Electrochemically Activated CNT Sheet as a Cathode for Zn-CO2 Batteries.

High demand for electrochemical storage devices is increasing the need for high-performance batteries. A Zn-CO2 battery offers a promising solution for CO2 reduction as well as energy storage applications. For this study, a Zn-CO2 battery was fabricated using a Carbon Nanotube (CNT) sheet as a cathode and a Zn plate as an anode. The electrochemical activation technique was used to increase the surface area of the CNT electrode by roughly 4.5 times. Copper (Cu) as a catalyst was then deposited onto the activated CNT electrode using electrodeposition method and different Cu loadings were investigated to optimize CO2 reduction. The final assembled Zn-CO2 battery has a 1.6 V output voltage at a current density of 0.063 mA/cm2, which is higher than most devices reported in the literature. This study demonstrates the importance of activation process which enabled more catalyst loading on the cathode resulted in additional active sites for electroreduction process. This paper presents the activated CNT sheet as a promising cathode material for Zn-CO2 batteries.

Visual Acuity and Self-Reported Visual Function among Migrant Farmworkers.

PURPOSE: Visual impairment presents significant risks for occupational injuries among farmworkers, a vulnerable population with limited access to vision care. Although previous research has noted farmworkers' low lifetime experience with vision screening and high rates of complaints of eye ailments and poor vision, there have been few screening data collected to evaluate these self-reports. The objectives of this analysis are to (1) describe farmworker visual health using standardized visual acuity screening data and self-reported visual function, and (2) to compare the screening and self-report data. METHODS: Data are from a cross-sectional study of eye health among Latino migrant farmworkers in North Carolina with uncorrected vision (n = 289). Workers were recruited using methods to achieve a representative sample of a hard-to-reach population. Visual acuity data were collected using Snellen Tumbling E charts for nearsightedness and farsightedness. Binocular data are reported here. Interviews were conducted to obtain personal characteristics and self-assessed visual function. RESULTS: About 75% of farmworkers reported never having had a vision screening. Based on binocular screening, 1.7% (distance vision) and 6.9% (near vision) had moderate to severe visual impairment (>20/40). Farmworkers self-reported poorer visual function, compared with screening results; only 36.4% reported good or very good vision. Sensitivity of distance and near vision self-reports were 60 and 20%, respectively, but specificity was high. CONCLUSIONS: This study confirms past reports of little vision screening among farmworkers. Visual impairment for distance is comparable to other studies of Latinos in the US, though these studies have not reported near vision. Self-reports of vision problems are not a sensitive measure of visual acuity among farmworkers. Screening is needed to identify visual impairment that can create occupational safety risks in this health disparate population.

A Spray-On Carbon Nanotube Artificial Neuron Strain Sensor for Composite Structural Health Monitoring.

We present a nanocomposite strain sensor (NCSS) to develop a novel structural health monitoring (SHM) sensor that can be easily installed in a composite structure. An NCSS made of a multi-walled carbon nanotubes (MWCNT)/epoxy composite was installed on a target structure with facile processing. We attempted to evaluate the NCSS sensing characteristics and benchmark compared to those of a conventional foil strain gauge. The response of the NCSS was fairly good and the result was nearly identical to the strain gauge. A neuron, which is a biomimetic long continuous NCSS, was also developed, and its vibration response was investigated for structural damage detection of a composite cantilever. The vibration response for damage detection was measured by tracking the first natural frequency, which demonstrated good result that matched the finite element (FE) analysis.

Inverse-Ordered Fabrication of Free-Standing CNT Sheets for Supercapacitor.

Free-standing thin carbon nanotube (CNT) sheets are challenging to handle and control for device fabrication. In this paper, we report on the inverse-ordered fabrication method from thick CNT sheets to thin free-standing CNT sheets. As proof of the concept, thin CNT sheets for a supercapacitor were fabricated from 200 thick layers. The results show that the thin CNT sheet was electrochemically stable and had enhanced capacitive performance. The smaller the number of layers is, the larger the specific capacitances we have (from 10.10 F g(-1) to 51.37 F g(-1)). Energy and power density were increased from 0.50 to 2.57 Wh kg(-1) and from 0.33 to 2.31 kW kg(-1), respectively. This simple and scalable inverse-ordered method is capable to fabricate CNT sheets in various forms, allowing fast trials on various applications.

One-year incidence of carpal tunnel syndrome in Latino poultry processing workers and other Latino manual workers.

OBJECTIVE: To determine the incidence of carpal tunnel syndrome (CTS) over 1 year in Latino poultry processing workers. METHODS: Symptoms and nerve conduction studies were used to identify Latino poultry processing workers (106 wrists) and Latinos in other manual labor occupations (257 wrists) that did not have CTS at baseline, and these individuals were then evaluated in the same manner 1 year later. RESULTS: Based on wrists, the 1-year incidence of CTS was higher in poultry processing workers than non-poultry manual workers (19.8% vs. 11.7%, P = 0.022). Poultry workers had a higher odds (1.89; P = 0.089) of developing CTS over 1 year compared to non-poultry manual workers. DISCUSSION: Latino poultry processing workers have an incidence of CTS that is possibly higher than Latinos in other manual labor positions. Latino poultry workers' high absolute and relative risk of CTS likely results from the repetitive and strenuous nature of poultry processing work.

Scaling a Hydraulic Motor for Minimally Invasive Medical Devices.

Aligned with the medical device industry's trend of miniaturization, academic and commercial researchers are constantly attempting to reduce device sizes. Many applications require miniature actuators (2 mm range) to perform mechanical work; however, biocompatible micromotors are not readily available. To that end, a hydraulic motor-driven cutting module that aims to combine cutting and drug delivery is presented. The hydraulic motor prototype developed has an outside diameter (OD) of ~4 mm (twice the target size) and a 1 mm drive shaft to attach a cutter. Four different designs were explored and fabricated using additive manufacturing. The benchtop experimental data of the prototypes are presented herein. For the prototype motor with fluid inlet perpendicular to the blades, the average angular velocity was 10,593 RPM at a flowrate of 3.6 mL/s and 42,597 RPM at 10.1 mL/s. This design was numerically modeled using 3D-transient simulations in ANSYS CFX (version 2022 R2) to determine the performance characteristics and the internal resistance of the motor. Simplified mathematical models were also used to compute and compare the peak torque with the simulation estimates. The viability of current design represents a crucial milestone in scaling the hydraulic motor to a 2 mm OD to power a microcutter.

Nanoimprint Lithography for Next-Generation Carbon Nanotube-Based Devices.

This research reports the development of 3D carbon nanostructures that can provide unique capabilities for manufacturing carbon nanotube (CNT) electronic components, electrochemical probes, biosensors, and tissue scaffolds. The shaped CNT arrays were grown on patterned catalytic substrate by chemical vapor deposition (CVD) method. The new fabrication process for catalyst patterning based on combination of nanoimprint lithography (NIL), magnetron sputtering, and reactive etching techniques was studied. The optimal process parameters for each technique were evaluated. The catalyst was made by deposition of Fe and Co nanoparticles over an alumina support layer on a Si/SiO2 substrate. The metal particles were deposited using direct current (DC) magnetron sputtering technique, with a particle ranging from 6 nm to 12 nm and density from 70 to 1000 particles/micron. The Alumina layer was deposited by radio frequency (RF) and reactive pulsed DC sputtering, and the effect of sputtering parameters on surface roughness was studied. The pattern was developed by thermal NIL using Si master-molds with PMMA and NRX1025 polymers as thermal resists. Catalyst patterns of lines, dots, and holes ranging from 70 nm to 500 nm were produced and characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Vertically aligned CNTs were successfully grown on patterned catalyst and their quality was evaluated by SEM and micro-Raman. The results confirm that the new fabrication process has the ability to control the size and shape of CNT arrays with superior quality.

Prevalence of bifid median nerves and persistent median arteries and their association with carpal tunnel syndrome in a sample of Latino poultry processors and other manual workers.

INTRODUCTION: The prevalence of bifid median nerves and persistent median arteries, their co-occurrence, and their relationship to carpal tunnel syndrome (CTS) are only understood partially. METHODS: We screened 1026 wrists of 513 Latino manual laborers in North Carolina for bifid median nerves and persistent median arteries using electrodiagnosis and ultrasound. RESULTS: A total of 8.6% of wrists had a bifid median nerve, and 3.7% of wrists had a persistent median artery independent of subgroup ethnicity, age, gender, or type of work. An association with definite carpal tunnel syndrome was not found. The presence of either anatomic variant was associated with a high likelihood of co-occurrence of another variant in the same or the contralateral wrist. CONCLUSIONS: The occurrence of median anatomic variants can be determined in field studies using ultrasound. Persistent median arteries and bifid median nerves tend to co-occur but do not put manual laborers at additional risk of developing CTS.

Ultrasound for carpal tunnel syndrome screening in manual laborers.

INTRODUCTION: Manual laborers are at increased risk for carpal tunnel syndrome (CTS), and a combination of history, physical examination, and nerve conduction studies is often used to screen for CTS in this population. Neuromuscular ultrasound may be a better screening tool, because it is painless. In this study we compare the accuracy of nerve conduction studies and ultrasound for CTS screening. METHODS: Five hundred thirteen manual laborers were screened prospectively for CTS using nerve conduction studies and neuromuscular ultrasound, and the accuracy of the 2 techniques was compared using the Katz hand diagram as the diagnostic standard. RESULTS: The ROC curves for the 2 techniques were not significantly different (P = 0.542), indicating that the approaches had similar diagnostic accuracy. CONCLUSIONS: Neuromuscular ultrasound is a painless technique that has diagnostic accuracy similar to nerve conduction studies and can be used to screen large populations at risk for CTS.

Upper body musculoskeletal symptoms of Latino poultry processing workers and a comparison group of Latino manual workers.

BACKGROUND: Upper body musculoskeletal injuries are often attributed to rapid work pace and repetitive motions. These job features are common in poultry processing, an industry that relies on Latino immigrants. Few studies document the symptom burden of immigrant Latinos employed in poultry processing or other manual jobs. METHODS: Latino poultry processing workers (n = 403) and a comparison population of 339 Latino manual workers reported symptoms for six upper body sites during interviews. We tabulated symptoms and explored factors associated with symptom counts. RESULTS: Back symptoms and wrist/hand symptoms lasting more than 1-day were reported by over 35% of workers. Poultry processing workers reported more symptoms than comparison workers, especially wrist and elbow symptoms. The number of sites at which workers reported symptoms was elevated for overtime workers and workers who spoke an indigenous language during childhood. CONCLUSION: Workplace conditions facing poultry processing and indigenous language speaking workers deserve further exploration.

Prevalence of epicondylitis, rotator cuff syndrome, and low back pain in Latino poultry workers and manual laborers.

BACKGROUND: The goal of this study is to improve understanding of immigrant Latino manual workers' occupational health, focusing on upper body musculoskeletal injury. METHODS: Physical exams were conducted with a representative sample of 516 Latino poultry workers and manual laborers in western North Carolina; outcome measures were prevalence of epicondylitis, rotator cuff syndrome, and low back pain. RESULTS: Low back pain (n = 89; 17.2%) and rotator cuff syndrome (n = 76; 14.7%) indicated by physical exam was common. Epicondylitis was less common, but still frequent (n = 30; 5.8%). Prevalence of each outcome did not differ between poultry processing workers and other manual workers. Workers >40 years old had greater incidence of rotator cuff syndrome and epicondylitis. CONCLUSIONS: Epicondylitis, rotator cuff syndrome, and low back pain are common in immigrant Latino workers, and may negatively impact long-term health and contribute to occupational health disparities.

Design and Modeling of a Miniature Hydraulic Motor for Powering a Cutting Tool for Minimally Invasive Procedures.

Miniaturization of multifunctional instruments is key to evolving less invasive medical procedures. The current work outlines steps towards developing a miniature motor to power a cutting tool of a millimeter-scale robot/device (target outside diameter ~2 mm) for minimally invasive procedures. Multiple motor concepts were explored and ranked using a Pugh matrix. The single-rotor hydraulic design was deemed most viable for prototyping and scale-down to the target size. Prototypes were manufactured to be progressively smaller using additive manufacturing. The smallest prototype fabricated was 2:1 scale of the desired final size with a 2 mm outside diameter (OD) rotor and a device OD of 4 mm. The scaled prototypes with an 8 mm rotor were lab tested and achieved average speeds of 5000-6000 RPM at a flowrate of 15-18 mL/s and 45 PSI water pressure. Ansys CFX was used as a design tool to explore the parameter space and 3D transient simulations were implemented using the immersed solid method. The predicted rotor RPM from the modeling matched the experimental values within 3% error. The model was then used to develop performance curves for the miniature hydraulic motor. In summary, the single-rotor hydraulic design shows promise for miniaturization to the target 2 mm size.

Manufacturing Scalable Carbon Nanotube-Silicone/Kevlar Fabrics.

Carbon nanotube (CNT) hybrid composites were formed by combining a CNT and silicone elastomer solution with Kevlar yarn, Kevlar fabric, and Kevlar veil materials. The integration of a CNT-silicone matrix with Kevlar yarn and fabric materials produced a composite with moderate electrical and thermal conductivity due to CNT fabric combined with the strength of Kevlar fabric or yarn. In the material synthesis, a notable difficulty was that the CNT-silicone did not bond strongly to the Kevlar. The composites passed the Vertical Flame Test ASTM D6413 and the Forced Air Oven Test NFPA 1971. These hybrid composites can have multiple applications in areas requiring favorable conductivity, strength, and flame and heat resistance. The application areas include firefighter apparel, military equipment, conductive/smart structures, and flexible electronics. The synthesis process used to manufacture CNT-silicone/Kevlar composites yielded composite sheets with an area of 2250 cm2. The process is scalable and customizable for the synthesis of CNT composites with tailored properties. Improvements in the bonding of CNT-silicone to Kevlar are being investigated.

Carbon Hybrid Materials-Design, Manufacturing, and Applications.

Carbon nanotubes (CNTs) have extraordinary properties and are used for applications in various fields of engineering and research. Due to their unique combination of properties, such as good electrical and thermal conductivity and mechanical strength, there is an increasing demand to produce CNTs with enhanced and customized properties. CNTs are produced using different synthesis methods and have extraordinary properties individually at the nanotube scale. However, it is challenging to achieve these properties when CNTs are used to form macroscopic sheets, tapes, and yarns. To further improve the properties of macroscale forms of CNTs, various types of nanoparticles and microfibers can be integrated into the CNT materials. The nanoparticles and microfibers can be chosen to selectively enhance the properties of CNT materials at the macroscopic level. In this paper, we propose a technique to manufacture carbon hybrid materials (CHMs) by combining CNT non-woven fabric (in the form of sheets or tapes) with microfibers to form CNT-CF hybrid materials with new/improved properties. CHMs are formed by integrating or adding nanoparticles, microparticles, or fibers into the CNT sheet. The additive materials can be incorporated into the synthesis process from the inlet or the outlet of the reactor system. This paper focuses on CHMs produced using the gas phase pyrolysis method with microparticles/fibers integrated at the outlet of the reactor and continuous microfiber tapes integrated into the CNT sheet at the outlet using a tape feeding machine. After synthesis, characterizations such as microscopy and thermogravimetric analysis were used to study the morphology and composition of the CNTs, and examples for potential applications are discussed in this paper.

Reversible vancomycin susceptibility within emerging ST1421 Enterococcus faecium strains is associated with rearranged vanA-gene clusters and increased vanA plasmid copy number.

Vancomycin variable enterococci (VVE) are van-positive enterococci with a vancomycin-susceptible phenotype (VVE-S) that can convert to a resistant phenotype (VVE-R) and be selected for during vancomycin exposure. VVE-R outbreaks have been reported in Canada and Scandinavian countries. The aim of this study was to examine the presence of VVE in whole genome sequenced (WGS) Australian bacteremia Enterococcus faecium (Efm) isolates collected through the Australian Group on Antimicrobial resistance (AGAR) network. Eight potential VVEAus isolates, all identified as Efm ST1421, were selected based on the presence of vanA and a vancomycin-susceptible phenotype. During vancomycin selection, two potential VVE-S harboring intact vanHAX genes, but lacking the prototypic vanRS and vanZ genes, reverted to a resistant phenotype (VVEAus-R). Spontaneous VVEAus-R reversion occurred at a frequency of 4-6 × 10-8 resistant colonies per parent cell in vitro after 48 h and led to high-level vancomycin and teicoplanin resistance. The S to R reversion was associated with a 44-bp deletion in the vanHAX promoter region and an increased vanA plasmid copy number. The deletion in the vanHAX promoter region enables an alternative constitutive promoter for the expression of vanHAX. Acquisition of vancomycin resistance was associated with a low fitness cost compared with the corresponding VVEAus-S isolate. The relative proportion of VVEAus-R vs. VVEAus-S decreased over time in serial passages without vancomycin selection. Efm ST1421 is one of the predominant VanA-Efm multilocus sequence types found across most regions of Australia, and has also been associated with a major prolonged VVE outbreak in Danish hospitals.

Synthesis and structure-activity relationships of imidazo[1,2-a]pyrimidin-5(1H)-ones as a novel series of beta isoform selective phosphatidylinositol 3-kinase inhibitors.

A series of PI3K-beta selective inhibitors, imidazo[1,2-a]-pyrimidin-5(1H)-ones, has been rationally designed based on the docking model of the more potent R enantiomer of TGX-221, identified by a chiral separation, in a PI3K-beta homology model. Synthesis and SAR of this novel chemotype are described. Several compounds in the series demonstrated potent growth inhibition in a PTEN-deficient breast cancer cell line MDA-MB-468 under anchorage independent conditions.

Ethnic and racial differences of baseline stroke knowledge in a "stroke belt" community.

Acute stroke is often a treatable condition; however, intervention is time dependent and typically should ensue within 3 hr from onset of symptoms. The ability of individuals to understand stroke risk factors to reduce individual risk and to recognize warning signs and symptoms of stroke as signals to initiate medical care is paramount to decreasing stroke-related morbidity and mortality. This descriptive study presents ethnic and racial differences of baseline stroke knowledge among residents (n = 1,904) of two North Carolina counties situated in the Stroke Belt. Findings suggest a global stroke knowledge deficit that is more pronounced among Hispanics. Future community stroke education campaigns need to consider various educational mediums and outlets to ensure inclusion of persons at highest risk for stroke. Suggestions are provided for possible content of future stroke knowledge and prevention campaigns.

Flexible and Lightweight Carbon Nanotube Composite Filter for Particulate Matter Air Filtration.

Particulate Matter (PM) has become an important source of air pollution. We proposed a flexible and lightweight carbon nanotube (CNT) composite air filter for PM removal. The developed CNT filtering layers were fabricated using a floating catalyst chemical vapor deposition (FC-CVD) synthesis process and then combined with conventional filter fabrics to make a composite air filter. Filtration performance for CNT filtering layer alone and composited with other conventional filter fabrics for particles size 0.3 µm to 2.5 µm was investigated in this study. The CNT composite filter is highly hydrophobic, making it suitable for humid environments. The CNT composite filter with two layers of tissue CNT performed best and achieved a filtration efficiency over 90% with a modest pressure drop of ~290 Pa for a particle size of 2.5 µm. This CNT composite filter was tested over multiple cycles to ensure its reusability. The developed filter is very light weight and flexible and can be incorporated into textiles for wearable applications or used as a room filter.

The characterization of a novel V1b antagonist lead series.

The SAR around a V1b antagonist HTS hit 3 was explored to produce a series of thiazole sulfonamides as a lead series with selectivity over the related V1 and oxytocin receptors.

Chlorosulfonic Acid Stretched Carbon Nanotube Sheet for Flexible and Low-Voltage Heating Applications.

The carbon nanotube (CNT) is celebrated for its electrothermal property, which indicates the capability of a material to transform electrical energy into heat due to the Joule effect. The CNT nanostructure itself, as a one-dimensional material, limits the electron conduction path, thereby creating a unique heating phenomenon. In this work, we explore the possible correlation between CNT alignment in sheets and heating performance. The alignment of carbon nanotubes is induced by immersion and stretching in chlorosulfonic acid (CSA) solution. The developed CSA-stretched CNT sheet demonstrated excellent heating performance with a fast response rate of 6.5 °C/s and reached 180 °C in less than 30 s under a low voltage of 2.5 V. The heating profile of the stretched CNT sheet remained stable after bending and twisting movements, making it a suitable heating material for wearable devices, heatable smart windows, and in de-icing or defogging applications. The specific strength and specific conductance of the CSA-stretched CNT sheet also increased five- and two-fold, respectively, in comparison to the pristine CNT sheet.