Search

Abstract In this work we compare the predictions for the scattering length and effective range of the channels $$K^0 \Sigma ^+, K^+ \Sigma ^0, K^+ \Lambda $$ K 0 Σ + , K + Σ 0 , K + Λ and $$\eta p$$ η p , assuming the $$N^*(1535)$$ N ∗ ( 1535 ) state as a molecular state of these channels, or an original genuine state, made for instance from three quarks. Looking at very different scenarios, what we conclude is that the predictions of these two pictures are drastically different, to the point that we advise the measurement of these magnitudes, accessible for instance by measuring correlation functions, in order to gain much valuable information concerning the nature of this state.

Abstract In this paper, molecular dynamics simulations have been employed to investigate the phonon thermal transport in bilayer polycrystalline graphene nanoribbon (pGNR/pGNR), compared with bilayer graphene nanoribbon (GNR/GNR) and pGNR/GNR heterostructure. The interfacial thermal resistance (ITR) of bilayer structures was also calculated using the heat dissipation method. The effects of interlayer interaction, grain size, and vacancy defects on ITR and in-plane phonon thermal conductivity of bilayer structures were investigated. It was found that the ITR as well as in-plane phonon thermal conductivity of pGNR/pGNR was less than that of pGNR/GNR and much less than that of GNR/GNR, for the same size. For the studied bilayer structures, both the ITR and in-plane phonon thermal conductivity decrease with increasing interlayer interactions. Moreover, ITR increases with increasing grain area size whereas decreases with increasing vacancy defects in pGNR-based bilayers. The introduction of pGNR interface roughness and vacancy defects results in an enhanced phonon coupling in pGNR-based bilayers compared to pure GNR/GNR bilayers. Presented simulation investigations will help to understand the interlayer thermal transport properties of polycrystalline graphene and provide essential guidance for experimentally regulating phonon thermal transport between layers of polycrystalline graphene.

Abstract We study the Belle reaction $$\Xi _c^+ \rightarrow \Xi ^- \pi ^+ \pi ^+$$ Ξ c + → Ξ - π + π + looking at the mass distribution of $$\pi ^+ \Xi $$ π + Ξ , where clear signals for the $$\Xi (1620)$$ Ξ ( 1620 ) and $$\Xi (1690)$$ Ξ ( 1690 ) resonances are seen. These two resonances are generated dynamically from the interaction in coupled channels of $$\pi \Xi , {\bar{K}} \Lambda , {\bar{K}} \Sigma $$ π Ξ , K ¯ Λ , K ¯ Σ and $$\eta \Xi $$ η Ξ within the chiral unitary approach. Yet, the weak decay process at the quark level, together with the hadronization to produce pairs of mesons, does not produce the $$\pi \pi \Xi $$ π π Ξ final state. In order to produce this state one must make transitions from the $${\bar{K}} \Lambda , {\bar{K}} \Sigma $$ K ¯ Λ , K ¯ Σ and $$\eta \Xi $$ η Ξ components to $$\pi \Xi $$ π Ξ , and this interaction is what produces the resonances. So, the reaction offers a good test for the molecular picture of these resonances. Adding the contribution of the $$\Xi ^*(1530)$$ Ξ ∗ ( 1530 ) and some background we are able to get a good reproduction of the mass distribution showing the signatures of the two resonances as found in the experiment.

Conformal metasurface antenna embedded on the platform with an arbitrary shape is of great significance for communication systems in practical applications. Herein, a convenient design strategy for conformal transmissive metasurface antenna with arbitrary cylinder surface is presented. First, a novel‐phase compensation concept for curved surface is inspired by ray‐tracing technique. Then, by using arc differentiation and numerical integration, the meta‐atoms’ coordinates calculation method is analyzed for arbitrary cylindrical surface. Next, the electromagnetic responses of planar and curved transmissive meta‐atoms are discussed, and conformal metasurfaces in single‐quadratic surfaces are simulated to validate the feasibility of the design strategy. Finally, for potential applications, three combined quadratics conformal metasurface antennas with capabilities of beam focusing, beam deflecting, and vortex generation are designed and measured. It is indicated in the results that the three conformal metasurface antennas with combined quadratic cylinder surfaces can transform the spherical wave efficiently into the plane wave, deflected beam, and vortex beam, respectively, verifying the validity of the designs. The convenient strategy has good generality and flexibility because it is applicable to arbitrary cylindrical metasurface with a specific alignment function, which has promising perspective in practical applications, and offers a novel approach to design conformal antennas without changing aerodynamic shapes of platforms.

Perfect absorbers are highly desirable in many military applications, such as radar cross section (RCS) reduction, cloaking devices, and also sensor detectors; however, most approaches (such as wedge and pyramidal absorbers, multi-resonant absorbers) intrinsically suffer from very large size at low-frequency domain, limited bandwidth, as well as low absorption ratio issues. In this paper, we solve these issues via combining the Huygens metasurface and three-layers slab impedance metasurface, with the former satisfying the novel impedance matching theory and the latter exhibiting multi-resonant property and optimized conductivities, which achieve high-efficiency absorption at lower frequency range (1-3 GHz) and higher frequency region (3-18 GHz), respectively. To demonstrate our concept, we design/fabricate a realistic metasurface absorber working in the microwave region, and perform experiments to demonstrate that it can achieve an ultra-broadband (1-18 GHz) performance with absorption rate better than 75%. The numerical simulations are in good agreements with experiments, indicating that the absorption efficiency can be further pushed to 92% within the whole working band by optimizing our designs. More importantly, our device is insensitive for different polarizations and oblique incidences. Our findings can stimulate the realizations of ultra-broadband meta-devices, particularly can enhance the cloaking technology relying on high-efficiency absorption.

Metasurface-based vortex beam generators are very promising and applicable to enhance transmission data capacity in wireless communication system. However, most designs to date are ceased to predict their far-field characteristic, which is actually in demand when applied to wireless communication. Here, we find for the first time a deterministic and robust strategy to fastly estimate the exact far-field patterns and gain limit of a vortex beam based on the theoretical analysis of aperture field with spiral phase profile. For verification, a broadband metasurface-based vortex-beam generator based on geometric phase is designed, numerically calculated and experimentally measured at microwave regime. Excellent agreements are observed among far-field results obtained based on the proposed method, numerical simulations and experimental measurements, firmly demonstrating the validity and correctness of the proposed strategy. Such a deterministic and robust strategy of predicting far-field characteristics of a vortex beam may pave the way for its applications in many engineering scenarios, such as conical beam design, wireless communication, et al.

The full-space metasurface generally integrates the functions of traditional reflection and transmission metasurfaces. In this paper, a meta-film with ring slot is used to reflect and propagate complete-polarization waves with lower and higher frequency bands, respectively. Then meta-atoms can be placed up and down of the ring slot to achieve different functions of reflection and transmission. As a verification of this concept, reflection-mode with the function of radar cross section reduction is implemented by using chessboard meta-atoms while the transmission-mode with deflection function is obtained by using geometric elements. Our findings provide a way of designing full-space metasurface with complete-polarization control.

In this paper, a broadband bi-functional metasurface is presented with capabilities of generating vortex beam for y-polarization and reducing the backward radar cross section (RCS) for x-polarization. With careful optimization, a meta-atom is first designed to control reflection phases for orthogonally polarized wave independently. Then, an integrated phase profile is employed to convert y-polarized spherical wavefront into a vortex spiral one, shaping a vortex high gain beam in the far-field region. By arranging a checkerboard-like phase profile onto the surface for x-polarization, the reflected wave in the backward direction will be canceled, consequently leading to the backward RCS reduction for x-polarization. Combining the above-mentioned cases into a whole, a compact bi-functional metasurface is designed, simulated, physically implemented, and finally measured. In good agreement with the simulated results, the measured ones show that the RCS reduction of 10 dB for x-polarization in comparison with a same-sized metallic plate can be realized over a 67.7 % frequency bandwidth (9-18.2 GHz). Besides, high-efficiency vortex beam conversion effect for y-polarization over a broad range of 11.2-18.2 GHz (47.6%) can also be observed from the measured results.

To construct circular barrier coverage (CBC) with multistatic radars, a deployment optimization method based on equipartition strategy is proposed in this paper. In the method, the whole circular area is divided into several sub-circles with equal width, and each sub-circle is blanketed by a sub-CBC that is built based on the multistatic radar deployment patterns. To determine the optimal deployment patterns for each sub-CBC, the optimization conditions are firstly studied. Then, to optimize the deployment of the whole circular area, a model based on minimum deployment cost is proposed, and the proposed model is divided into two sub-models to solve the optimization issue. In the inner model, it is assumed that the width of a sub-circle is given. Based on the optimization conditions of the deployment pattern, integer linear programming (ILP) and exhaustive method (EM) are jointly adopted to determine the types and numbers of deployment patterns. Moreover, a modified formula is introduced to calculate the maximum valid number of receivers in a pattern, thus narrowing the search scope of the EM. In the outer model, the width of a sub-circle is assumed to be a variable, and the EM is adopted to determine the minimum total deployment cost and the optimal deployment patterns on each sub-circle. Moreover, the improved formula is exploited to determine the range of width for a sub-circle barrier and reduce the search scope of the EM. Finally, simulations are conducted in different conditions to verify the effectiveness of the proposed method. The simulation results indicate that the proposed method can spend less deployment cost and deploy fewer transmitters than the state-of-the-artwork.

Background: Nonlinguistic cognitive impairment has become an important issue for aphasic patients, but currently there are few neuropsychological cognitive assessment tests for it. To get more information on cognitive impairment of aphasic patients, this study aimed to develop a new cognitive assessment test battery for aphasic patients, the Non-language-based Cognitive Assessment (NLCA), and evaluate its utility in Chinese-speaking patients with aphasia. Methods: The NLCA consists of five nonverbal tests, which could assess five nonlinguistic cognitive domains such as visuospatial functions, attention test, memory, reasoning, and executive functions of aphasic patients. All tests are modified from the nonverbal items of the current existed tests with some changes to the characteristics of Chinese culture. The NLCA was tested in 157 participants (including 57 aphasic patients, 50 mild cognitive impairment (MCI) patients, and 50 normal controls), and was compared with other well-established relative neuropsychological tests on the reliability, validity, and utility. Results: The NLCA was fully applicable in the MCI patients and the normal controls, almost working in the aphasic patients (57/62 patients, 91.9%). The NLCA scores were 66.70 ± 6.30, 48.67 ± 15.04, and 77.58 ± 2.56 for the MCI group, the aphasic group, and the control group, respectively , and a significant difference was found among three groups (F = 118.446, P < 0.001). The Cronbach's alpha of the NLCA as an index of internal consistency was 0.805, and the test-retest and interrater reliability was adequate (r=0.977 and r= 0.970, respectively). The correlations of the cognitive subtests and their validation instruments were between 0.540 and 0.670 (all P < 0.05). Spearman's correlation analysis indicated that the coefficient of internal consistency of each subtest itself was higher than other subtests. When choosing the Montreal Cognitive Assessment score of

In this study, we examined the role of mRNAs and miRNAs in variations in intramuscular fat content in the longissimus dorsi muscle in Xinjiang brown cattle. Two groups of Xinjiang brown cattle with extremely different intramuscular fat content in the longissimus dorsi were selected for combined of miRNA and mRNA analysis using an RNA-Seq. In total, 296 mRNAs and 362 miRNAs were significantly differentially expressed, including 155 newly predicted miRNAs, 275 significantly upregulated genes, 252 significantly upregulated miRNAs, 21 significantly downregulated genes and 110 significantly downregulated miRNAs. The combined miRNA and mRNA analysis identified 96 differentially expressed miRNAs and 27 differentially expressed mRNAs. In all, 47 upregulated miRNAs had a regulatory effect on 14 differentially downregulated target genes, and 49 downregulated miRNAs had a regulatory effect on 13 upregulated target genes. To verify the sequencing results, 10 differentially expressed genes (DEGs) and 10 differentially expressed miRNAs were selected for qRT-PCR. The qRT-PCR results confirmed the sequencing results. The results of this study shed light on the molecular regulation of bovine adipose tissue, which might help with the development of new strategies for improving meat quality and animal productivity in beef cattle to provide healthier meat products for consumers.

This paper analyzed clinical data of 6 patients with central pontine myelinolysis (CPM). Among them 4 cases were male, 2 cases were female, with age 24 to 55 years old and average age 36 years old. Serious somatic diseases occured in all 6 cases. The main clinical manifestations included disturbance of consciousness, pseudobulbar paralysis and flaccid paralysis. Cranial MRI showed all of the patients appeared symmetrical lesions in central pontine. After intravenous drip of glucocorticoids, 5 patients were improved. DOI: 10.3969/j.issn.1672-6731.2015.08.013

By the fluid dynamics theory analysis of the sealing interface, the importance of sealing contact pressure research for sealing performance is discussed. By experiments and data analysis for nitrile rubber buna and polyurethane, Mooney–Rivlin model parameters of two materials are obtained. By the finite element analysis of bud-shaped composite sealing ring under different pressures and secondary analysis, sealing contact pressure distribution curve of finite element analysis has been obtained. Sealing experimental apparatus is designed and assembled. The contact pressure distribution curve and three-dimensional pressure distribution field are obtained using the pressure-sensitive film. The results from finite element analysis and experiment are consistent with the conclusion of fluid dynamics theory analysis. The research content and design have great significance for sealing mechanism study.

Cancer, which is a leading cause of death worldwide, places a big burden on health-care system. In this study, an order-prediction model was built to predict a series of cancer drug indications based on chemical-chemical interactions. According to the confidence scores of their interactions, the order from the most likely cancer to the least one was obtained for each query drug. The 1(st) order prediction accuracy of the training dataset was 55.93%, evaluated by Jackknife test, while it was 55.56% and 59.09% on a validation test dataset and an independent test dataset, respectively. The proposed method outperformed a popular method based on molecular descriptors. Moreover, it was verified that some drugs were effective to the 'wrong' predicted indications, indicating that some 'wrong' drug indications were actually correct indications. Encouraged by the promising results, the method may become a useful tool to the prediction of drugs indications.

Protein concentrations depend not only on the mRNA level, but also on the translation rate and the degradation rate. Prediction of mRNA's translation rate would provide valuable information for in-depth understanding of the translation mechanism and dynamic proteome. In this study, we developed a new computational model to predict the translation rate, featured by (1) integrating various sequence-derived and functional features, (2) applying the maximum relevance & minimum redundancy method and incremental feature selection to select features to optimize the prediction model, and (3) being able to predict the translation rate of RNA into high or low translation rate category. The prediction accuracies under rich and starvation condition were 68.8% and 70.0%, respectively, evaluated by jackknife cross-validation. It was found that the following features were correlated with translation rate: codon usage frequency, some gene ontology enrichment scores, number of RNA binding proteins known to bind its mRNA product, coding sequence length, protein abundance and 5'UTR free energy. These findings might provide useful information for understanding the mechanisms of translation and dynamic proteome. Our translation rate prediction model might become a high throughput tool for annotating the translation rate of mRNAs in large-scale.

This paper presents a high gain Fabry-Perot antenna with radar cross section (RCS) reduction property. A receiver-transmitter metasurface is designed and used as the partially reflective surface (PRS) of the antenna to realize high gain and wideband RCS reduction. Firstly, the working principle of the unit cell is similar to the reception and radiation of two patch antennas. The unit cell is designed to present high reflectivity through tuning the impedance matching between two patches. This can ensure that the antenna obtains high gain. Then, the ground plane in the middle makes the reflection phase from different sides of the unit cell be tuned independently. Two unit cells with same reflection phase from the bottom side and 180° reflection phase difference from the top side are obtained through tuning the size of the transmitter patch. With the improved chessboard arrangement of these two unit cells, the incident wave can be scattered into many directions. So the metasurface presents a good RCS reduction property. More importantly, thanks to the high reflectivity of the metasurface, almost all the electromagnetic waves from the outside are reflected and rarely enter the cavity. Therefore, the antenna achieves good in band RCS reduction. The measured results of the fabricated antenna agree well with the simulated ones, which verify the correctness of the design. The antennas reaches the maximum gain of 18.2 dBi at 10GHz. Wideband RCS reduction and good in band RCS reduction are also obtained by the antenna. [ABSTRACT FROM AUTHOR]

The ability to sense temperature changes is crucial for mammalian survival. Mammalian thermal sensing is primarily carried out by thermosensitive transient receptor potential channels (Thermo-TRPs). Some mammals hibernate to survive cold winter conditions, during which time their body temperature fluctuates dramatically. However, the underlying mechanisms by which these mammals regulate thermal responses remain unclear. Using quantitative realtime polymerase chain reaction (qRT-PCR) and the Western blotting, we found that Myotis ricketti bats had high levels of heat-activated TRPs (e.g., TRPV1 and TRPV4) during torpor in winter and coldactivated TRPs (e.g., TRPM8 and TRPC5) during active states in summer. We also found that laboratory mice had high mRNA levels of coldactivated TRPs (e.g., Trpm8 and Trpc5) under relatively hot conditions (i.e., 40 °C). These data suggest that small mammals up-regulate the expression of cold-activated TRPs even under warm or hot conditions. Binding site analysis showed that some homeobox (HOX) transcription factors (TFs) regulate the expression of hot- and cold-activated TRP genes and that some TFs of the Pit-Oct-Unc (POU) family regulate warm-sensitive and coldactivated TRP genes. The dual-luciferase reporter assay results demonstrated that TFs HOXA9, POU3F1, and POU5F1 regulate TRPC5 expression, suggesting that Thermo-TRP genes are regulated by multiple TFs of the HOX and POU families at different levels. This study provides insights into the adaptive mechanisms underlying thermal sensing used by bats to survive hibernation. [ABSTRACT FROM AUTHOR]

We investigate the size effects on the structures and thermal conductivity of silicon nanoclusters (SiNCs) using molecular dynamics simulations. We demonstrate that as the diameter of the SiNCs increases from 1.80 nm to 3.46 nm, the cluster structure changes from an amorphous state to a crystalline state at 300 K, which is in good agreement with the experimental findings. Our calculated thermal conductivity of the SiNCs shows a size-dependent effect due to the remarkable phonon-boundary scattering and can be about three orders of magnitude lower than that of bulk Si.

Introduction: The long non-coding RNAs (lncRNAs) urothelial cancer associated 1 (UCA1) and metastasis associated lung adenocarcinoma transcript 1 (MALAT1) are known to impact cancer cell regulation. The aim of the present study was to determine the relationship between the expression of these lncRNAs in esophageal squamous cell carcinoma (ESCC) tissues and disease prognosis.Material and Methods: The expression of UCA1 and MALAT1 lncRNAs was assessed in ESCC and adjacent carcinoma tissues (5 cm away from the tumor) and evaluated in relation to overall survival (OS) and disease-free survival (DFS) of patients. This prospective study included 100 ESCC patients who were admitted to the First Hospital of Yulin City between January 2007 and January 2014.Results: The expression levels of UCA1 and MALAT1 lncRNAs in ESCC tissues were significantly higher than those in adjacent carcinoma tissues, and there were statistically significant differences in TNM staging between the patients with high lncRNA expression and low lncRNA expression. The OS and DFS of patients with high UCA1 and MALAT1 lncRNA expression levels were significantly shorter than those with low expression levels. Furthermore, the OS and DFS of ESCC patients appeared to be correlated with TNM staging.Conclusions: These results imply that the up-regulation of UCA1 and MALAT1 lncRNAs in ESCC tissues can impact the degree of tumor progression and is predictive of postoperative survival. Therefore, the expression levels of these lncRNAs can be used as measurement indexes to determine the prognosis of ESCC patients. [ABSTRACT FROM AUTHOR]

The laboratory rat, widely used in biomedical research, is domesticated from wild brown rat. The origin and genetic mechanism underlying domestication of the laboratory rat remain largely elusive. In the present study, large scale genomes supported a single origin for the laboratory rat, possibly from a sister group to wild rats from Europe/ Africa/Middle East. Genomic and transcriptomic analyses uncovered many artificially selected genes (e.g., FOXP2, B3GAT1, and CLOCK) involved in the nervous system. These genes associate with learning ability and regulation of circadian rhythm, which likely enabled the successful domestication of the laboratory rat. Particularly, many genes, including mitochondrial genes responsible for energy metabolism, displayed a substantially increased expression in the brain of laboratory rats compared with wild rats. Our findings demystify the origin and evolution of this model animal, and provide insight into the process of its domestication. [ABSTRACT FROM AUTHOR]

An X/Ku-band flat lens antenna based on a dual-frequency anisotropic metasurface is proposed in this paper. The function of the anisotropic metasurface is to focus the incident plane waves around 10GHz and 14GHz on different spots. Then we place a Vivaldi antenna with its phase centers at 10 GHz and 14 GHz well matching the focal spot of the metasurface at each frequency to build a flat lens antenna. The lens antenna has a peak gain of 18.5 dB and cross-polarization levels of lower than -20 dB at 10 GHz with -1 dB gain bandwidth of 9.8-10.4GHz, while it has a peak gain of 18.8 dB and cross-polarization levels of lower than -30 dB at 14 GHz with the bandwidth of 13.8-14.2 GHz. Besides single working band, the antenna can simultaneously operate at 10GHz and 14GHz with gains of 16.2 dB and 16.5 dB, respectively. Measured results have a good agreement with the simulated ones. [ABSTRACT FROM AUTHOR]

In this communication, a circularly polarized (CP) double-folded transmitarray antenna (DFTA) is proposed and experimentally verified for the first time in the open literature. It is designed based on a receiver–transmitter metasurface (RTMS) and a polarization rotating (PR) metasurface (MS). A linearly polarized (LP) patch antenna is integrated on the RTMS instead of a horn antenna to feed the DFTA. Through double-folded reflecting, twice PR, LP wave receiving, CP wave transmitting, and transmission phase manipulating, the LP spherical wave from the feed is transformed into the high-gain pencil-shaped CP beam. The strategies innovatively break the restriction that the previous folded reflectarray (FRA) and folded transmitarray (FTA) antennas are only LP. Moreover, the double-folded design further reduces the antenna profile to about 1/4 of the focal length. The simulation and experiment results are in good agreement, which exhibits a peak gain of 21.8 dBic at 9.8 GHz and a maximum aperture efficiency of 40%. Meanwhile, the DFTA obtains a −1 dB gain bandwidth of 6% (9.6–10.2 GHz), in which the axial ratio is lower than 1.5 dB. [ABSTRACT FROM AUTHOR]

We propose a wideband multifunctional device which combines a linear-to-circular polarization convertor with focusing metasurface. The proposed design is built by a novel dual-layered metal cross and cross ring unit cell which exhibits satisfying performance for controlling the reflecting phase of the electromagnetic wave polarization-independently. The device is illuminated by a Vivaldi antenna, and the functions of polarization conversion and gain enhancement have been simultaneously achieved in the band of 9.12-10.2 GHz. In addition, the polarization helicity of the system can be reconfigured by rotating the feed antenna. The device has not only greatly presented the flexibility and superiority of the metasurface in steering the electromagnetic waves, but also promoted the development of the multifunctional metasurface. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the physicochemical and textural characteristics and volatile compounds of Kazakh dry-cured beef made in China. Two types of Kazakh dry-cured beef were investigated: Kazakh drycured beef made with smoking and spices (Tl) and without smoking and spices (T2). There were significant (P < 0.05) differences in values of aw, moisture, L*, cohesiveness and chewiness between the two types. A total of 86 volatile compounds were isolated by solid phase microextraction-gas chromatography/mass spectrometry (SPME-GC/MS). Hydrocarbons were the most abundant in Tl products and aldehydes in T2 products. Principal component analysis showed that the first principal component (PCI) was highly related to smoke derivatives-- naphthalene, 2-cyclopenten-l-one derivatives, 4-methyl-4-hepten-3-one, acetophenone, 2,3-dihydro-lH-Inden-l-one, 2-furanmethanol, methoxy-phenyl-oxime, furfural, l-(2-furanyl)-ethanone and phenols--and the second principal component (PC2) to lipid derivatives--straight-chain aliphatic aldehydes, methyl ketone, straight-chain alcohols and 2-pentyl-furan. [ABSTRACT FROM AUTHOR]

Background: Metabolic pathway is a highly regulated network consisting of many metabolic reactions involving substrates, enzymes, and products, where substrates can be transformed into products with particular catalytic enzymes. Since experimental determination of the network of substrate-enzyme-product triad (whether the substrate can be transformed into the product with a given enzyme) is both time-consuming and expensive, it would be very useful to develop a computational approach for predicting the network of substrate-enzyme-product triads. Results: A mathematical model for predicting the network of substrate-enzyme-product triads was developed. Meanwhile, a benchmark dataset was constructed that contains 744,192 substrate-enzyme-product triads, of which 14,592 are networking triads, and 729,600 are non-networking triads; i.e., the number of the negative triads was about 50 times the number of the positive triads. The molecular graph was introduced to calculate the similarity between the substrate compounds and between the product compounds, while the functional domain composition was introduced to calculate the similarity between enzyme molecules. The nearest neighbour algorithm was utilized as a prediction engine, in which a novel metric was introduced to measure the "nearness" between triads. To train and test the prediction engine, one tenth of the positive triads and one tenth of the negative triads were randomly picked from the benchmark dataset as the testing samples, while the remaining were used to train the prediction model. It was observed that the overall success rate in predicting the network for the testing samples was 98.71%, with 95.41% success rate for the 1,460 testing networking triads and 98.77% for the 72,960 testing non-networking triads. Conclusions: It is quite promising and encouraged to use the molecular graph to calculate the similarity between compounds and use the functional domain composition to calculate the similarity between enzymes for studying the substrate-enzyme-product network system. The software is available upon request. [ABSTRACT FROM AUTHOR]

The 4-bp deletion (-CTTT) at codon 41/42 (CD41/42) of the human β-globin gene represents one of the most common β-thalassemia mutations in East Asia and Southeast Asia, which is historically afflicted with endemic malaria, thus hypothetically evolving under natural selection by malaria infection. To understand the evolutionary process of generating the βCD41/42 allele and its maintenance, including the effect of natural selection on the pattern of linkage disequilibrium (LD), we sequenced a 15.933-kb region spanning 20.693 kb of the β-globin cluster surrounding the 4-bp deletion using a sample from a Chinese population consisting of 24 normal individuals and 16 heterozygotes for the deletion. Forty-nine polymorphic sites were found. Analysis of the data, using a variety of methods including formal population genetics analysis and visual approaches, suggests that the spread of the CD41/42 (-CTTT) deletion is most likely mediated by interallelic gene conversion, although independent deletions in different lineages are also possible. The neutrality test resulted in a significant positive Tajima’s D for the β-globin locus, which is consistent with the existence of balancing selection. This suggests that the 4-bp deletion that occurred at this locus may be an event that is subject to natural selection, due to malaria, which leads to the heterozygote advantage, spread widely with further help by conversion and migration. The evolutionary process of this mutant through gene conversion that could conceivably take place between the 4-bp deletion and the normal sequence in the respective region is discussed in detail. [ABSTRACT FROM AUTHOR]

Cyclic stretch is an important inducer of vascular smooth muscle cell (VSMC) proliferation, which is crucial in vascular remodeling during hypertension. However, the molecular mechanism remains unclear. We studied the effects of emerin and lamin A/C, two important nuclear envelope proteins, on VSMC proliferation in hypertension and the underlying mechano-mechanisms. In common carotid artery of hypertensive rats in vivo and in cultured cells subjected to high (15%) cyclic stretch in vitro, VSMC proliferation was increased significantly, and the expression of emerin and lamin A/C was repressed compared with normotensive or normal (5%) cyclic stretch controls. Using targeted siRNA to mimic the repressed expression of emerin or lamin A/C induced by 15% stretch, we found that VSMC proliferation was enhanced under static and 5%-stretch conditions. Overexpression of emerin or lamin A/C reversed VSMC proliferation induced by 15% stretch. Hence, emerin and lamin A/C play critical roles in suppressing VSMC hyperproliferation induced by hyperstretch. ChIP-on-chip and MOTIF analyses showed that the DNAs binding with emerin contain three transcription factor motifs: CCNGGA, CCMGCC, and ABTTCCG; DNAs binding with lamin A/C contain the motifs CVGGAA, GCCGCYGC, and DAAGAAA. Protein/DNA array proved that altered emerin or lamin A/C expression modulated the activation of various transcription factors. Furthermore, accelerating local expression of emerin or lamin A/C reversed cell proliferation in the carotid artery of hypertensive rats in vivo. Our findings establish the pathogenetic role of emerin and lamin A/C repression in stretch-induced VSMC proliferation and suggest mechanobiological mechanism underlying this process that involves the sequence-specific binding of emerin and lamin A/C to specific transcription factor motifs. [ABSTRACT FROM AUTHOR]