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Authors = Xinxin Li

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Open AccessArticle Long-Term Streamflow Forecasting Based on Relevance Vector Machine Model
Water 2017, 9(1), 9; doi:10.3390/w9010009
Received: 26 September 2016 / Revised: 14 December 2016 / Accepted: 21 December 2016 / Published: 28 December 2016
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Abstract
Long-term streamflow forecasting is crucial to reservoir scheduling and water resources management. However, due to the complexity of internally physical mechanisms in streamflow process and the influence of many random factors, long-term streamflow forecasting is a difficult issue. In the article, we mainly
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Long-term streamflow forecasting is crucial to reservoir scheduling and water resources management. However, due to the complexity of internally physical mechanisms in streamflow process and the influence of many random factors, long-term streamflow forecasting is a difficult issue. In the article, we mainly investigated the ability of the Relevance Vector Machine (RVM) model and its applicability for long-term streamflow forecasting. We chose the Dahuofang (DHF) Reservoir in Northern China and the Danjiangkou (DJK) Reservoir in Central China as the study sites, and selected the 500 hpa geopotential height in the northern hemisphere and the sea surface temperatures in the North Pacific as the predictor factors of the RVM model and the Support Vector Machine (SVM) model, and then conducted annual streamflow forecasting. Results indicate that forecasting results in the DHF Reservoir is much better than that in the DJK Reservoir when using SVM, because streamflow process in the latter basin has a magnitude bigger than 1000 m3/s. Comparatively, accurate forecasting results in both the two basins can be gotten using the RVM model, with the Nash Sutcliffe efficiency coefficient bigger than 0.7, and they are much better than those gotten from the SVM model. As a result, the RVM model can be an effective approach for long-term streamflow forecasting, and it also has a wide applicability for the streamflow process with a discharge magnitude from dozen to thousand cubic meter per second. Full article
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Open AccessArticle Gene-Silencing-Induced Changes in Carbohydrate Conformation in Relation to Bioenergy Value and Carbohydrate Subfractions in Modeled Plant (Medicago sativa) with Down-Regulation of HB12 and TT8 Transcription Factors
Int. J. Mol. Sci. 2016, 17(5), 720; doi:10.3390/ijms17050720
Received: 14 January 2016 / Revised: 21 April 2016 / Accepted: 3 May 2016 / Published: 13 May 2016
Cited by 1 | Viewed by 747 | PDF Full-text (1883 KB) | HTML Full-text | XML Full-text
Abstract
Gene silencing with RNA interference (RNAi) technology may be capable of modifying internal structure at a molecular level. This structural modification could affect biofunctions in terms of biodegradation, biochemical metabolism, and bioactive compound availability. The objectives of this study were to (1) Detect
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Gene silencing with RNA interference (RNAi) technology may be capable of modifying internal structure at a molecular level. This structural modification could affect biofunctions in terms of biodegradation, biochemical metabolism, and bioactive compound availability. The objectives of this study were to (1) Detect gene silencing-induced changes in carbohydrate molecular structure in an alfalfa forage (Medicago sativa spp. sativa: alfalfa) with down-regulation of genes that encode transcription factors TT8 and HB12; (2) Determine gene silencing-induced changes in nutrient bioutilization and bioavailability in the alfalfa forage (Medicago sativa); and (3) Quantify the correlation between gene silencing-induced molecular structure changes and the nutrient bioutilization and bioavailability in animals of ruminants. The experimental treatments included: T1 = Non-transgenic and no-gene silenced alfalfa forage (code “NT”); T2 = HB12-RNAi forage with HB12 gene down regulation (code “HB12”); T3 = TT8-RNAi forage with TT8 gene down regulation (code “TT8”). The HB12 and TT8 gene silencing-induced molecular structure changes were determined by non-invasive and non-destructive advanced molecular spectroscopy in a middle infrared radiation region that focused on structural, non-structural and total carbohydrate compounds. The nutrient bioutilization and bioavailability of the modified forage were determined using NRC-2001 system in terms of total digestive nutrient (TDN), truly digestible fiber (tdNDF), non-fiber carbohydrate (tdNDF), fatty acid (tdFA), crude protein (tdCP) and bioenergy profiles (digestible energy, metabolizable energy, net energy) for ruminants. The carbohydrate subfractions were evaluated using the updated CNCPS 6.0 system. The results showed that gene silencing significantly affected tdNFC (42.3 (NT) vs. 38.7 (HB12) vs. 37.4% Dry Matter (TT8); p = 0.016) and tdCP (20.8 (NT) vs. 19.4 (HB12) vs. 22.3% DM (TT8); p = 0.009). The gene-silencing also affected carbohydrate CA4 (7.4 (NT) vs. 4.2 (HB12) and 4.4% carbohydrate (CHO) (TT8), p = 0.063) and CB1 fractions (5.3 (NT) vs. 2.0 (HB12) and 2.6% CHO (TT8), p = 0.006). The correlation study showed that the structural CHO functional group peak area intensity at ca. 1315 cm−1 was significantly correlated to the TDN1x (r = −0.83, p = 0.042) and the tdNFC (r = −0.83, p = 0.042), the structural CHO functional group height intensity at ca. 1370 cm−1 was significantly correlated to the tdNDF (r = −0.87, p = 0.025). The A_Non-stCHO to A_StCHO ratio and A_Non-stCHO to A_CHO ratio were significantly correlated to the tdFA (r = 0.83–0.91, p < 0.05). As to carbohydrate fractions, both CA4 and CB1 correlated with carbohydrate spectral intensity of the H_1415 and the H_1315 (p = 0.039; p = 0.059, respectively), CB3 tended to correlate with the H_1150, H_1100 and H_1025 (p < 0.10). In conclusion, RNAi-mediated silencing of HB12 and TT8 modified not only inherent CHO molecular structure but also the biofunctions. The CHO molecular structure changes induced by RNAi gene silencing were associated with biofunctions in terms of the carbohydrate subfractions and nutrient digestion. Full article
(This article belongs to the Section Bioactives and Nutraceuticals)
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Open AccessReview Advanced Nanoporous Materials for Micro-Gravimetric Sensing to Trace-Level Bio/Chemical Molecules
Sensors 2014, 14(10), 19023-19056; doi:10.3390/s141019023
Received: 29 August 2014 / Revised: 1 October 2014 / Accepted: 9 October 2014 / Published: 13 October 2014
Cited by 16 | Viewed by 2400 | PDF Full-text (7230 KB) | HTML Full-text | XML Full-text
Abstract
Functionalized nanoporous materials have been developed recently as bio/chemical sensing materials. Due to the huge specific surface of the nano-materials for molecular adsorption, high hopes have been placed on gravimetric detection with micro/nano resonant cantilevers for ultra-sensitive sensing of low-concentration bio/chemical substances. In
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Functionalized nanoporous materials have been developed recently as bio/chemical sensing materials. Due to the huge specific surface of the nano-materials for molecular adsorption, high hopes have been placed on gravimetric detection with micro/nano resonant cantilevers for ultra-sensitive sensing of low-concentration bio/chemical substances. In order to enhance selectivity of the gravimetric resonant sensors to the target molecules, it is crucial to modify specific groups onto the pore-surface of the nano-materials. By loading the nanoporous sensing material onto the desired region of the mass-type transducers like resonant cantilevers, the micro-gravimetric bio/chemical sensors can be formed. Recently, such micro-gravimetric bio/chemical sensors have been successfully applied for rapid or on-the-spot detection of various bio/chemical molecules at the trace-concentration level. The applicable nanoporous sensing materials include mesoporous silica, zeolite, nanoporous graphene oxide (GO) and so on. This review article focuses on the recent achievements in design, preparation, functionalization and characterization of advanced nanoporous sensing materials for micro-gravimetric bio/chemical sensing. Full article
(This article belongs to the Special Issue Nanopore Sensors: Fabrications, Properties and Applications)
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Open AccessArticle Monolithic Composite “Pressure + Acceleration + Temperature + Infrared” Sensor Using a Versatile Single-Sided “SiN/Poly-Si/Al” Process-Module
Sensors 2013, 13(1), 1085-1101; doi:10.3390/s130101085
Received: 26 November 2012 / Revised: 27 December 2012 / Accepted: 5 January 2013 / Published: 16 January 2013
Cited by 2 | Viewed by 2447 | PDF Full-text (1284 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
We report a newly developed design/fabrication module with low-cost single-sided “low-stress-silicon-nitride (LS-SiN)/polysilicon (poly-Si)/Al” process for monolithic integration of composite sensors for sensing-network-node applications. A front-side surface-/bulk-micromachining process on a conventional Si-substrate is developed, featuring a multifunctional SiN/poly-Si/Al layer design for diverse sensing functions.
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We report a newly developed design/fabrication module with low-cost single-sided “low-stress-silicon-nitride (LS-SiN)/polysilicon (poly-Si)/Al” process for monolithic integration of composite sensors for sensing-network-node applications. A front-side surface-/bulk-micromachining process on a conventional Si-substrate is developed, featuring a multifunctional SiN/poly-Si/Al layer design for diverse sensing functions. The first “pressure + acceleration + temperature + infrared” (PATIR) composite sensor with the chip size of 2.5 mm × 2.5 mm is demonstrated. Systematic theoretical design and analysis methods are developed. The diverse sensing components include a piezoresistive absolute-pressure sensor (up to 700 kPa, with a sensitivity of 49 mV/MPa under 3.3 V supplied voltage), a piezoresistive accelerometer (±10 g, with a sensitivity of 66 μV/g under 3.3 V and a −3 dB bandwidth of 780 Hz), a thermoelectric infrared detector (with a responsivity of 45 V/W and detectivity of 3.6 × 107 cm·Hz1/2/W) and a thermistor (−25–120 °C). This design/fabrication module concept enables a low-cost monolithically-integrated “multifunctional-library” technique. It can be utilized as a customizable tool for versatile application-specific requirements, which is very useful for small-size, low-cost, large-scale sensing-network node developments. Full article
(This article belongs to the Section Physical Sensors)
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Open AccessArticle Expression of Sox2 and Oct4 and Their Clinical Significance in Human Non-Small-Cell Lung Cancer
Int. J. Mol. Sci. 2012, 13(6), 7663-7675; doi:10.3390/ijms13067663
Received: 11 April 2012 / Revised: 15 June 2012 / Accepted: 19 June 2012 / Published: 21 June 2012
Cited by 38 | Viewed by 2726 | PDF Full-text (407 KB) | HTML Full-text | XML Full-text
Abstract
Sox2 and Oct4 are transcription factors with the characteristics of regulating self-renewal and differentiation of embryonic stem cell. The aim of this study was to detect the expression of Sox2 and Oct4 and analyze their clinical significance in human non-small-cell lung cancer (NSCLC).
[...] Read more.
Sox2 and Oct4 are transcription factors with the characteristics of regulating self-renewal and differentiation of embryonic stem cell. The aim of this study was to detect the expression of Sox2 and Oct4 and analyze their clinical significance in human non-small-cell lung cancer (NSCLC). Expression of Sox2 and Oct4 were assayed in cancer tissues and their corresponding paracancerous tissues from 44 patients with NSCLC and 21 patients with benign tumors using immunohistochemistry, Western blot, reverse transcription polymerase chain reaction (RT-PCR). The correlation between the expression of Sox2 and Oct4 and tumor type, grade and prognosis and the utility of the two genes in discriminating between benign and malignant tumors were analyzed as well. The results showed that Sox2 and Oct4 positive staining was only seen in the nuclei of cancer cells but not in either the precancerous tissues or benign tumor tissues by immunohistochemistry (p < 0.01). Furthermore, in the lung cancer tissue, the positive rate for Sox2 and Oct4 was 70.5% and 54.5%, respectively. Meanwhile, clinicopathological correlations showed that the Oct4 expression level was significantly associated with poorer differentiation and higher TNM stage of the cancer (p < 0.05). Western blot and RT-PCR analysis showed similar results to immunohistochemistry. Follow-up analysis revealed that expression of Oct4 was significantly associated with poor prognosis of lung cancer. The conclusion is that Sox2 and Oct4 may act as the promising unit markers in directing NSCLC diagnosis and therapy. Also, Oct4 can be regarded as a novel predictor of poor prognosis for NSCLC patients undergoing resection. Full article
(This article belongs to the Special Issue Advances in Molecular Oncology (special issue))
Open AccessArticle Fabrication of Submicron Beams with Galvanic Etch Stop for Si in TMAH
Sensors 2009, 9(4), 2470-2477; doi:10.3390/s90402470
Received: 17 February 2009 / Revised: 15 March 2009 / Accepted: 2 April 2009 / Published: 9 April 2009
Cited by 3 | Viewed by 9795 | PDF Full-text (270 KB) | HTML Full-text | XML Full-text
Abstract
A novel method has been developed to fabricate submicron beams with galvanic etch stop for Si in TMAH. The different Au:Si area ratios before and after the release of the beams are used to trigger the galvanic etch stop to fabricate submicron single
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A novel method has been developed to fabricate submicron beams with galvanic etch stop for Si in TMAH. The different Au:Si area ratios before and after the release of the beams are used to trigger the galvanic etch stop to fabricate submicron single crystal Si beams in standard Si wafers. Before the beams are released from the substrate, the Au electrodes are connected to the substrate electrically. The Au:Si area ratios are much smaller than the threshold value. TMAH etches the Si wafers. After the beams are fully released, they are mechanically supported by the Au wires, which also serve as the galvanic etch stop cathodes. The Au:Si area ratios are much larger than the threshold value. The beams are protected by galvanic etch stop. The thicknesses of the beams are determined by shallow dry etching before TMAH etching. A 530 nm thick beam was fabricated in standard (111) wafers. Experiments showed that the beam thicknesses did not change with over etching, even if the SiO2 layers on the surface of the beams were stripped. Full article
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