Preparation and application of fluorescent monoclonal antibodies recognizing goat CD4+CD25+ regulatory T cells.

Regulatory T cells (Tregs) are a subset of T cells participating in a variety of diseases including mycoplasmal pneumonia, contagious ecthyma, and so on. The role of Tregs in goat contagious ecthyma is not completely understood due to the lack of species-specific antibodies. Here, we developed a combination of CD4 and CD25 fluorescence monoclonal antibodies (mAb) to recognize goat Tregs and assessed its utility in flow cytometry, immunofluorescence staining. Using immunofluorescence staining, we found that the frequency of Treg cells was positively correlated with the viral load during orf virus infection. These antibodies could serve as important tools to monitor Tregs during orf virus infection in goats. KEY POINTS: • A combination of fluorescent mAbs (C11 and D12) was prepared for the detection of goat Tregs. • C11 and D12 are effective in flow cytometry, immunofluorescence staining, and C11 has excellent species specificity. • The frequency of Treg cells was positively correlated with the viral load during orf virus infection.

Therapeutic potential of enzymatically extracted eumelanin from squid ink in type 2 diabetes mellitus ICR mice: Multifaceted intervention against hyperglycemia, oxidative stress and depression.

BACKGROUND: Type 2 diabetes mellitus (T2DM) is a prevalent metabolic disease that poses significant health risks due to its numerous complications. However, the effects of eumelanin on oxidative stress, hyperglycemia and depression in diabetic mice have not been extensively studied. RESULTS: Our study employed an enzymatic approach to extract eumelanin from squid ink and characterized it using spectroscopic techniques. Remarkably, eumelanin extracted with alkaline-neutral-flavor protease (ANF) displayed superior inhibitory activity against α-glucosidase and α-amylase, while enhancing glucose utilization and hepatic glycogen synthesis in human hepatocellular carcinoma cell line (HepG2) insulin resistance model. Further evaluation of ANF in a T2DM ICR mouse model demonstrated its significant potential in alleviating hyperglycemia, reducing glycosylated serum protein levels, improving glucose tolerance and modulating total cholesterol and low-density lipoprotein levels, as well as antioxidant indices at a dosage of 0.04 g kg-1 . Additionally, ANF exhibited positive effects on energy levels and reduced immobility time in antidepressant behavioral experiments. Moreover, ANF positively influenced the density and infiltration state of renal cells, while mitigating inflammatory enlargement and deformation of liver cells, without inducing any adverse effects in mice. CONCLUSION: Overall, these findings underscore the significant therapeutic potential of ANF in the treatment of T2DM and its associated complications. By augmenting lipid and glucose metabolism, mitigating oxidative stress and alleviating depression, ANF emerges as a promising candidate for multifaceted intervention. © 2023 Society of Chemical Industry.

In Situ Self-Fluorescence 3D Imaging of Micro/Nano Damage in Silicone Gel for Understanding Insulation Failure under High-Frequency Electric Fields.

Strong electromagnetic and heat flux stresses can induce severe damage to solid insulation materials, leading to faults in power equipment and power electronics devices. However, in the absence of suitable in situ imaging methods for observing the development and morphology of electrical damage within insulation materials, the mechanism of insulation failure under high-frequency electric fields has remained elusive. In this work, a recently discovered fluorescence self-excitation phenomenon in electrical damage channels of polymers is used as the basis for a laser confocal imaging method that is able to realize three-dimensional (3D) in situ imaging of electrical tree channels in silicone gel through nondestructive means. Based on the reconstructed morphology of the damaged area, a spatial equivalent calculation model is proposed for analysis of the 3D geometric features of electrical trees. The insulation failure mechanism of silicone gel under electric fields of different frequencies is analyzed through ReaxFF molecular dynamics simulations of the thermal cracking process. This work provides a new method for in situ nondestructive 3D imaging of micro/nanoscale damage structures within polymers with potential applications to material analysis and defect diagnosis.

Melanin: insights into structure, analysis, and biological activities for future development.

Melanin, a widely distributed pigment found in various organisms, possesses distinct structures that can be classified into five main types: eumelanin (found in animals and plants), pheomelanin (found in animals and plants), allomelanin (found in plants), neuromelanin (found in animals), and pyomelanin (found in fungi and bacteria). In this review, we present an overview of the structure and composition of melanin, as well as the various spectroscopic identification methods that can be used, such as Fourier transform infrared (FTIR) spectroscopy, electron spin resonance (ESR) spectroscopy, and thermogravimetric analysis (TGA). We also provide a summary of the extraction methods of melanin and its diverse biological activities, including antibacterial properties, anti-radiation effects, and photothermal effects. The current state of research on natural melanin and its potential for further development is discussed. In particular, the review provides a comprehensive summary of the analysis methods used to determine melanin species, offering valuable insights and references for future research. Overall, this review aims to provide a thorough understanding of the concept and classification of melanin, its structure, physicochemical properties, and structural identification methods, as well as its various applications in the field of biology.

Genome-Wide Identification and Characterization of the Msr Gene Family in Alfalfa under Abiotic Stress.

Alfalfa (Medicago sativa) is an important leguminous forage, known as the "The Queen of Forages". Abiotic stress seriously limits the growth and development of alfalfa, and improving the yield and quality has become an important research area. However, little is known about the Msr (methionine sulfoxide reductase) gene family in alfalfa. In this study, 15 Msr genes were identified through examining the genome of the alfalfa "Xinjiang DaYe". The MsMsr genes differ in gene structure and conserved protein motifs. Many cis-acting regulatory elements related to the stress response were found in the promoter regions of these genes. In addition, a transcriptional analysis and qRT-PCR (quantitative reverse transcription PCR) showed that MsMsr genes show expression changes in response to abiotic stress in various tissues. Overall, our results suggest that MsMsr genes play an important role in the response to abiotic stress for alfalfa.

Role of a 3D Nanoskeleton in Hindering Electrical Tree Growth in Nanocomposites: Insights from in Situ Self-Fluorescence Imaging.

Despite the proposal of nanodielectrics in 1994, the impact of nano- and microstructures on composite performance is still not completely understood. A key reason for this knowledge gap is the lack of in situ characterization of micro- and nanoscale structures within materials. In this study, we observed the self-excited fluorescence of a microscale-damaged microchannel inside a composite under the influence of an electric field. Furthermore, we conducted in situ imaging of the internal microstructures and discharge channels in the composite utilizing external laser excitation. The imaging results reveal that the electrical treelike damage in the composites grows with a single channel under the guidance of the nanoskeleton embedded in the matrix, which demonstrates that the three-dimensional (3D) nano-order skeleton hinders the development of electrical trees. Furthermore, we analyzed the nanoskeleton intervention's enhancement mechanism on the insulation properties of the composites. This work aids in the precision imaging-guided structural design of nanodielectrics.

Speciation and transformation of nitrogen for sewage sludge hydrothermal carbonization-influence of temperature and carbonization time.

Hydrothermal carbonization (HTC) is an effective means of energizing high-water-content biomass that can be used to convert sewage sludge (SS) into hydrochar and reduce nitrogen content. To further reduce the emission of NOx during the combustion of hydrochar and seek proper disposal method of liquid product, the mechanism of nitrogen conversion was studied in the range of 180-320 °C and 30-90 min. At 180-220 °C, 42.15-52.91% of the nitrogen in SS was transferred to liquid by hydrolysis of proteins and inorganic salts. At 240-280 °C, the nitrogen in hydrochar was mainly in the form of heterocyclic -N (quaternary-N, pyrrole-N, and pyridine-N). The concentration of NH4+-N increased from 6.82 mg/L (180 °C) to 26.58 mg/L (280 °C) due to the enhancement of the deamination reaction. At 300-320 °C, pyrrole-N (from 15.92% to 9.38%) and pyridine-N (from 5.52% to 3.73%) in the hydrochar were converted to the more stable quaternary-N (from 0.31% to 4.28%). Meanwhile, the NH4+-N and amino-N in the liquid decomposed into NH3. Prolonging the carbonization time promoted the hydrolysis of proteins, the conversion of heterocyclic -N, and the production of NH3. Under optimal reaction conditions (280 °C and 60 min), the nitrogen in the SS is converted to stable forms and the energy balance meets the requirements of circular-economy. The results show that temperature determines the nitrogen form and the carbonization time affects the nitrogen distribution. So HTC has the potential to reduce NOx emissions from SS energy utilization processes.

Pyrolytic kinetics, reaction mechanisms and gas emissions of waste automotive paint sludge via TG-FTIR and Py-GC/MS.

The present study experimentally quantified the pyrolysis behaviors of waste solvent-based automotive paint sludge (OAPS) and water-based automotive paint sludge (WAPS) at four different heating rates using thermogravimetric-Fourier transform infrared (TG-FTIR) spectrometry and pyrolysis-gas chromatography-mass (Py-GC/MS) spectrometry analyses. Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods combined with the master-plots method were employed to investigate the pyrolysis kinetics and reaction mechanisms of waste automotive paint sludge. Three reaction stages and three reaction peaks in stage 2 were distinguished for both OAPS and WAPS degradation. The average activation energy (Ea) estimates for OAPS (FWO: 179.09 kJ/mol; KAS: 168.28 kJ/mol) were slightly higher than WAPS (FWO: 175.90 kJ/mol; KAS: 164.80 kJ/mol) according to FWO and KAS methods. The main pyrolysis reaction mechanisms of both OAPS and WAPS closely matched with the order-based model corresponding to 3rd and 2nd order random nucleation on an individual particle. The evolved gas species of CH4, CO2, phenols, NH3, H2O, and CO from OAPS and WAPS pyrolysis were identified by TG-FTIR. According to Py-GC/MS, hydrocarbons (47.2%) and O-components (42.7%) were relatively large after OAPS and WAPS pyrolysis, respectively. Melamine was the most abundant N-component product after pyrolysis of OAPS (5.8%) and WAPS (4.8%).

Development and validation of diffusion-controlled model for predicting polycyclic aromatic hydrocarbons from baking-free brick derived from oil - based drilling cuttings.

Investigating the release of organic pollutants from bricks made from solid waste is essential. Based on Fick's laws of diffusion, the diffusion model and diffusion-degradation model of polycyclic aromatic hydrocarbon (PAH) emission from the bricks were deduced. The degradation and 64-day emission of PAHs in solid bricks made of oil-based drill cuttings were observed experimentally. The emission and degradation characteristics of 14 PAHs were obtained and fitted with the diffusion and diffusion-degradation models. The emission of most of the PAHs from the bricks at the beginning was in good agreement with the diffusion model, except for benzo[a]anthracene, pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, and benzo[a]pyrene. However, the emission of PAHs after some time was significantly lower than the theoretical value of the diffusion model. Moreover, fitting with the diffusion-degradation model gave better results, indicating that a joint diffusion-degradation mechanism controlled the emission of PAHs. Therefore, the diffusion-degradation model can better predict the long-term emission of PAHs in bricks made of oil-based drill cuttings.

The Effect of N-Acetylation on the Anti-Inflammatory Activity of Chitooligosaccharides and Its Potential for Relieving Endotoxemia.

Endotoxemia is mainly caused by a massive burst of inflammatory cytokines as a result of lipopolysaccharide (LPS) invasion. Chitooligosaccharides (COS) is expected to be a potential drug for relieving endotoxemia due to its anti-inflammatory properties. However, the structural parameters of COS are often ambiguous, and the effect of degree of acetylation (DA) of COS on its anti-inflammatory remains unknown. In this study, four COSs with different DAs (0%, 12%, 50% and 85%) and the same oligomers distribution were successfully obtained. Their structures were confirmed by 1H NMR and MS analysis. Then, the effect of DA on the anti-inflammatory activity and relieving endotoxemia potential of COS was researched. The results revealed that COS with a DA of 12% had better anti-inflammatory activity than COSs with other DAs, mainly in inhibiting LPS-induced inflammatory cytokines burst, down-regulating its mRNA expression and reducing phosphorylation of IκBα. Furthermore, this COS showed an obviously protective effect on endotoxemia mice, such as inhibiting the increase in inflammatory cytokines and transaminases, alleviating the injury of liver and intestinal tissue. This study explored the effect of DA on the anti-inflammatory activity of COS for the first time and lays the foundation for the development of COS as an anti-inflammatory drug against endotoxemia.

Microwave Synthesis and Enhanced Thermoelectric Performance of p-Type Bi0.90Pb0.10Cu1-xFexSeO Oxyselenides.

BiCuSeO oxyselenide, one of the best oxygen-containing thermoelectric materials, is promising with great potential applications. In this work, we present a high ZT of >1.3 in Bi0.90Pb0.10Cu0.96Fe0.04SeO fabricated via microwave synthesis and subsequent spark plasma sintering (SPS). We added 3-4 atom % Fe to the Pb-doped BiCuSeO to regulate the hole carrier concentration and mobility to 0.8-1.0 × 1020 cm-3 and ∼40 cm2 V-1 S-1, respectively, achieving moderate electrical conductivity, high Seebeck coefficient, and low carrier thermal conductivity simultaneously in a dual-doped sample. Under the synergistic enhancement by stress field, dislocation, and nanophase, the lattice thermal conductivity of Bi0.90Pb0.10Cu0.96Fe0.04SeO is limited to 0.24-0.49 W m-1 K-1 at 300-873 K. The development of efficient preparation methods for high-performance thermoelectric materials is significant to promote the application of thermoelectric conversion technology.

Impact of COVID-19 on physical activity: A rapid review.

Background: Physical activity is a commonly prescribed medicine for people with conditions such as obesity and diabetes who are also at increased risk of being hospitalized or severely ill from COVID-19. However, many people are reporting challenges in engaging in a healthy dose of physical activity amid the pandemic. Objective: This rapid review synthesizes the current empirical evidence about the impacts of COVID-19 on people's outdoor physical activity and sedentary behavior while highlighting the role of community environments in promoting or hindering physical activity during the pandemic. Methods: Literature searches were conducted using keywords related to COVID-19: physical activity, mobility, and lifestyle behaviors. Eligibility criteria were peer-reviewed empirical and quantitative studies published in English, addressing COVID-19 and using physical activity and/or sedentary behavior as the study outcomes. Results: Out of 61 eligible studies, the majority (78.3%) were conducted in Asian and European countries, with only four (6.7%) being US studies. The results showed that COVID-19 was linked with significant decreases in mobility, walking, and physical activity, and increases in sedentary activity. A few studies also reported contradicting results including increased uses of parks/trails and increased recreational activity among certain groups of population. Conclusions: Evidence suggests an overall negative impact of COVID-19 on physical activity, with differential effects across different sub-populations. Significant knowledge gaps are also found in the roles of social and physical attributes that can promote physical activity during pandemics with reduced safety risks.

COVID-19 in Long-Term Care Facilities: A Rapid Review of Infection Correlates and Impacts on Mental Health and Behaviors.

BACKGROUND: Long-term care facilities (LTCFs) with compact, group-living arrangements have become COVID-19 hot spots during the pandemic. Systematic research is needed to understand factors associated with COVID-19 infections in LTCFs and the inadvertent effects of preventive measures adopted by LTCFs. OBJECTIVES: This rapid review identifies factors associated with LTCF residents' COVID-19 infections and the impacts of the pandemic and the corresponding preventive measures on residents' mental health and behavioral problems. METHODS: Following the preferred reporting items for systematic reviews and meta-analyses guidelines, we identified and reviewed relevant literature in Medline, PsycINFO, and AgeLine. RESULTS: Thirty-seven articles were identified and reviewed, including 30 reporting factors associated with COVID-19 infections in LTCFs and seven reporting the impact of the pandemic and corresponding prevention measures on LTCF residents. Results revealed four domains of factors associated with COVID-19 infections: facility physical environments, resident characteristics, facility management and testing, and community factors. The pandemic and infection control measures increased residents' depression, anxiety, loneliness, and behavioral problems (e.g., agitation, hallucinations). Residents without cognitive impairments were more vulnerable to these adverse effects. CONCLUSION AND IMPLICATIONS: LTCF managers/policymakers and healthcare designers can help mitigate COVID-19 infections by (1) providing additional resources to vulnerable LTCFs; (2) enhancing the training of personal protective equipment use and guideline compliance; and (3) investing in amenities, such as sinks, quarantine rooms, and outdoor spaces. Digital activities and accessible green spaces can mitigate mental health and behavior issues. Future LTCF design can benefit from flexible spaces, natural ventilation, and reducing crowding.

Nursing Home Design and COVID-19: Implications for Guidelines and Regulation.

OBJECTIVES: Nursing homes (NHs) are important health care and residential environments for the growing number of frail older adults. The COVID-19 pandemic highlighted the vulnerability of NHs as they became COVID-19 hotspots. This study examines the associations of NH design with COVID-19 cases, deaths, and transmissibility and provides relevant design recommendations. DESIGN: A cross-sectional, nationwide study was conducted after combining multiple national data sets about NHs. SETTING AND PARTICIPANTS: A total of 7785 NHs were included in the study, which represent 50.8% of all Medicare and/or Medicaid NH providers in the United States. METHODS: Zero-inflated negative binomial models were used to predict the total number of COVID-19 resident cases and deaths, separately. The basic reproduction number (R0) was calculated for each NH to reflect the transmissibility of COVID-19 among residents within the facility, and a linear regression model was estimated to predict log(R0 - 1). Predictors of these models included community factors and NHs' resident characteristics, management and rating factors, and physical environmental features. RESULTS: Increased percentage of private rooms, larger living area per bed, and presence of a ventilator-dependent unit are significantly associated with reductions in COVID-19 cases, deaths, and transmissibility among residents. After setting the number of actual residents as the exposure variable and controlling for staff cases and other variables, increased number of certified beds in the NH is associated with reduced resident cases and deaths. It also correlates with reduced transmissibility among residents when other risk factors, including staff cases, are controlled. CONCLUSIONS AND IMPLICATIONS: Architectural design attributes have significant impacts on COVID-19 transmissions in NHs. Considering the vulnerability of NH residents in congregated living environments, NHs will continue to be high-risk settings for infection outbreaks. To improve safety and resilience of NHs against future health disasters, facility guidelines and regulations should consider the need to increase private rooms and living areas.

Role of Fucoxanthin towards Cadmium-induced renal impairment with the antioxidant and anti-lipid peroxide activities.

Kidney damages caused by cadmium are considered to be one of the most dangerous consequences for the human body. This study aimed to investigate the protective effects of fucoxanthin supplementation on mice models subjected to cadmium-induced kidney damage. The mice treated with cadmium chloride (CdCl2) were observed to have significantly reduced the cross-section area of glomeruli. Cadmium exposure has also caused the damage of the structural integrity of mitochondria and increased blood urea nitrogen (BUN), kidney injury molecule 1 (KIM1), and neutrophil gelatinase associated lipocalin (NGAL) levels. Peroxidase (POD), superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) levels in cadmium-exposed mice were markedly declined. Caspase3, caspase8, and caspase9 gene expressions in association with apoptosis were dramatically elevated in renal tissues. The CdCl2 treated mice were orally administered with 50 mg/kg Shenfukang, 10 mg/kg, 25 mg/kg, and 50 mg/kg fucoxanthin for 14 days. The results revealed that high doses of fucoxanthin administration significantly decreased BUN, KIM1, NGAL levels, increasing POD, SOD, CAT, and ascorbate APX levels. Fucoxanthin administration also promoted recovery of the renal functions, micro-structural organization, and ultra-structural organization in the renal cells. In summary, the ameliorative effects of fucoxanthin supplementation against cadmium-induced kidney damage were mediated via inhibiting oxidative stress and apoptosis, promoting the recovery of structural integrity of mitochondria.

Characterization of Different Salt Forms of Chitooligosaccharides and Their Effects on Nitric Oxide Secretion by Macrophages.

In this paper, chitooligosaccharides in different salt forms, such as chitooligosaccharide lactate, citrate, adipate, etc., were prepared by the microwave method. They were characterized by SEM, FTIR, NMR, etc., and the nitric oxide (NO) expression was determined in RAW 264.7 cells. The results showed that pure chitooligosaccharide was an irregular spherical shape with rough surface, and its different salt type products are amorphous solid with different honeycomb sizes. In addition to the characteristic absorption peaks of chitooligosaccharides, in FTIR, the characteristic absorption of carboxyl group, methylene group, and aromatic group in corresponding acid appeared. The characteristic absorption peaks of carbon in carboxyl group, hydrogen and carbon in methyl, methylene group, and aromatic group in corresponding acid also appeared in NMR. Therefore, the sugar ring structure and linking mode of chitooligosaccharides did not change after salt formation of chitooligosaccharides. Different salt chitooligosaccharides are completely different in promoting NO secretion by macrophages, and pure chitooligosaccharides are the best.

Effect of Fucoxanthin Administration on Thyroid Gland Injury Induced by Cadmium in Mice.

The intervention effect of fucoxanthin, which is reportedly a powerful antioxidant, on cadmium-induced thyroid damage in mice was evaluated. Animals (N = 120) were divided into control group (given pure water, N = 20) and CdCl2-exposed group (given CdCl2 orally at a dose of 30 mg/kg body weight (bw)/day for 30 days, N = 100). Besides, the CdCl2-exposed group was divided into the following 5 groups (N = 20) to evaluate the intervention effect of fucoxanthin: (1) negative control group (NCG; animals were supplied with pure water); (2) positive control group (PCG; animals were supplied with 50 mg/kg bw/day thyroid tablets. Thyroid tablets are made from the thyroid glands of pigs, cattle, sheep and other food animals (the main components of T4). But because they are extracts of the thyroid glands, they may contain a small amount of T3. The specific amount of T3 is unknown.); (3) low fucoxanthin concentration group (F1; animals were supplied with 10 mg/kg bw/day fucoxanthin); (4) medium fucoxanthin concentration group (F2; animals were supplied with 25 mg/kg bw/day fucoxanthin); (5) high fucoxanthin concentration groups (F3; animals were supplied with 50 mg/kg bw/day fucoxanthin). A 14-day treatment was conducted for these animals. The levels of T4, T3, MDA, ascorbate peroxidase (APX) and catalase were measured, and the expression levels of Bax, Bcl-2, ERK1, ERK2, MEK1, eIf2α, p-eIf2α, GRP78 and GRP94 genes were determined using real-time reverse transcriptase-polymerase chain reactions (RT-PCR). In addition, tissue histopathology and ultrastructure were recorded and analysed. We found that the injection of cadmium chloride (CdCl2) decreased serum T4 and T3 levels to 27.10 ng/ml and 837.74 pg/ml, respectively. In addition, CdCl2 intoxication induced oxidative stress, structural abnormalities and apoptosis in thyroid follicles. Our results showed that the treatment of CaCl-exposed mice with 25-50 mg/kg bw/day fucoxanthin appreciably decreased oxidative stress and apoptosis induced by CdCl2 and restored the microstructural and ultrastructural organisations of the thyroid gland towards normalcy. Compared with the negative control group, fucoxanthin treatment groups showed significant increase in T4 and T3 levels (52.17 ng/ml and 1669.18 ng/ml, respectively; P < 0.05), relieved oxidative stress by decreasing malondialdehyde level and increasing catalase and APX levels and increased apoptosis inhibition through inhibiting the ERK1/2 pathway and preventing endoplasmic reticulum stress in thyroid follicular epithelial cells. Herein, our study provides evidence of the protective effects of fucoxanthin supplementation against thyroid damage and suggests therapeutic potential of this pigment in cases of Cd intoxication and hypothyroidism.

NH3 Sensor Based on 3D Hierarchical Flower-Shaped n-ZnO/p-NiO Heterostructures Yields Outstanding Sensing Capabilities at ppb Level.

Hierarchical three-dimensional (3D) flower-like n-ZnO/p-NiO heterostructures with various ZnxNiy molar ratios (Zn5Ni1, Zn2Ni1, Zn1Ni1, Zn1Ni2 and Zn1Ni5) were synthesized by a facile hydrothermal method. Their crystal phase, surface morphology, elemental composition and chemical state were comprehensively investigated by XRD, SEM, EDS, TEM and XPS techniques. Gas sensing measurements were conducted on all the as-developed ZnxNiy-based sensors toward ammonia (NH3) detection under various working temperatures from 160 to 340 °C. In particular, the as-prepared Zn1Ni2 sensor exhibited superior NH3 sensing performance under optimum working temperature (280 °C) including high response (25 toward 100 ppm), fast response/recovery time (16 s/7 s), low detection limit (50 ppb), good selectivity and long-term stability. The enhanced NH3 sensing capabilities of Zn1Ni2 sensor could be attributed to both the specific hierarchical structure which facilitates the adsorption of NH3 molecules and produces much more contact sites, and the improved gas response characteristics of p-n heterojunctions. The obtained results clear demonstrated that the optimum n-ZnO/p-NiO heterostructure is indeed very promising sensing material toward NH3 detection for different applications.

Chitin extraction from shrimp (Litopenaeus vannamei) shells by successive two-step fermentation with Lactobacillus rhamnoides and Bacillus amyloliquefaciens.

Chitin was extracted from shrimp shells powders (SSP) by successive two-step fermentation. The best microorganisms Lactobacillus rhamnoides and Bacillus amyloliquefaciens (BA01) for demineralization (DM) and deproteinization (DP) were obtained and the optimal fermentation conditions for two-step fermentation were established. Firstly, we determined the cultured conditions (inoculum level 4%, initial pH 6.5, cultured temperature 37 °C, glucose concentration 5%, cultured time 48 h) of Lactobacillus rhamnoides and the organic acid quantities and types of fermentation broth of Lactobacillus rhamnoides. Under the conditions, the pH of fermentation broth was 3.4, the DM efficiency was 97.5% and the ash in the final residue was 1.2%, and the main organic acid was lactic acid. Secondly, the optimal cultured conditions of BA01 were inoculum level 6%, initial pH 6.5, cultured temperature 37 °C, glucose concentration 4%, and cultured time 84 h. Under the conditions, the protease activity of fermentation broth was 701.3 U/mL, the DP efficiency was 96.8%, the protein in the final residue was 1.5%, and the chitin yield was 19.6%. In addition, the chitin obtained by fermentation was compared with the commercial chitin using scanning Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), Thermogravimetric analysis (TGA), Solid-state 13C CP/MAS-NMR spectra, and Scanning electron microscope (SEM). The results showed the chitin obtained by fermentation maintains the excellent physicochemical and structural properties of commercial chitin. Moreover, in order to make full use of shrimp and crab shells resources, the amino acid composition of fermentation broth was detected. The results showed that the fermentation broth had high nutritional value and could be used as a health nutrient in animal feed, even food.