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A 3D structured composite was designed to improve the conductivity and to ease the volume problems of Si anode during cycling for lithium-ions batteries. An in situ method via a controllable gelation process was explored to fabricate the 3D composite of a multilayer carbon matrix toughened by cross-linked carbon nanotubes (CNTs) and decorated with conductive Cu agents. Structurally, a bifunctional carbon shell was formed on the surface of Si to improve the conductivity but alleviate side reactions. Cu particles as conducting agents decorated in the carbon matrix are also used to further improve the conductivity. The volume issue of Si particles can be effectively released via toughening the carbon matrix through the multilayered structure and cross-linked CNTs. Moreover, the carbon matrix might prevent silicon particles from agglomeration. Consequently, the Si@C@Cu composite is expected to exhibit benign electrochemical performances with a commendable capacity of 1500 mAh g–1 (900 cycles, 1 A g–1) and a h...

Nϵ-carboxymethyl-lysine (CML), an advanced glycation end product, is involved in vascular calcification (VC) in diabetic atherosclerosis. This study aimed to investigate the effects of CML on VC in diabetic atherosclerosis induced by vascular smooth muscle cell (VSMC)-derived foam cells. Human studies, animal studies and cell studies were performed. The human study results from 100 patients revealed a poor blood glucose and lipid status and more severe coronary lesions and stenosis in patients with coronary artery disease and diabetes mellitus. Intraperitoneal injection of streptozotocin combined with a high-fat diet was used to build a diabetic atherosclerosis model in ApoE-/- mice. The animal study results indicated that CML accelerated VC progression in diabetic atherosclerosis by accelerating the accumulation of VSMC-derived foam cells in ApoE-/- mice. The cell study results illustrated that CML induced VSMC-derived foam cells apoptosis and aggravated foam cells calcification. Consistent with this finding, calcium content and the expression levels of alkaline phosphatase, bone morphogenetic protein 2 and runt-related transcription factor 2 were significantly elevated in A7r5 cells treated with oxidation-low-density lipoprotein and CML. Thus, we concluded that CML promoted VSMC-derived foam cells calcification to aggravate VC in diabetic atherosclerosis, providing evidence for the contribution of foam cells to diabetic VC.

In this paper, pure ZnO, Co3O4-ZnO, Pd@ZnO and Pd@Co3O4-ZnO composite nanofibers were synthesized by electrospinning method. Multiple characterizations were employed to investigate the crystal structure, composition, morphology, and bonding states of the Pd@Co3O4-ZnO composite nanofibers. The sensing properties of the as-synthesized nanofibers were evaluated toward different volatile organic components (VOCs) including ethanol, acetone, isopropanol and formaldehyde under the various operating temperatures. The obtained results have clearly demonstrated that the Pd@Co3O4-ZnO composite nanofibers exhibits significantly enhanced VOC sensing performance compared with other nanofibers. Specifically, the response of Pd@Co3O4-ZnO composite nanofibers toward 200 ppm ethanol is 59 at 240℃, which is much higher than that of ZnO nanofibers. The enhanced VOC sensing properties of Pd@Co3O4-ZnO composite nanofibers could be attributed to the electronic and chemical sensitizations of Pd and the p-n junction formation at the interface of Co3O4 and ZnO.

We have synthesized pristine SnO2 and NiO/SnO2 hierarchical structures by a facile hydrothermal method. Structural and morphological characterizations of the obtained NiO/SnO2 samples were systematically studied using XRD, SEM, TEM and XPS. Meanwhile, gas-sensing properties of the as-fabricated pristine SnO2 and NiO/SnO2 sensor devices were investigated toward ppb-level acetone detection. The measured results show that the Ni1Sn3 gas sensor can reach a response of 20.18 toward 50 ppm acetone under optimum operating temperature (300 °C), which is about 3.3 times higher than that of pristine sensor. Moreover, the Ni1Sn3 gas sensor also exhibits fast response/recovery time (2 s/9 s), low detection limit (10 ppb) and good selectivity. We attribute the enhanced gas-sensing properties of NiO/SnO2 hierarchical structures to the synergetic effect as well as p-n heterojunction between the NiO and SnO2 structures.

Pristine and different amounts of praseodymium oxide (Pr6O11)-functionalized tin oxide (SnO2) flower-like architectures were synthesized by a facile one-step hydrothermal method. Their crystal structure, surface morphology, and chemical compositions were analyzed by XRD, SEM, TEM, and XPS. Measured results showed that Pr existing was in the form of Pr6O11. Compared with pristine SnO2 architectures, the gas sensing properties toward acetone of Pr6O11-functionalized SnO2 architectures could significantly be enhanced under different working temperatures. The response of the as-synthesized Pr6O11/SnO2 (Pr(mol):Sn(mol) = 1:50) sensor to 100 ppm acetone was about 27, which was about three times higher than that of pristine SnO2 architectures. The response/recovery time was 2/36 s at 200 °C. When acetone concentration was down to 1 ppm, Pr6O11/SnO2 (Pr(mol):Sn(mol) = 1:50) sensor also exhibited an obvious response. Meanwhile, the enhanced gas sensing mechanism of Pr6O11-functionalized SnO2 architectures was discussed, and the results indicated that the architectures are promising candidates for the practical acetone sensing.

Ag nanoparticles functionalized flower-like molybdenum disulfide (MoS2) hybrid nanostructures (AgNPs/MoS2) were successfully synthesized by a facile hydrothermal method. The structure and surface morphology were subsequently characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. The as-synthesized AgNPs/MoS2 hybrid nanostructures were modified on a glassy carbon electrode (GCE) and further utilized for amperometric hydrogen peroxide (H2O2) detection. The electrochemical behaviors and sensing performance of the AgNPs/MoS2/GCE were studied by cyclic voltammetry (CV) and single-potential amperometry methods. The obtained results have demonstrated that the developed AgNPs/MoS2/GCE amperometric sensor possesses an excellent catalytic performance toward the reduction of H2O2. The as-prepared electrochemical sensor exhibits fast response time of less than 3 s, large linear detection range of 0.025-135.2 mM (R-2=0.998) and high sensitivity of 54.5 mu A.mM(-1). cm(-2). Moreover, the developed H2O2 sensor has shown good anti interference ability, outstanding stability and reproducibility, which represents a great potential for H2O2 detection in practical applications.

In this paper, the reduced graphene oxide (rGO) and molybdenum disulfide (MoS2) (rGO-MoS2) heterostructures have been successfully synthesized by a facile hydrothermal method. The crystal phase, surface morphology, and chemical composition of the obtained heterostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) techniques. The electrochemical properties of the nitrite sensor attached with rGO-MoS2 heterostructures were investigated using cyclic voltammetry (CV) and single-potential amperometry methods. The measured results show that the as-prepared sensor based on rGO-MoS2/GCE exhibits a wide linear measurement range (0.2–4800 μM), low detection limit (0.17 μM), high sensitivity (0.46 μA μM−1 cm−2), and good selectivity and reproducibility towards nitrite detection. The anti-interference property and real sample analysis were also investigated, which shows that the as-prepared rGO-MoS2 heterostructures present great potential for practical applications.

In this work, palladium (Pd) nanoparticles functionalized reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNTs) hybrid structures (Pd/rGO-MWCNTs) were successfully prepared by a combination of electrochemical reduction with electrodeposition method. The morphology, structure, and composition of the Pd/rGO-MWCNTs hybrid were characterized by scanning electron microscopy, transmission electron microscopy and energy dispersive spectroscopy. The as-synthesized hybrid structures were modified on the glassy carbon electrode (GCE) and further utilized for hydrazine sensing. Electrochemical impedance spectroscopic, cyclic voltammetry and single-potential amperometry experiments were carried out on Pd/rGO-MWCNTs hybrid structures to investigate the interface properties and sensing performance. The measured results demonstrate that the fabricated Pd/rGO-MWCNTs/GCE sensor show a high sensitivity of 7.09 μA μM −1 cm −2 in a large concentration range of 1.0 to 1100 μM and a low detection limit of 0.15 μM. Moreover, the as-prepared sensor exhibits good selectivity and stability for the determination of hydrazine under interference conditions.

Flower-like pure and Mo-loaded In2O3 hierarchical microstructures were synthesized by a facile hydrothermal method. The morphology, crystal structures, and compositions of the samples were characterized by SEM, XRD, TEM, showing nanosheets with dimensions of 4 μm diameter and 25 nm thickness. Gas sensing experiments were conducted on the as-prepared MoO3/In2O3 gas sensors, and the results prove that Mo-loaded In2O3 gas sensors exhibit enhanced gas sensing properties at 185 °C. In particular, the 3 mol% Mo-loaded In2O3 provided a high response (7 to 100 ppm ethanol), fast response and recovery time (11 s and 94 s), low detection limit (50 ppb), good selectivity and stability for ethanol detection, which is promising for low concentration ethanol detection in practical applications.

Diabetic mellitus (DM) portends poor prognosis concerning pressure overloaded heart disease. Branched-chain amino acids (BCAAs), elements of essential amino acids, have been found altered in its catabolism in diabetes decades ago. However, the relationship between BCAAs and DM induced deterioration of pressure overloaded heart disease remains controversial. This study is aimed to investigate the particular effect of BCKA, a metabolite of BCAA, on myocardial injury induced by pressure overloaded. Primary cardiomyocytes were incubated with or without BCKA and followed by treatment with isoproterenol (ISO); then cell viability was detected by CCK8 and apoptosis was examined by TUNNEL stain and caspase-3 activity analysis. Compared to non-BCKA incubated group, BCKA incubation decreased cell survival and increased apoptosis concentration dependently. Furthermore, Western blot assay showed that mTORC2-Akt pathway was significantly inactivated by BCKA incubation. Moreover, overexpression of rictor, a vital component of mTORC2, significantly abolished the adverse effects of BCKA on apoptosis susceptibility of cardiomyocytes. These results indicate that BCKA contribute to vulnerability of cardiomyocytes in stimulated stress via inactivation of mTORC2-Akt pathway.

In this work, uniform single-crystalline α-Fe2O3 concave and hollow nanocrystals have been synthesized by a facile top-down etching method. Phosphate ions were employed as an etching agent to etch pristine icositetrahedra along their [006] direction in a top-down manner. The etched Fe2O3 concave and hollow nanocrystals exhibit a much larger specific surface area (SSA) and more edges, corners and rough structures (hot spots) on the crystal surface compared to their mother crystal, thus serving as the possible origin of their comparative photocatalytic activities in the degradation of cationic dye Rhodamine B. These characteristics make them promising candidates as catalysts and sensing materials.

In this paper, brush-like ZnO nanowires were synthesized by two-step method combining electrospinning and hydrothermal. The phase purity, morphology, and structure of the brush-like ZnO hierarchical structures were characterized, which exhibited the improved surface area, comparing with ZnO nanofibers. The gas-sensing experiments were carried out on brush-like ZnO nanowires and ZnO nanofibers sensors under optimum working temperature. The highest response of brush-like ZnO nanowires to 100 ppm toluene and CO can reach to 12.7 and 5.9, respectively, which was much higher than that of ZnO nanofibers. Moreover, the brush-like ZnO nanowires sensor also shows fast response/recovery time to toluene (9/4 s) and CO (6/2 s), low detection limit (1 ppm to toluene). The measured results demonstrate that brush-like ZnO nanowires are potential as a novel sensing material for practical gas-sensing applications.

Vascular complications are the major causes of death in patients with diabetes, and endothelial dysfunction is the earliest event in vascular complications of diabetes. It has been reported that plasma irisin level is significantly reduced in patients with type 2 diabetic patients. The present study aimed to investigate whether irisin improved endothelial function in type 2 diabetes as well as the underlying mechanisms. The type 2 diabetes model was established by feeding C57BL/6 mice with high-fat diet. The type 2 diabetic mice exhibited reduced serum irisin level and impaired endothelial function. Irisin treatment (0.5 mg/kg/d) for two weeks improved vascular function based on the evaluation of endothelium-dependent vasorelaxation and p-VASP levels. To investigate the direct endothelial protective effects of irisin, diabetic aortic segments were incubated with irisin (1 μg/ml) ex vivo. Exposure to irisin improved endothelium-dependent vasorelaxation of diabetic aortas. Mechanically, the diabetic aortic segments exhibited increased oxidative/nitrative stresses. Irisin reduced the diabetes-induced oxidative/nitrative stresses evidenced by reducing overproduction of superoxide and peroxynitrite, and down-regulation of iNOS and gp91(phox). To further investigate the protective effects of irisin on endothelial cells and the underlying mechanisms, human umbilical vein endothelial cells (HUVECs) cultured in high-glucose/high-fat (HG/HF) medium were pre-incubated with irisin. Irisin (1 μg/ml) reduced the oxidative/nitrative stresses and apoptosis induced by HG/HF in HUVECs probably via inhibiting activation of PKC-β/NADPH oxidase and NF-κB/iNOS pathways. Taken together, irisin alleviates endothelial dysfunction in type 2 diabetes partially via reducing oxidative/nitrative stresses through inhibiting signaling pathways implicating PKC-β/NADPH oxidase and NF-κB/iNOS, suggesting that irisin may be a promising molecule for the treatment of vascular complications of diabetes.

We report a simple and large-scale fabrication of carbon-coated Cu/Cu2O nanocomposite materials (Cu/Cu2O@carbon) and their application as sensing materials for hydrazine detection in a neutral medium. The Cu/Cu2O@carbon nanocomposite structures were successfully synthesized using a facile, cost-effective calcination method. The morphology, crystalline structure, and composition of the prepared Cu/Cu2O@carbon were characterized by scanning electron microscopy, X-ray diffraction, energy dispersive spectroscopy and high-resolution transmission electron microscopy. The hydrazine electrochemical sensor was fabricated by painting Cu/Cu2O@carbon on a glassy carbon electrode and immobilized using Nafion. By optimizing the Cu/Cu2O@carbon modified quantity and evaluating the performance using cyclic voltammetry and amperometry techniques, we demonstrated an optimal hydrazine electrochemical sensor with a high sensitivity of 2.37 μA μM−1 cm−2, an excellent linear concentration range of 0.25 μM to 800 μM, and a low detection limit of 0.022 μM.

Hydrangea-like Ag@ZnO nanostructures were synthesized utilizing aqueous solution method, followed by calcination at different temperatures in air. The crystal structure, surface morphology and chemical state of synthesized nanostructures were analyzed. The results showed that hydrangea-like Ag@ZnO architectures exhibited the diameters in the range of 1.54–3.54 μm and decorated with Ag nanoparticles approximately 15 nm. The photocatalytic experiments were conducted on the as-prepared Ag@ZnO samples for photocatalytic degradation of rhodamine B after calcinations from 400 to 900 °C. The measured results demonstrate that both the calcination temperature and the content of Ag can significant influence the photocatalytic activities. Moreover, the 0.5 mol% Ag@ZnO exhibits the highest photocatalytic activity under the optimum calcination temperature of 700 °C. This study indicates that the as-prepared Ag@ZnO nanostructures have promising potential applications in the fields such as photocatalysis, solar energy conversion and sensing detection.

International audience; A highly sensitive electrochemical sensor of hydrazine has been fabricated by Au nanoparticles (AuNPs) coating of carbon nanotubes-electrochemical reduced graphene oxide composite film (CNTs-ErGO) on glassy carbon electrode (GCE). Cyclic voltammetry and potential amperometry have been used to investigate the electrochemical properties of the fabricated sensors for hydrazine detection. The performances of the sensors were optimized by varying the CNTs to ErGO ratio and the quantity of Au nanoparticles. The results show that under optimal conditions, a sensitivity of 9.73 μA·μM−1·cm−2, a short response time of 3 s, and a low detection limit of 0.065 μM could be achieved with a linear concentration response range from 0.3 μM to 319 μM. The enhanced electrochemical performances could be attributed to the synergistic effect between AuNPs and CNTs-ErGO film and the outstanding catalytic effect of the Au nanoparticles. Finally, the sensor was successfully used to analyse the tap water, showing high potential for practical applications.

Cardiac metabolic remodeling is a central event during heart failure (HF) development following myocardial infarction (MI). It is well known that myocardial glucose and fatty acid dysmetabolism contribute to post-MI cardiac dysfunction and remodeling. However, the role of amino acid metabolism in post-MI HF remains elusive. Branched chain amino acids (BCAAs) are an important group of essential amino acids and function as crucial nutrient signaling in mammalian animals. The present study aimed to determine the role of cardiac BCAA metabolism in post-MI HF progression. Utilizing coronary artery ligation-induced murine MI models, we found that myocardial BCAA catabolism was significantly impaired in response to permanent MI, therefore leading to an obvious elevation of myocardial BCAA abundance. In MI-operated mice, oral BCAA administration further increased cardiac BCAA levels, activated the mammalian target of rapamycin (mTOR) signaling, and exacerbated cardiac dysfunction and remodeling. These data demonstrate that BCAAs act as a direct contributor to post-MI cardiac pathologies. Furthermore, these BCAA-mediated deleterious effects were improved by rapamycin cotreatment, revealing an indispensable role of mTOR in BCAA-mediated adverse effects on cardiac function/structure post-MI. Of note, pharmacological inhibition of branched chain ketoacid dehydrogenase kinase (BDK), a negative regulator of myocardial BCAA catabolism, significantly improved cardiac BCAA catabolic disorders, reduced myocardial BCAA levels, and ameliorated post-MI cardiac dysfunction and remodeling. In conclusion, our data provide the evidence that impaired cardiac BCAA catabolism directly contributes to post-MI cardiac dysfunction and remodeling. Moreover, improving cardiac BCAA catabolic defects may be a promising therapeutic strategy against post-MI HF.

The advanced glycation end products (AGEs) are associated with increased cardiac endothelial injury. However, no causative link has been established between increased AGEs and enhanced endothelial injury after ischemia/reperfusion. More importantly, the molecular mechanisms by which AGEs may increase endothelial injury remain unknown. Adult rat cardiac microvascular endothelial cells (CMECs) were isolated and incubated with AGE-modified bovine serum albumin (BSA) or BSA. After AGE-BSA or BSA preculture, CMECs were subjected to simulated ischemia (SI)/reperfusion (R). AGE-BSA increased SI/R injury as evidenced by enhanced lactate dehydrogenase release and caspase-3 activity. Moreover, AGE-BSA significantly increased SI/R-induced oxidative/nitrative stress in CMECs (as measured by increased inducible nitric oxide synthase expression, total nitric oxide production, superoxide generation, and peroxynitrite formation) and increased SI/R-induced nitrative inactivation of thioredoxin-1 (Trx-1), an essential cytoprotective molecule. Supplementation of EUK134 (peroxynitrite decomposition catalyst), human Trx-1, or soluble receptor of advanced end product (sRAGE) (a RAGE decoy) in AGE-BSA precultured cells attenuated SI/R-induced oxidative/nitrative stress, reduced SI/R-induced Trx-1 nitration, preserved Trx-1 activity, and reduced SI/R injury. Our results demonstrated that AGEs may increase SI/R-induced endothelial injury by increasing oxidative/nitrative injury and subsequent nitrative inactivation of Trx-1. Interventions blocking RAGE signaling or restoring Trx activity may be novel therapies to mitigate endothelial ischemia/reperfusion injury in the diabetic population.

Wood-polymer composites (WPC) have been extensively used for building products, outdoor decking, automotive, packaging materials, and other applications. WPC is subject to fungal and termite attacks due to wood components enveloped in the thermoplastic matrix. Much effort has been made to improve decay resistance of WPC using zinc borate and other chemicals. In this study, chitosan copper complex (CCC) compounds were used as a potential preservative for wood-HDPE composites. CCC was formulated by reacting chitosan with copper salts under controlled conditions. Inductively coupled plasma (ICP) analytical results indicated that chitosan had high chelating efficiency with copper cations. CCC-treated wood-HDPE composites had a thermal behavior similar to untreated and zinc borate-treated wood-HDPE composites. Incorporation of CCC in wood-HDPE composites did not significantly influence board density of the resultant composites, but had a negative effect on tensile strength at high CCC concentration. In comparison with solid wood and the untreated wood-HDPE composites, 3% CCC-treated wood-HDPE composites significantly improved the decay resistance against white rot fungus Trametes versicolor and brown rot fungus Gloeophyllum trabeum. Especially, CCC-treated wood-HDPE composites were more effectively against the brown rot than the untreated and chitosan-treated wood-HDPE composites. Moreover, CCC-treated wood-HDPE composites performed well as zinc borate-treated wood-HDPE composites on fungal decay resistance. Accordingly, CCC can be effectively used as a preservative for WPC.

The effects of the monomer ratio, surfac- tant, and crosslinker contents on the particle size and phase-transition behavior of the copolymer poly(N-isopro- pylacrylamide-co-methacrylic acid) (PNIPAAm-MAA) were investigated with Fourier transform infrared, differ- ential scanning calorimetry, and dynamic laser scattering techniques. In addition to the thermoresponsive property of poly(N-isopropylacrylamide), ionized methacrylic acid groups brought pH sensitivity to the PNIPAAm-MAA co- polymer particles. The polymer particle size varied with the amounts of the monomer ratio, surfactant, and cross- linker. As the monomer ratio and crosslinker content increased and the amount of the surfactants decreased, the particle size increased. The influence of the crosslinker content on the particle size was less significant than the effect of the monomer ratio and surfactants. When the temperature increased, the particles tended to shrink and decreased in size to near or below 100 nm. Particle sizes at 208C decreased to less than 100 nm with increased surfac- tant content. The control of the particle size within the 100-nm range makes PNIPAAm-MAA copolymer particles useful for biomedical and heavy-metal-ion adsorption applications. 2008 Wiley Periodicals, Inc. J Appl Polym Sci 108: 2226-2232, 2008

According to the low temperature and high effective bonding problem of microdevices made of degradable polymer PLGA, chemical, plasma, and UV irradiation method are used to study the experimental surface treatment of PLGA films and microdevices bonding process. The results show that all three methods can reduce the surface contact angle of PLGA films, the contact angle increases with time at room temperature, and the PLGA films contact angle is almost unchanged under refrigeration. The PLGA film bonding temperature is significantly reduced after UV irradiation, and the bonding interfaces also generate diffusion cross linking layer are dense and uniform.

The receptor for advanced glycation end products (RAGE) and thioredoxin (Trx) play opposing roles in diabetic myocardial ischemia-reperfusion (MI/R) injury. We recently demonstrated nitrative modification of Trx leads to its inactivation and loss of cardioprotection. The present study is to determine the relationship between augmented RAGE expression and diminished Trx activity pertaining to exacerbated MI/R injury in the diabetic heart. The diabetic state was induced in mice by multiple intraperitoneal low-dose streptozotocin injections. RAGE small-interfering RNA (siRNA) or soluble RAGE (sRAGE, a RAGE decoy) was via intramyocardial and intraperitoneal injection before MI/R, respectively. Mice were subjected to 30 min of myocardial infarction followed by 3 or 24 h of reperfusion. At 10 min before reperfusion, diabetic mice were randomized to receive EUK134 (peroxynitrite scavenger), recombinant hTrx-1, nitrated Trx-1, apocynin (a NADPH oxidase inhibitor), or 1400W [an inducible nitric oxide synthase (iNOS) inhibitor] administration. The diabetic heart manifested increased RAGE expression and Nε-(carboxymethyl)lysine (CML, major advanced glycation end product subtype) content, reduced Trx-1 activity, and increased Trx nitration after MI/R. RAGE siRNA or administration of sRAGE in diabetic mice decreased MI/R-induced iNOS and gp91phox expression, reduced Trx nitration, preserved Trx activity, and decreased infarct size. Apocynin or 1400W significantly decreased nitrotyrosine production and restored Trx activity. Conversely, administration of either EUK134 or reduced hTrx, but not nitrated hTrx, attenuated MI/R-induced superoxide production, RAGE expression, and CML content and decreased cardiomyocyte apoptosis in diabetic mice. Collectively, we demonstrate that RAGE modulates the MI/R injury in a Trx nitrative inactivation fashion. Conversely, nitrative modification of Trx blocked its inhibitory effect upon RAGE expression in the diabetic heart. This is the first direct evidence demonstrating the alternative cross talk between RAGE overexpression and nitrative Trx inactivation, suggesting that interventions interfering with their interaction may be novel means of mitigating diabetic MI/R injury.

Composites based on high density polyethylene (HDPE), pine flour, and organic clay were made by melt compounding and injection molding. The influence of clay on crystallization behavior, mechanical properties, water absorption, and thermal stability of HDPE/pine composites were investigated. The HDPE/pine composites containing exfoliated clay were made by a two-step melt compounding procedure with a maleated polyethylene (MAPE) as a compatibilizer. Adding 2% clay to a HDPE/pine composite without MAPE decreased the crystallization temperature (Tc ) and rate, and the crystallinity level. When 2% MAPE was added, the Tc and crystallization rate increased, but the crystallinity level was lowered. The flexural strength and the tensile strength of HDPE/pine composites increased 19.6% and 24.2% respectively with addition of 1% clay but then decreased slightly as the clay content was increased to 3%. The tensile modulus and tensile elongation were increased 11.8% and 13% respectively with addition of 1% clay but the storage and loss moduli barely change as the clay content was increased to 3%. The impact strength was lowered 7.5% by adding 1% clay, but did not decrease further as more clay was added. The moisture content and thickness swelling of the HDPE/pine composites was reduced by the clay, but did not improve the thermal stability.Copyright © 2007 by ASME

Fluorescence calibration is usually done by preparing bio-samples with a series of concentrations and measuring their corresponding fluorescence intensities. A simplified approach is studied by using a microfluidic chip and microspheres. The fluorescence calibration can be carried out on the chip with only one concentration of the microspheres. Microspheres with the diameter of 1~5μm are very useful in bio-detection research. These microspheres are manufactured using high-quality, ultraclean polystyrene microspheres and loaded with a variety of proprietary dyes. They can be labeled with biotin-, NeutrAvdin-, streptavidin- and protein, which can be used as tracers for bio-detections. A microfluidic chip was successfully fabricated for the experiment, and preliminary experimental results have proved the feasibility of the approach for fluorescence calibration.

The detection of saccharides in biological media is of great current importance for the monitoring of disease states. We have previously reported that solutions of boronic acid-functionalized macrocycles form acyclic oligomeric materials in situ. The oligomers contain fluorescent xanthene moieties. Current efforts are aimed at modulating the spectroscopic responses of these materials for the analysis of specific sugars. We describe conditions whereby the xanthene boronic acids exhibit high colorimetric fructose selectivity. In contrast, at physiological levels selective glucose monitoring can be achieved via fluorescence. Additionally, we describe a method which exhibits promise for detecting both glucose and fructose at dual wavelengths in the UV-Vis region. Mechanistic rationale for each of these findings is presented.

The determination of cysteine and homocysteine levels is of great current interest for the monitoring of desease states. A new colorimetric method for the simultaneous detection of l-cysteine and l-homocysteine has been developed. A fluorescein derivative reacts with the above amino acids, producing their respective thiazolidines resulting in color changes. Interference from other amino acids and proteins is minimal.

The Western meat-rich diet is both high in protein and fat. Although the hazardous effect of a high fat diet (HFD) upon liver structure and function is well recognized, whether the co-presence of high protein intake contributes to, or protects against, HF-induced hepatic injury remains unclear. Increased intake of branched chain amino acids (BCAA, essential amino acids compromising 20% of total protein intake) reduces body weight. However, elevated circulating BCAA is associated with non-alcoholic fatty liver disease and injury. The mechanisms responsible for this quandary remain unknown; the role of BCAA in HF-induced liver injury is unclear. Utilizing HFD or HFD + BCAA models, we demonstrated BCAA supplementation attenuated HFD-induced weight gain, decreased fat mass, activated mammalian target of rapamycin (mTOR), inhibited hepatic lipogenic enzymes, and reduced hepatic triglyceride content. However, BCAA caused significant hepatic damage in HFD mice, evidenced by exacerbated hepatic oxidative stress, increased hepatic apoptosis, and elevated circulation hepatic enzymes. Compared to solely HFD-fed animals, plasma levels of free fatty acids (FFA) in the HFD + BCAA group are significantly further increased, due largely to AMPKα2-mediated adipocyte lipolysis. Lipolysis inhibition normalized plasma FFA levels, and improved insulin sensitivity. Surprisingly, blocking lipolysis failed to abolish BCAA-induced liver injury. Mechanistically, hepatic mTOR activation by BCAA inhibited lipid-induced hepatic autophagy, increased hepatic apoptosis, blocked hepatic FFA/triglyceride conversion, and increased hepatocyte susceptibility to FFA-mediated lipotoxicity. These data demonstrated that BCAA reduces HFD-induced body weight, at the expense of abnormal lipolysis and hyperlipidemia, causing hepatic lipotoxicity. Furthermore, BCAA directly exacerbate hepatic lipotoxicity by reducing lipogenesis and inhibiting autophagy in the hepatocyte., Highlights • BCAA cause hepatic injury via complex mechanisms involving both adipocytes and hepatic cells. • In the adipocyte, BCAA activate AMPKα2 and stimulate lipolysis, increasing plasma free fatty acids (FFA), which in turn results in hepatic FFA accumulation. • In the liver, BCAA activate mTOR and inhibit FFA to TG conversion and autophagy, intensifying FFA lipotoxicity. High fat diet (HFD) induces systemic BCAA catabolic defects. Under HFD conditions, increased BCAA consumption further increases circulating BCAA abundance. BCAA-enhanced adipocyte lipolysis induces hyperlipidemia through activating AMPKα2. Elevated circulating FFA results in insulin resistance and hepatic lipotoxicity. Moreover, BCAA activate hepatic mTOR, inhibit lipogenesis and autophagy, therefore increasing hepatic susceptibility to FFA-mediated lipotoxicity. As BCAA are abundant in protein, our results call for caution regarding the ingestion of high protein diets in obesity and diabetic individuals, unless their BCAA metabolic pathways are determined normal.