High efficiency removal of NO using waste calcium carbide slag by facile KOH modification

Waste calcium carbide slags (CS), which are widely applied to desulfurisation, are not typically used in denitration. Herein, to well achieve waste control by waste, a facile and high-efficiency denitration strategy is developed using KOH to modify the calcium carbide slags (KCS). Various KCS samples were investigated using a series of physical and chemical characterisations. The performance test results showed that the KOH concentration and reaction temperature are the main factors affecting the denitration efficiency of KCS, and CS modified with 1.5 mol/L KOH (KCS-1.5) can achieve 100% denitration efficiency at 300°C. Such excellent removal efficiency is due to the catalytic oxidation of the oxygen-containing functional groups derived from the KCS. Further studies showed that KOH treatment significantly increased the concentration of oxygen vacancies, nitro compounds, and basic sites of CS. This study provides a novel strategy for the resource utilisation of waste CS in the future.

Synthesis and characterizations of conocarpus- and azadirachta-derived activated carbons as wastewater recycling material

Water being the most important fluid supporting the life as well as industry is getting sparse and polluted day by day. Activated carbon (AC) can be utilized in various applications of significant environmental impact and sustainable living such as carbon dioxide sensing and capturing, air purification, and water recycling. However, in the wake of the recent corona pandemic which resulted in global lockdown and took the entire world by shock, a cost-effective and simple synthesis of such a useful material remains dire need of time. Therefore, this paper describes a simple and cost-effective synthesis of activated carbon (AC) of high porosity and surface area derived from the pruning of conocarpus and azadirachta trees. In reference to the study under consideration, alongside numerous others, a furnace was employed to synthesize activated carbon. However, our approach utilized a more conventional methodology wherein the environmental parameters were not optimized. In furnace-based procedures, factors such as temperature, pressure, and humidity are meticulously regulated, contrasting with the conventional methodologies where such parameters lack optimal control. Consequently, employing a furnace does not constitute a cost-effective approach for the physical activation of organic samples thus proving a furnace is not imperative for physical activation. The synthesis was carried out by physical activation in the form of carbonization followed by chemical activation with potassium hydroxide (KOH). The influence of activated carbon from each pruning over filtration of water containing industrial dye was investigated. Activation temperature and impregnation ratio of 600-800 °C and 1:5 were selected respectively. X-ray diffraction patterns (XRD) for all AC samples indicted the appearance of broad peaks at 2θ value of 20-30° which confirms the presence of carbon in the sample. The physical morphology arrangement by SEM analysis showed uneven arrangement of pores of conocarpus which indicated higher iodine number and hence higher adsorption capacity of 442.13 mg/g.

Incidence of KOH Positive Elements in Chronic Discharging Ear -A Retrospective Study

The term chronic suppurative otitis media (CSOM) refers to middle ear infections lasting more than three months that lead to perforated tympanic membrane. Low socioeconomic strata of the society are more likely to have the disease in developing countries. There have been many studies focusing on the bacterial flora of CSOM, but little is known about the mycological aspects, which have become increasingly important over the last few decades. The present study was aimed to speculate the presence of fungal flora responsible for the cases of CSOM among patients who attended the Ear, Nose, and Throat Department of our hospital a tertiary care center. This retrospective study was conducted in a tertiary care centre after taking the approval of the protocol review committee and institutional ethics committee. Total 100 Patients of chronic otitis media were included with no history using ear drops for last one week and using two sterile swab without touching the external auditory canal, discharge was taken from middle ear and placed in sterile container and sent for potassium hydroxide (KOH) mount and observed. The age ranged from 18 months to 87 years and the mean age was 37.27+/- 12.59 years. The study population of male is 42 (41.6%) and female is 59 (58.4%). Distribution of KOH positivity observed for 33 (32.7%) and KOH negative for the study population of 68 (67.3%). When antibacterial treatment does not seem to relieve persistent otorrhea, otologists should suspect mycotic otitis media probable cause.

An Effective Strategy to Synthesize Well-Designed Activated Carbon Derived from Coal-Based Carbon Dots via Oxidation before Activation with a Low KOH Content as Supercapacitor Electrodes

The development of coal-based activated carbon for supercapacitors provides a robust and effective approach toward the clean and efficient use of coal, and it also offers high-quality and low-cost raw materials for energy storage devices. However, the one-step activation method for preparing coal-based activated carbon has problems, such as difficulty in introducing surface-functional groups and high KOH dosage. In our work, activated carbon was prepared through an effective strategy of oxidation and KOH activation with a low KOH content by employing coal-based carbon dots as raw material. The influence of temperature during the KOH activation of carbon dots on a specific surface area, pore structure, and various quantities and types of surface-functional groups, as well as on the electrochemical performance of supercapacitors, was systematically studied. The as-prepared sample, with the alkali-carbon ratio of 0.75, processes a large specific surface area (1207 m2 g-1) and abundant surface-functional groups, which may provide enormous active sites and high wettability, thus bringing in high specific capacitance and boosted electrochemical performances. The oxygen and nitrogen content of the activated carbon decreases while the carbon content increases, and the activation temperature also increases. The as-prepared activated carbon reaches the highest specific capacitance of 202.2 F g-1 in a 6 M KOH electrolyte at a current density of 10 A g-1. This study provides new insight into the design of high-performance activated carbon and new avenues for the application of coal-based carbon dots.

Rapid Diagnosis and Epidemiology of Fungal Rhinosinusitis in PostCOVID-19 Patients

Background

Fungal rhinosinusitis (FRS) cases are not exiguous for the world. However, their spike as a postCOVID sequelae has alarmed the world, especially India. Adding to the woes is the high mortality rate and poor prognosis associated with acute invasive fungal rhinosinusitis (AIFR) in such immunocompromised patients. In such a scenario, early and precise diagnosis of AIFR is what a patient and physician banks upon. KOH and histopathology are the two frontline investigations for the diagnosis of FRS. Our study aimed at analyzing the cases of FRS by histopathology and comparing these with KOH.

Study Design and Materials and Methods

Prospective longitudinal study including suspected postCOVID FRS patients over a period of 1.5 months. Their clinical, histopathological, and KOH findings were then correlated.

Results

About 72.5% clinically suspected fungal infection specimens were found to be positive for fungal elements on histopathology. Of these, only 30 cases were positive by KOH mount. Maximum patients belonged to 40-70 years of age; males (67%) more than females. Sites involved were paranasal sinuses (100%), nasal (88%), and orbital (25%). Histopathology revealed mucormycosis (100%) and aspergillosis (16%). Angioinvasion was identified in 38% of the mucormycosis cases.

Conclusion

In a state of crisis, when the gold standard for fungal identification i.e., culture can take as many as 21 days for final report and early and judicious antifungal treatment is sine qua non of recovery, histopathology has proved to be better than KOH as far as early and precise diagnosis of fungal elements and their invasion is concerned.

Enhanced Assembling of N-and-K-Riched Macroalgae as Carbon Adsorbent for CO2 Capture with Ni(NO3)2/KOH as Co-Catalysts

Porous-activated carbons have drawn great attention due to their important role in CO2 capture. Ni(NO3)2/KOH, as co-catalysts under different temperatures, were studied to obtain porous graphitized carbon from Sargassum horneri feedstock. The results indicated that the properties of the porous graphitized carbon generated at 850 °C were greatly enhanced, showing a large specific surface area of 1486.38 cm3·g-1 with narrowly distributed micropores (~0.67 nm) and abundant functional groups, which endowed high CO2 uptake; moreover, the high CO2 uptake was mainly attributed to the synergistic effect of Ni(NO3)2 and KOH, both in chemical modification and pore formation. The fitted values of the four kinetic models showed that the double exponential model provided the best description of carbon adsorption, indicating both physical and chemical adsorption. It is worth noting that carbon could be reused four times in the adsorption/desorption procedure in this research with good stability. This work focuses on the high-value-added comprehensive utilization of macroalgae, which not only is important for high-performance adsorbent preparation but also has positive benefits for the development and utilization of macroalgae resources.

Evolution of phosphorus with the promotion of KOH in supercritical water gasification of dewatered cyanobacteria from ion perspective

Phosphorus is a very important resource, and dewatered cyanobacteria contains a large amount of it. Basic additives, such as KOH, are often used to promote hydrogen production during supercritical water gasification (SCWG) of biomass, but their effects phosphorus transformation have rarely been investigated. In this study, SCWG of dewatered cyanobacteria with potassium salt and KOH was conducted in autoclave at 400 °C for 10 min, to investigate the effect of K⁺ on the transformation of phosphorus under neutral and alkaline conditions. Results showed that K⁺ increased the proportion of phosphorus in the solid phase from 88.4% to 90.8-98.3%. Furthermore, K⁺ could promote the transformation of iron-combined phosphorus to calcium-combined phosphorus and occluded phosphate. Only when the reaction environment was alkaline, the proportion of phosphorus in the solid phase was significantly reduced to a minimum of 26.1%. When the amount of OH^- was sufficient, can this part of phosphorus and organic phosphorus, which was decomposed and transformed by the promotion of OH^-, be transferred to the liquid products. Results from this study laid a foundation simultaneously for hydrogen production and phosphorus recovery more environmentally and high-effectively.

Contamination from microplastics and other anthropogenic particles in the digestive tracts of the commercial species Engraulis encrasicolus and Sardina pilchardus

Fragments of microplastics (<5 mm) found in commercial species of fish, crustaceans, and bivalves, are an issue of global concern. The bioaccumulation of microplastics and other anthropogenic particles in different levels of the food web may provoke unwanted impacts on marine ecosystems and cause pernicious effects on human health. Here, we study the presence of anthropogenic particles and the fraction of microplastics in the target organs of two representative commercial fish species in Spain; the European anchovy (Engraulis encrasicolus) and the European pilchard (Sardina pilchardus). The individuals were sampled along the continental shelf of the Gulf of Cádiz, from the Bay of Cádiz to Cape Santa Maria. The isolation of the microplastics (MPs) was carried out with a complete alkaline-oxidant organic digestion (KOH-H₂O₂) of the digestive tract, including both the contents ingested and the muscle tissues. Anthropogenic particles were found in all individuals of both species with an average of 8.94 ± 5.11 items·ind^-1. Fibres made up 93 % of the items while fragments and films were represented by the remaining 7 %. The average size of the anthropogenic particles was 0.89 ± 0.82 mm. In addition to the fragment and film particles identified as microplastics, 29 % of the fibres were estimated to be microplastics by Fourier-transform infrared spectroscopy (FTIR) analysis. The main polymer found in both species was nylon. No significant correlation was found between the abundance and size of anthropogenic particles ingested and individual size or other body variables. The analysis of similarities (ANOSIM) and the distanced-based multiple linear regression model showed a high homogeneity in anthropogenic particle contamination in both species throughout the study area along the continental shelf of the Gulf of Cádiz.

Carbon dioxide adsorbents from flame-made diesel soot nanoparticles

Carbon dioxide (CO₂) is the top contributor to global warming. On the other, soot particles formed during fuel combustion and released into the atmosphere are harmful and also contribute to global warming. It would therefore be highly advantageous to capture soot and make use of it as a feedstock to synthesize carbon-based materials for applications such as carbon dioxide adsorption. In this work, flame-made diesel soot nanoparticles were used to produce a variety of activated carbons by combined oxidative treatment with hydrogen peroxide (H₂O₂) and potassium hydroxide (KOH), and their performance towards CO₂ adsorption was evaluated. The effect of the chemical activation of soot with H₂O₂ for different reaction times and with KOH on the physicochemical properties of the activated carbons was investigated and compared to fresh soot. Interestingly, hollow aggregates of carbonaceous nanoparticles of a high interplanar distance, reduced polycyclic aromatic hydrocarbons (PAH) size, shorter PAH stacks, mesoporous structure, and a high content of oxygen functionalities along with other structural defects in PAHs were obtained in the synthesized activated carbons. Among the various analysis techniques employed, Raman spectroscopy indicated that the I_D/I_G ratio in soot decreased after simultaneous chemical treatment, though it did not indicate any enhancement in the graphitic character since the carbonyl and carboxylic containing PAHs and monovacancies (which cause defects in PAHs) also contribute to the increase in the intensity of the graphitic band. The activated carbons possessed promising CO₂ adsorption capacities, adsorption kinetics and CO₂/N₂ selectivity. For example, one of the activated carbons, following H₂O₂ treatment for 9 h and a subsequent KOH activation, exhibited a CO₂ adsorption capacity of 1.78 mmol/g at 1 bar and 25 °C, representing an increase of 161 % in capacity as compared to fresh soot. Hollow aggregates of carbonaceous nanoparticles consisting of shorter PAHs with a larger number of defects led to enhanced CO₂ adsorption rate and CO₂/N₂ selectivity on activated carbons.

Transforming micropores to mesopores by heat cycling KOH activated petcoke for improved kinetics of adsorption of naphthenic acids

Formation of activated carbon from petroleum coke by KOH, results in high specific surface area materials that are predominantly microporous. This initial microporosity means that the adsorption kinetics of target species are not as rapid as they could be, thus limiting environmental remediation applications for the material. To address this problem a series of additional heat cycles with no additional chemical inputs were applied after activation but prior to the removal of activating agents. This process resulted in the oxidation of residual potassium metal from the initial activation which allows it to function again as an activating agent for the subsequent cycles. The heat cycling resulted in an increase in mesoporosity by 10-25% with each successive cycle independent of the KOH to feedstock ratio. This was shown to be demonstrably different than equivalently extended heating times, thus identifying the importance of thermal cycling. Adsorption kinetics of three model naphthenic acids showed faster kinetics for the pore widened activated carbon. The t_1/2 times dropped from 20 to 6.6 min for diphenyl acetic acid, 34.3 to 4.5 min for cyclohexane acetic acid, and 51.4 to 12.0 min for heptanoic acid.

Production of highly porous biochar via microwave physiochemical activation for dechlorination in water treatment

Most biomass is composted into low-grade biofertilizer or processed into energy fuel for burning. At the same time, waste palm shell is potentially converted into highly porous biochar for dechlorination in water treatment. A single-mode microwave activation was developed to perform microwave activation that incorporated the application of steam, KOH, and a physiochemical process. The single-mode microwave activation was performed at the activation temperature ranging from 550-600 °C and recorded a short process duration of 5 min. The steam-activated biochar showed a mass yield of 88.3 wt%, a surface area of 527.4 m²/g, and a dechlorination efficiency of 25.5 mg/g. KOH-activated biochar showed a mass yield of 90.5 wt%, a surface area of 301.1 m²/g and a dechlorination efficiency of 24.0 mg/g. The physiochemical activated biochar showed the highest pores surface area of 717.8 m²/g and dechlorination efficiency of 35.8 mg/g but the lowest mass yield of 77.6 wt%. The results demonstrate that the greater the surface area, the higher the dechlorination efficiency. Using microwave heating and physiochemical activation technology demonstrates a promising way to produce activated biochar for the dechlorination of drinking water.

Alternative activated/KOH adsorbent for phenol adsorption: experimental, industrial case study and mass transfer interpretation

Removal of phenol from wastewater is essential to achieve permitted concentrations according to the recommendations of USEPA. The adsorption capacity of phenol in activated adsorbent with KOH of Enterolobium contortisiliquum (TAC) was evaluated at different temperatures. The Langmuir isotherm represented the equilibrium data of this study. Thermodynamic process was endothermic, spontaneous, and reversible. The mass transfer parameters ranged from K_E 0.68 to 0.96 × 10^-3 (cm s^-1), Ds 8.95 to 14.35 × 10^-9 (cm² s^-1), and Dp 5.023 × 10^-8 (cm² s^-1). The PVSDM model represented the adsorption kinetics. Intraparticle diffusion limits the mass transfer process Biot > 100. The two-stage process minimized the total amount of TAC required to achieve the permitted specification of phenol concentration in wastewater from different industrial sectors. TAC showed significant performance in the removal of phenol from wastewater.

Biomass ash pyrolyzed from municipal sludge and its adsorption performance toward tetracycline: effect of pyrolysis temperature and KOH activation

Large amount of municipal sludge is difficult to handle; its resource utilization is an effective measure. In this study, the municipal sludge from sewage treatment plant was pyrolyzed without gas protection at different temperatures and potassium hydroxide (KOH) concentrations for activation. The pyrolysis products, named biomass ash, with higher surface area and enriched pore structures could be obtained at the pyrolysis temperature of 773 K. Moreover, the KOH activation for raw municipal sludge could further increase the surface area of the pyrolysis biomass ash. The maximum specific surface area was 44.71 m2/g, which was obtained under 2 mol/L KOH activation before pyrolysis at 773 K. And in this situation, the obtained pyrolysis biomass ash as adsorbent showed the maximum adsorption capacity of 50.75 mg/g toward tetracycline (TC). Moreover, the TC adsorption onto pyrolysis biomass ash obtained under various conditions followed the pseudo-second-order kinetic model. Adsorption thermodynamics analysis suggested the TC adsorption onto the pyrolysis biomass ash with no pre-activation was mainly due to the multi-molecule heterogeneous adsorption, while the TC adsorption onto pyrolysis biomass ash pretreated through the activation of KOH followed the monomer adsorption mechanism. This different adsorption mechanism was largely related to the pore structure, polarity, and aromaticity of the adsorbent.

One-pot synthesis of porous N-doped hydrochar for atrazine removal from aqueous phase: Co-activation and adsorption mechanisms

KOH-activated N-doped hydrochar (KHCN) was synthesized via co-activation method to eliminate atrazine (AT) in water efficiently. Compared to primitive HC, KHCN had advantages of splendid specific surface area (1205.82 m2/g) and developed microsphere structures on the surface. Specially for KHCN, the extra melamine added strengthened and preserved partial structure of polar oxygen-containing groups that were decomposed in the process of pore making. Besides, the estimated uptake amount of AT onto KHCN (216.50 mg/g) was remarkably superior to KHC (114.25 mg/g). KHCN exhibited the pH-dependence for AT removal, and presented excellent uptake capacity at a relatively neutral environment. Notably, the proposed mechanisms for AT removal by KHCN included electrostatic attraction, pore filling, π-π EDA, H-bond as well as hydrophilic effect. Hence, the porous N-doped hydrochar was a kind of adsorbent which was easy to prepare and had the application prospect for AT removal in natural water.

Epidemiological, clinical and mycological characteristics of pityriasis versicolor: Results of a study from a teaching hospital in rural part of Northern India

Background and Objectives

Pityriasis versicolor is a common fungal infection of the skin which leads to the formation of scaly and discoloured small lesions on skin. The main objective of this study is to describe clinical and mycological characteristics and the predisposing factors in patients with pityriasis versicolor.

Material and Methods

In this prospective, observational, hospital-based cross-sectional study, patients of all ages with clinically suspected lesions of pityriasis versicolor were included. After detailed history and thorough clinical examination, skin scrapings were examined with 10% potassium hydroxide (KOH) under light microscope. The scrapings were also subjected to culture examination.

Results

A total of 113 patients [78 (69.0%) male; 35 (31%) female] were included in the study. A total of 87 (76.9%) patients were from rural area. Outdoor occupation and positive family history of pityriasis versicolor was present in 65 (57.5%) and 38 (33.6%) patients, respectively. Recurrent episodes were reported by 66 (60%) patients. Excessive sweating and oily skin were seen in 36 (31.8%) and 24 (21.1%) patients, respectively. History of occlusive clothing was present in 22 (19.4%) patients. Chest, back, and shoulders were affected in 36 (31.8%), 22 (19.4%), and 08 (07.0%) patients, respectively. Hypopigmented lesions were seen in 97 (85.8%) patients. Patches and macules were observed in 60 (53.1%) and 53 (46.9%) patients, respectively. A total of 27 (23.8%) patients reported mild prutitus. A total of 79 (69.9%) patients were KOH positive and culture negative, whereas 26 (23.0%) patients were KOH as well as culture positive. Eight (7.0%) patients were both KOH and culture negative.

Conclusion

Pytiriasis versicolor is more common in young adults and males with the most common presentation of hypopigmentation lesions. In our study population, presentation with large patches was more common than macular lesions. Pruritus was more in patients with large patches than those with macules.

Gastrointestinal mucormycosis in the pediatric age group: an evolving disease

BACKGROUND

Mucormycosis is a devastating opportunistic fungal infection resulting in significant mortality, especially in pediatric patients with predisposing risk factors.

MATERIALS & METHODS

Biopsies and surgical specimens reported and proven as Mucormycosis in children under 12 years of age were retrieved from the records for three years (January 2018 to January 2021). Complete data, predisposing factors, treatment, and clinical outcome were recorded.

RESULTS

15 cases were identified, ranging from 9 days to 5 years. The male-female ratio was 3:1; three children were preterm. Fourteen children were diagnosed with gastrointestinal Mucormycosis (14/15), and one had palatal and sinusoidal involvement. Abdominal pain with distention was the most typical complaint. On microscopy, biopsies and surgical specimens showed extensive liquefactive necrosis with broad aseptate fungal hyphae. An intraoperative diagnosis was rendered in two cases. All neonates underwent exploratory laparotomy with surgical debridement and were administered Liposomal Amphotericin B. However, only two neonates survived out of the fifteen cases, one with disease limited to the appendix and pouch colon. The others succumbed to the disease despite antifungal therapy and surgical debridement. Thus, the overall mortality in the current study was calculated to be 86%, with neonatal mortality of 75%.

CONCLUSION

Gastrointestinal involvement is more common in neonates and infants with a male preponderance. The diagnosis relies on direct microscopy, histopathology, and fungal culture. Intraoperative tissue may be sent in all suspected cases for direct microscopic examination for rapid diagnosis and treatment.

Clinico-Laboratory Findings of Malassezia Folliculitis in Indonesia: a Multicenter Study

BACKGROUND

Malassezia folliculitis (MF) is a humid-favored fungal skin disease caused by Malassezia species. Inaccurate treatments, changes in skin flora, and disease exacerbation are often occurred due to oversights in the diagnosis. Several diagnostic methods are established for MF.

OBJECTIVE

To identify clinico-laboratory findings of Malassezia folliculitis in Indonesia.

METHODS

The study was conducted from January 2014 to December 2018 in seven referral teaching hospitals. Medical records of MF-diagnosed patients were obtained and analyzed using the binomial test, chi-square test, and Cohen's Kappa coefficient in SPSS 26.0.

RESULTS

A total of 353 cases of MF were identified in seven referral teaching hospitals in Indonesia, 66.3% of which were males and 33.7% were females, dominated by the 17-25 years old group (44.5%). Itchy sensation (83.9%) was a major subjective complaint. Lesions were majorly found on the trunk-chest, back, and shoulder (68.3%), while the clinical manifestation are mostly follicular papule-pustular lesions (62.1%). Patients were 87.4% positive by KOH examination (modified Jacinto Jamora's criteria) and 69.1% positive by Wood's lamp. Generally, sex, age, subjective complaint, lesion location, clinical manifestation, and both examinations were statistically significant (p<0.001). A significant relationship between all the clinical criteria of the patients in the KOH; especially the clinical manifestation was significantly related to the Wood's lamp. The Cohen's Kappa assessment suggested that there was an agreement between KOH and Wood's lamp (κ = -0,272, p<0.001).

CONCLUSION

The clinical symptoms of Malassezia folliculitis are dominated by pruritus, papulopustular follicular lesions on the trunk, and the presence of spore load.

Reuse of KOH Solutions during Black Ripe Olive Processing, Effect on the Quality of the Final Product and Valorization of Wastewaters as Possible Fertilizer Product

A high volume of water is needed to produce black ripe olives, which also entails a significant volume of wastewater with a high organic and inorganic contaminant charge. To reduce this problem, the reuse of KOH solutions (lyes) in a new process was studied. Once the lyes were removed from the tanks, KOH was then added for a new darkening process. Reusing the lyes up to four times gave rise to a product with similar physico–chemical and organoleptic characteristics as obtained with fresh solutions. The application of this process reduced coadjutant consumption by 32% and water by 20%, while global wastewater presented a high K content whose concentration could be valorized as a fertilizer by replacing commercial potassium nitrate.

Porous Carbon Material Derived from Steam-Exploded Poplar for Supercapacitor: Insights into Synergistic Effect of KOH and Urea on the Structure and Electrochemical Properties

The electrochemical performance of supercapacitors using porous carbon as electrodes is strongly affected by the fabrication process of carbon material. KOH is commonly used as an activator combined with urea as a nitrogen dopant. However, the roles of KOH and urea in pore structure configuration and the electrochemical behavior of porous carbon electrodes are still ambiguous. Herein, the optimum porous carbon is obtained when KOH and urea are used simultaneously. KOH is used as a pore-forming substance, whereas urea is employed as a nitrogen source for the nitrogen doping of porous carbon, which increases its defect sites while reducing the graphitization degree. More importantly, urea also expands pores as a pore-enlarging agent, inducing interconnected porous structures. As a result, a hierarchical porous structure is formed and ascribed to the synergistic effect of KOH and urea, and the specific surface area reached 3282 m² g⁻¹ for sample PC800-4. The specific capacitance is 319 F g⁻¹ at 0.5 A g⁻¹ with excellent cycling stability over 2500 cycles. Furthermore, the symmetric supercapacitor reaches an excellent energy density of 11.6 W h kg⁻¹ under 70.0 W kg⁻¹ in a 6 M KOH electrolyte. Our work contributes to the rational designation of the porous carbon structure for supercapacitor applications.

Supplementation of KOH to improve salt tolerance of methanogenesis in the two-stage anaerobic digestion of food waste using pre-acclimated anaerobically digested sludge by air-nanobubble water

Air-nanobubble water (NBW) was applied to pre-acclimate anaerobically digested sludge that was then used as the inoculum in the two-stage anaerobic digestion (AD) of high saline (20 g NaCl/L) food waste (FW) to optimize NBW application in the AD of high saline FW. K⁺ was simultaneously supplemented during the methanogenic stage to resist the inhibition of salt on methanogens. Results showed that after the second pre-acclimation cycle, the inoculum activity was increased 27% in the Air-NBW supplemented reactor in comparison to the deionized water (DW) supplemented one. In the first-stage AD, H₂ yield was enhanced by 46% in the Air-NBW pre-acclimated sludge reactor compared with the DW pre-acclimated sludge reactor. Besides, supplementation of KOH in the methanogenic stage could enhance methane production by 17-25% in the DW reactors at initial pH 7.5, 8.0, and 9.0 when compared to the control reactor (using NaOH adjusted initial pH to 7.5), respectively.

Boosting the photocatalytic hydrogen production performance of graphitic carbon nitride nanosheets by tailoring the cyano groups

Graphitic carbon nitride (g-C₃N₄) is a promising visible light responsive photocatalyst for solar hydrogen production. However, pristine g-C₃N₄ suffers from severe charge recombination, resulting in a poor photocatalytic activity. Herein, a facile KOH-assisted sealed heating process is designed to tailor the electronic structure of g-C₃N₄, leading to a significantly enhanced and stable photocatalytic hydrogen production rate of 225.1 µmol h^-1 using only 50 mg of the photocatalyst. An excellent apparent quantum efficiency of 16.82% is achieved at 420 nm. Systematic studies reveal that KOH-assisted sealed heating can generate more cyano groups onto the framework of g-C₃N₄, which can increase the charge carrier density and reduce the surface charge transfer resistance, promoting charge separation and transfer. The new findings demonstrated in this work provide a facile strategy for the design of low-cost and efficient photocatalyst for solar fuel production.

Effect of fertilisation with black table olive wastewater solutions on production and quality of tomatoes cultivated under open field conditions

This study was aimed at making progress on the valorisation of table olive wastewater that currently represent a big environmental problem for factories. Concentrates from vacuum evaporation of the wastewater generated during processing of black ripe olives treated with KOH were tested as fertilisers of tomato plants in open field assays for three consecutive crops. Fertilisation was performed by drip irrigation every 15 days; the first treatment being 15 days after transplanting, and a total of five fertilisation treatments were carried out. A phytotoxic effect was not observed on plants or fruit in any case but higher yield (fruit/plant and g/plant) was obtained in comparison to irrigation with only tap water. Moreover, the combined use of the olive concentrate with inorganic nitrogen supply (NH₄NO₃), in order to comply with the nutrient needs of plants, was also tested. The results demonstrated that the olive concentrates could be a good substitute for inorganic potassium (as KNO₃) during the cultivation of tomato plants without any negative effect on the tomato quality (pH, °Brix, sugars, organic acids) or content of bioactive substances (phenolic compounds and carotenoids).

Electrochemical treatment in KOH renews and activates carbon fiber microelectrode surfaces

Carbon fiber microelectrodes (CFMEs) are the standard electrodes for fast-scan cyclic voltammetry (FSCV) detection of neurotransmitters. CFMEs are generally used untreated but the surface can be activated with different treatments to improve electrochemical performance. In this work, we explored electrochemical treatments to clean and activate the CFME surface. We used different solution conditions for electrochemical treatment and found that electrochemical pretreatment in KOH outperforms treatment in KCl, H₂O₂, or HCl by accelerating the surface renewal process. The etching rate of carbon with electrochemical treatment in KOH is 37 nm/min, which is 10 times faster than that in the other solutions. Electrochemical treatment in KOH for several minutes regenerates a new carbon surface, which introduces more oxygen functional groups beneficial for adsorption and electron transfer. The KOH-treated CFMEs improved the limit of detection (LOD) to 9 ± 2 nM from 14 ± 4 nM for untreated CFMEs, and they successfully detected stimulated dopamine release in rat brain slices, demonstrating that they are stable and sensitive enough to use in biological systems. Electrochemical treatment in KOH completely restores the electrode sensitivity after biofouling. The proposed electrochemical treatment is simple and fast and can be applied prior to using CFMEs or after use to restore the surface. Thus, the method has potential to be a standard step to clean the carbon surface, or restore the sensitivity of electrodes from biofouling.

Post Covid-19 Infection Presenting as Rhino-Orbital Mycosis

Rhino-orbital mycosis has been recently recognised as one of the sequelae in COVID-19 recovered patients. In India, detection of mucormycosis is declared as notifiable disease. In this article, the authors aim to describe the characteristics of patients presenting with post covid fungal infection which could be detected on 10% potassium hydroxide (KOH) wet mount and Giemsa stain put on crush biopsy smear. We describe 10 COVID-19 recovered patients admitted to ENT department of the hospital during second wave of COVID-19 infection. They presented with post covid fungal sinusitis and ophthalmic complications and planned for surgery. KOH mount and Giemsa stain were used for possible opinion and confirmed by culture. The observations were described in mean and percentages. All ten (100%) COVID-19 recovered patients were previously diagnosed with type 2 diabetes mellitus (DM) for 2-11 years. All 10 patients (100%) were given oral or intravenous corticosteroids for mean of 21 days (3 weeks-till presentation to ENT department). Simple procedures with 10% KOH mount and Giemsa stain could detect fungal hypae in all the cases and could provide possible opinion in 9 of 10 (90%) cases for timely management of the patients. The authors hypothesize that uncontrolled DM and prolonged use of corticosteroids may act as culprits of rhino-orbital mycosis in COVID-19 recovered patients. Simple and routine 10% KOH mount and Giemsa stain may provide early opinion of fungal hypae to ensure quick management and survival of the patients.

Separation and identification of microplastics in marine organisms by TGA-FTIR-GC/MS: A case study of mussels from coastal China

Microplastics are ubiquitous in the marine environment but characterizing them in marine organisms is challenging. Herein we describe a method to detect, identify, and quantify microplastics in marine mussels (Mytilus edulis) using thermal gravimetric analysis - Fourier Transform infrared spectroscopy - gas chromatography mass spectrometry (TGA-FTIR-GC/MS) after extracting and isolating the microplastics using chemical digestion, density separation, and filtration. Combining the three instrumental techniques adds discriminatory power as temperature profiles, chromatograms, and vibrational and mass spectra differ among common plastics. First, we tested several digestion schemes after spiking the mussels with plastics commonly found in the marine environment, including polyethylene (PE), polystyrene (PS), polypropylene (PP) and polyvinyl chloride (PVC). KOH (10%, w/v) was the most suitable reagent, providing good recoveries (>97%) without degrading the microplastics. We show that the technique TGA-FTIR-GC/MS can be optimized to readily determine both the type (polymer) and amount (mass) of microplastics in the sample. Applied to 100 mussels from each of six locations along the coast of China, we found an average of 0.58 mg of plastic per kg of tissue (range 0.16-1.71 mg/kg), with PE being the most abundant type of plastic measured. Among the coastal cities, mussels from Dalian had the highest microplastic content. Overall, we demonstrate that the method is a powerful technique to quantify masses of microplastics in marine mussels, a species commonly used as a bioindicator of pollution, and may be applied to other biota as well.

Investigation of the Demodex Lid Infestation with in Vivo Confocal Microscopy versus Light Microscopy in Patients with Seborrheic Blepharitis

Aim: The comparison of the diagnostic efficiency of a reference method (light microscopy [LM] using 10% potassium hydroxide [KOH]) with the use of 100% alcohol to in vivo confocal microscopy (IVCM) for the detection of Demodex eyelid infestation in seborrheic blepharitis patients.Methods: Eyelashes were epilated from the right eyes for the reference method and the left eyes for the alcohol group in 58 eyes of 29 patients. IVCM was used on the left eyes. The primary outcomes were the number of Demodex mites per lash and the rate of Demodex positivity (≥1 mite).Results: The rate of Demodex positivity was similar among the three groups (KOH: 82.8%, alcohol: 86.2%, IVCM: 72.4%; p >.05). The mean number of mites per lash in the KOH group (1.5 ± 1.3) was higher than in the alcohol (0.9 ± 0.6, p =.041) and IVCM groups (0.9 ± 0.9, p =.036).Conclusion: KOH was found to be superior in terms of the quantification of mites compared to alcohol and IVCM.

Nocardia Infections: Ten Years Experience from a Tertiary Health Care Center in North India (2007-2016)

BACKGROUND

Nocardia species are important cause of infections in humans but are underreported due to missed diagnosis as well as misdiagnosis. Majority of the literature on these infections consists of case reports or series with few articles describing high number of cases.

OBJECTIVE

To study the epidemiology of Nocardia infections in a tertiary care center.

MATERIALS AND METHODS

This retrospective observational study was done in a tertiary care centre of North India over a period of 10 years (2007-2016). The detection of Nocardia spp. from clinical specimens was done by conventional methods viz. direct microscopy (Gram's stain, modified Ziehl -Neelsen stain [1%], KOH examination) and culture.

RESULTS

A total of 25 cases of nocardiosis were diagnosed during the study period. The mean age of the patients was 50.9 years (range 30-72 years) with a male:female ratio of 3:2. The site of disease in these patients included pulmonary (n=18), cutaneous (n=4), perinephric abscess (n=1), ocular (n=1) and bone (n=1). Risk factors associated were underlying lung disease (n=11), smoking (n=7), diabetes (n=5) and steroid therapy (n=4) in pulmonary nocardiosis, iatrogenic (n=1) and leprosy (n=1) in cutaneous nocardiosis, diabetes in perinephric abscess and cataract surgery in ocular nocardiosis. Culture was positive in 12/25 (48%) patients for Nocardia spp. Direct microscopy was positive in 22 patients. We wish to highlight that meticulous observation of KOH wet mount examination helped in clinching the diagnosis of Nocardiosis in 3 cases which were earlier missed by other methods.

CONCLUSION

Good communication with the clinician alongside a meticulous effort in the laboratory is essential for appropriate diagnosis and management of these cases.

Clay-activated carbon adsorbent obtained by activation of spent bleaching earth and its application for removing Pb(II) ion

BE/C-A750-1/1 is prepared by carbonizing SBE and then activating with KOH. BE/C-A750-1/1 has good adsorption capacity for Pb(II), and the adsorption capacity for Pb(II) is 206.65 mg/g. The harmful effects of coexisting cations are listed in ascending order: K⁺ < Na⁺ < Mg²⁺. Adsorption and desorption studies show that the adsorption capacity of BE/C-A750-1/1 for Pb(II) after adsorption and desorption 3 times is 183.62 mg/g. The adsorption mechanism mainly includes electrostatic attraction, ion exchange, physical adsorption, and chemical complexation. This suggests that activated BE/C may be a promising candidate for removing Pb(II) from industrial wastewater. Clay/carbon nanocomposites were prepared by carbonizing and activating the spent bleaching earth served as adsorbents for the efficient removal of Pb(II) from wastewater.

Progress on green table olive processing with KOH and wastewaters reuse for agricultural purposes

Table olive wastewaters are seriously polluting and a difficult to treat effluent worldwide, mainly due to their high content in sodium. An alternative approach could be the treatment of the olives with KOH instead of NaOH, in order to reuse the olive streams as biofertilizers. In this study, the debittering of olives with KOH was investigated at pilot plant scale in two olive seasons. The results indicated that a concentration between 1.7 and 2.0% of KOH (similar to that employed with NaOH) led to a fermented product with the same physicochemical and organoleptic characteristics than the traditional one. The spent lyes and washing waters from the KOH treatments were gathered and vacuum evaporated, giving rise to a concentrated solution rich in potassium (52 g/L) that was tested as biofertilizer in open tomato fields. Furthermore, the drip irrigation of the tomato plants with a combined olive solution and mineral fertilizer (NH₄NO₃) produced similar tomato yield and quality than the irrigation with only mineral fertilizer (NH₄NO₃ + KNO₃). Overall, it has been demonstrated that Spanish-style green olives can be processed with KOH and the effluents valorized to be used as biofertilizer.

Flexible Nanoporous Template for the Design and Development of Reusable Anti-COVID-19 Hydrophobic Face Masks

Since the outbreak of the severe respiratory disease caused by the novel coronavirus (COVID-19), the use of face masks has become ubiquitous worldwide to control the rapid spread of this pandemic. As a result, the world is currently facing a face mask shortage, and some countries have placed limits on the number of masks that can be bought by each person. Although the surgical grade N95 mask provides the highest level of protection currently available, its filtration efficiency for sub-300 nm particles is around 85% due to its wider pore size (∼300 nm). Because the COVID-19 virus shows a diameter of around 65-125 nm, there is a need for developing more efficient masks. To overcome these issues, we demonstrate the development of a flexible, nanoporous membrane to achieve a reusable N95 mask with a replaceable membrane and enhanced filtration efficiency. We first developed a flexible nanoporous Si-based template on a silicon-on-insulator wafer using KOH etching and then used the template as a hard mask during a reactive ion etching process to transfer the patterns onto a flexible and lightweight (<0.12 g) polymeric membrane. Pores with sizes down to 5 nm were achieved with a narrow distribution. Theoretical calculations show that airflow rates above 85 L/min are possible through the mask, which confirms its breathability over a wide range of pore sizes, densities, membrane thicknesses, and pressure drops. Finally, the membrane is intrinsically hydrophobic, which contributes to antifouling and self-cleaning as a result of droplets rolling and sliding on the inclined mask area.

Influence of the epitaxial composition on N-face GaN KOH etch kinetics determined by ICP-OES

Roughening by anisotropic etching of N-face gallium nitride is the key aspect in today's production of blue and white light emitting diodes (LEDs). Both surface area and number of surface angles are increased, facilitating light outcoupling from the LED chip. The structure of a GaN layer stack grown by metal organic chemical vapour deposition (MOCVD) was varied in the unintentionally doped u-GaN bulk region. Different sequences of 2D and 3D grown layers led to a variation in dislocation density, which was monitored by photoluminescence microscopy (PLM) and X-ray diffraction (XRD). Thin-film processing including laser lift off (LLO) was applied. The influence of epitaxial changes on the N-face etch kinetics was determined in aqueous KOH solution at elevated temperature. Inductively-coupled plasma optical emission spectroscopy (ICP-OES) was used to measure the etch progress in small time increments with high precision. Thereby, the disadvantages of other techniques such as determination of weight loss or height difference were overcome, achieving high accuracy and reproducibility.

Investigation of the Environmental Stability of Poly(vinyl alcohol)-KOH Polymer Electrolytes for Flexible Zinc-Air Batteries

Next-generation wearable and portable electronic devices require the development of flexible energy-storage devices with high energy density and low cost. Over the past few decades, flexible zinc–air batteries (FZABs), characterized by their extremely high theoretical energy density from consuming oxygen in air and low cost, have been regarded as one of the most promising power supplies. However, their unique half-open structure poses great challenges for the environmental stability of their components, including the electrolyte and electrodes. As an important ionic conductor, the poly(vinyl alcohol) (PVA)–KOH gel polymer electrolyte (GPE) has been widely utilized in FZABs. To date, most studies have focused on investigations of the electrode, electrocatalyst materials and battery configuration, while very few have paid attention to the influence of the environment on the electrolyte and the corresponding FZAB performance. Herein, for the first time, the environmental stability of PVA–KOH GPE, such as dimensional stability and water and ionic conductivity retention capability, for FZABs in ambient air has been thoroughly studied. Moreover, the properties of the assembled FZABs in terms of cycling stability, discharge performance and power output are investigated. This report aims to play a leading role in examining the environmental stability of electrolytes in FZABs, which is critical for their practical applications.

Temperature Investigation on 3C-SiC Homo-Epitaxy on Four-Inch Wafers

In this work, results related to the temperature influence on the homo-epitaxial growth process of 3C-SiC is presented. The seed for the epitaxial layer was obtained by an innovative technique based on silicon melting: after the first step of the hetero-epitaxial growth process of 3C-SiC on a Si substrate, Si melts, and the remaining freestanding SiC layer was used as a seed layer for the homo-epitaxial growth. Different morphological analyses indicate that the growth temperature and the growth rate play a fundamental role in the stacking faults density. In details, X-ray diffraction and micro-Raman analysis show the strict relationship between growth temperature, crystal quality, and doping incorporation in the homo-epitaxial chemical vapor deposition CVD growth process of a 3C-SiC wafer. Furthermore, photoluminescence spectra show a considerable reduction of point defects during homo-epitaxy at high temperatures.

Clinicomycological Study of Dermatophytosis in a Tertiary Care Hospital in Eastern India: A Cross-sectional Study

Introduction:

Dermatophytosis is a fungal infection of the skin, hair, and nails. In the past several years, it has emerged as a general public health problem in our country. Studies from different regions reveal varying patterns of etiological distribution of the disease.

Aims and Objectives:

To estimate the prevalence of different fungal species associated with dermatophytosis and to find out any possible association of the type of fungus with different clinical parameters of the disease.

Materials and Methods:

This was a cross-sectional study among 311 clinically diagnosed dermatophytosis cases from a tertiary care center in eastern India. Potassium hydroxide (KOH) mount and fungal culture were done from samples of skin, hair, and nails, and various clinical parameters were analyzed.

Results:

There was a male preponderance among cases and maximum patients belonged to third decade of life. Most common presentation was tinea corporis et cruris (39.5%). Family history was positive in 48.8% of cases. Trichophyton mentagrophytes was the most common fungal species (79.91%) grown in culture followed by Trichophyton rubrum (13.53%). Majority of patients had a mild body surface area involvement. We did not find statistically significant association of any clinical parameters with type of organism isolated.

Conclusion:

Trichophyton mentagrophytes was the most common isolated fungal species. This is in contrast to several studies where T.rubrum was the frequently found organism. There was no significant association of any clinical parameters like body surface area, number of sites, or duration of diseasewith fungal species isolated in culture.

Processing of table olives with KOH and characterization of the wastewaters as potential fertilizer

In Mediterranean countries the table olive industry produces a huge volume of wastewaters that are phytotoxic due to their high sodium content. Olives intended for Spanish-style green olives are currently debittered with NaOH that generates lyes and washing waters that cannot be used for agronomic purposes. In this study, the substitution of NaOH with KOH during the debittering of Manzanilla and Hojiblanca cultivars was assessed as well as the vacuum evaporation of the olive wastewaters to comply with fertilizer requirements. Typical lactic acid fermentation occurred in brines of olives treated with KOH and a final product with similar color and flavor characteristics to those treated with NaOH was achieved. However, lower texture was found in olives debittered with KOH than those with NaOH, using them at the same molar concentration. Furthermore, the lyes and washing waters from the KOH treatment were concentrated up to 10% of their initial volume and they complied with Spanish requirements to be considered as organo-mineral fertilizers (C_organic > 4%, K₂O > 2%, N_total + K₂0 > 6%) although an external source of nitrogen would be needed. They also had a high content in phenolic compounds, particularly hydroxytyrosol. This research demonstrates that table olives can be processed with KOH and the generated waste streams could have potential applications in agriculture or being a source of bioactive substances.

Synthesis of Diverse Green Carbon Nanomaterials through Fully Utilizing Biomass Carbon Source Assisted by KOH

With multiple properties, green carbon nanomaterials with high specific surface area have become extensively attractive as energy storage devices with environmental-friendly features. The primary synthesis attempts were based on alkalis activation, which, however, faced the dilemma of low utilization rate of carbon sources. Herein, the green carbon with ultrahigh surface area (up to 3560 m²/g) was prepared by the KOH-assisted biomass carbonization. Moreover, the redundant K₂O steam and C_xH_y flow were further utilized; as a result, the carbon materials with a wide range of morphological diversity were collected on the Cu foam. Accordingly, we carried out density functional theory simulations to reveal the mechanism of O-adatom-promoted CH₄ dissociation over the Cu surface for carbon formation. The electrodes of electrochemical capacitor fabricated by carbon synthesis possess a 170% higher specific capacitance compared with commercial carbon electrodes. As such, this strategy might be promising in developing hierarchical carbons along with sufficient carbon sources for broadening their potential applications.

An efficient and gentle enzymatic digestion protocol for the extraction of microplastics from bivalve tissue

Standardized methods for the digestion of biota for microplastic analysis are currently lacking. Chemical methods can be effective, but can also cause damage to some polymers. Enzymatic methods are known to be gentler, but often laborious, expensive and time consuming. A novel tissue digestion method with pancreatic enzymes and a pH buffer (Tris) is here presented in a comparison to a commonly applied digestion protocol with potassium hydroxide. The novel protocol demonstrates a highly efficient removal of bivalve tissue (97.7 ± 0.2% dry weight loss) already over-night. Furthermore, it induces no impairment in terms of ability to correctly identify four pre-weathered plastic polymers and six textile fiber polymers by Fourier transform infrared spectroscopy after exposure. The high-throughput protocol requires minimal handling, is of low cost and does not pose risk to the performer or the environment. It is therefore suggested as a candidate for a standardized digestion protocol, enabling successful analysis of microplastics ingested by bivalves.

Evaluation of activated carbon synthesized by one-stage and two-stage co-pyrolysis from sludge and coconut shell

Waste biomass and sewage sludge were used to obtain an adsorbent material with excellent performance qualities by adopting a KOH activation process via one-stage (AC_one) or two-stage (AC_two) co-pyrolysis. The main purpose of this work was to investigate the effects of both methods in terms of the physicochemical properties and adsorption capacities for methylene blue (MB). Textural analyses revealed that the surface area (S_tot= 683.82 m²/g) and total pore volume (V_tot= 0.72 cm³/g) of AC_two were more than two-fold compared with AC_one (S_tot= 285.33 m²/g; V_tot= 0.35 cm³/g). Thus, two-stage co-pyrolysis produced activated carbon with increased porosity, which was favorable for MB adsorption. Nevertheless, the intensity of the surface functional groups of AC_two was weaker than for AC_one, which could be due to the pore-forming mechanism. Two-stage co-pyrolysis increased the yield and aromaticity of activated carbon, but sufficient activation caused more functional groups to decompose. For the adsorbate MB, the maximum adsorption capacity of AC_two (602.80 mg/g) was more than five-fold greater than that of AC_one (101.88 mg/g), due to its excellent porosity properties. Furthermore, the interactions of MB molecules with activated carbon were via hydrogen bonds and electrostatic attraction. The adsorption process of MB onto activated carbon was accurately described by the pseudo-second-order kinetic model. Adsorption equilibrium evaluated Langmuir isotherms demonstrated that MB formed a monolayer by adsorption onto the activated carbon. Adsorption thermodynamics was used to investigate the influence of temperature on the adsorption process. Thermodynamic parameters indicated that MB adsorption onto activated carbon was spontaneous and endothermic. In conclusion, our results showed that two-stage co-pyrolysis improves the adsorption capabilities of activated carbon, so achieving better economic value from waste materials.

Production of mouse fetuses using spermatozoa exposed temporarily to high temperature or continuously to room temperature after freeze-drying in Na+-free/K+-rich EGTA buffer

Present study aimed to determine to what extent freeze-dried spermatozoa were able to withstand high-temperature conditions: transient increase in storage temperature and long-term exposure to room temperature. Mouse spermatozoa were freeze-dried in EGTA/Tris-HCl buffered solution alkalinized using KOH (K-ETBS, pH 7.7), and then stored for up to 7 months at 4 °C or 25 °C. After 2 months' storage, some of the 4°C-stored spermatozoa were exposed to 40 °C for 1 week or 1 month, then again stored at 4 °C for the remaining storage period. Following storage, rehydrated spermatozoa were injected into mouse oocytes. The resulting zygotes were assessed for chromosome damage, in vitro development up to the blastocyst stage, and post-implantation development to normal fetuses on day 18 of gestation. In storage at 4 °C, one-week exposure to 40 °C had no adverse effect on the chromosome integrity and developmental competence compared to non-exposure to 40 °C (continuous storage at 4 °C). In contrast, one-month exposure to 40 °C caused an increasing level of chromosome damage (36%, P < 0.05) and reduced frequencies of blastocysts (54%, P < 0.05) and normal fetuses (36%, P < 0.05) compared to the frequencies obtained by continuous storage at 4 °C (15%, 82% and 52%, respectively). Storage at 25 °C resulted in accumulation of chromosome damage (27%, P < 0.05), leading to decreased blastocyst formation (63%, P < 0.05). But, the frequency of normal fetus (44%) was not significantly different from that obtained by continuous storage at 4 °C. Consequently, mouse spermatozoa freeze-dried in K-ETBS withstood temporary exposure to 40 °C for 1 week. Chromosome damage accumulated in spermatozoa during storage at 25 °C.

Rapid increases in soil pH solubilise organic matter, dramatically increase denitrification potential and strongly stimulate microorganisms from the Firmicutes phylum

Rapid and transient changes in pH frequently occur in soil, impacting dissolved organic matter (DOM) and other chemical attributes such as redox and oxygen conditions. Although we have detailed knowledge on microbial adaptation to long-term pH changes, little is known about the response of soil microbial communities to rapid pH change, nor how excess DOM might affect key aspects of microbial N processing. We used potassium hydroxide (KOH) to induce a range of soil pH changes likely to be observed after livestock urine or urea fertilizer application to soil. We also focus on nitrate reductive processes by incubating microcosms under anaerobic conditions for up to 48 h. Soil pH was elevated from 4.7 to 6.7, 8.3 or 8.8, and up to 240-fold higher DOM was mobilized by KOH compared to the controls. This increased microbial metabolism but there was no correlation between DOM concentrations and CO₂ respiration nor N-metabolism rates. Microbial communities became dominated by Firmicutes bacteria within 16 h, while few changes were observed in the fungal communities. Changes in N-biogeochemistry were rapid and denitrification enzyme activity (DEA) increased up to 25-fold with the highest rates occurring in microcosms at pH 8.3 that had been incubated for 24-hour prior to measuring DEA. Nitrous oxide reductase was inactive in the pH 4.7 controls but at pH 8.3 the reduction rates exceeded 3,000 ng N₂-N g^-1 h^-1 in the presence of native DOM. Evidence for dissimilatory nitrate reduction to ammonium and/or organic matter mineralisation was observed with ammonium increasing to concentrations up to 10 times the original native soil concentrations while significant concentrations of nitrate were utilised. Pure isolates from the microcosms were dominated by Bacillus spp. and exhibited varying nitrate reductive potential.

Micro-mesoporous carbons from original and pelletized rice husk via one-step catalytic pyrolysis

This paper studied the KOH-catalyzed pyrolysis of rice husk (RH) and its pellet (RHP) at a high temperature (750 °C) for activated bio-carbons production. The mass ratio of KOH and biomass greatly impacted the pyrolysis kinetic and biochar property. The KOH catalysis (mass ratio: 1) reduced significantly the activation energy to 41 kJ/mol. During carbonization with KOH, the in-situ generated K₂CO₃ tailored the morphology and size of the self-template (SiO₂ nanoparticles), giving rise to the chars with the open foam-like porous architectures enrich in micro- and meso-pores. Thus, the KOH activation via one-step pyrolysis could produce the micro-mesoporous carbons (e.g., RH-char 1 and RHP-char 1) with high specific surface areas and high content of oxygen-functionalities. Furthermore, the hierarchical porous carbons have high potential applications in adsorption process and electrochemical energy storage (e.g., supercapacitor) because of their unique physicochemical properties.

Effect of acidic, neutral and alkaline conditions on product distribution and biocrude oil chemistry from hydrothermal liquefaction of microalgae

Hydrothermal liquefaction (HTL) of microalgae produces high amount of water-insoluble organic compounds, the biocrude oil. Using high-growth-rate Spirulina platensis as feedstock, product fraction distribution and biocrude oil chemistry from HTL at a temperature of 240-300 °C under acidic, neutral and alkaline condition were studied. Positive effects on biocrude oil yield were only found with KOH and acetic acid, and these effects were stronger under milder HTL conditions. FT-ICR MS showed that O₂ class in the biocrude was high due to higher carbohydrate in the biomass, numbers of N₃O_5-6 species present in the sample from acetic acid run, indicating its less decarboxylation ability. GC-MS showed more ketones and amides were formed from fatty acids in catalytic HTL, and this effect was sensitive toward reaction temperature. GPC suggested more light volatiles were in biocrude from KOH run, while analysis from NMR, FT-IR and elemental confirmed its high oil quality.

Butanolysis: Comparison of potassium hydroxide and potassium tert-butoxide as catalyst for biodiesel preparing from rapeseed oil

Biodiesel is a mixture of esters of fatty acids (most often palmitic, stearic and oleic) and lower alcohols (in our work butanol) produced by transesterification. It is a renewable source of energy, prepared from triacylglycerides, which are contained in vegetable oils and animal fats. This work focuses on alkaline catalyzed transesterification of rapeseed oil with butanol and comparison of two catalysts (potassium hydroxide and potassium tert-butoxide). In industry is usually transesterification of rapeseed oil carried out like reaction catalyzed by potassium hydroxide. Potassium hydroxide have high content of K₂CO₃, KHCO₃ and water. Moreover water is formed by neutralization of potassium hydroxide with free fatty acids contained in oil. In cause of tert-butoxide catalyzed reaction, it is not possible because tert-butoxide have not a OH^- aniont, which is needed for water forming. The influence of various conditions (addition of water, temperature of separation, intensity of stirring and type of catalyst) on butanolysis process was studied for both catalysts. For both catalysts dependence of conversions on time were plotted. When tert-butoxide was used, satisfactory phase separation was not achieved. The only way was separation of hot crude reaction mixture without adding water. Ester formed by this method had high content of free glycerol and soaps, but reached higher conversion. The best results were obtained with KOH and subsequent separation of cold crude reaction mixture with the addition of water and slow stirring. The difference between reactions catalyzed by potassium hydroxide and potassium tert-butoxide was described.

Sporotrichosis: From KOH to Molecular Biology

Sporotrichosis is a cosmopolitan, chronic granulomatous mycosis, acquired by traumatic inoculation and caused by Sporothrix schenckii complex. Several methods of diagnostic are available, from KOH to molecular biology. In this review, we describe from the simplest (clinical diagnosis) to the most advanced diagnostic techniques (molecular biology).

Nanorods on surface of GaN-based thin-film LEDs deposited by post-annealing after photo-assisted chemical etching

This study investigates the optoelectronic characteristics of gallium nitride (GaN)-based thin-film light-emitting diodes (TF-LEDs) that are formed by a two-step transfer process that involves wet etching and post-annealing. In the two-step transfer process, GaN LEDs were stripped from sapphire substrates by the laser lift-off (LLO) method using a KrF laser and then transferred onto ceramic substrates. Ga-K nanorods were formed on the surface of the GaN-based TF-LEDs following photo-assisted chemical etching and photo-enhanced post-annealing at 100 °C for 1 min. As a result, the light output power of GaN-based TF-LEDs with wet etching and post-annealing was over 72% more than that of LEDs that did not undergo these treatments.

Prevention of high-temperature-induced chromosome damage in mouse spermatozoa freeze-dried using Ca2+ chelator-containing buffer alkalinized with NaOH or KOH

In order to protect sperm chromosomes against degradation when they are being stored for relatively high temperatures, we investigated the optimal pH of the freeze-drying solution, EGTA/Tris-HCl buffered solution alkalinized by NaOH (Na-ETBS) or KOH (K-ETBS). Mouse spermatozoa suspended in Na-ETBS or K-ETBS were freeze-dried at pH 5.0-8.4 and stored at 4 °C or 50 °C for 3 days. Some freeze-dried samples were stored at 25 °C for 3 days or 1 month. After storage, samples injected into oocytes using intracytoplasmic sperm injection were assessed for chromosome damage in resulting zygotes. Irrespective of freeze-drying solutions and storage temperatures, almost all the zygotes (97-100%) produced using the spermatozoa freeze-dried at pH 5.0 had structural chromosome aberrations of sperm origin. When freeze-drying was conducted at pH 8.0-8.4 using Na-ETBS, the incidence of chromosome damage decreased to 14-17% in 4 °C storage and 24-26% in 50 °C storage. When freeze-dried in K-ETBS, the lowest level of chromosome damage occurred at pH levels of 7.7-8.4 at 4 °C storage (13-15%) and at pH 7.7-8.0 at 50 °C storage (16-23%). Spermatozoa freeze-dried in Na-ETBS at pH 8.2 and K-ETBS at pH 7.7 showed no significant increase in chromosome damage during 25 °C storage from 3 days to 1 month (11%-20% in Na-ETBS; 13%-18% in K-ETBS). Thus, use of the solutions optimized for short-term storage at high temperature (50 °C, 3 days) permits prolonged storage (1 month) of freeze-dried spermatozoa at room temperature.

Dermoscopic patterns in patients with a clinical diagnosis of onychomycosis-results of a prospective study including data of potassium hydroxide (KOH) and culture examination

Background:

Onychomycosis is the most common nail disease, representing 50% of cases affecting the nail apparatus. The diagnosis is made by clinical examination along with the KOH exam of the nail and culture of the sample. However, not all dermatologists have access to a mycology lab.

Objective:

To determine the correlation between KOH examination and dermoscopic patterns in patients with clinical diagnosis of onychomycosis.

Patients/Methods:

A descriptive, open, observational, prospective, cross-sectional study of 178 patients with clinical suspicion of onychomycosis was conducted. All patients underwent clinical examination, dermoscopy with a DermLite PHOTO dermatoscope (3Gen, San Juan Capistrano, CA, USA), KOH assessment and culture analysis. The most frequent dermoscopic patterns were identified and their correlation with the clinical subtype of onychomycosis was analyzed.

Results:

The study included 178 patients with clinical suspicion of onychomycosis. Of these, 155 (87.1%) had positive direct KOH examination for onychomycosis. Eighty-seven patients (56.13%) presented with clinical onychomycosis pattern of total dystrophic onychomycosis (TDO), 67 (43.23%) with distal lateral subungual onychomycosis (DLSO), 1 (0.65%) with trachyonychia). Dermoscopic patterns of onychomycosis showed the following frequencies: the spiked pattern was present in 22 patients (14.19%), longitudinal striae pattern in 51 patients (32.9%) and linear edge pattern in 21 patients (13.55%). We identified a pattern described as “distal irregular termination” in 41 patients with TDO and 26 with DLSO.

Conclusions:

This is the fist study conducted in a Mexican population that uses dermoscopy as a diagnostic tool along with the KOH examination for the diagnosis of onychomycosis. Dermoscopy may be used as an important diagnostic tool when evaluating nail disease. However, it should not be used as the only diagnostic criteria for onychomycosis.

The 3,7-diazabicyclo[3.3.1]nonane scaffold for subtype selective nicotinic acetylcholine receptor ligands. Part 2: carboxamide derivatives with different spacer motifs

3,7-Diazabicyclo[3.3.1]nonane (bispidine) based nicotinic acetylcholine receptor (nAChR) ligands have been synthesized and evaluated for nAChRs interaction. Diverse spacer motifs were incorporated between the hydrogen bond acceptor (HBA) part and a variety of substituted (hetero)aryl moieties. Bispidine carboxamides bearing spacer motifs often showed high affinity in the low nanomolar range and selectivity for the α4β2(∗) nAChR. Compounds 15, 25, and 47 with Ki values of about 1 nM displayed the highest affinities for α4β2(∗) nAChR. All evaluated compounds are partial agonists or antagonists at α4β2(∗), with reduced or no effects on α3β4(∗) with the exception of compound 15 (agonist), and reduced or no effect at α7 and muscle subtypes.

The 3,7-diazabicyclo[3.3.1]nonane scaffold for subtype selective nicotinic acetylcholine receptor (nAChR) ligands. Part 1: the influence of different hydrogen bond acceptor systems on alkyl and (hetero)aryl substituents

3,7-Diazabicyclo[3.3.1]nonane is a naturally occurring scaffold interacting with nicotinic acetylcholine receptors (nAChRs). When one nitrogen of the 3,7-diazabicyclo[3.3.1]nonane scaffold was implemented in a carboxamide motif displaying a hydrogen bond acceptor (HBA) functionality, compounds with higher affinities and subtype selectivity for α4β2(∗) were obtained. The nature of the HBA system (carboxamide, sulfonamide, urea) had a strong impact on nAChR interaction. High affinity ligands for α4β2(∗) possessed small alkyl chains, small un-substituted hetero-aryl groups or para-substituted phenyl ring systems along with a carboxamide group. Electrophysiological responses of selected 3,7-diazabicyclo[3.3.1]nonane derivatives to Xenopus oocytes expressing various nAChR subtypes showed diverse activation profiles. Compounds with strongest agonistic profiles were obtained with small alkyl groups whereas a shift to partial agonism/antagonism was observed for aryl substituents.