Quantum Criticality of the Ising-like Screw Chain Antiferromagnet SrCo_{2}V_{2}O_{8} in a Transverse Magnetic Field.

The quantum criticality of an Ising-like screw chain antiferromagnet SrCo_{2}V_{2}O_{8}, with a transverse magnetic field applied along the crystalline a axis, is investigated by ultralow temperature NMR measurements. The Néel temperature is rapidly and continuously suppressed by the field, giving rise to a quantum critical point (QCP) at H_{C_{1}}≈7.03 T. Surprisingly, a second QCP at H_{C_{2}}≈7.7 T featured with gapless excitations is resolved from both the double-peak structure of the field-dependent spin-lattice relaxation rate 1/^{51}T_{1} at low temperatures and the weakly temperature-dependent 1/^{51}T_{1} at this field. Our data, combined with numerical calculations, suggest that the induced effective staggered transverse field significantly lowers the critical fields, and leads to an exposed QCP at H_{C_{2}}, which belongs to the one-dimensional transverse-field Ising universality.

Bio-syncretic tweezers actuated by microorganisms: modeling and analysis.

Advancements in micro-/nano-technology have led to the development of micro-manipulators. However, some challenges remain; for instance, the efficiency, precision and flexibility of micro-manipulators restrain their applications. This paper proposes a bio-tweezer system to flexibly manipulate micro-objects with bio-actuation via local light-induced high-concentration microorganisms in two different manipulation modes: light-spot induced mode and geometric shape-induced mode. Depending on the shape of micro-objects, either 2-dimensional translation or 1-dimensional rotation can be achieved. Based on the Langevin equation, a mathematical model considering both hydrodynamics and mimicked Brownian motion is proposed to analyze the bio-manipulation performance of the microorganisms; the model was validated by experiments to translate micro-particles in a two-dimensional plane and to rotate a micro-gear structure around its axis. This paper will aid in the development of micro-manipulators and the quantitative understanding of micro-/nano-manipulation actuated by microorganisms.

Mutagenicity of ZnO nanoparticles in mammalian cells: Role of physicochemical transformations under the aging process.

Zinc oxide nanoparticles (ZnO NPs) potentially undergo physicochemical transformation in the environment, which may lead to unexpected environmental and health risks. The "aging" process is essential for better understanding the toxicity and fate of NPs in the environment. However, the mutagenic effects of aged ZnO NPs are still unexplored. The present study focused on investigating the physicochemical transformation during aging process and clarifying the mutagenicity of naturally aged ZnO NPs in human-hamster hybrid (AL) cells. It was found that ZnO NPs underwent sophisticated physicochemical transformations with aging regardless of original morphology or size, such as the microstructural changes, the formation of hydrozincite (Zn5(CO3)2(OH)6) and the release of free zinc ions. Interestingly, the aged ZnO NPs were investigated to be able to result in much lower cytotoxicity while relatively high degree mutation than fresh ZnO NPs. With characterization of the soluble and insoluble fractions of aged ZnO NPs suspension, together with the control measurements using metal chelator (TPEN) and endocytosis inhibitor (Nystatin), it was revealed that the release of zinc ions and nanoparticle uptake made significantly different contributions to the mutagenicity of fresh and aged ZnO NPs. This study clearly demonstrated that the physicochemical transformation of ZnO NPs with aging plays important and comprehensive roles in the ZnO NPs-induced mutagenicity in mammalian cells.

Isolation of a Bluetongue virus group-specific monoclonal antibody and application to a diagnostic competitive ELISA.

The Bluetongue virus (BTV) VP7 protein represents an important group-specific antigen that can serve as a basis for diagnostic tests. Here, we report the generation of a novel BTV group-specific monoclonal antibody (Mab; herein named 4H7) that recognizes a conformational epitope in the VP7 protein. We used a phage-displayed peptide screen and site-directed mutagenesis to define the VP7 amino acid residues that most strongly contribute to the conformational epitope recognized by Mab 4H7. Amino acid residues at positions 175, 185, 186, and 278 of the BTV VP7 protein strongly contributed to Mab 4H7 binding. These key amino acid residues are conserved among all BTV serotypes, whereas related Orbiviruses possess at least one amino acid substitution at these positions. We developed a competitive enzyme-linked immunosorbent assay (c-ELISA) using Mab 4H7 and recombinant BTV VP7 protein to detect serum antibodies against this BTV group-specific VP7 epitope. The c-ELISA was used to screen 833 clinical samples collected from animals in three provinces of China. BTV seroprevalence in the three provinces ranged from 25.42 to 47.45 %. This work provides the foundation for a new diagnostic c-ELISA that can be further applied to BTV surveillance activities and informs our understanding of the structure of the BTV VP7 protein.

Nanoscale distribution of CD20 on B-cell lymphoma tumour cells and its potential role in the clinical efficacy of rituximab.

Rituximab is an exciting monoclonal antibody drug approved for treating B-cell lymphomas and its target is the CD20 antigen which is expressed on the surface of B cells. In recent years, the variable efficacies of rituximab among different lymphoma patients have become an important clinical issue and urgently need to be solved for further development of antibodies with enhanced efficacies. In this work, atomic force microscopy (AFM) was used to investigate the nanoscale distribution of CD20 on the surface of tumour B cells from lymphoma patients to examine its potential role in the clinical therapeutic effects of rituximab. By performing ROR1 fluorescence labelling (ROR1 is a specific tumour cell surface marker) on the bone marrow cells prepared from B-cell lymphoma patients, the tumour B cells were recognized, and then AFM tips carrying rituximabs via polyethylene glycol crosslinkers were moved to the tumour cells to probe the specific CD20-rituximab interactions. By applying AFM single-molecule force spectroscopy (SMFS) at the local areas (500×500 nm²) on the surface of tumour B cells, the nanoscale distributions of CD20 on the surface of tumour B cells were mapped, visually showing that CD20 distributed heterogeneously on the cell surface. Bone marrow cell samples from three clinical B-cell lymphoma cases were collected to analyze the binding affinity and nanoscale distribution of CD20 on tumour cells. The experimental results showed that CD20 distribution on tumour cells were to some extent related to the clinical therapeutic outcomes while the CD20-rituximab binding forces did not have distinct effects to the clinical outcomes. These results can provide novel insights in understanding the rituximab's clinical efficacies from the nanoscale distribution of CD20 on the tumour cells at single-cell and single-molecule levels.

Elevated visfatin levels in obese children are related to proinflammatory factors.

BACKGROUND: Obesity and related metabolic diseases are associated with a state of chronic low-grade inflammation,which is characterized by abnormal cytokine production and increased synthesis of proinflammatory proteins.Recent studies have indicated that visfatin is both an adipokine and an inflammatory cytokine. OBJECTIVE: In this study, we assessed the association between serum visfatin concentrations and markers of systemic inflammation [high-sensitivity C-reactive protein (hs-CRP), interleukin 6 (IL-6), and tumor necrosis factor a (TNF-a)] and insulin resistance in Chinese obese children. METHODS: A total of 44 obese Chinese children (23 boys and 21 girls) and 50 age- and gender-matched normal weight children (23 boys and 27 girls) were enrolled in the study. Anthropometric measurements and blood pressure were taken. Fasting levels of visfatin, hs-CRP, IL-6, TNF-a,glucose, insulin, and lipid profile were assayed, and the homeostasis model assessment for insulin resistance was calculated as a marker of insulin resistance. RESULTS: Serum visfatin levels [obese group (OB):7.48±0.39 vs. C: 5.31±0.28, pO.OS); there were no significant differences in visfatin, hs-CRP, IL-6, and TNF-a concentrations between girls and boys. The correlations between visfatin and anthropometric, metabolic parameters,and inflammatory [body mass index (BMI), waist circumference, triglyceride, hs-CRP, IL-6, TNF-a] revealed differences between genders; visfatin correlated with BMI(r=0.247, p=0.029) and IL-6 (r=0.427, p=0.013) in boys only. CONCLUSION: The association of circulating visfatin with anthropometric parameters, metabolic parameters, and inflammatory factors is dependent on gender, although no such correlation was observed between serum visfatin concentration and insulin resistance. Visfatin could bean important inflammatory cytokine representing a low grade inflammatory state in obesity.

Gate dependent photo-responses of carbon nanotube field effect phototransistors.

Gate dependent photoconductivity of carbon nanotube (CNT) field effect phototransistors (FEPs) was systematically investigated in this study. The photo-response comparisons of CNT FEPs with symmetric and asymmetric metal structures connecting to the same CNT revealed that the gate effect contributed to a sensitivity improvement with a lower dark current, a higher photocurrent, and an enhanced photovoltage. A functionalized asymmetric FEP, fabricated by partially doping the CNT utilizing a polyethylene imine (PEI) polymer, verified that FEPs delivered a better performance by using asymmetric structures. A multi-gate FEP, with three pairs of side-gates that can electrostatically dope different sections of a CNT independently, was fabricated to examine the gate structure dependent photo-responses. Experimental measurements showed an unconventional photocurrent improvement that was weakly dependent on the gate location, which was attributed to the unique charge distribution of one-dimensional semiconductors.

Childhood psoriasis treatment: evidence published over the last 5 years.

Psoriasis is a common skin condition seen in pediatrics. Treatment modalities used to treat psoriasis in children are different from those prevailing in the adult population and require adequate testing in pediatric subjects. This article reviews the published evidence on the different treatment modalities for pediatric psoriasis over the past 5 years.

The relationship between plasma level of adiponectin and coronary lesion complexity in the population of north-east China.

The relationship between plasma adiponectin and severity of coronary artery disease (CAD) in 683 cases of suspected CAD from north-east China was determined. Cases were divided into four groups, as follows: group 1, no stenosis; group 2, > 50% stenosis of one vessel; group 3, > 50% stenosis of two vessels; group 4, > 50% stenosis of three or more vessels. Group 1 was classified as a non-CAD group (control) and groups 2, 3 and 4 were classified as CAD groups. Plasma adiponectin levels were significantly correlated with coronary artery stenosis and were lower in the CAD groups than in the non-CAD group. Adiponectin concentration decreased from group 2 to group 4, but this difference was not significant. Adiponectin levels among females were also lower than for males in the CAD groups. There was a significant difference between plasma adiponectin levels in patients with coronary stenoses versus those without, but there were no significant differences between the three CAD groups in terms of plasma adiponectin levels.

Force measurement and mechanical characterization of living Drosophila embryos for human medical study.

The objective of this paper is to investigate and characterize the force behaviour and mechanical properties of living Drosophila embryos using an in situ polyvinylidene fluoride (PVDF) piezoelectric microforce-sensing tool with a resolution in the range of sub-micro newtons. The Drosophila embryo is one of the most studied organisms in biological research, medical research, genetics, and developmental biology and has implications in the cure of human diseases. It is also used to study the wiring of the human brain and the nervous system. For a highly efficient and accurate microinjection of genetic material into a Drosophila embryo, it is absolutely necessary to allow close monitoring of the magnitude and direction of microinjection and other biomanipulation forces acting on the embryo during the injection process. In this paper, a networked microrobotic biomanipulation platform integrating a two-axis (two-dimensional) PVDF microforce-sensing tool is used to implement force sensing and injection of living Drosophila embryos. Based on the event synchronization for the feedback of injection video and microforce, the developed networked microrobotic platform can greatly advance operations in microinjection and biomanipulation. Through experiments, quantitative relationships between the applied force and membrane structural deformation of embryos in different stages of embryogenesis and their microinjection force behaviours were investigated. Ultimately, the technology will provide a critical and major step towards the development of automated biomanipulation for batch injection of living embryos in genetic and developmental studies, which will facilitate the development of medicine for the cure of human diseases.

Interaction of Cu(II) 3,5-diisopropylsalicylate with human serum albumin--an evaluation of spectroscopic data.

The copper(II) complex of 3,5-diisopropylsalicylate is a lipophilic water-insoluble binuclear complex, Cu(II)2(3,5-DIPS)4, that has attracted interest because of a wide range of pharmacological activities. This study was undertaken to examine bonding interactions between the complex and human serum albumin (HSA) to help elucidate the mode of transport of the complex in vivo. Electron paramagnetic resonance, numerical magnetic resonance and UV-visible absorption spectroscopic studies were performed using 200 microM aqueous solutions (pH 7.5) of HSA to which had been added up to three molar equivalents of CuCl2, CuSO4, or Cu(II)2(3,5-DIPS)4. Both EPR and UV-visible spectra demonstrated the presence of more than one copper bonding site on HSA, and proton NMR spectra showed that the 3,5-DIPS ligand is also bonded to HSA. These results indicate that there is no observable direct coordination of the ligand to copper in the presence of HSA, and that the majority of the copper and 3,5-DIPS bond to HSA at separate sites. Addition of solid Cu(II)2(3,5-DIPS)4 to HSA at pH 7.5 similarly resulted in spectra suggest that there are no ternary Cu(II)(3,5-DIPS), Cu(II)(3,5-DIPS)2, or Cu(II)2(3,5-DIPS)4 complexes formed with HSA. It is concluded that any ternary complexes formed in the presence of HSA are below the spectroscopic detection limits and represent less than 5% of the total copper.

[Studies on octanol-water partition coefficient and nasal drug absorption].

In order to find out the quantitative relationship between physicochemical properties of drugs and their nasal absorption, diltiazem hydrochloride and paracetamol were selected as model drugs and their octanol-water partition coefficient was determined. In situ nasal recirculation method at different pH values was used to estimate the rate constant of nasal drug absorption in rats. Results showed that quantitative relationship existed between partition coefficient and nasal absorption constant, with correlation coefficient being 0.9761(n = 9). Besides methods of partition coefficient determination, the in situ nasal recirculation manipulation was also improved.

[Artificial reconstituted pulmonary surfactant used for prevention and treatment of adult respiratory distress syndrome. II. Bioluminescence method for optimizing formulation].

Based on optimizing the formulations of artificial reconstituted pulmonary surfactant (APS) used for the prevention and treatment of adult respiratory distress syndrome (ARDS) by a surface chemical method, a quartz lung animal model to obtain active alveolar macrophages (AMs) was established, using a bioluminescence technique to optimize APS's formulation according to the free-radical-scavenging abilities of APS. An optimal formulation was obtained, which showed good surface properties and free-radical-scavenging abilities. The APS preparation will be used in ARDS animal model test.

[Artificial reconstituted pulmonary surfactant used for prevention and treatment of adult respiratory distress syndrome. III. Prevention in animal model].

Based on two major factors resulted in adult respiratory distress syndrome (ARDS), lack of pulmonary surfactant and damage of free radicals, an artificial reconstituted pulmonary surfactant (APS) was prepared. The results of prevention of ARDS in ARDS rats showed that APS reduced the mortality of animal model significantly (from 46.47% to 16.17%) and the ratio of wet/dry lung weight (from 5.55 to 4.84). The surface properties of lung lavage of treated animals were improved effectively [balancing surface tension from 61.86 mN.m-1 to 47.02 mN.m-1, (normal 43.94 mN.m-1), minimal surface tension from 30.41 mN.m-1 to 7.16 mN.m-1(normal 3.49 mN.m-1)]. These results indicate that the APS preparation showed better effect on prevention of ARDS in rats.

[Studies on HPLC method for determination of 4-methylaminoantipyrine and relative bioavailabilities of analgin nasal drops in human volunteers].

A new HPLC method for the determination of a metabolite of analgin, MAA (4-methylaminoantipyrine), in plasma and its application to determine the bioavailabilities of analgin nasal drops in human volunteers is reported in this paper. A Waters Model 481 instrument was used throughout the experiment. IAA (isopropylaminoantipyrine) was shown to be the most suitable internal standard at absorption wavelength of 254 nm. A mixture of phosphate buffer (pH 5.5) and methanol (68:32) was used as the mobile phase with a flow rate of 2 ml.min-1, and YWG-C18H37 as stationary phase. Calibration curve was linear (gamma = 0.9998) in the concentration range of 0.1-5 micrograms.ml-1. The within day and day-to-day precision (RSD) of this method were 2.35% and 2.61%, respectively, with average recoveries of 99.3%-103.9%. No interference was found in the body fluid. The plasma samples of healthy volunteers were treated with acid and extracted with ether. The system of mobile phase and the process of blood sample treatment were simpler than those reported in literature. So, the method is suitable for the study of pharmacokinetics and clinical determination of blood level of analgin. The studies on bioavailabilities of analgin nasal drops were carried out in 8 men relative to intramuscular injection and 6 men relative to oral tablets, respectively, at the dose of 250 mg analgin in different preparations administered by cross-over method. The main pharmacokinetic parameters were shown in Table 3. The results indicate that analgin nasal drops exhibited a higher bioavailability (relative to injection) and faster absorption (relative to tablet). So, analgin is suitable to be developed as a nasal preparation.

[Toxicity of drugs on nasal mucocilia and the method of its evaluation].

Effect of solutions or suspensions of eight drugs including analgin, paracetamol, propafenone hydrochloride, propranolol hydrochloride, ephedrine hydrochloride, gentamycin sulfate, sodium deoxycholate and hydrocortisone on ciliary movement were evaluated with in vitro or in situ toad palate model and scanning electron microscope. In vitro toad palate model: 0.2 ml of test drug solution or suspension was applied to a piece of freshly dissected upper palate of toad. The mucocilia were examined with an optical microscope and the lasting time of ciliary movement was recorded after drug application. The upper palate was rinsed with physiological saline when the ciliary movement stopped. The lasting time of ciliary movement after rinsing was then recorded again. In situ palate model: 0.5 ml of test drug solution or suspension was applied to the upper palate of toad for 30 min, and rinsed with physiological saline. The palate was dissected out and the operation was carried out in a similar manner. The results showed that the in situ toad palate model is a satisfactory method for studying the ciliotoxicity of drugs. The in vitro toad palate model is unsuitable for suspension and gel. The results of the eight drugs revealed that ciliary movement is frequently affected by many drugs and, therefore, care must be taken in developing any nasal dosage form to ensure its least ciliotoxicity.

[Comparison of concentration of piroxicam in blood and local site after two routes of administration].

The systematic and local concentrations of piroxicam after oral and transdermal administration were determined and compared. Mice were randomly grouped, and oral suspensions (0.72 mg.ml-1) or transdermal gels 1 mg.ml-1 were given. Systematic concentration (Cs) and local concentration (C1) of the drug in each mouse were determined by HPLC method. After transdermal administration of 0.25 mg of piroxicam gels Cmax(s) = 8.06 micrograms.ml-1 and AUC(s)0-24(s) = 58.36 micrograms.h.ml-1 were obtained, whereas after oral administration of 0.026 mg.10 g-1 body weight of piroxicam suspensions Cmax(s) was 36.82 micrograms.ml-1 and AUC(s)0-24 was 155.59 micrograms.h.ml-1. The C1/Cs ratio (0.01) through oral route was far lower than the C1/Cs ratio (0.13) through transdermal route. The area under local concentration-time curve (15.85 micrograms.h.ml-1) calculated from transdermal administration was much higher than that from oral administration (1.93 micrograms.h.ml-1). So, it seems to be unreasonable that only serum concentration is taken as a criterion for bioavailability test of piroxicam for local dosage forms, the local drug concentration should also be investigated and evaluated.

[A reversed-phase HPLC method for determining tretinoin].

Tretinoin (Tre) and its active stereo isomer isotretinoin (Iso) were simultaneously determined by reversed-phase high pressure liquid chromatographic method with a uv detector adjusted to 348 nm. Separation was accomplished on YWG-C18 column by using a MeOH:NH4Ac buffer (pH 6.0) 85:15 (vol:vol), chlorpromazine (Chl) being chosen as internal standard. Minimal detectable amount of Tre was 0.5 ng. Calibration curve was linear (r = 0.9999) in the concentration range of 25-2500 ng.ml-1. This method was used to determinate the transdermal amounts of Tre from three different preparations in Franz diffusion cell in vitro. The results showed that the proposed method could distinguish the transdermal differences from various formulations or different skin samples. In addition, it is able to be used in quantitative analysis of Tre and Iso.