bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of Amorphous/Crystalline State in Cu-Hf-Al Alloys
Authors: Nagy E. , Rontó Viktória , Sólyom Jenő , Roósz András
Published: May 2010

Cu-Hf-Al alloys are considered to be relatively new ones among Cu-based bulk amorphous alloys. Cu-Hf-Al alloys have high strength in amorphous state and this property makes many applications feasible for the industry. During the production of amorphous alloys the most important purpose is to produce them in the biggest diameter to make them suitable for a wide range of applications. The circumstances of the production process have a great influence on the developing structure.
In the present work solidification of Cu-Hf-Al alloys were investigated. The alloys were cast into different shapes with different Al contents with special regard to the appearance of the amorphous/crystalline structure. The appearance and the structure of crystalline phases were determined by X-ray diffraction and X-ray, DSC and metallographic measurements were used to investigate the developing structure.
Exergy-Based Model of the Depletion of Mineral Resources
Authors: Sun Bo Xue , Nie Zuo Ren , Liu Yu , Wang Zhi Hong , Gong Xian Zheng
Published: May 2010

The primary problem of eco-materials is how to judge whether a material is environmentally friendly or not, and the method of life cycle assessment is usually used to evaluate it. The depletion of mineral resources is a very important indicator of LCA, but its characterization is still filled with dispute. At present, the most commonly used method is CML, which is put forward by Leiden University, and its core idea is that using the ratio of exploitation amount and reserves of mineral resources as the degree of scarcity. Although being accepted by most of the scholars at work on LCA, CML doesn’t grasp the essence of the depletion of mineral resources. Recently, a new assessment method, injecting new ideas to the conventional life cycle assessment, combines exergy with LCA is arising, which can be used to solve some specific problems of LCA especially the depletion of mineral resources. In this paper, two results of elements’ exergy calculated by Rivero and Szargut respectively are compared, and the exergy of some natural minerals, which can be used in LCA and other minerals-related research, is calculated based on the data of Chinese mineral resources.
Effect of La2O3 Content on Mechanical Properties and Toughened Mechanics of SiC Nanowires Toughened Cw/SiC Composites
Authors: Zhang Yun Long , Zhang Yu Min , Han Jie Cai
Published: May 2010

In this paper, micrometers long and 20–100nm diameter SiC nanowires had been synthesized in the Cw/SiC composites by annealing treatment. The present work demonstrated that it is possible to fabricate in-situ SiC nanowires toughening Cw/SiC composites. La2O3 had a significant effect on the morphology and distribution of the SiC nanowires in the Cw/SiC composites. The excess lanthanum resulted in the growth of SiC nanowires with an increasing growth rate in the longitudinal direction and a decreasing growth rate in radial direction. The addition of La2O3 would improve the mechanical properties in the room-temperature. The vapor–liquid-solid growth mechanism of the SiC nanowires along <111> direction was proposed. The combination of grain bridging, crack deflection, whisker debonding and SiC nanowires can improve fracture toughness.
Vacancy Phonon Scattering and Thermoelectric Properties in In2Te3–SnTe Compounds
Authors: Fu Hong , Ying Peng Zhan , Cui J.L. , Yan Y.M. , Zhang X.J.
Published: May 2010

Solid solution formation is a common and effective way to reduce the lattice thermal conductivity for thermoelectric materials because of additional phonon scattering by point defects and grain boundaries. In the present work we prepared In2Te3–SnTe compounds using a mild solidification technique and evaluated their thermoelectric properties in the temperature range from 318705 K. Measurements reveal that the transport properties are strongly dependent on the chemical composition  In2Te3 content, and lattice thermal conductivity significantly reduces above a minimum In2Te3 concentration, which can possibly be explained by an introduction of the vacancy on the indium sublattice and periodical vacancy planes. The highest thermoelectric figure of merit ZT of 0.19 can be achieved at 705 K, and a big improvement of In2Te3 based alloys would be expected if a proper optimization to the chemical compositions and structures were made.
Effects of Power on Properties of ZnO:Al Films Deposited on Flexible Substrates by RF Magnetron Sputtering
Authors: Wang Xiao Jing , Lei Qing Song , Yuan Jun Ming , Zhou Wei Li , Yu Jun
Published: May 2010

Aluminium doped ZnO thin films(ZnO:Al) films were deposited on transparent TPT substrate at room temperature by RF magnetron sputtering. The effects of sputtering power on structural, optical and electrical properties were investigated by X-ray diffractometery (XRD), scanning electron microscope (SEM), UV-visible spectrophotometer, as well as Hall Effect Measurement System. Results revealed that the obtained film had a hexagonal structure and a highly (0 0 2) preferred orientation with the c-axis perpendicular to the substrate. The grain size and preferred orientation of crystallites showed dependence on the sputtering power. The optical transmittance of the ZAO films depended strongly on the sputtering power and decreased with increasing power.The transmittance of the ZAO film at 80W was over 80% in the visible region. And the electrical properties of the ZAO films are improved with the increase of the sputtering power.The resistivity of obtained film at 200W was 3.15×10-2Ω•cm.
Preparation and Design of Function Aggregate in Concrete
Authors: Hu S. , Yang T. , Wang F. , Wang J.
Published: May 2010

In order to essentially improve interfacial transition zone between cement paste and aggregate, the concept and ideal model of function aggregate are developed. Function aggregate is composed of a porous matrix with high strength and low water absorption, and a coating layer which can hydrate in cement paste. It can improve ITZ between aggregate and cement paste and control curing range of cement paste. Based on optimization of raw materials and processing techniques, high strength aggregate with low absorption and minor C2S and C4AF phase in coating layer is acquired. Results indicate that cordierite is formed in aggregate when MgO content reaches 2%, and it shows that the presence of cordierite minimizes the potential for micro-crack formation, thus decreases water absorption.
Effects of Phosphorus on Laves Phase Dissolution and Elemental Diffusion in GH706 Alloy
Authors: Xin Xin , Sun Wen Ru , Guo Shou Ren , Liu Fang , Qi Feng , Zhang Shi Hong , Yang Hong Cai , Hu Zhuang Qi
Published: May 2010

The effects of P on element segregation, Laves phase dissolution and elemental diffusion in GH706 alloy have been investigated. The results show that P promotes the segregation of Nb and Ti. Phosphorus was enriched in Laves phase, which enhanced the precipitation of blocky Laves phase, while constrained the formation of eutectic Laves phase. Moreover, more needle-like phase was formed around blocky Laves phase in high P-doped alloy. It also demonstrated that P slightly lowered the melting-point of Laves phase. During the homogenization process, P hindered the diffusion of Nb which blocks the diffusion of Nb and dissolution of Laves phase, and complicated the homogenization treatment.
Effect of W on Deformation Resistance of Co-Bearing 12Cr Ferrite Heat-Resistant Steel for USC Steam Turbines
Authors: Cui Hui Ran , Sun Feng , Zhang Lan Ting , Shan Ai Dang , Wu Jian Sheng
Published: May 2010

12Cr heat resistant steels with different concentration of Co and W, while Mo equivalent (Mo+1/2W) was fixed at 1.6, were prepared by arc-melting and hot rolling. Mechanical properties were evaluated by tensile tests conducted with the strain rate 2×10-5S-1 at 575oC, 600oC and 625oC instead of time-consuming creep tests. The results show that when Co content is fixed, the steel with 1.5 wt% W is found having the best deformation resistance which is strong work hardening and slow strain softening. Apparent activation energy of the steel with 3.1 wt% Co and 1.5 wt% W is in the range of 370~413 kJ/mol, higher than those of the other steels in our study, which are close to the self-diffusion activation energy of iron (239 kJ/mol). Therefore, the steel with 3.1 % Co and 1.5% W is suggested as a potential candidate material for 625oC~650oC class USC steam turbines.
Effects of Long-Term Aging at 1070°C on Microstructure and Mechanical Properties of Ni3Al-Base Alloy IC6E
Authors: Li Ming , Song Jin Xia , Li Shu Suo , Han Ya Fang
Published: May 2010

The effect of long-term aging at 1070°C on microstructure and mechanical properties of Ni3Al-base equiaxed superalloy IC6E was investigated. The microstructure change during aging for periods of 100 to 1500h was examined by SEM . Results showed that alloy IC6E underwent following microstructure changes during aging: γ' phases coalesced and grew, γ phases became disconnected and coarsened, the content of Mo (the solution-hardening element of γ and γ' phases) in γ' phases decreased, Y-NiMo phases precipitated from γ phases both at grain boundaries and within grains, and γ' bands and large γ phases emerged along grain boundaries. The tensile and stress rupture properties after aging were determined. The results showed that the yield strength of alloy IC6E at room temperature decreased obviously after aging for 100 h, and reduced slowly during further aging. The stress rupture life under 1070°C, 80MPa also had no essential change during aging.
Oxidation Behaviour of MCrAlY and MCrAlY +ZrO2 Coatings on Ni-Based IC6 Superalloy
Authors: He Di , Li Shu Suo , Han Ya Fang
Published: May 2010

MCrAlY coatings were deposited on Ni-based IC6 superalloy by HVOF(high velocity oxy-fuel), and the ZrO2 coatings were prepared using plasma spray technique. The oxidation kinetic curves of the IC6 superalloy were obtained after the heat treatment. The results indicated that the oxidation resistance of IC6 superalloy was markedly improved by coatings with MCrAlY and MCrAlY+ZrO2. The oxidation product of the MCrAlY coating mainly consisted of α-Al2O3,NiO at 1100°C, oxidation product was not found on the MCrAlY+ZrO2 coating at 1100°C.
Study to Microstructure and Mechanical Properties of Mg Containing High Entropy Alloys
Authors: Li Rui , Gao Jia Cheng , Fan Ke
Published: May 2010

In this paper, alloys with compositions of Mgx(MnAlZnCu)100-x (x: atomic percentage; x=20, 33, 43, 45.6 and 50 respectively) were designed by using the strategy of equiatomic ratio and high entropy of mixing. Microstructure and mechanical properties of the new high entropy alloy were studied. The alloys were prepared by induction melting and then were cast in a copper mold in air. The alloy samples were examined by microhardness tester, XRD, SEM, thermal analyzer and testing machine for material strength. Alloys were composed mainly of h.c.p phase and Al-Mn icosahedral quasicrystal phases. The alloys exhibited moderate densities which were from 4.29g•cm-3 to 2.20g•cm-3, high hardness (429HV-178HV) and high compression strength (500MPa-400MPa) at room temperature. The extensibility was increased with Mg from 20at% (atomic percentage) to 50at%.
Preperties of Linear Polyaspartic Polyurea Coated Concrete under NaCl Solution Immersion and Co-Action of Load and NaCl Solution Immersion
Authors: Lu Ping , Huang Wei Bo , Shi Hui , Zhu Li
Published: May 2010

In this paper both the NaCl immersion and the co-action of load and NaCl solution immersion were employed to analyze the wet adhesive property and resistance of chlorion diffusivity of two types of linear polyaspartic ester (PAE) polyureas coated concrete: B2（PAE-b-H12MDI prepolymerH66）coated concrete and F2（PAE-f-H12MDI prepolymerH62） coated concrete. The research on the adhesion of B2 and F2 coated concrete showed that the adhesion were about 2N/mm and 1.5N/mm respectively before exposure, and the adhesion reduced about 6.8% and 11.8% respectively after 10% NaCl immersion for 300 days and made 8% and 5% further decrease under the co-action of load and NaCl solution immersion, double-factor exposure for 300 days. Compared with single NaCl solution immersion, the co-action of load and NaCl solution immersion also had more influence on the chlorion diffusivity of the coated concrete. The average chlorion content of B2 and F2 coated concrete increased about 19-21%, and the diffusion coefficient of chlorion of B2 and F2 coated concrete was 10－13-10－14m2/s, due to the micro-crack of concrete in tensile area increased under bending load, accelerating chlorion diffusion and permeation. The research showed that chlorion diffusion behaviour of B2 and F2 coated concrete under the NaCl immersion and the co-action of load and NaCl solution immersion satisfied second Fick’s law.
Formation and Mechanical Properties of Mg-Cu-Al-Gd Bulk Metallic Glass Composites
Authors: Wang Yi Ming , Zheng Li Jing , Pang Shu Jie
Published: May 2010

The effect of Al addition to Mg65Cu25Gd10 glassy alloy on the microstructure, thermal properties and mechanical properties were investigated. The Mg65Cu25-xAlxGd10 (x=1-7at. %) bulk metallic glass composites were formed by copper mold casting, and the fraction and size of the crystalline phases in the glassy matrix changed with the Al content. The Mg65Cu24Al1Gd10 glass composite consisted of a small amount of crystalline phases in the glassy matrix possesses high compressive strength up to about 850 MPa.
Preparation and Microstructure Analysis of Ti-Al Sheet by Electron Beam Physical Vapor Deposition
Authors: Zhao Yi Jie , Ma Li , He Xiao Dong
Published: May 2010

By using electron beam physical vapor deposition (EB-PVD) technology, Ti-Al thin sheet with dimension of 450mm×450mm×0.2mm was prepared and the microstructure of Ti-Al deposit was investigated by means of scanning electron microscopy (SEM), atom force microscopy (AFM) and X-ray diffraction (XRD), and then the effect on deposit by re-evaporation of Al was explored by calculating the ratio of re-evaporating capacity with depositing capacity of Al on the substrate. The results indicate that there existed equiaxed crystal and columnar crystal along the cross-sectional may resulted from the transformation latent heats released during the transition course of atoms from gaseous state to solid state, and the variation of target-substrate distance would take effect on the phase composition due to the changing of atoms collision probability and radiant heat quantity absorbed by substrate. The effect on deposit by re-evaporation of Al could be neglected because the re-evaporating capacity of Al was far below that of the depositing capacity.
Microstructure and Properties of Pure Mg/ZK60 Laminate Processed by Accumulative Roll Bonding
Authors: Xu C. , Zheng Ming Yi , Chang Hai , Hu Xiao Shi , Wu Kun , Gan Wei Min , Brokmeier Heinz Günter
Published: May 2010

Commercial pure magnesium with excellent damping capacity and ZK60 magnesium alloy with high strength were accumulative roll bonded (ARBed) at 300oC up to 3 cycles to fabricate Mg laminate consisting of alternating layers of pure Mg and ZK60. Microstructure, tensile properties and damping capacity of the sheets were analyzed. The research suggests that Mg sheet having both high strength and excellent damping capacity can be developed by accumulative roll bonding of pure Mg and ZK60 Mg alloy.
The Formation and Morphology of PVA Ferrogel Nanofibre by the Electrospinning Process
Authors: Wan Tao Yu , Chowdhury Mohammad , Stylios George K.
Published: May 2010

Aqueous solutions of polyvinyl alcohol (PVA) with FeCl3 were homogenously mixed and subsequently electrospun; and its characteristics were studied as a function of voltage, tip-target distance and solution flow rate. Fiber mats of (PVA)/FeCl3 composite, in the diameter of 700–1100 nm were prepared by electrospinning. Lower concentrations of solution tended to facilitate the formation of fibres with beads. With increasing concentration, the morphology was improved with smooth and uniform fibres and the increased fibre diameters in the nano range. Spinning voltage also had an important influence on the diameters of the nano fibres, while the collection distance affected fibre diameters. Nano fibres of smaller diameter were formed when lower voltages are applied. The morphology of the electrospun from PVA/FeCl3 nano fibres and their magnetic power was observed and analyzed by scanning electron microscopy (SEM).The fibres produced in this way could potentially be applied to manufacture magnetic sensors, flexible magnets.
CD93/AA4.1: A Novel Regulator of Inflammation in Murine Focal Cerebral Ischemia
Authors: Harhausen Denise , Prinz Vincent , Ziegler Gina , Gertz Karen , Endres Matthias , Lehrach Hans , Gasque Philippe , Botto Marina , Stahel Philip F. , Dirnagl Ulrich , Nietfeld Wilfried , Trendelenburg George
Published: May 2010

The stem-cell marker CD93 (AA4.1/C1qRp) has been described as a potential complement C1q-receptor. Its exact molecular function, however, remains unknown. By using global expression profiling we showed that CD93-mRNA is highly induced after transient focal cerebral ischemia. CD93 protein is upregulated in endothelial cells, but also in selected macrophages and microglia. To elucidate the potential functional role of CD93 in postischemic brain damage, we used mice with a targeted deletion of the CD93 gene. After 30 min of occlusion of the middle cerebral artery and 3 d of reperfusion these mice displayed increased leukocyte infiltration into the brain, increased edema, and significantly larger infarct volumes (60.8 ± 52.2 versus 23.9 ± 16.6 mm3) when compared with wild-type (WT) mice. When the MCA was occluded for 60 min, after 2 d of reperfusion the CD93 knockout mice still showed more leukocytes in the brain, but the infarct volumes were not different from those seen in WT animals. To further explore CD93-dependent signaling pathways, we determined global transcription profiles and compared CD93-deficient and WT mice at various time points after induction of focal cerebral ischemia. We found a highly significant upregulation of the chemokine CCL21/Exodus-2 in untreated and treated CD93-deficient mice at all time points. Induction of CCL21 mRNA and protein was confirmed by PCR and immunohistochemistry. CCL21, which was formerly shown to be released by damaged neurons and to activate microglia, contributes to neurodegeneration. Thus, we speculate that CD93-neuroprotection is mediated via suppression of the neuroinflammatory response through downregulation of CCL21.
Association of Microsatellite Variations of Plasmodium falciparum Na+/H+ Exchanger (Pfnhe-1) Gene with Reduced In Vitro Susceptibility to Quinine: Lack of Confirmation in Clinical Isolates from Africa
Authors: Andriantsoanirina Valérie , Ménard Didier , Rabearimanana Stéphane , Hubert Véronique , Bouchier Christiane , Tichit Magali , Bras Jacques Le , Durand Rémy
Published: May 2010

We sought to test the association of polymorphisms in Plasmodium falciparum nhe-1 (Pfnhe-1, gene PF13_0019) with in vitro susceptibility to quinine, which was previously reported in a limited number of reference strains or culture-adapted isolates. Determination of in vitro susceptibility to quinine, genotyping of Pfnhe-1 ms4760 microsatellite and polymorphism in codon 76 of Pfcrt were performed for 83 isolates obtained from symptomatic malaria-infected travelers returning from various African countries to France or from subjects living in Madagascar. Nineteen different ms4760 microsatellite profiles of Pfnhe-1 were found including 14 not previously described. Multivariate analysis showed no significant association between the in vitro susceptibility to quinine with particular ms4760 profiles. Contrary to previous reports, we only observed that the number of NHNDNHNNDDD repeats was positively associated with the increased IC50 of QN (P = 0.01). We concluded that the studied polymorphisms in Pfnhe-1 did not appear as valid molecular markers of in vitro susceptibility to quinine in P. falciparum isolates from Africa. Because we did not include any isolate of Asian origin in our series, these results did not exclude the possibility of regional associations, for example in South-East Asia.
Heterogeneity of Leishmania infantum chagasi Kinetoplast DNA in Teresina (Brazil)
Authors: Alonso Diego Peres , Costa Dorcas Lamounier , de Mendonça Ivete Lopes , Costa Carlos Henrique Nery , Ribolla Paulo Eduardo Martins
Published: May 2010

Leishmania infantum chagasi is the causative agent of visceral leishmaniasis in Brazil. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of kinetoplast DNA (kDNA) minicircles was used to evaluate genetic profiles of 48 Leishmania infantum chagasi strains from dog and human parasite cultures, fresh collected dog bone marrow aspirates, and from infected sand flies. Results revealed that heterogeneity in kDNA minicircles depends mostly on the source of the samples, with cultured parasites showing a high degree of homogeneity.
Assessment of CD8+ T Cell Differentiation in Trypanosoma cruzi-Infected Children
Authors: Albareda María Cecilia , Olivera Gabriela Carina , De Rissio Ana María , Postan Miriam
Published: May 2010

We previously reported that the T cell compartment in chronically Trypanosoma cruzi-infected adult subjects display functional and phenotypic signs of immune senescence. This study aimed to investigate the differentiation and the senescent profile of the overall CD8+ T cell compartment in T. cruzi-infected children at the early stage of the disease. We found a lower percentage of naive (CD27+CD28+CD45RA+) and early antigen-experienced (CD45RA−CD27+CD28+), and higher percentages of late differentiated antigen-experienced (CD45RA−CD27−CD28−) CD8+ T cells in T. cruzi-infected children as compared with age-matched uninfected controls. The expression of the interleukin (IL)-7R is also decreased on naive and on antigen-experienced total CD8+ T cells with various degrees of differentiation. Conversely, the expression of HLA-DR, caspase-3, and CD57 did not vary on the total CD8+ T cell compartment. These findings suggest that the duration of the infection is relevant in the process of immune senescent that this parasite can induce.
Spatial Risk Assessments Based on Vector-Borne Disease Epidemiologic Data: Importance of Scale for West Nile Virus Disease in Colorado
Authors: Winters Anna M. , Eisen Rebecca J. , Delorey Mark J. , Fischer Marc , Nasci Roger S. , Zielinski-Gutierrez Emily , Moore Chester G. , Pape W. John , Eisen Lars
Published: May 2010

We used epidemiologic data for human West Nile virus (WNV) disease in Colorado from 2003 and 2007 to determine 1) the degree to which estimates of vector-borne disease occurrence is influenced by spatial scale of data aggregation (county versus census tract), and 2) the extent of concordance between spatial risk patterns based on case counts versus incidence. Statistical analyses showed that county, compared with census tract, accounted for approximately 50% of the overall variance in WNV disease incidence, and approximately 33% for the subset of cases classified as West Nile neuroinvasive disease. These findings indicate that sub-county scale presentation provides valuable risk information for stakeholders. There was high concordance between spatial patterns of WNV disease incidence and case counts for census tract (83%) but not for county (50%) or zip code (31%). We discuss how these findings impact on practices to develop spatial epidemiologic data for vector-borne diseases and present data to stakeholders.
Assessing Human Risk of Exposure to Plague Bacteria in Northwestern Uganda Based on Remotely Sensed Predictors
Authors: Eisen Rebecca J. , Griffith Kevin S. , Borchert Jeff N. , MacMillan Katherine , Apangu Titus , Owor Nicholas , Acayo Sara , Acidri Rogers , Zielinski-Gutierrez Emily , Winters Anna M. , Enscore Russell E. , Schriefer Martin E. , Beard Charles B. , Gage Kenneth L. , Mead Paul S.
Published: May 2010

Plague, a life-threatening flea-borne zoonosis caused by Yersinia pestis, has most commonly been reported from eastern Africa and Madagascar in recent decades. In these regions and elsewhere, prevention and control efforts are typically targeted at fine spatial scales, yet risk maps for the disease are often presented at coarse spatial resolutions that are of limited value in allocating scarce prevention and control resources. In our study, we sought to identify sub-village level remotely sensed correlates of elevated risk of human exposure to plague bacteria and to project the model across the plague-endemic West Nile region of Uganda and into neighboring regions of the Democratic Republic of Congo. Our model yielded an overall accuracy of 81%, with sensitivities and specificities of 89% and 71%, respectively. Risk was higher above 1,300 meters than below, and the remotely sensed covariates that were included in the model implied that localities that are wetter, with less vegetative growth and more bare soil during the dry month of January (when agricultural plots are typically fallow) pose an increased risk of plague case occurrence. Our results suggest that environmental and landscape features play a large part in classifying an area as ecologically conducive to plague activity. However, it is clear that future studies aimed at identifying behavioral and fine-scale ecological risk factors in the West Nile region are required to fully assess the risk of human exposure to Y. pestis.
Comparison of extraction methods for quantitative analysis of core and intact polar glycerol dialkyl glycerol tetraethers (GDGTs) in environmental samples
Authors: Huguet Carme , Martens‐Habbena Willm , Urakawa Hidetoshi , Stahl David A. , Ingalls Anitra E.
Published: May 2010

Archaeal membranes are composed of core lipids called glycerol dialkyl glycerol tetraethers (GDGTs) that contain polar head groups (intact GDGTs) in living cells. The reliability of Archaeal membrane lipids in studies of paleogeochemistry, population distributions, and physiological state depend on efficient extraction and detection of these lipids. We compare existing methods for extraction of core and intact GDGTs so that they can be used as quantitative indicators of living archaeal biomass. We used an active culture of the marine archaeon, Nitrosopumilus maritimus, to document limitations of methods in current use and as a reference for methodological improvement. We found that all extractable GDGTs in the culture were intact and that acid hydrolysis is the only way to quantitatively recover GDGTs from exponentially growing cells. Because acid hydrolysis removes polar head groups, it is not suitable for analysis of intact lipids. In contrast to the culture, high recovery was achieved for intact and core lipids from environmental samples, including water column particles, sediments, and soils. The high recovery from environmental samples and the large portion of core GDGTs relative to intact GDGTs suggest that lipids in the environment are largely derived from dead or dying cells. Because previous studies measured core GDGTs without acid hydrolysis, lipids contained in living cells were not detected and thus these results do not reflect viable biomass. We present a method to accurately quantify living and relict GDGTs by choosing the most efficient extraction protocol and measuring core GDGTs in extracts before and after acid hydrolysis.
Acoustic imaging of natural gas seepage in the North Sea: Sensing bubbles controlled by variable currents
Authors: von Deimling J. Schneider , Greinert J. , Chapman N. R. , Rabbel W. , Linke P.
Published: May 2010

Natural seepage from the seafloor is a worldwide phenomenon but quantitative measurements of gas release are rare, and the entire range of the dynamics of gas release in space, time, and strength remains unclear so far. To mitigate this, the hydroacoustic device GasQuant (180 kHz, multibeam) was developed to monitor the tempo‐spatial variability of gas bubble releases from the seafloor. GasQuant was deployed in 2005 on the seafloor of the seep field Tommeliten (North Sea) for 36 h. This in situ approach provides much better spatial and temporal resolution of seeps than using conventional ship‐born echo sounders. A total of 52 gas vents have been detected. Detailed time series analysis revealed a wide range of gas release patterns ranging from very short periodic up to 50 min long‐lasting events. The bulk gas seepage in the studied area is active for more than 70% of observation time. The venting clearly exhibits tidal control showing a peak in the second quarter of the tidal pressure cycle, where pressure drops fastest. The hydroacoustic results are compared with video observations and bubble flux estimates from remotely operated vehicle dives described in the literature. An advanced approach for identifying and visualizing rising bubbles in the sea by hydroacoustics is presented in which water current data were considered. Realizing that bubbles are moved by currents helps to improve the detection of gas bubbles in the data, better discriminate bubbles against fish echoes, and to enhance the S/N ratio in the per se noisy acoustic data.
Social Determinants of Health and Delivery of Rehabilitation to Older Adults During ICU Hospitalization
Authors: Jain Snigdha , Murphy Terrence E. , Falvey Jason R. , Leo-Summers Linda , O’Leary John R. , Zang Emma , Gill Thomas M. , Krumholz Harlan M. , Ferrante Lauren E.
Published: May 2024

Importance

Older adults with socioeconomic disadvantage develop a greater burden of disability after critical illness than those without socioeconomic disadvantage. The delivery of in-hospital rehabilitation that can mitigate functional decline may be influenced by social determinants of health (SDOH). Whether rehabilitation delivery differs by SDOH during critical illness hospitalization is not known.

Objective

To evaluate whether SDOH are associated with the delivery of skilled rehabilitation during critical illness hospitalization among older adults.

Design, Setting, and Participants

This cohort study used data from the National Health and Aging Trends Study linked with Medicare claims (2011-2018). Participants included older adults hospitalized with a stay in the intensive care unit (ICU). Data were analyzed from August 2022 to September 2023.

Exposures

Dual eligibility for Medicare and Medicaid, education, income, limited English proficiency (LEP), and rural residence.

Main Outcome and Measures

The primary outcome was delivery of physical therapy (PT) and/or occupational therapy (OT) during ICU hospitalization, characterized as any in-hospital PT or OT and rate of in-hospital PT or OT, calculated as total number of units divided by length of stay.

Results

In the sample of 1618 ICU hospitalizations (median [IQR] patient age, 81.0 [75.0-86.0] years; 842 [52.0%] female), 371 hospitalizations (22.9%) were among patients with dual Medicare and Medicaid eligibility, 523 hospitalizations (32.6%) were among patients with less than high school education, 320 hospitalizations (19.8%) were for patients with rural residence, and 56 hospitalizations (3.5%) were among patients with LEP. A total of 1076 hospitalized patients (68.5%) received any PT or OT, with a mean rate of 0.94 (95% CI, 0.86-1.02) units/d. After adjustment for age, sex, prehospitalization disability, mechanical ventilation, and organ dysfunction, factors associated with lower odds of receipt of PT or OT included dual Medicare and Medicaid eligibility (adjusted odds ratio, 0.70 [95% CI, 0.50-0.97]) and rural residence (adjusted odds ratio, 0.65 [95% CI, 0.48-0.87]). LEP was associated with a lower rate of PT or OT (adjusted rate ratio, 0.55 [95% CI, 0.32-0.94]).

Conclusions and Relevance

These findings highlight the need to consider SDOH in efforts to promote rehabilitation delivery during ICU hospitalization and to investigate factors underlying inequities in this practice.
Zooming into lipid droplet biology through the lens of electron microscopy
Authors: Dudka Wioleta , Salo Veijo T. , Mahamid Julia
Published: May 2024

Electron microscopy (EM), in its various flavors, has significantly contributed to our understanding of lipid droplets (LD) as central organelles in cellular metabolism. For example, EM has illuminated that LDs, in contrast to all other cellular organelles, are uniquely enclosed by a single phospholipid monolayer, revealed the architecture of LD contact sites with different organelles, and provided near‐atomic resolution maps of key enzymes that regulate neutral lipid biosynthesis and LD biogenesis. In this review, we first provide a brief history of pivotal findings in LD biology unveiled through the lens of an electron microscope. We describe the main EM techniques used in the context of LD research and discuss their current capabilities and limitations, thereby providing a foundation for utilizing suitable EM methodology to address LD‐related questions with sufficient level of structural preservation, detail, and resolution. Finally, we highlight examples where EM has recently been and is expected to be instrumental in expanding the frontiers of LD biology.
Beta‐amyloid interacts with and activates the long‐form phosphodiesterase PDE4D5 in neuronal cells to reduce cAMP availability
Authors: Sin Yuan Yan , Cameron Ryan T. , Schepers Melissa , MacLeod Ruth , Wright Tom A. , Paes Dean , van den Hove Daniel , Willems Emily , Vanmierlo Tim , Prickaerts Jos , Blair Connor M. , Baillie George S.
Published: May 2024

Inhibition of the cyclic‐AMP degrading enzyme phosphodiesterase type 4 (PDE4) in the brains of animal models is protective in Alzheimer's disease (AD). We show for the first time that enzymes from the subfamily PDE4D not only colocalize with beta‐amyloid (Aβ) plaques in a mouse model of AD but that Aβ directly associates with the catalytic machinery of the enzyme. Peptide mapping suggests that PDE4D is the preferential PDE4 subfamily for Aβ as it possesses a unique binding site. Intriguingly, exogenous addition of Aβ to cells overexpressing the PDE4D5 longform caused PDE4 activation and a decrease in cAMP. We suggest a novel mechanism where PDE4 longforms can be activated by Aβ, resulting in the attenuation of cAMP signalling to promote loss of cognitive function in AD.
Comparative genome analysis of three classical E. coli cloning strains designed for blue/white selection: JM83, JM109 and XL1‐Blue
Authors: Achatz Stefan , Skerra Arne
Published: May 2024

The development of the Escherichia coli K‐12 laboratory strains JM83, JM109 and XL1‐Blue was instrumental in early gene technology. We report the comprehensive genome sequence analysis of JM83 and XL1‐Blue using Illumina and Oxford Nanopore technologies and a comparison with both the wild‐type sequence (MG1655) and the genome of JM109 deposited at GenBank. Our investigation provides insight into the way how the genomic background that allows blue/white colony selection—by complementing a functionally inactive ω‐fragment of β‐galactosidase (LacZ) with its α‐peptide encoded on the cloning vector—has been implemented independently in these three strains using classical bacterial genetics. In fact, their comparative analysis reveals recurrent motifs: (i) inactivation of the native enzyme via large deletions of chromosomal regions encompassing the lac locus, or a chemically induced frameshift deletion at the beginning of the lacZ cistron, and (ii) utilization of a defective prophage (ϕ80), or an F′‐plasmid, to provide the lacZ∆M15 allele encoding its ω‐fragment. While the genetic manipulations of the E. coli strains involved repeated use of mobile genetic elements as well as harsh chemical or physical mutagenesis, the individual modified traits appear remarkably stable as they can be found even in distantly related laboratory strains, beyond those investigated here. Our detailed characterization at the genome sequence level not only offers clues about the mechanisms of classical gene transduction and transposition but should also guide the future fine‐tuning of E. coli strains for gene cloning and protein expression, including phage display techniques, utilizing advanced tools for site‐specific genome engineering.
Obeticholic Acid Inhibit Mitochondria Dysfunction Via Regulating ERK1/2‐DRP Pathway to Exert Protective Effect on Lipopolysaccharide‐Induced Myocardial Injury
Authors: Miao Huijie , Tang Xiaomeng , Cui Yun , Shi Jingyi , Xiong Xi , Wang Chunxia , Zhang Yucai
Published: May 2024

Farnesoid X receptor (FXR) plays critical regulatory roles in cardiovascular physiology/pathology. However, the role of FXR agonist obeticholic acid (OCA) in sepsis‐associated myocardial injury and underlying mechanisms remain unclear. C57BL/6J mice are treated with OCA before lipopolysaccharide (LPS) administration. The histopathology of the heart and assessment of FXR expression and mitochondria function are performed. To explore the underlying mechanisms, H9c2 cells, and primary cardiomyocytes are pre‐treated with OCA before LPS treatment, and extracellular signal‐regulated protein kinase (ERK) inhibitor PD98059 is used. LPS‐induced myocardial injury in mice is significantly improved by OCA pretreatment. Mechanistically, OCA pretreatment decreased reactive oxygen species (ROS) levels and blocked the loss of mitochondrial membrane potential (ΔΨm) in cardiomyocytes. The expression of glutathione peroxidase 1 (GPX1), superoxide dismutase 1 (SOD1), superoxide dismutase 2 (SOD2), and nuclear factor erythroid 2‐related factor 2 (NRF‐2) increased in the case of OCA pretreatment. In addition, OCA improved mitochondria respiratory chain with increasing Complex I expression and decreasing cytochrome C (Cyt‐C) diffusion. Moreover, OCA pretreatment inhibited LPS‐induced mitochondria dysfunction via suppressing ERK1/2‐DRP signaling pathway. FXR agonist OCA inhibits LPS‐induced mitochondria dysfunction via suppressing ERK1/2‐DRP signaling pathway to protect mice against LPS‐induced myocardial injury.
The Role of Chemical Composition in Determining the Charge‐Carrier Dynamics in (AgI)x(BiI3)y Rudorffites
Authors: Lal Snigdha , Righetto Marcello , Putland Benjamin W. J. , Sansom Harry C. , Motti Silvia G. , Jin Heon , Johnston Michael B. , Snaith Henry J. , Herz Laura M.
Published: May 2024

Silver‐bismuth‐based perovskite‐inspired materials (PIMs) are increasingly being explored as non‐toxic materials in photovoltaic applications. However, many of these materials exhibit an ultrafast localization of photogenerated charge carriers that is detrimental for charge‐carrier extraction. In this work, such localization processes are explored for thermally evaporated thin films of compositions lying along the (AgI)x(BiI3)y series, namely BiI3, AgBi2I7, AgBiI4, Ag2BiI5, Ag3BiI6, and AgI, to investigate the impact of changing Ag+/Bi3+ content. A persistent presence of ultrafast charge‐carrier localization in all mixed compositions and BiI3, together with unusually broad photoluminescence spectra, reveal that eliminating silver will not suppress the emergence of a localized state. A weak change in electronic bandgap and charge‐carrier mobility reveals the resilience of the electronic band structure upon modifications in the Ag+/Bi3+ composition of the mixed‐metal rudorffites. Instead, chemical composition impacts the charge‐carrier dynamics indirectly via structural alterations: Ag‐deficient compositions demonstrate stronger charge‐carrier localization most likely because a higher density of vacant sites in the cationic sublattice imparts enhanced lattice softness. Unraveling such delicate interplay between chemical composition, crystal structure, and charge‐carrier dynamics in (AgI)x(BiI3)y rudorffites provides crucial insights for developing a material‐by‐design approach in the quest for highly efficient Bi‐based PIMs.
Robust Flexible Electret Tactile Sensor for Identification on Mushy Material in Harsh Environment
Authors: Xu Jiani , Teng Junchi , Cao Zeyuan , Guo Xingqi , Ding Rong , Ren Chao , Yuan Yongfei , Wang Xuan , Yin Pengfei , Ye Xiongying
Published: May 2024

In traditional food industry, the assessment of mushy materials plays an important role in high‐quality food production, which still relies heavily on human tactile perception. In this work, to address this issue for enhancing food production efficiency, a flexible electret tactile sensor that can mimic expert touch is developed. The sensor consists of a pair of electrodes, a microstructural spacer, and a pre‐charged electret. Benefiting from the electrostatic induction‐based working mechanism, the sensor attains high sensitivity and is ideal for precise sensing in actions similar to those of skilled Baijiu distillers. Due to its hermetic and electromagnetic interference‐resistant encapsulation with polypropylene/aluminum/parylene films, the sensor remained durable in vinasse in the real distillery, with its high water and alcohol content, for over 21 days. This demonstrates its long‐term stability in harsh environment. Based on the proposed flexible electret tactile sensor, an automated and intelligent vinasse identification system is built, mimicking the actions of Baijiu distillers in vinasse assessment. Combining tactile sensing data with machine learning, the system can distinguish 8 kinds of vinasses with different ingredient ratios, achieving an accuracy of 98%. This work significantly demonstrates the practical potential of the sensor in the food industry.
Ultrathin Bi‐Switchable Vanadium Dioxide‐Based Multifunctional Metamaterial for Terahertz Polarization Modulation
Authors: Jalal Abdul , Qasim Muhammad , Qurashi Ubaid Ur Rahman
Published: May 2024

A broadband multi‐functional bi‐switchable ultrathin optical metamaterial design is investigated, which can achieve a high polarization conversion efficiency over a wide band of frequencies in the terahertz (THz) regime. The proposed design switches from a linear and circular polarization converter (LPC/CPC) to an efficient absorber by using the phase change property of a functional material, vanadium dioxide (VO2). The proposed design shows switching from an absorber to a reflector using the mechanical configuration of the functional material, and therefore the design can be used as a bi‐switchable device. The first type of switching is accomplished by changing the conductivity of the functional material, while the second type of switching is achieved with the help of the mechanical configuration of the functional material. Moreover, the structure is responsive to wide incident angles. The proposed switchable design has the potential to contribute to the development of tunable polarization rotating devices and on/off switching LPC devices, which have wide applications in detection, sensing, and communications.
A laser‐Engraved Wearable Electrochemical Sensing Patch for Heat Stress Precise Individual Management of Horse
Authors: Pan Yuxiang , Su Xiaoyu , Liu Ying , Fan Peidi , Li Xunjia , Ying Yibin , Ping Jianfeng
Published: May 2024

In point‐of‐care diagnostics, the continuous monitoring of sweat constituents provides a window into individual's physiological state. For species like horses, with abundant sweat glands, sweat composition can serve as an early health indicator. Considering the salience of such metrics in the domain of high‐value animal breeding, a sophisticated wearable sensor patch tailored is introduced for the dynamic assessment of equine sweat, offering insights into pH, potassium ion (K+), and temperature profiles during episodes of heat stress and under normal physiological conditions. The device integrates a laser‐engraved graphene (LEG) sensing electrode array, a non‐invasive iontophoretic module for stimulated sweat secretion, an adaptable signal processing unit, and an embedded wireless communication framework. Profiting from an admirable Truth Table capable of logical evaluation, the integrated system enabled the early and timely assessment for heat stress, with high accuracy, stability, and reproducibility. The sensor patch has been calibrated to align with the unique dermal and physiological contours of equine anatomy, thereby augmenting its applicability in practical settings. This real‐time analysis tool for equine perspiration stands to revolutionize personalized health management approaches for high‐value animals, marking a significant stride in the integration of smart technologies within the agricultural sector.
Engineering Built‐In Electric Field Microenvironment of CQDs/g‐C3N4 Heterojunction for Efficient Photocatalytic CO2 Reduction
Authors: Xu Yun , Hou Weidong , Huang Kai , Guo Huazhang , Wang Zeming , Lian Cheng , Zhang Jiye , Wu Deli , Lei Zhendong , Liu Zheng , Wang Liang
Published: May 2024

Graphitic carbon nitride (CN), as a nonmetallic photocatalyst, has gained considerable attention for its cost‐effectiveness and environmentally friendly nature in catalyzing solar‐driven CO2 conversion into valuable products. However, the photocatalytic efficiency of CO2 reduction with CN remains low, accompanied by challenges in achieving desirable product selectivity. To address these limitations, a two‐step hydrothermal‐calcination tandem synthesis strategy is presented, introducing carbon quantum dots (CQDs) into CN and forming ultra‐thin CQD/CN nanosheets. The integration of CQDs induces a distinct work function with CN, creating a robust interface electric field after the combination. This electric field facilitates the accumulation of photoelectrons in the CQDs region, providing an abundant source of reduced electrons for the photocatalytic process. Remarkably, the CQD/CN nanosheets exhibit an average CO yield of 120 µmol g−1, showcasing an outstanding CO selectivity of 92.8%. The discovery in the work not only presents an innovative pathway for the development of high‐performance photocatalysts grounded in non‐metallic CN materials employing CQDs but also opens new avenues for versatile application prospects in environmental protection and sustainable cleaning energy.
Multi‐Selenophene Strategy Enables Dimeric Acceptors‐Based Organic Solar Cells with over 18.5% Efficiency
Authors: Bai Yuyang , Chen Tianqi , Ji Xinyi , Wang Jiaying , Zhao Wenkai , Yuan Shaohui , Zhang Yunxin , Long Guankui , Zhang Zhe , Wan Xiangjian , Kan Bin , Chen Yongsheng
Published: May 2024

Dimeric acceptor (DMA) becomes a promising alternative to small‐molecular and polymeric acceptor‐based organic solar cells (OSCs) due to its well‐defined chemical structure, high batch‐to‐batch reproducibility, and low molecular diffusion properties. However, DMAs usually exhibit blueshifted absorptions, limiting their photon utilization abilities. Herein, multi‐selenophene strategies are adopted to develop redshifted DMAs. From monomer (YSe) to dimers (DYSe‐1 and DYSe‐2), reduced electron reorganization energies and exciton binding energies enable the efficient charge dynamics in the DMAs‐based OSCs. Together with their effective absorption extending to ≈920 nm, DYSe‐1‐ and DYSe‐2‐ based OSCs exhibit outstanding short‐circuit current densities (JSCs) over 27 mA cm−2, which are the best among DMAs. Besides, compared with the YSe‐based device, both DMA‐based devices have higher electroluminescence quantum efficiencies and thus reduce nonradiative recombination loss (ΔE3), contributing to their reduced energy losses. The resultant open‐circuit voltages (VOCs) of DYSe‐1‐ and DYSe‐2‐ based OSCs are ≈0.88 V, which, combining their super JSC values, lead to the promising power conversion efficiencies of 18.56% and 18.22%, respectively. These results are among the best in DMAs‐based OSCs and highlight the great potential of the multi‐selenophene strategy for the development of redshifted DMAs with high performance.