Recent Advances in Touch Sensors for Flexible Wearable Devices.

Many modern user interfaces are based on touch, and such sensors are widely used in displays, Internet of Things (IoT) projects, and robotics. From lamps to touchscreens of smartphones, these user interfaces can be found in an array of applications. However, traditional touch sensors are bulky, complicated, inflexible, and difficult-to-wear devices made of stiff materials. The touch screen is gaining further importance with the trend of current IoT technology flexibly and comfortably used on the skin or clothing to affect different aspects of human life. This review presents an updated overview of the recent advances in this area. Exciting advances in various aspects of touch sensing are discussed, with particular focus on materials, manufacturing, enhancements, and applications of flexible wearable sensors. This review further elaborates on the theoretical principles of various types of touch sensors, including resistive, piezoelectric, and capacitive sensors. The traditional and novel hybrid materials and manufacturing technologies of flexible sensors are considered. This review highlights the multidisciplinary applications of flexible touch sensors, such as e-textiles, e-skins, e-control, and e-healthcare. Finally, the obstacles and prospects for future research that are critical to the broader development and adoption of the technology are surveyed.

Electrodeposited Hybrid Biocathode-Based CO2 Reduction via Microbial Electro-Catalysis to Biofuels.

Microbial electrosynthesis is a new approach to converting C1 carbon (CO2) to more complex carbon-based products. In the present study, CO2, a potential greenhouse gas, was used as a sole carbon source and reduced to value-added chemicals (acetate, ethanol) with the help of bioelectrochemical reduction in microbial electrosynthesis systems (MES). The performance of MES was studied with varying electrode materials (carbon felt, stainless steel, and cobalt electrodeposited carbon felt). The MES performance was assessed in terms of acetic acid and ethanol production with the help of gas chromatography (GC). The electrochemical characterization of the system was analyzed with chronoamperometry and cyclic voltammetry. The study revealed that the MES operated with hybrid cobalt electrodeposited carbon felt electrode yielded the highest acetic acid (4.4 g/L) concentration followed by carbon felt/stainless steel (3.7 g/L), plain carbon felt (2.2 g/L), and stainless steel (1.87 g/L). The alcohol concentration was also observed to be highest for the hybrid electrode (carbon felt/stainless steel/cobalt oxide is 0.352 g/L) as compared to the bare electrodes (carbon felt is 0.22 g/L) tested, which was found to be in correspondence with the pH changes in the system. Electrochemical analysis revealed improved electrotrophy in the hybrid electrode, as confirmed by the increased redox current for the hybrid electrode as compared to plain electrodes. Cyclic voltammetry analysis also confirmed the role of the biocatalyst developed on the electrode in CO2 sequestration.

Nanoremediation technologies for sustainable remediation of contaminated environments: Recent advances and challenges.

A major and growing concern within society is the lack of innovative and effective solutions to mitigate the challenge of environmental pollution. Uncontrolled release of pollutants into the environment as a result of urbanisation and industrialisation is a staggering problem of global concern. Although, the eco-toxicity of nanotechnology is still an issue of debate, however, nanoremediation is a promising emerging technology to tackle environmental contamination, especially dealing with recalcitrant contaminants. Nanoremediation represents an innovative approach for safe and sustainable remediation of persistent organic compounds such as pesticides, chlorinated solvents, brominated or halogenated chemicals, perfluoroalkyl and polyfluoroalkyl substances (PFAS), and heavy metals. This comprehensive review article provides a critical outlook on the recent advances and future perspectives of nanoremediation technologies such as photocatalysis, nano-sensing etc., applied for environmental decontamination. Moreover, sustainability assessment of nanoremediation technologies was taken into consideration for tackling legacy contamination with special focus on health and environmental impacts. The review further outlines the ecological implications of nanotechnology and provides consensus recommendations on the use of nanotechnology for a better present and sustainable future.

Magnesium ferrite spinels as anode modifier for the treatment of Congo red and energy recovery in a single chambered microbial fuel cell.

Magnesium Ferrite (MgFe2O4) spinel structures prepared by a solid-state reaction was used as an anode modifier in the microbial fuel cell (MFC) treatment of Congo red dye. The performance of the reactors with unmodified stainless-steel mesh anode (CR-1) and MgFe2O4 coated stainless steel mesh anode (CR-2) were tested and compared followed by aerobic treatment. The peak power density was observed to be 295.936 (CR-1) and 430.336 mW/m2 (CR-2) revealing increased bioenergy output and better electron transfer in the reactor with the MgFe2O4 modified anode. The final decolourisation efficiencies were found to be 92.053% for CR-1 and 98.386% for CR-2. The formation of metabolites (diaminonaphthalene-1-sulfonate, 1-(biphenyl-4-yl)-2-(naphthalene-2-yl) diazene, benzidine and phthalic acid, monoethyl ether) during the anaerobic-aerobic biotreatment of azo dye was confirmed using Gas chromatography coupled Mass spectrometry system. Scanning electron microscopy confirmed a uniform coating of MgFe2O4 on the anode surface with evidence of biofilm formation in the system. Electrochemical studies confirmed the superior performance of spinel coated anode with enhanced redox activity. In addition, the charge-discharge studies confirmed the high capacitive nature of the modified electrode improving the electrodes charge holding capacity. The study suggested an effective treatment strategy for the treatment of Congo red dye.

Investigation of CNT/PPy-Modified Carbon Paper Electrodes under Anaerobic and Aerobic Conditions for Phenol Bioremediation in Microbial Fuel Cells.

The study presents the comparative bioelectrochemical treatment of phenol in anodic and cathodic compartments of four identical dual chambered microbial fuel cells (MFCs) with bare and multiwalled carbon nanotube/polypyrrole (MWCNT/PPy)-coated electrodes, respectively. It was observed that systems performing biocathodic treatment of phenol performed better as compared to the systems performing bioanodic treatment. The maximum power densities for bioanodic phenol treatment using bare and coated electrodes were found to be 469.038 and 560.719 mW/m2, while for biocathodic treatment, they were observed to be 604.804 and 650.557 mW/m2, respectively. The MFCs performing biocathodic treatment of phenol consistently showed higher chemical oxygen demand removal efficiency, Coulombic efficiency, and power density and indicated the better performance of the biocathodic bare (B-MFC) and coated (C-MFC) MFCs as compared to the bioanodic B-MFC and C-MFC. UV/vis spectrophotometry revealed that the MWCNT/PPy-coated carbon paper worked significantly better in the treatment of phenol with admirable treatment obtained within a week of the experiment as compared to the system with bare carbon paper. Cyclic voltammetry asserted better electrochemical activity of the MFC systems with coated electrodes in the treatment of phenol. The electrochemical impedance spectroscopy data also supported the better performance of biocathodic phenol treatment with lower internal and charge transfer resistances. The scanning electron microscopy images confirmed the active biofilm formation on the electrode surface. The study indicates MFC as a viable option for the treatment of recalcitrant chemical compounds with energy recovery.

Captivity stress influences the DNA damage of Pavo cristatus under environmental conditions of Faisalabad, Pakistan.

The surroundings of wild and captive birds are divergent in existence. Wild birds inhabiting their natural environment have unlimited resources availability. They face variety of captivity stresses when moved from wild habitat to caged enclosures. The effect of similar captivity stresses on the DNA of birds living in cages for longer stretches of time is addressed in this study. The laboratory analysis to investigate DNA damage in Pavo cristatus was performed using single-cell gel electrophoresis (SCGE) or comet assay. Our results showed that measurable DNA damage was observed in Pavo cristatus species. Endogenous stress factors owing to long-term captivity were responsible to cause this damage. The caged conditions provided to the captive birds can be improved in order to prevent DNA impairment. Moreover, appropriate monitoring and effective management are necessary on continual basis to ensure the well-being of caged birds.

Deciphering the effects of temperature on bio-methane generation through anaerobic digestion.

Anaerobic digestion (AD) is a sustainable wastewater treatment technology which facilitates energy, nutrient, and water recovery from organic wastes. The agricultural and industrial wastes are suitable substrates for the AD, as they contain a high level of biodegradable compounds. The aim of this study was to examine the AD of three different concentrations of phenol (100, 200, and 300 mg/L) containing wastewater with and without co-substrate (acetate) at four different temperatures (25, 35, 45, and 55 °C) to produce methane (CH4)-enriched biogas. It was observed that the chemical oxygen demand (COD) and phenol removal efficiencies of up to 76% and 72%, respectively, were achieved. The CH4 generation was found higher in anaerobic batch reactors (ABRs) using acetate as co-substrate, with the highest yield of 189.1 µL CH4 from 500 µL sample injected, obtained using 200 mg/L of phenol at 35 °C. The results revealed that the performance of ABR in terms of degradation efficiency, COD removal, and biogas generation was highest at 35 °C followed by 55, 45, and 25 °C indicating 35 °C to be the optimum temperature for AD of phenolic wastewater with maximum energy recovery. Scanning electron microscopy (SEM) revealed that the morphology of the anaerobic sludge depends greatly on the temperature at which the system is maintained which in turn affects the performance and degradation of toxic contaminants like phenol. It was observed that the anaerobic sludge maintained at 35 °C showed uniform channels leading to higher permeability through enhanced mass transfer to achieve higher degradation rates. However, the denser sludge as in the case of 55 °C showed lesser permeability leading to limited transfer and thus reduced treatment. Quantitative real-time PCR (qPCR) analysis revealed a more noteworthy change in the population of the microbial communities due to temperature than the presence of phenol with the methanogens being the dominating species at 35 °C. The findings suggest that the planned operation of the ABR could be a promising choice for CH4-enriched biogas and COD removal from phenolic wastewater.

Bio-electrodegradation of 2,4,6-Trichlorophenol by mixed microbial culture in dual chambered microbial fuel cells.

2,4,6-Trichlorophenol (TCP) was bioelectrochemically treated in anodic and cathodic compartments of two identical dual chambered microbial fuel cells MFC-A and MFC-B under anaerobic and aerobic conditions, respectively, and energy was recovered in the form of electricity. It was observed that MFC-B with bio-cathodic treatment of TCP outcompeted the MFC-A with bio-anodic treatment. The maximum power density for MFC-A with bio-anode was found to be 446.76 mW/m2 while for MFC-B with bio-cathode it was 1059.58 mW/m2. The MFC-B consistently showed higher coulombic efficiency, power density and chemical oxygen demand removal efficiency indicating the better performance of the MFC-B as compared to the MFC-A. Scanning electron micrograph also confirmed better accumulation of microbes on the anode of MFC-B and hence its better performance in terms of energy recovery. Some major genera present in the microbial community were quantified using quantitative real-time polymerase chain reaction technique. It also confirmed the dominance of electroactive species in the bio-anodic sludge of MFC-B over the bio-anodic sludge of MFC-A. Cyclic voltammogram also asserted better electrochemical activity of the bio-cathode in the treatment of chlorinated phenol toxicants in MFC-B system. The study shows that MFC can be a viable option in treatment of recalcitrant chemical compounds like TCP with the generation of energy in the form of electrical power.

Enzyme-catalysed production of n-butyl palmitate using ultrasound-assisted esterification of palmitic acid in a solvent-free system.

This work exhibits the implementation of ultrasound technology in solvent-free synthesis study of n-butyl palmitate using Fermase CALB™10000. Sequential experimental design study was instrumental in determining the most significant process variables. The effect of acid-alcohol molar ratio, enzyme dose, temperature, power and duty cycle on the reaction kinetics was studied. Highest conversion of ~ 96.6% was observed in 50 min at 1:1 molar ratio of palmitic acid to n-butanol, 70 °C temperature, 4% w/w enzyme loading, 40 W power, 70% duty cycle, 25 kHz frequency and 100 rpm speed of impeller. Ping-pong bisubstrate model showed the best fit with kinetic parameters, Vmax = 21.88 M/min/g catalyst, KA = 0.011 M, KB = 8.74M, KiA = 0.014M, KiB = 0.00036M and SSE = 0.0000193. Ultrasound reduced the reaction time by over 70%. The enzyme was reusable for four successive cycles after which it showed decline in conversion.

Proposed global drooping and wrinkles classification and scoring system for aging face with validation and experience on 54 Indian subjects.

BACKGROUND: Aging is an inevitable biological change, but understanding the process of aging of face is important to customize the treatment options for facial rejuvenation. Evidence-based estimation of global facial aging is necessary for the validation of various treatment modalities. AIMS: Classification and implementation of a scoring system for aging face based upon volume loss and surface changes as evident by drooping of different areas of the face and appearance of fine and deep wrinkles, respectively, and to apply this drooping-wrinkles classification on 54 participants to evaluate and understand the validity of scoring. METHODS: An observational study was conducted, and scores were calculated based on 13 parameters (7 areas of drooping and 6 areas of wrinkles on the face) at Aura Skin Institute, Chandigarh, India. Accordingly, age was divided in different age groups followed by clinical estimation of facial age and calculation of scores. RESULTS: According to our classification and scoring system, 61% (33 out of 54) of the participants were correlated with their chronological age group. Out of the remaining 21 (39%) participants who were aging faster, 13 (24%) were in the age group of 25-35 years. Approximately one-fourth of the patients in the age groups 36-45 and 46-55 years were aging faster. Only 1 patient had scores showing younger age in comparison to chronological age. Overall, there was a good correlation between the calculated score and the chronological age of patients. Moreover, a gradual increase in scores was noticed with increasing age groups. CONCLUSIONS: This is a new clinical classification and scoring system for facial age which is much easier to apply in daily clinical practice for easy calculation of baseline scores and customizing their antiaging treatment options. Moreover, it will also make it easier to compare the efficacy of treatment in their future follow-ups. The limitation of this study is that it has been proposed for all skin types but validation has been done only for Indian participants.

Energy generation through bioelectrochemical degradation of pentachlorophenol in microbial fuel cell.

Bio-electrochemical degradation of pentachlorophenol was carried out in single as well as dual chambered microbial fuel cell (MFC) with simultaneous production of electricity. The maximum cell potential was recorded to be 787 and 1021 mV in single and dual chambered systems respectively. The results presented nearly 66 and 89% COD removal in single and dual chambered systems with corresponding power densities of 872.7 and 1468.85 mW m-2 respectively. The highest coulombic efficiency for single and dual chambered counterparts was found to be 33.9% and 58.55%. GC-MS data revealed that pentachlorophenol was more effectively degraded under aerobic conditions in dual-chambered MFC. Real-time polymerase chain reaction showed the dominance of exoelectrogenic Geobacter in the two reactor systems with a slightly higher concentration in the dual-chambered system. The findings of this work suggested that the aerobic treatment of pentachlorophenol in cathodic compartment of dual chambered MFC is better than its anaerobic treatment in single chambered MFC in terms of chemical oxygen demand (COD) removal and output power density.

Effect of co-substrates on biogas production and anaerobic decomposition of pentachlorophenol.

This study aims to examine the effect of different co-substrates on the anaerobic degradation of pentachlorophenol (PCP) with simultaneous production of biogas. Acetate and glucose were added as co-substrates to monitor and compare the methanogenic reaction during PCP degradation. During the experiment, a chemical oxygen demand (COD) removal efficiency of 80% was achieved. Methane (CH4) production was higher in glucose-fed anaerobic reactors with the highest amount of CH4 (303.3µL) produced at 200ppm of PCP. Scanning electron microscopy (SEM) demonstrates the high porous structure of anaerobic sludge with uniform channels confirming better mass transfer and high PCP removal. Quantitative real-time PCR (qPCR) revealed that methanogens were the dominating species while some sulfate reducing bacteria (SRBs) were also found in the reactors. The study shows that strategic operation of the anaerobic reactor can be a feasible option for efficient degradation of complex substrates like PCP along with the production of biogas.

Concurrent evaluation of microscopic observation of drug susceptibility assay for pulmonary and extrapulmonary tuberculosis.

BACKGROUND: Methods for detection and drug susceptibility of tuberculosis (TB) with solid media are inexpensive but slow and laborious. Rapid methods to diagnose TB and multidrug-resistant TB (MDR-TB) are a global priority for TB control. OBJECTIVES: A study was performed to compare the sensitivity of detection of mycobacterial growth and time of culture positivity by microscopic observation of drug susceptibility (MODS) assay with that of Lowenstein-Jensen (LJ) culture in pulmonary and extrapulmonary TB and to evaluate the concordance of the susceptibilities to isoniazid (INH) and rifampicin (RIF) by MODS and proportion method on LJ. MATERIALS AND METHODS: A prospective, laboratory-based study was conducted on a total of 300 samples from suspected cases of pulmonary and extrapulmonary TB. Samples were inoculated on LJ medium as per the standard guidelines and MODS assay was performed. RESULTS: Sensitivity of MODS assay was 80% and 83.3% and specificity was 92.9% and 83.3% for pulmonary and extrapulmonary samples, respectively. Difference between mean time to detection of Mycobacterium TB (MTB) by LJ medium and MODS was statistically significant, with MODS being faster. drug susceptibility testing (DST) by MODS when compared to economic variant of proportion method was 87.87% for RIF, 90.9% for INH, and 96.96% for MDR-TB detection. CONCLUSION: MODS assay provides rapid, safe, and sensitive detection of TB faster than the existing gold standard. It is extremely promising in effectively diagnosing MDR-TB.

Drug susceptibility testing of rapidly growing mycobacteria in extrapulmonary tuberculosis.

There has been an increasing awareness of the rapidly growing mycobacteria (RGM), of which numerous species and phylogenetic groups are clearly established human pathogens. It is important to appropriately distinguish RGM from other mycobacteria, as first-line antituberculous drugs are ineffective for their treatment. Variability in susceptibility of RGM is seen in relation to species, different geographical areas, and time. Therefore, we conducted a study to speciate the isolates of RGM and perform antimicrobial susceptibility testing. The study was carried out in the department of microbiology of a tertiary care hospital. This study included 40 isolates of RGM obtained from clinical specimens from suspected cases of extrapulmonary tuberculosis. Forty isolates of RGM were speciated by phenotypic methods and drug susceptibility testing was done by broth microdilution method. Of the 40 isolates of RGM, 55% belonged to Mycobacterium fortuitum group, 35% were M. smegmatis group, and 10% were M. chelonae-abscessus group. In M. fortuitum group, sensitivity was seen to amikacin (13.63%), cefoxitin (18.18%), imipenem (31.81%), ceftriaxone (22.72%), and cotrimoxazole (31.81%). Only 14.28% and 7.14% of M. smegmatis were sensitive to cotrimoxazole and amikacin, respectively. M. chelonae-abscessus group was resistant to all the antibiotics tested and showed only intermediate sensitivity to amoxicillin-clavulanic acid (50%) and gatifloxacin (25%). A variability in sensitivity to different antimicrobials exists in all groups. Hence, it is advisable to perform antimicrobial susceptibility test before commencement of therapy.

Lipase catalysed synthesis of cetyl oleate using ultrasound: Optimisation and kinetic studies.

The current paper exemplifies the application of ultrasound technology to enzymatic synthesis of a cosmetic emollient ester, cetyl oleate. Fermase CALB™10000, a commercial Candida antarctica lipase B was used as a catalyst to accomplish the ultrasound supported synthesis. Multiple process parameters like reaction time, temperature, enzyme dose, alcohol to acid molar ratio, ultrasound power, frequency and speed of agitation were optimised. Maximum conversion of ∼95.96% was discerned at optimum conditions, i.e., 60°C temperature, 5% enzyme dose, 2:1 alcohol:acid ratio, 60 W ultrasound power, 25 kHz ultrasound frequency, 80% duty cycle and 80 rpm speed of agitation after purification steps. It was observed that the reaction reached equilibrium in a short duration of 30 min under the optimised conditions. This was considerably lesser than the time required for attaining equilibrium in conventional mechanical stirring method which was over 2h. Bisubstrate kinetic models like random bi-bi, ping pong bi-bi and ordered bi-bi were applied to the experimental data to determine initial rates and other kinetic parameters. Ordered bi-bi model showed the best fit with kinetic parameters, Vmax=0.029 M/min/gcatalyst, KA=0.00001 M, KB=4.8002 M, KiA=0.00014 M, KiB=3.7914 M & SSE=0.00022 for enzymatic cetyl oleate synthesis under ultrasound irradiation with inhibition by both acid and alcohol at high concentrations.

Green synthesis of isopropyl ricinoleate.

Increased environmental awareness is slowly driving the industry to develop alternatives to chemical routes for synthesis. Lipase catalysed synthesis is one such alternative route that is environmentally more acceptable. In this study, immobilized Candida antarctica lipase (Lipozyme 435) was used for the esterification of ricinoleic acid and isopropyl alcohol. Molecular sieves were used to remove the water formed during esterification to drive the reaction in forward direction. The optimal conditions observed were 40°C temperature, 4% enzyme concentration, 1:1 acid: alcohol ratio and 4 hours time interval. Under the described conditions, the reusability of lipase was tested and it was found that above 80% esterification was observed for over three cycles.