Assessment of the spatial extent of permafrost in the Upper Indus Basin(UIB)

Climate change differentially influences the frozen ground,a major dynamic component of the cryosphere,on a local and regional scale.Under the warming climate with pronounced effects reported at higher altitudes,the characterization of the frozen ground is very important in the Upper Indus Basin(UIB),an important and critical region with respect to climate and hydro-glaciological dynamics.In this study,the efficiency and reliability of the surface frost number model are assessed in delineating the spatial extent of different classes of frozen ground in the region.The daily MODIS land surface temperature(LST)with ground surface temperature(GST)and surface geomorphological expressions as ground validation datasets are used jointly in efficiently determining the extent of different classes of frozen ground(continuous and discontinuous permafrost and seasonal frost).The LST and GST resonate with each other in the annual cycle of temperature variation,however,with mean annual LST exhibiting an offset(cold bias)of 5 to 7℃relative to mean GST.This study shows that the highest permafrost extent is observed in areas where the lowest thinning rates of glacier ice are reported and vice versa.The surface frost number model categorizes an area of 38%±3%and 15%±3%in the UIB as permafrost and seasonal frost,respectively.Based on the altitude model,the lower limit of alpine permafrost is approximated at a mean altitude of 4919±590 m a.s.l.in the UIB.The present study acts as preliminary work in the data sparse and inaccessible regions of the UIB in characterizing the frozen and unfrozen ground and may act as a promising input data source in glaciohydro-meteorological models for the Himalaya and Karakoram.In addition,the study also underlines the consideration of this derelict cryospheric climatic variable in defining and accounting for the sustainable development of socio-economic systems through its intricate ramification on agricultural activity,landscape stability and infrastructure.

Half-a-century(1971–2020)of glacier shrinkage and climatic variability in the Bhaga basin,western Himalaya

Glacier shrinkage is a globally occurring phenomena.High-resolution change detection based on frequent mapping and monitoring of high-altitude glaciers is necessary to precisely evaluate future water availability and to understand glacier evolution under different climatic scenarios in the Hindukush-Karakoram-Himalayan(HKH)region.This also holds true for the Bhaga basin of the western Himalaya.This study investigates glacier and glacier lake changes in the Bhaga basin,over the last five decades based on satellite imagery including Corona KH4(1971),Landsat 7 Enhanced Thematic Mapper Plus(ETM+;2000),Linear Imaging Self-Scanning Sensor(LISS Ⅳ;2013),and Sentinel 2(2020).Regional temperature and precipitation trends were evaluated from gridded climatic datasets(1900–2020).In the Bhaga basin 306 glaciers(>0.2 km^(2))were mapped with a total area of 360.3±4.0 km^(2),of which 55.7±0.6 km^(2)was covered with debris in 2013.The total glacier covered area decreased by∼8.2±1.5%(0.16±0.03%yr-1)during the entire observation period 1971–2020,with noticeable heterogeneity between tributary watersheds.In the past two decades(2000–2020),the deglaciation rate has increased significantly(0.25%yr-1)compared to the previous decades(1971–2000;0.12%yr-1).Glacier lake area increased by 0.6±0.1 km^(2)(0.012 km^(2)yr-1)between 1971 and 2020.The NCEP/NCAR climatic data reveals an increase of 0.63℃in temperature and a decrease of 6.39 mm in precipitation for the period 1948–2018.In comparison,APHRODITE data shows an increasing trend in temperature of 1.14℃between 1961 and 2015 and decreasing trend in precipitation of 31 mm between 1951 and 2007.Both NCEP/NCAR and APHRODITE data reveal significant temperature increase and precipitation decrease since the 1990s,which have probably augmented ice loss in the Bhaga basin during the early 21st century.

Aptasensors in Health, Environment and Food Safety Monitoring

Biosensors have been developed using various types of sensing elements like biomacromolecules (viz. enzymes, antibodies, receptors, nucleic acids, etc.) organelles, tissues, intact cells of both microorganisms and higher organisms. A recent trend is the emergence of aptamers as sensing elements that has the potential to replace all the above ligands. This is possible due to the unique features of aptamers (sensitivity, specificity, reusability, stability, non-immunogenic- ity), which can be easily exploited in biosensor technology. Aptasensors are thus basically biosensors based on aptamers as ligand molecules. Here we review the various applications of aptasensors in health (specifically in diagnostics), food industry and environmental monitoring.

The Synthesis of Gold Nanoparticles Using <i>Amaranthus spinosus</i>Leaf Extract and Study of Their Optical Properties

We report here the application of a medicinally important plant Amaranthus spinosus for the synthesis of gold nanoparticles (AuNPs). Different concentrations of ethanolic leaf extract of the plant were reacted with aqueous solution of HAuCl4·4H2O under mild reaction conditions. Synthesis of AuNPs was confirmed from the UV-Vis study of surface plasmon resonance property of the colloidal solution. Transmission electron microscopy (TEM) revealed particles as spherical and triangular in shape. X-ray diffraction (XRD) confirmed the crystalline nature of AuNPs with average size of 10.74 nm as determined by Debye-Scherrer’s Equation. Fourier transform infra-red (FT-IR) analysis of leaf extract and lyophilized AuNPs showed the presence of various functional groups present in diverse phytochemicals. Energy dispersive X-ray (EDX) of purified AuNPs confirmed the formation of AuNPs and surface adsorption of biomolecules. We further investigated the toxicity of the synthesized AuNPs and found non toxic to the cancer cell lines and could be used for biomedical applications.

中国北方晚第四纪气候变化的沙漠与黄土记录——以光释光年代为基础的直接对比

中国北方有约200×10^4km^2的面积被黄土、沙漠和荒漠戈壁沉积物覆盖，这些地区堆积物的形成变化与第四纪气候变化密切相关。关于中国北方沙漠与黄土记录晚第四纪古气候变化的研究不少，但是，由于受到方法和条件等限制，系统的（高密度的）和独立的年代学工作比较薄弱，从而使诸多已经发表的关于沙漠-黄土记录的亚轨道时间尺度气候变化的结论受到质疑。文章通过对黄土高原代表性的4个末次冰期以来的黄土剖面以及毛乌素、浑善达克和科尔沁沙地的20多个末次冰期-全新世的沙-砂质古土壤剖面的研究，获得了150多个独立的光释光年龄数据。在此基础上，结合200多个样品的粒度、有机质含量和磁化率数据，重建末次冰期以来中国北方气候变化过程，对比分析沙地与黄土古气候记录的联系。结果表明，中国北方古气候在57．5—52．5kaB．P．相对干旱，41．5—37．3kaB．P．相对湿润，26—22kaB．P．逐渐干旱，22—18kaB．P．极端干旱，15—10kaB．P．干旱，10—8kaB．P．为干旱减弱的时期，8．0—2．4kaB．P．相对湿润，而2．4kaB．P．以来气候为相对干旱。其间，在8．0—2．4kaB．P．的湿润时期有几次干旱事件，而2．4kaB．P．以来气候变化频繁。具有独立年代控制的黄土和沙漠记录表明，中国北方的气候变化对轨道时间尺度的太阳辐射变化有大约3—4ka的滞后。

Coating of bioactive glass on magnesium alloys to improve its degradation behavior: Interfacial aspects

The preferable mechanical properties of Mg alloys along with excellent compatibility with human bone have established their applicability as implant biomaterials.However,a higher corrosion/degradation rate of Mg alloys in body fluids limits its biomedical applications.In this direction,surface modification and coating are explored as appropriate strategies to mode the degradation rate of Mg alloys.The constituents of bioactive glass(BG)provide strength,bio-inertness and bone bonding capability.Hence,researchers have explored the coating of BG on Mg alloys and investigated chemical,mechanical and biological properties of the coated alloys.In this review,we have made an attempt to compile the literature works done on the coating of BG on Mg alloys and its features.Underlying interfacial aspects of the coated substrates towards the degradation behavior are highlighted.The way forward to further improve the coating characteristics of BG coated Mg alloys are remarked.

Hepatitis E virus in patients with acute severe liver injury

AIM: To examine the incidence of hepatitis E(HepE) in individuals with acute liver injury severe enough to warrant treatment at a transplant unit.METHODS: Hepatitis E virus(HEV) is an emerging pathogen in developed countries causing severe illness, particularly in immunocompromised patients or those with underlying chronic liver disease. HepE infection isoften under diagnosed, as clinicians can be reluctant to test patients who have not travelled to regions traditionally considered hyperendemic for HepE. There are few data regarding the significance of HEV in patients with very severe acute liver injury in developed countries. Eighty patients with acute severe liver injury attending the Scottish Liver Transplant unit were tested for HEV and anti-HEV IgG and IgM. Severe acute liver injury was defined as a sudden deterioration in liver function confirmed by abnormal liver function tests and coagulopathy or presence of hepatic encephalopathy. Eighty percent of these patients were diagnosed with paracetomol overdose. No patients had a history of chronic or decompensated chronic liver disease at time of sampling. IgG positive samples were quantified against the World Health Organization anti-HEV IgG standard. Samples were screened for HEV viral RNA by quantitative reverse transcription polymerase chain reaction.RESULTS: Four cases of hepatitis E were identified. Three of the four cases were only diagnosed on retrospective testing and were initially erroneously ascribed to drug-induced liver injury and decompensated chronic liver disease, with the cause of the decompensation uncertain. One case was caused by HEV genotype 1 in a traveller returning from Asia, the other three were autochthonous and diagnosed on retrospective testing. In two of these cases(where RNA was detected) HEV was found to be genotype 3, the most prevalent genotype in developed countries. Three patients survived, two of whom had been misdiagnosed as having drug induced liver injury. The fourth patient died from sepsis and liver failure precipitated as a result of hepatitis E infection and previously undiagnosed cirrhosis. Histopathology data to date is limited to mainly that seen for endemic HepE. All patients, with the exception of patient 1, demonstrated characteristics of HepE infection, as seen in previously described locally acquired cases.CONCLUSION: In patients with acute severe liver injury, HEV testing should be part of the initial diagnostic investigation algorithm irrespective of suspected initial diagnosis, age or travel history.

Biosurfactant-assisted phytoremediation of potentially toxic elements in soil:Green technology for meeting the United Nations Sustainable Development Goals

Biosurfactants are biomolecules produced by microorganisms, low in toxicity, biodegradable, and relatively easy to synthesize using renewable waste substrates. Biosurfactants are of great importance with a wide and versatile range of applications, including the bioremediation of contaminated sites. Plants may accumulate soil potentially toxic elements(PTEs), and the accumulation efficacy may be further enhanced by the biosurfactants produced by rhizospheric microorganisms. Occasionally, the growth of bacteria slows down in adverse conditions, such as highly contaminated soils with PTEs. In this context,the plant's phytoextraction capacity could be improved by the addition of metal-tolerant bacteria that produce biosurfactants. Several sources, categories,and bioavailability of PTEs in soil are reported in this article, with the focus on the cost-effective and sustainable soil remediation technologies, where biosurfactants are used as a remediation method. How rhizobacterial biosurfactants can improve PTE recovery capabilities of plants is discussed, and the molecular mechanisms in bacterial genomes that support the production of important biosurfactants are listed. The status and cost of commercial biosurfactant production in the international market are also presented.

Building the new international science of the agriculture-food-water-environment Nexus in China and the world

The multiple,complex and systemic problems of the agriculture-food-water-environment nexus(“Nexus”)are among the most significant challenges of the 21st century.China is a key site for Nexus research amidst profound socio-environmental problems.The policy implications of these problems have been authoritatively summarized elsewhere.This study presents discussions at an international workshop in Guangzhou that asked instead“What science is needed to deliver the growing policy commitments regarding these challenges?And,What changes are needed to the science itself?”Understanding and effective intervention regarding the Nexus calls for a paradigm shift:to a new kind of science of(capacity for)international,interdisciplinary,and impactful research working with and within complex socio-natural systems.We here argue that science must become proactive in approach,striving only for“minimal harm”not“silver bullet”solutions,and adopting an explicitly long-term strategic perspective.Together,these arguments lead to calls for reorienting science and science policy in three ways:from short-term remediation to longer-term optimization;from a focus on environmental threats to one on the opportunities for international collaborative learning;and toward supporting new forms of scientific career.We bring these points together by recommending a new form of scientific institution:a global network of collaborative Nexus Centres,under the umbrella of a global Food Nexus Organization akin to those of the human genome and proteome.

Green synthesis of biocompatible gold nanoparticles using Fagopyrum esculentum leaf extract

This report describes the use of ethnolic extract of Fagopyrum esculentum leaves for the synthesis of gold nanoparticles. UV-visible spectroscopy analysis indicated the successful formation of gold nanoparticles. The synthesized nanoparticles were characterized by transmission electron microscopy （TEM）, high resolution TEM （HRTEM） and were found to be spherical, hexagonal and triangular in shape with an average size of 8.3 nm. The crystalline nature of the gold nanoparticles was confirmed from X.ray diffraction （XRD） and selected-area electron diffraction （SAED） patterns. Fourier transform infrared （FT-IR） and energy.dispersive X-ray analysis （EDX） suggested the presence of organic biomolecules on the surface of the gold nanoparticles. Cytotoxicity tests against human HeLa, MCF-7 and IMR-32 cancer cell lines revealed that the gold nanoparticles were non-toxic and thus have potential for use in various biomedical applications.

高密度光释光测年揭示的距今约15～10ka黄土高原侵蚀事件

中国黄土堆积作为晚新生代陆相最好的古气候记录之一,得到了众多研究,其揭示的冰期-间冰期时间尺度的气候变化具有全球意义.但是,中国黄土研究中还有一些基本科学问题或假设没有得到证实,从而使一些研究结论受到质疑.为了进一步认识黄土堆积的连续性、绝对年龄和时间分辨率等问题,对黄土高原西北-东南方向上代表性的晚更新世-全新世黄土剖面进行了间距10cm的连续光释光年龄测定和古气候替代性指标测试,获得了108个绝对年龄数据.结果发现,在黄土高原塬区代表性的晚第四纪黄土剖面中存在约4～5ka的间断.这一直接的年代学证据表明,在千年时间尺度上黄土沉积是不连续的.新的年代证据指出,以前基于粉尘沉降模式获得的时间标尺是不准确的,从而使已发表的关于亚轨道时间尺度黄土古气候记录的研究工作需要重新审视.初步分析认为,黄土堆积的加剧侵蚀可能受气候变化控制.

An erosional hiatus in Chinese loess sequences revealed by closely spaced optical dating

Chinese loess deposits are some of the best continental records of palaeoclimatic and pa- laeoenvironmental changes in the late Cenozoic. Many investigations have shown that the long-time climate variations recorded by the loess-paleosol sequences can be correlated with global environ- mental changes. However,there are still some foundational questions concerning loess deposition that are not well answered,casting uncertainty on many previous conclusions,especially high-resolu- tion palaeoclimatic records. In this study,three typical loess-paleosol sections spanning the last glacial cy- cle were closely sampled for optically stimulated lu- minescence (OSL) dating and palaeoclimate inter- pretation along a northwest-southeast transect in Chinese Loess Plateau. Results show that there is a 4-5 ka hiatus in the typical loess deposits,and as a consequence suggests that the loess record is not continuous over millennial time scales. As such,pre- vious conclusions on climatic and environmental changes at millennial-centennial time scale,recon- structed through the loess record,should be reinves- tigated. The erosional hiatus may be forced by a pe- riod with strengthened East Asian winter monsoon and the less vegetation cover in the investigated sites.

Water and nutrient and energy systems in urbanizing watersheds

Driven by considerations of sustainability, it has become increasingly difficult over the past 15-20 years -- at least intellectually -- to separate out the water infrastructure and water metabolism of cities from their intimately inter-related nutrient and energy metabolisms. Much of the focus of this difficulty settles on the wastewater component of the city＇s water infrastructure and its associated fluxes of nutrients （N, P, C, and so on）. Indeed, notwithstanding the massive volumes of these materials flowing into and out of the city, the notion of an urban nutrient infrastructure is conspicuous by its absence. Likewise, we do not tend to discuss, or conduct research into, ＂soilshed＂ agencies, or soilshed management, or Integrated Nutrient Resources Management （as opposed to its most familiar companion, Integrated Water Resources Management, or IWRM）. The paper summarizes some of the benefits （and challenges） deriving from adopting this broader, multi-sectoral ＂systems＂ perspective on addres- sing water-nutrient-energy systems in city-watershed settings. Such a perspective resonates with the growing interest in broader policy circles in what is called the ＂water-food-energy security nexus＂. The benefits and challenges of our Multi-sectoral Systems Analysis （MSA） are illustrated through computational results from two primary case studies： Atlanta, Georgia, USA; and London, UK. Since our work is part of the International Network on Cities as Forces for Good in the Environment （CFG; see www.cfgnet.org）, in which other case studies are currently being initiated -- for example, on Kath- mandu, Nepal we close by reflecting upon these issues of water-nutrient-energy systems in three urban settings with quite different styles and speeds of development.

Metallic wastewater treatment by sulfate reduction using anaerobic rotating biological contactor reactor under high metal loading conditions

This study was aimed at investigating the performance of anaerobic rotating biological cont- reactor treating synthetic wastewater containing a mixture of heavy metals under sulfate redu condition. Statistically valid factorial design of experiments was carried out to understand dynamics of metal removal using this bioreactor system. Copper removal was maximum （〉98% followed by other heavy metals at their respective low inlet concentrations. Metal loading rates than 3.7 mg/L· h in case of Cu（II）; less than 1.69 mg/L· h for Ni（II）, Pb（II）, Zn（II）, Fe（III） and C are favorable to the performance of the An-RBC reactor. Removal efficiency of the heavy metals 1 mixture depended on the metal species and their inlet loading concentrations. Analysis of n precipitates formed in the sulfidogenic bioreactor by field emission scanning electron microscopyalong with energy dispersive X-ray spectroscopy （FESEM-EDX） confirmed metal sulfide precipitationby SRB. All these results clearly revealed that the attached growth biofilm bioreactor is well suited for heavy metal removal from complex mixture.