCF) variable showed a significant main effect as a function of muscle group (p < 0.0001). Age (p = 0.18), sex (p = 0.09), and handedness (p = 0.50) were not significant factors. As shown in Table 2b, MVCF marginal means were approximately 2.26 to 2.66 times greater for the thumb-index pinch (15.83 to 20.08 N) compared to lower lip compression (7.09 to 7.42N) (p<0.0001, d = 1.064 to 1.529).

Discussion

Thumb-Index Finger Pinch Versus Lower Lip Compression

One of the themes that emerged from the project was the performance advantage of the fingers over the lower lip in terms of hold-phase variability and force recruitment. Overall, the lower lip showed greater hold-phase variability and a shallower slope for force recruitment to the initial peak. The lower lip showed slower reaction times and a lower MVCF when compared with the fingers. Gentil, et al. [11] studied fine force generation in the fingers and lips of adults, and found that the fingers demonstrated a higher degree of precision, hold-phase stability, and force control accuracy when compared with the lips Gentil, et al. [11].

Age Differences

Another of the emergent trends throughout the research was the different performance capabilities of the two age groups. Overall, the younger children manifest much more variance in their force trials, inconsistency in peaks during force recruitment, hold-phase isometric contraction stability, and a lesser degree of end-point accuracy at each target force level when compared with the older cohort. The older children also showed higher force recruitment rates to the initial peak and shorter reaction times than the younger children. This trend was consistent across muscle groups measured. Ager, et al. [12] found age to be a significant factor in pinch strength of children between ages 5 and 12 years, with strength (MVCF) increasing with age. Similarly, Mathiowetz, et al. [13] found that maximum pinch force increases with age in children between 6 and 19 years of age [14]. For the lower lip, Chigira, et al. [12] found that in typically developing young children, lip pressure increases between 5 months and 5 years of age. They also found that the coefficient of variation for lip pressure decreased with increasing age, supporting this study’s findings of less variance and greater force stability in older children. Limitations of this study include a relatively small sample size (N=29) divided across two age groups, a greater number of female participants (16F/13M), and a greater number of younger children (16 young/13 older). The scope of the study can be expanded to include younger children and teenagers to complement existing data Barlow, et al. [3] sampled using the same ForceWIN10 system to create a developmental profile of active force dynamics over the human lifespan. Further research applications will extend into participants with neuromotor disease and/or brain injury resulting in movement disorders of the hand and/or face Barlow, et al. [4]. The real-time visuomotor tracking features of ForceWIN, also offer many possibilities for motor rehabilitation applications in patients recovering from cerebrovascular stroke and other insults to the brain that affect fine motor control.

Conclusion

This study investigated the orofacial and hand force dynamics of neurotypical children using wireless force transducers and realtime data analytics for the thumb-index finger pinch and the lower lip compression forces. This study found multiple significant effects related to muscle group and age. Overall, the lower lip showed a higher degree of hold-phase variability, slower reaction time, greater standard deviation, and lower MVCF when compared with the fingers. For age, the younger children had greater inconsistency in peak force and hold-phase contractile stability, as well as poorer end-point accuracy when compared to the older children. The ForceWIN10 system, featuring wireless sensing technology and advanced data analytics, has been used to test neurotypical adults Barlow, et al. [3], and survivors of cerebrovascular ischemic MCA strokes Barlow, et al. [4]. The present study is the first to demonstrate the feasibility of ForceWIN10 in a pediatric population to advance our understanding of active force dynamics and development in the lower face and thumb-index finger of each hand.

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