A major change in precipitation gradient on the Chinese Loess Plateau at thePliocene-Quaternary boundary

Spatiotemporal variations in East Asian Monsoon (EAM) precipitation during the Quaternary have been intensively studied. However, spatial variations in pre-Quaternary EAM precipitation remain largely uninvestigated, preventing a clear understanding of monsoon dynamics during a warmer climatic period. Here we compare the spatial differences in heavy mineral assemblages between Quaternary loess and pre-Quaternary Red Clay on the Chinese Loess Plateau (CLP) to analyze spatial patterns in weathering. Prior studies have revealed that unstable hornblende is the dominant (&sim;50%) heavy mineral in Chinese loess deposited over the past 500 ka, whereas hornblende content decreases to &lt; 10% in strata older than &sim;1 Ma in the central CLP because of diagenesis. In the present study we found that hornblende is the dominant heavy mineral in 2&ndash;2.7 Ma loess on the northeastern CLP (at Jiaxian), which today receives little precipitation. Conversely, hornblende content in the upper Miocene-Pliocene Red Clay at Jiaxian is &lt; 10%, as in the central CLP. The early Quaternary abundance of hornblende at Jiaxian indicates that the current northwestward-decreasing precipitation pattern and consequent dry climate at Jiaxian must have been initiated since &sim;2.7 Ma, preventing hornblende dissolution to amounts &lt; 10% as observed in the central CLP. By contrast, the 7 Ma and 3 Ma Jiaxian Red Clay hornblende content is significantly less than that of the Xifeng samples, despite the fact that today Xifeng receives more precipitation than Jiaxian, with expected enhanced hornblende weathering. This suggests that the northeastern CLP received more precipitation during the Late Miocene-Pliocene than at Xifeng, indicating that the precipitation gradient on the CLP was more east&ndash;west during the Late Miocene-Pliocene rather than northwestsoutheast as it was in the Quaternary. A comparison of magnetic susceptibility records for these sections confirms this inference. We attribute this major change in climatic patterns at &sim;2.7 Ma to decreased northward moisture transportation associated with Northern Hemisphere glaciation and cooling in the Quaternary. This study therefore demonstrates the potential usefulness of employing heavy mineral analysis in both paleoclimatic and paleooceanographic reconstructions.<br style="line-height: normal; text-align: -webkit-auto; text-size-adjust: auto;" /

The Alternating Access Transport Mechanism in LacY

Lactose permease of Escherichia coli (LacY) is highly dynamic, and sugar binding causes closing of a large inward-facing cavity with opening of a wide outward-facing hydrophilic cavity. Therefore, lactose/H+ symport via LacY very likely involves a global conformational change that allows alternating access of single sugar- and H+-binding sites to either side of the membrane. Here, in honor of Stephan H. White’s seventieth birthday, we review in camera the various biochemical/biophysical approaches that provide experimental evidence for the alternating access mechanism

The influence of soil communities on the temperature sensitivity of soil respiration

Soil respiration represents a major carbon flux between terrestrial ecosystems and the atmosphere, and is expected to accelerate under climate warming. Despite its importance in climate change forecasts, however, our understanding of the effects of temperature on soil respiration (RS) is incomplete. Using a metabolic ecology approach we link soil biota metabolism, community composition and heterotrophic activity, to predict RS rates across five biomes. We find that accounting for the ecological mechanisms underpinning decomposition processes predicts climatological RS variations observed in an independent dataset (n = 312). The importance of community composition is evident because without it RS is substantially underestimated. With increasing temperature, we predict a latitudinal increase in RS temperature sensitivity, with Q10 values ranging between 2.33 ±0.01 in tropical forests to 2.72 ±0.03 in tundra. This global trend has been widely observed, but has not previously been linked to soil communities

Susceptibility to tuberculosis is associated with variants in the ASAP1 gene encoding a regulator of dendritic cell migration

Human genetic factors predispose to tuberculosis (TB). We studied 7.6 million genetic variants in 5,530 people with pulmonary TB and in 5,607 healthy controls. In the combined analysis of these subjects and the follow-up cohort (15,087 TB patients and controls altogether), we found an association between TB and variants located in introns of the ASAP1 gene on chromosome 8q24 (P = 2.6 × 10−11 for rs4733781; P = 1.0 × 10−10 for rs10956514). Dendritic cells (DCs) showed high ASAP1 expression that was reduced after Mycobacterium tuberculosis infection, and rs10956514 was associated with the level of reduction of ASAP1 expression. The ASAP1 protein is involved in actin and membrane remodeling and has been associated with podosomes. The ASAP1-depleted DCs showed impaired matrix degradation and migration. Therefore, genetically determined excessive reduction of ASAP1 expression in M. tuberculosis–infected DCs may lead to their impaired migration, suggesting a potential mechanism of predisposition to TB

Asian dust-storm activity dominated by Chinese dynasty changes since 2000 BP

The Asian monsoon (AM) played an important role in the dynastic history of China, yet it remains unknown whether AM-mediated shifts in Chinese societies affect earth surface processes to the point of exceeding natural variability. Here, we present a dust storm intensity record dating back to the first unified dynasty of China (the Qin Dynasty, 221–207 B.C.E.). Marked increases in dust storm activity coincided with unified dynasties with large populations during strong AM periods. By contrast, reduced dust storm activity corresponded to decreased population sizes and periods of civil unrest, which was co-eval with a weakened AM. The strengthened AM may have facilitated the development of Chinese civilizations, destabilizing the topsoil and thereby increasing the dust storm frequency. Beginning at least 2000 years ago, human activities might have started to overtake natural climatic variability as the dominant controls of dust storm activity in eastern China

Fuzzy Inference Systems for Invariant Pattern Recognition in MFL NDE

Defect related information present in NDE signals is frequently obscured by the presence of operational variables inherent in the system. A typical NDE system comprises of an energy source, a test specimen and a sensor array. Operational variables include uncontrollable changes in source signal strength and/or frequency, variations in the sensitivity of the sensor and alterations in the material properties of the test specimen. These operational variables can confuse subsequent signal interpretation schemes, such as those relying on artificial neural networks. Invariant pattern recognition methods are required to ensure accurate signal characterization in terms of the underlying defect geometry. This paper describes a generalized invariance transformation technique to compensate for operational variables in NDE systems. An application to magnetic flux leakage (MFL) inspection of gas transmission pipelines is presented. The technique is employed to compensate for variations in magnetization characteristics in the pipe wall

Mutagenicity of Chinese traditional medicine Semen Armeniacae amarum by two modified Ames tests

<p>Abstract</p> <p>Background</p> <p>Semen armeniacae amarum (SAA) is a Chinese traditional medicine and has long been used to control acute lower respiratory tract infection and asthma, as a result of its expectorant and antiasthmatic activities. However, its mutagenicity <it>in vitro </it>and <it>in vivo </it>has not yet been reported. The Ames test for mutagenicity is used worldwide. The histidine contained in biological samples can induce histidine-deficient cells to replicate, which results in more <it>his</it>⁺colonies than in negative control cells, therefore false-positive results may be obtained. So, it becomes a prerequisite to exclude the effects of any residual histidine from samples when they are assayed for their mutagenicity. Chinese traditional herbs, such as SAA, are histidine-containing biological sample, need modified Ames tests to assay their <it>in vitro </it>mutagenicity.</p> <p>Methods</p> <p>The mutagenicity of SAA was evaluated by the standard and two modified Ames tests. The first modification used the plate incorporation test same as standard Ames teat, but with new negative control systems, in which different amounts of histidine corresponding to different concentrations of SAA was incorporated. When the number of his⁺revertants in SAA experiments was compared with that in new negative control, the effect of histidine contained in SAA could be eliminated. The second modification used a liquid suspension test similar to the standard Ames test, except with histidine-rich instead of histidine-limited medium. The aim of this change was to conceal the effect of histidine contained in SAA on the final counting of <it>his</it>⁺revertants, and therefore to exclude false-positive results of SAA in the Ames test. Furthermore, the effect of SAA on chromosomal aberration in mammalian bone marrow cells was tested.</p> <p>Results</p> <p>The standard Ames test showed a positive result for mutagenicity of SAA. In contrast, a negative response was obtained with the modified plate incorporation and modified suspension Ames tests. Moreover, no apparent chromosomal aberrations were observed in mammalian bone marrow cells treated with SAA.</p> <p>Conclusion</p> <p>The standard Ames test was not suitable for evaluating the mutagenicity of SAA, because false-positive result could be resulted by the histidine content in SAA. However, the two modified Ames tests were suitable, because the experimental results proved that the effect of histidine in SAA and therefore the false-positive result were effectively excluded in these two modified Ames tests. This conclusion needs more experimental data to support in the future. Moreover, the experimental results illustrated that SAA had no mutagenicity <it>in vitro </it>and <it>in vivo</it>. This was in agreement with the clinical safety of SAA long-term used in China.</p

Bioactive Electrospun Scaffolds Delivering Growth Factors and Genes for Tissue Engineering Applications

A biomaterial scaffold is one of the key factors for successful tissue engineering. In recent years, an increasing tendency has been observed toward the combination of scaffolds and biomolecules, e.g. growth factors and therapeutic genes, to achieve bioactive scaffolds, which not only provide physical support but also express biological signals to modulate tissue regeneration. Huge efforts have been made on the exploration of strategies to prepare bioactive scaffolds. Within the past five years, electrospun scaffolds have gained an exponentially increasing popularity in this area because of their ultrathin fiber diameter and large surface-volume ratio, which is favored for biomolecule delivery. This paper reviews current techniques that can be used to prepare bioactive electrospun scaffolds, including physical adsorption, blend electrospinning, coaxial electrospinning, and covalent immobilization. In addition, this paper also analyzes the existing challenges (i.e., protein instability, low gene transfection efficiency, and difficulties in accurate kinetics prediction) to achieve biomolecule release from electrospun scaffolds, which necessitate further research to fully exploit the biomedical applications of these bioactive scaffolds

Patients' experiences of the quality of long-term care among the elderly: comparing scores over time

Contains fulltext : 108999.pdf (publisher's version ) (Open Access)BACKGROUND: Every two years, long-term care organizations for the elderly are obliged to evaluate and publish the experiences of residents, representatives of psychogeriatric patients, and/or assisted-living clients with regard to quality of care. Our hypotheses are that publication of this quality information leads to improved performance, and that organizations with substandard performance will improve more than those whose performance is relatively good. METHODS: The analyses included organizational units that measured experiences twice between 2007 (t(0)) and 2009 (t(1)). Experiences with quality of care were measured with Consumer Quality Index (CQI) questionnaires. Besides descriptive analyses (i.e. mean, 5(th) and 95(th) percentile, and 90% central range) of the 19 CQI indicators and change scores of these indicators were calculated. Differences across five performance groups (ranging from 'worst' to 'best') were tested using an ANOVA test and effect sizes were measured with omega squared (omega(2)). RESULTS: At t0 experiences of residents, representatives, and assisted-living clients were positive on all indicators. Nevertheless, most CQI indicators had improved scores (up to 0.37 change score) at t(1). Only three indicators showed a minor decline (up to -0.08 change score). Change scores varied between indicators and questionnaires, e.g. they were more profound for the face-to-face interview questionnaire for residents in nursing homes than for the other two mail questionnaires (0.15 vs. 0.05 and 0.04, respectively), possibly due to more variation between nursing homes on the first measurement, perhaps indicating more potential for improvement. A negative relationship was found between prior performance and change, particularly with respect to the experiences of residents (omega(2) = 0.16) and assisted-living clients (omega(2) = 0.15). However, the relation between prior performance and improvement could also be demonstrated with respect to the experiences reported by representatives of psychogeriatric patients and by assisted-living clients. For representatives of psychogeriatric patients, the performance groups 1 and 2 ([much] below average) improved significantly more than the other three groups (omega(2) = 0.05). CONCLUSIONS: Both hypotheses were confirmed: almost all indicator scores improved over time and long-term care organizations for the elderly with substandard performance improved more than those with a performance which was already relatively good

Fluorescence Modified Chitosan-Coated Magnetic Nanoparticles for High-Efficient Cellular Imaging

Labeling of cells with nanoparticles for living detection is of interest to various biomedical applications. In this study, novel fluorescent/magnetic nanoparticles were prepared and used in high-efficient cellular imaging. The nanoparticles coated with the modified chitosan possessed a magnetic oxide core and a covalently attached fluorescent dye. We evaluated the feasibility and efficiency in labeling cancer cells (SMMC-7721) with the nanoparticles. The nanoparticles exhibited a high affinity to cells, which was demonstrated by flow cytometry and magnetic resonance imaging. The results showed that cell-labeling efficiency of the nanoparticles was dependent on the incubation time and nanoparticles’ concentration. The minimum detected number of labeled cells was around 104by using a clinical 1.5-T MRI imager. Fluorescence and transmission electron microscopy instruments were used to monitor the localization patterns of the magnetic nanoparticles in cells. These new magneto-fluorescent nanoagents have demonstrated the potential for future medical use