内建电场辅助光催化甲烷干重整的研究进展

甲烷(CH_(4))和二氧化碳(CO_(2))是导致全球变暖的两种主要温室气体.甲烷干重整技术能够同时消耗两种温室气体并制备氢气(H2)和一氧化碳(CO),是减少温室效应的理想策略之一.CH_(4)和CO_(2)在热力学上具有很高的稳定性,所以活化CH_(4)和CO_(2)需要克服较高的能垒,导致传统的甲烷干重整技术总是需要高热能来触发该反应发生.光催化技术的发展为在温和条件下启动甲烷干重整反应提供了更多的可能.然而,由于光激发载流子之间的快速重组,光催化效率仍然较低,难以满足工业需求.研究人员发现,通过构建内置电场增强电荷载流子的分离和转移动力学是解决上述问题的可靠策略.本文首先介绍了甲烷干重整的反应机理和用于甲烷干重整的工业热催化材料.随后,总结了光催化甲烷干重整的优点和潜在的光催化材料,重点介绍了两类催化剂:(1)由铁电效应产生的永久自发极化进而构筑的内建电场的光催化剂.由于自发极化引起的电场,基于铁电材料的光催化剂在促进电荷转移方面显示出较大潜力.(2)由异质结结构在界面处引发内建电场的光催化剂.基于两种具有合适能带结构的半导体构建Ⅱ型异质结也是一种有效方法,由于交错间隙结构,在界面处形成内置电场,导致不同半导体分别进行氧化和还原过程.此外,Z型载流子转移机制可以保留具有更强还原能力的电子和更强氧化能力的空穴,将较低氧化还原能力的光生载流子重组,从而通过界面电场促进光催化甲烷干重整过程.(3)局域表面等离激元共振(LSPR)效应引发内建热电场的光催化剂.金属纳米颗粒在可见-近红外(Vis-NIR)光的照射下会产生共振现象,将会导致金属中的电子结构不连续,从而构建局部电场.因此,LSPR效应在提高光(热)催化甲烷干重整效率方面具有巨大潜力.随着光催化甲烷干重整技术的发展,人们对理解反应机理或阐明光催化剂中特定组分在反应中的作用提出了更多要求,导致原位表征技术和理论计算受到了极大的关注.最后,介绍了先进的原位表征和理论计算在该领域应用的主要进展,并预测了原位表征在光催化甲烷干重整领域的潜在功能,为从事该领域且处于起步阶段的年轻研究者提供了一定参考.虽然在光催化甲烷干重整领域已经取得了许多突破和进展,但仍存在一些挑战需要克服.根据已有的研究结果,本文总结了内建电场辅助光催化甲烷干重整领域的主要面临挑战,并提出了应对这些挑战的可行性策略,为未来对该领域进行更深入的研究提供借鉴.

Characterization of hepatitis B virus X gene quasispecies complexity in mono-infection and hepatitis delta virus superinfection

Hepatitis delta virus(HDV) seems to strongly suppress hepatitis B virus(HBV)replication, although little is known about the mechanism of this interaction. Both these viruses show a dynamic distribution of mutants, resulting in viral quasispecies. Next-generation sequencing is a viable approach for analyzing the composition of these mutant spectra. As the regulatory hepatitis B X protein(HBx) is essential for HBV replication, determination of HBV X gene(HBX)quasispecies complexity in HBV/HDV infection compared to HBV monoinfection may provide information on the interactions between these two viruses.AIM To compare HBV quasispecies complexity in the HBX 5' region between chronic hepatitis delta(CHD) and chronic HBV mono-infected patients.METHODS Twenty-four untreated patients were included: 7/24(29.2%) with HBeAgnegative chronic HBV infection(CI, previously termed inactive carriers), 8/24(33.3%) with HBeAg-negative chronic hepatitis B(CHB) and 9/24(37.5%) with CHD. A serum sample from each patient was first tested for HBV DNA levels.The HBX 5' region [nucleotides(nt) 1255-1611] was then PCR-amplified for subsequent next-generation sequencing(MiSeq, Illumina, United States). HBV quasispecies complexity in the region analyzed was evaluated using incidencebased indices(number of haplotypes and number of mutations), abundancebased indices(Hill numbers of order 1 and 2), and functional indices(mutation frequency and nucleotide diversity). We also evaluated the pattern of nucleotide changes to investigate which of them could be the cause of the quasispecies complexity.RESULTS CHB patients showed higher median HBV-DNA levels [5.4 logIU/mL,interquartile range(IQR) 3.5-7.9] than CHD(3.4 logIU/mL, IQR 3-7.6)(P = n.s.)or CI(3.2 logIU/mL, IQR 2.3-3.5)(P < 0.01) patients. The incidence and abundance indices indicated that HBV quasispecies complexity was significantly greater in CI than CHB. A similar trend was observed in CHD patients, although only Hill numbers of order 2 showed statistically significant differences(CHB2.81, IQR 1.11-4.57 vs CHD 8.87, 6.56-11.18, P = 0.038). There were no significant differences in the functional indices, but CI and CHD patients also showed a trend towards greater complexity than CHB. No differences were found for any HBV quasispecies complexity indices between CHD and CI patients. G-to-A and C-to-T nucleotide changes, characteristic of APOBEC3 G, were higher in CHD and CI than in CHB in genotype A haplotypes, but not in genotype D. The proportion of nt G-to-A vs A-to-G changes and C-to-T vs T-to-C changes in genotype A and D haplotypes in CHD patients showed no significant differences. In CHB and CI the results of these comparisons were dependent on HBV genotype.CONCLUSION The lower-replication CHD and CI groups show a trend to higher quasispecies complexity than the higher-replication CHB group. The mechanisms associated with this greater complexity require elucidation.

Network-centric medicine for peripheral nerve injury:treating the whole to boost endogenous mechanisms of neuroprotection and regeneration

Peripheral nerve injuries caused by accidents may lead to paralysis,sensory disturbances,anaesthesia,and lack of autonomic functions.Functional recovery after disconnection of the motoneuronal soma from target tissue with proximal rupture of axons is determined by several factors:motoneuronal soma viability,proper axonal sprouting across inhibitory zones and elongation toward specific muscle,effective synapse contact rebuilding,and prevention of muscle atrophy.Therapies,such as adjuvant drugs with pleiotropic effects,that promote functional recovery after peripheral nerve injury are needed.Toward this aim,we designed a drug discovery workflow based on a network-centric molecular vision using unbiased proteomic data and neural artificial computational tools.Our focus is on boosting intrinsic capabilities of neurons for neuroprotection;this is in contrast to the common approach based on suppression of a pathobiological pathway known to be associated with disease condition.Using our workflow,we discovered neuroheal,a combination of two repurposed drugs that promotes motoneuronal soma neuroprotection,is anti-inflammatory,enhances axonal regeneration after axotomy,and reduces muscle atrophy.This drug discovery workflow has thus yielded a therapy that is close to its clinical application.

Genomic patterns of homozygosity and inbreeding depression in MurcianoGranadina goats

Background:Inbreeding depression can adversely affect traits related to fitness,reproduction and productive performance.Although current research suggests that inbreeding levels are generally low in most goat breeds,the impact of inbreeding depression on phenotypes of economic interest has only been investigated in a few studies based on genealogical data.Results:We genotyped 1040 goats with the Goat SNP50 BeadChip.This information was used to estimate different molecular inbreeding coefficients and characterise runs of homozygosity and homozygosity patterns.We detected38 genomic regions with increased homozygosity as well as 8 ROH hotspots mapping to chromosomes 1,2,4,6,14,16 and 17.Eight hundred seventeen goats with available records for dairy traits were analysed to evaluate the potential consequences of inbreeding depression on milk phenotypes.Four regions on chromosomes 8 and 25were significantly associated with inbreeding depression for the natural logarithm of the somatic cell count.Notably,these regions contain several genes related with immunity,such as SYK,IL27,CCL19 and CCL21.Moreover,one region on chromosome 2 was significantly associated with inbreeding depression for milk yield.Conclusions:Although genomic inbreeding levels are low in Murciano-Granadina goats,significant evidence of inbreeding depression for the logarithm of the somatic cell count,a phenotype closely associated with udder health and milk yield,have been detected in this population.Minimising inbreeding would be expected to augment economic gain by increasing milk yield and reducing the incidence of mastitis,which is one of the main causes of dairy goat culling.

Communication of the Results of the Treatment with Probiotics in Two Cats with Chronic Gingivostomatitis

Feline chronic gingivostomatitis (GECF) is a disease of unknown etiology and considered as one of the most frequent paradontal diseases in cats of medium and/or advanced age. This problem is aggravated in the case of cats suffering from some immunosuppressive pathology such as feline leukemia virus (FeLV), feline immunodeficiency virus (HIV) or feline panleukopenia virus (VPF), in which the probability of suffering from GECF is increased. There is a wide variety of treatments against GECF but none of them ensures a complete cure of the disease, with signs of recurrence being observed at the month of treatment. For these reasons, in this investigation we have evaluated a strain of Lactobacillus plantarum with probiotic capacity for the preventive and/or therapeutic purpose of this oral pathology in cats. This investigation was performed in accordance with the Institutional Animal Ethics Committee of the Veterinary Faculty of the Autonomous University of Barcelona.

Suitability of the South Caribbean Coast of Costa Rica for Reintroduction of the Great Green Macaw <i>Ara ambiguus</i>

The Great Green Macaw Ara ambiguus is an endangered species whose most important food resource and nesting site in Costa Rica is the mountain almond tree Dipteryx panamensis, threatened mainly by deforestation. In this study, we analyse the suitability of reintroducing A. ambiguus in the South Caribbean Coast of Costa Rica by examining whether the ecological and socio-cultural conditions required for the reintroduction are met in the area. The methods developed in this work include biological sampling, cartographical analysis and semi-structured interviews, among others. We set La Ceiba Nature Reserve as study unit and starting point of the analysis due both to its conservation status, favouring the potential release of individuals, and its ecosystem representativeness. Our results suggest that the habitat is suitable for reintroduction, with frequent presence of D. panamensis in the region, as well as other feeding options and potential nesting sites in the study area. The cartographic study reveals that the species could rely on a forested surface of up to 7000 hectares, which would be sufficient for sustaining a viable population. As for the socio-cultural analysis, illegal logging and low protective frameworks were identified as the main potential threats for the species. Nevertheless, we perceived positive conservation attitudes among local people and a pro-active commitment of political stakeholders. We conclude that a viable South Caribbean reintroduction of A. ambiguus is possible in conjunction with a threat mitigation programme.

Determination of the Anti-Adhesive and Anti-Biofilm Capacity of a Wheat Extract on <i>Staphylococcus aureus</i>in Farms

The formation of biofilm by pathogenic microorganisms has become a problem in the livestock industry since it is considered a potential source of infection for farm animals while increasing microbial resistance to physical and chemical agents. Some plant extracts, such as soluble wheat extract, have been shown to be effective in inhibiting or destroying the biofilm of certain micro-organisms under specific conditions. The objective of this study is to evaluate the capacity of the pathogen to form biofilm on different surfaces used in livestock, as well as to evaluate the anti-biofilm capacity of the soluble wheat extract against S. aureus on these surfaces. The inhibition potential of inhibition or destruction of biofilm was tested in vitro. Wheat extract at a concentration of 0.29 mg/100mL showed anti-biofilm activity on S. aureus, inhibiting its formation, as well as destroying it greatly after a contact time of 24 hours, on those surfaces where the microorganism presents more adhesion capacity.

Exploratory study on microRNA profiles from plasma-derived extracellular vesicles in Alzheimer’s disease and dementia with Lewy bodies

Background:Because of the increasing life expectancy in our society,aging-related neurodegenerative disorders are one of the main issues in global health.Most of these diseases are characterized by the deposition of misfolded proteins and a progressive cognitive decline.Among these diseases,Alzheimer’s disease(AD)and dementia with Lewy bodies(DLB)are the most common types of degenerative dementia.Although both show specific features,an important neuropathological and clinical overlap between them hampers their correct diagnosis.In this work,we identified molecular biomarkers aiming to improve the misdiagnosis between both diseases.Methods:Plasma extracellular vesicles(EVs)-from DLB,AD and healthy controls-were isolated using size-exclusion chromatography(SEC)and characterized by flow cytometry,Nanoparticle Tracking Analysis(NTA)and cryo-electron microscopy.Next Generation Sequencing(NGS)and related bibliographic search was performed and a selected group of EV-associated microRNAs(miRNAs)was analysed by qPCR.Results:Results uncovered two miRNAs(hsa-miR-451a and hsa-miR-21-5p)significantly down-regulated in AD samples respect to DLB patients,and a set of four miRNAs(hsa-miR-23a-3p,hsa-miR-126-3p,hsa-let-7i-5p,and hsamiR-151a-3p)significantly decreased in AD respect to controls.The two miRNAs showing decreased expression in AD in comparison to DLB provided area under the curve(AUC)values of 0.9 in ROC curve analysis,thus suggesting their possible use as biomarkers to discriminate between both diseases.Target gene analysis of these miRNAs using prediction online tools showed accumulation of phosphorylation enzymes,presence of proteasome-related proteins and genes involved in cell death among others.Conclusion:Our data suggest that plasma-EV associated miRNAs may reflect a differential profile for a given dementia-related disorder which,once validated in larger cohorts of patients,could help to improve the differential diagnosis of DLB versus AD.

Antibiotic resistance and molecular characterization of diarrheagenic Escherichia coli and non-typhoidal Salmonella strains isolated from infections in Southwest China

Background:Bacterial diarrhea is one of the most common causes for medical consultations,mortality and morbidity in the world.Diarrheagenic Escherichia coli(DEC)and non-typhoidal Salmonella(NTS)are major intestinal pathogens in developing countries,and the indiscriminate use of antibiotics has greatly contributed to resistant strains.Hence,the aim of the present study is to identify the antimicrobial resistance patterns and the molecular characteristics of DEC and NTS in southwest,China.Methods:1121 diarrheal patients and 319 non-diarrheal subjects across all age groups were recruited from four sentinel hospitals from June 2014 to July 2015 in Kunming City,Yunnan Province.Each stool specimen was collected to detect DEC and NTS with standard microbiological and molecular methods.Antimicrobial resistance testing was performed with the Kirby-Bauer disk diffusion method,and the standards for antimicrobial susceptibility testing complied with the Clinical and Laboratory Standards Institute(CLSI).Molecular characterization of strains was carried out using pulsed-field gel electrophoresis(PFGE).A structured questionnaire was used to record basic epidemiological data(e.g.sex,age,residence,season,etc.).Data were analyzed using Chi-square or Fisher’s exact test.Results:DEC was detected in 127(11.33%)diarrhea cases and 9(2.82%)non-diarrheal cases(χ^(2)=20.69,P<0.001,OR=4.36,95%CI:2.19-8.65),and the prevalence of NTS isolated from diarrhea cases was higher than that of non-diarrheal cases across all age groups(n=42,3.75%,n=1,0.31%,χ^(2)=10.10,P=0.002,OR=12.38,95%CI:1.70-90.29).The rates of resistance to ten antibiotics of DEC and NTS showed significant differences(χ^(2)=386.77,P<0.001;χ^(2)=191.16,P<0.001).The rates of resistance to Amoxicillin and Clavulafiate(AMC),Cephalothin(CEP),Gentamicin(GEN)and Sulfamethoxazole-Trimethoprim(SXT)of DEC isolated from diarrhea cases were higher than those of NTS isolated from diarrhea patients(37.01%vs 14.29%,χ^(2)=7.57,P=0.006;29.92%vs 11.90%,χ^(2)=5.40,P=0.02;37.01%vs 11.90%,χ^(2)=5.80,P=0.016;62.20%vs 26.19%,χ^(2)=16.44,P<0.001;respectively).Ciprofloxacin(CIP)was the most sensitive antibiotic for DEC and NTS strains isolated from diarrhea cases.Resistance rates of DEC isolates from cases and controls to more than three kinds antimicrobials(multidrug resistance,MDR)showed no significant differences(81.10%vs 88.89%,P=0.33).Pulsotype patterns of DEC strains were highly diverse;however,the pulsotype pattern of NTS strains was closely related to the serotype.The pattern of S.enteritidis was highly similar,but the S.enterica Typhimurium strain was discrete.Conclusions:Antibiotic resistance of Enterobacteriaceae is of great concern.The societal effects of antibiotic use justify strict monitoring to combat increases in antimicrobial resistance.Molecular epidemiology and systematic epidemiological investigation can provide accurate evidence for tracking the infection source.

Using fireball networks to track more frequent reentries:Falcon 9 upperstage orbit determination from video recordings

On February 16,2021,an artificial object moving slowly over the Mediterranean was recorded by the Spanish Meteor Network(SPMN).Based on astrometric measurements,we identified this event as the reentry engine burn of a SpaceX Falcon 9 launch vehicle’s upper stage.To study this event in detail,we adapted the plane intersection method for near-straight meteoroid trajectories to analyze the slow and curved orbits associated with artificial objects.To corroborate our results,we approximated the orbital elements of the upper stage using four pieces of“debris”cataloged by the U.S.Government’s Combined Space Operations Center.Based on these calculations,we also estimated the possible deorbit hazard zone using the MSISE90 model atmosphere.We provide guidance regarding the interference that these artificial bolides may generate in fireball studies.Additionally,because artificial bolides will likely become more frequent in the future,we point out the new role that ground-based detection networks can play in the monitoring of potentially hazardous artificial objects in near-Earth space and in determining the strewn fields of artificial space debris.

Early life investment in antlers and body growth reflects adult performance in roe deer population under supplementary feeding conditions

Recent research has challenged the idea that cervid antlers are such costly traits,supporting the assertion early-life antler investment is an honest signal of adult phenotypic quality.However,inferences were made based on antler measurements while growing(velvet)and thus,studies on fully-formed clean antlers are needed to avoid possible bias caused by the inter-individual variation in antler growth phenology.We studied a semi-captive population of European roe deer inhabiting a sub-Mediterranean area(Valsemana research station)and living under optimal conditions(ad libitum food supply and veterinary care).Based on repeated measurements taken from 146 individuals,we assessed whether allocation to secondary sexual traits during early life affected body mass or antler development during adulthood.Furthermore,we evaluated which body measurements better predicted future male quality.Additionally,using 488 individuals,we described age-class-specific variation in male body measurements and assessed the decline in antler size between adult and senescent stages(i.e.magnitude of senescence).Results agree with the assertion that there is no negative effect of a high investment in antler during early life on adult antler size or body mass,but we suggest the use of clean antlers as a more robust and reliable measure.The variables that better predicted body mass during adulthood were yearling body mass and body size at 6 months.Antler score between 10 and 18 months resulted in the best indicator of adult antler size.Finally,we support the idea that the magnitude of senescence in antler size is smaller in environments with higher resource availability during winter.

ACE Score Identifies HBeAg-negative Inactive Carriers at a Single-point Evaluation,Regardless of HBV Genotype

Background and Aims:Hepatitis B virus(HBV)biomark-ers have been used for a better categorization of patients,even though the lack of simple algorithms and the impact of genotypes limit their application.Our aim was to assess the usefulness of noninvasive markers for the identification of HBV inactive carriers(ICs)in a single-point evaluation and to design a predictive model for their identification.Meth-ods:This retrospective-prospective study included 343 consecutive HBeAg-negative individuals.Clinical,analytical,and virological data were collected,and a liver biopsy was performed if needed.Subjects were classified at the end of follow-up as ICs,chronic hepatitis B and gray zone.A pre-dictive model was constructed,and validated by 1000-boot-strap samples.Results:After 39 months of follow-up,298 subjects were ICs,36 were chronic hepatitis B CHB,and nine were gray zone.Eighty-nine(25.9%)individuals re-quired a liver biopsy.Baseline HBV DNA hazard ratio(HR)6.0,p<0.001),HBV core-related antigen(HBcrAg)(HR 6.5,p<0.001),and elastography(HR 4.6,p<0.001)were inde-pendently associated with the IC stage.The ACE score(HBV DNA,HBcrAg,elastography),obtained by bootstrapping,yielded an area under the receiver operating characteris-tics(AUROC)of 0.925(95%CI:0.880-0.970,p<0.001)for identification of ICs.The AUROC for genotype D was 0.95,0.96 for A,0.90 for E,and 0.88 for H/F.An ACE score of<1 had a positive predictive value of 99.5%,and a score≤12 points had a diagnostic accuracy of 93.8%.Conclusions:Low baseline HBV DNA,HBcrAg,and liver stiffness were in-dependently associated with the IC phase.A score including those variables identified ICs at a single-point evaluation,and might be applied to implement less intensive follow-up strategies.