Phase/Interfacial-Engineered Two-Dimensional-Layered WSe2 Films by a Plasma-Assisted Selenization Process: Modulation of Oxygen Vacancies in Resistive Random-Access Memory

Here, we propose phase and interfacial engineering by inserting a functional WO₃ layer and selenized it to achieve a 2D-layered WSe₂/WO₃ heterolayer structure by a plasma-assisted selenization process. The 2D-layered WSe₂/WO₃ heterolayer was coupled with an Al₂O₃ film as a resistive switching (RS) layer to form a hybrid structure, with which Pt and W films were used as the top and bottom electrodes, respectively. The device with good uniformity in SET/RESET voltage and high low-/high-resistance window can be obtained by controlling a conversion ratio from a WO₃ film to a 2D-layered WSe₂ thin film. The Pt/Al₂O₃/(2D-layered WSe₂/WO₃)/W structure shows remarkable improvement to the pristine Pt/Al₂O₃/W and Pt/Al₂O₃/2D-layered WO₃/W in terms of low SET/RESET voltage variability (-20/20)%, multilevel characteristics (uniform LRS/HRS distribution), high on/off ratio (10⁴-10⁵), and retention (∼10⁵ s). The thickness of the obtained WSe₂ was tuned at different gas ratios to optimize different 2D-layered WSe₂/WO₃ (%) ratios, showing a distinctive trend of reduced and uniform SET/RESET voltage variability as 2D-layered WSe₂/WO₃ (%) changes from 90/10 (%) to 45/55 (%), respectively. The electrical measurements confirm the superior ability of the metallic 1T phase of the 2D-layered WSe₂ over the semiconducting 2H phase. Through systemic studies of RS behaviors on the effect of 1T/2H phases and 2D-layered WSe₂/WO₃ ratios, the low-temperature plasma-assisted selenization offers compatibility with the temperature-limited 3D integration process and also provides much better thickness control over a large area.

Ecofriendly Synthesis of Waste-Tire-Derived Graphite Nanoflakes by a Low-Temperature Electrochemical Graphitization Process toward a Silicon-Based Anode with a High-Performance Lithium-Ion Battery

Here, the successful transformation of graphitic carbon with a high degree of graphitization and a nanoflake structure from pyrolytic tire carbon black was demonstrated. First, amorphous carbon black with a porous structure was obtained after pyrolysis and simple preacid treatments. Subsequently, the carbon black was converted into a highly graphitic structure at a relatively low temperature (850 °C) through a facile electrochemical route using molten salt, which is ecofriendly and has high potential for large-scale graphitization compared to conventional incineration techniques. Moreover, we further improved the crystallinity and uniformity of the product simultaneously by directly mixing the metal oxide catalyst Fe₂O₃ with a carbon precursor. The mechanism of this metal-catalyzed electrochemical graphitization has been discussed in detail. To confirm their potential in practical applications, the as-prepared graphitized nanoflakes were used as conductive additives for silicon anodes in lithium-ion batteries, which showed a performance comparable to those utilizing commercial Super-P additives, exhibiting an initial Coulombic efficiency of approximately 79.7% and a high capacity retention of approximately 45.8% after 100 cycles with a reversible capacity of 1220 mAh g^-1 at a current rate of 400 mA g^-1. Hence, successfully recovered waste-tire-derived carbon black utilizing a low-temperature Fe₂O₃-catalyzed electrochemical process opens a pathway in low-temperature graphitization toward a sustainable value-added application in the field of energy storage.

Intercalation of Zinc Monochloride Cations by Deep Eutectic Solvents for High-Performance Rechargeable Non-aqueous Zinc Ion Batteries

Zinc ion batteries have been extensively studied with an aqueous electrolyte system. However, the batteries suffer from a limited potential window, gas evolution, cathode dissolution, and dendrite formation on the anode. Considering these limitations, we developed an alternative electrolyte system based on deep eutectic solvents (DESs) because of their low cost, high stability, biodegradability, and non-flammability, making them optimal candidates for sustainable batteries. The DES electrolyte enables reversible Zn plating/stripping and effectively suppresses zinc dendrite formation. Furthermore, in-depth characterizations reveal that the energy storage mechanism can be attributed to [ZnCl]⁺ ion intercalation and the intermediate complex ion plays a pivotal role in electrochemical reactions, which deliver a high reversible capacity of 310 mAh g^-1 at 0.1 A g^-1and long-term stability (167 mAh g^-1 at a current density of 0.3 A g^-1 after 300 cycles, Coulombic efficiency: ∼98%). Overall, this work represents our new finding in rechargeable batteries with the DES electrolyte.

[Analysis on dynamical mechanism of multi outbreaks of COVID-19]

Objective: In the context of COVID-19 pandemic, the epidemic severities, non-pharmaceutical intervention intensities, individual behavior patterns and vaccination coverage vary with countries in the world. China has experienced a long period without indigenous cases, unfortunately, multi local outbreaks caused by imported cases and other factors have been reported, posing great challenges to COVID-19 prevention and control in China. Thus it is necessary to explore the mechanisms of the re-emerged COVID-19 epidemics and their differences. Methods: Based on susceptible exposed infectious recovered (SEIR) epidemic dynamics model, we developed a set of novel evolution equations which can describe the dynamic processes of integrated influence of interventions, vaccination coverage and individual behavior changes on the re-emergency of COVID-19 epidemic. We developed methods to calculate the optimal intervention intensity and vaccination rate at which the size of susceptible population can be reduced to less than threshold for the re-emergency of COVID-19 epidemic. Results: If strong interventions or super interventions are lifted too early, even a small cause can lead to the re-emergence of COVID-19 epidemic at different degrees. Moreover, the stronger the early control measures lifted are, the more severe the epidemic is. The individual behavior changes for the susceptibility to the epidemic and the enhancement or lifting of prevention and control measures are key factors to influence the incidence the multi outbreaks of COVID-19. The optimist early intervention measures and timely optimization of vaccination can not only prevent the re-emergency of COVID-19 epidemic, but also effectively lower the peak of the first wave of the epidemic and delay its arrival. Conclusion: The study revealed that factors for the re-emergence of COVID-19 epidemics included the intensity and lifting of interventions, the change of individual behavior to the response of the epidemic, external incentives and the transmissibility of COVID-19.

Highly stable Pd/HNb3O8-based flexible humidity sensor for perdurable wireless wearable applications

Real-time, daily health monitoring can provide large amounts of patient data, which may greatly improve the likelihood of diagnosing health conditions at an early stage. One potential sensor is a flexible humidity sensor to monitor moisture and humidity information such as dehydration. However, achieving a durable functional nanomaterial-based flexible humidity sensor remains a challenge due to partial desorption of water molecules during the recovery process, especially at high humidities. In this work, we demonstrate a highly stable resistive-type Pd/HNb₃O₈ humidity sensor, which exhibits a perdurable performance for over 100 h of cycle tests under a 90% relative humidity (RH) without significant performance degradation. One notable advantage of the Pd/HNb₃O₈ humidity sensor is its ability to regulate hydroniums due to the strong reducibility of H atoms dissociated on the Pd surface. This feature realizes a high stability even at a high humidity (99.9% RH). Using this superior performance, the Pd/HNb₃O₈ humidity sensor realizes wireless monitoring of the changes in the fingertip humidity of an adult under different physiological states, demonstrating a facile and reliable path for dehydration diagnosis.

An Ultrasensitive Gateless Photodetector Based on the 2D Bilayer MoS2-1D Si Nanowire-0D Ag Nanoparticle Hybrid Structure

Atomically thin transition metal dichalcogenides (TMDC) have received much attention due to their wide variety of optical and electronic properties. Among various TMDC materials, molybdenum disulfide (MoS₂) has been intensely studied owing to its potential applications in nanoelectronics and optoelectronics. However, two-dimensional MoS₂ photodetectors suffer from low responsivity due to low optical cross section. Combining MoS₂ with plasmonic nanostructures can drastically increase scattering cross section and enhance local light-matter interaction. Moreover, suspended MoS₂ has been shown to exhibit higher photoluminescence intensity and strong photogating effect, which can be employed in photodetectors. Herein, we propose an approach to utilize plasmonic nanostructures and physical suspension for 2D MoS₂ photosensing enhancement by hybridizing 2D bilayer MoS₂, 1D silicon nanowires, and 0D silver nanoparticles. The hybrid structure shows a gateless responsivity of 402.4 A/W at a wavelength of 532 nm, which represents the highest value among the ever reported gateless plasmonic MoS₂ photodetector. The great responsivity and large active area results in an exceptional detectivity of 2.34 × 10¹² Jones. This study provides a new approach for designing high-performance 2D TMDC-based optoelectronic devices.

Design of Core-Shell Quantum Dots-3D WS2 Nanowall Hybrid Nanostructures with High-Performance Bifunctional Sensing Applications

Transition metal dichalcogenides (TMDCs) have recently attracted a tremendous amount of attention owing to their superior optical and electrical properties as well as the interesting and various nanostructures that are created by different synthesis processes. However, the atomic thickness of TMDCs limits the light absorption and results in the weak performance of optoelectronic devices, such as photodetectors. Here, we demonstrate the approach to increase the surface area of TMDCs by a one-step synthesis process of TMDC nanowalls from WO_x into three-dimensional (3D) WS₂ nanowalls. By utilizing a rapid heating and rapid cooling process, the formation of 3D nanowalls with a height of approximately 150 nm standing perpendicularly on top of the substrate can be achieved. The combination of core-shell colloidal quantum dots (QDs) with three different emission wavelengths and 3D WS₂ nanowalls further improves the performance of WS₂-based photodetector devices, including a photocurrent enhancement of 320-470% and shorter response time. The significant results of the core-shell QD-WS₂ hybrid devices can be contributed by the high nonradiative energy transfer efficiency between core-shell QDs and the nanostructured material, which is caused by the spectral overlap between the emission of core-shell QDs and the absorption of WS₂. Besides, outstanding NO₂ gas-sensing performance of core-shell QDs/WS₂ devices can be achieved with an extremely low detection limit of 50 ppb and a fast response time of 26.8 s because of local p-n junctions generated by p-type 3D WS₂ nanowalls and n-type core-shell CdSe-ZnS QDs. Our work successfully reveals the energy transfer phenomenon in core-shell QD-WS₂ hybrid devices and shows great potential in commercial multifunctional sensing applications.

Variability of T2-Relaxation Times of Healthy Lumbar Intervertebral Discs is More Homogeneous within an Individual Than across Healthy Individuals

BACKGROUND AND PURPOSE

When one uses T2 relaxometry to classify lumbar intervertebral discs as degenerated, it is unclear whether the normative data should be based on other intervertebral discs from the same individual or from a pool of extraneous controls. This study aimed to explore the extent of intra- versus intersubject variation in the T2 times of healthy intervertebral discs.

MATERIALS AND METHODS

Using prospectively acquired T2-relaxometry data from 606 intervertebral discs in 101 volunteers without back pain (47 men, 54 women) in a narrow age range (25-35 years), we calculated intra- and intersubject variation in T2 times of intervertebral discs graded by 2 neuroradiologists on the Pfirrmann scale. Intrasubject variation of intervertebral discs was assessed relative to other healthy intervertebral discs (Pfirrmann grade, ≤2) in the same individual. Multiple intersubject variability measures were calculated using healthy extraneous references ranging from a single randomly selected intervertebral disc to all healthy extraneous intervertebral discs, without and with segmental stratification. These variability measures were compared for healthy and degenerated (Pfirrmann grade ≥3) intervertebral discs.

RESULTS

The mean T2 values of healthy (493/606, 81.3%) and degenerated intervertebral discs were 121.1 ± 22.5 ms and 91.5 ± 18.6 ms, respectively (P < .001). The mean intrasubject variability for healthy intervertebral discs was 9.8 ± 10.7 ms, lower than all intersubject variability measures (P < .001), and provided the most pronounced separation for healthy and degenerated intervertebral discs. Among intersubject variability measures, using all segment-matched healthy discs as references provided the lowest variability (P < .001).

CONCLUSIONS

Normative measures based on the T2 times of healthy intervertebral discs from the same individual are likely to provide the most discriminating means of identifying degenerated intervertebral discs on the basis of T2 relaxometry.

Naringenin induces neuroprotection against homocysteine-induced PC12 cells via the upregulation of superoxide dismutase 1 expression by decreasing miR-224-3p expression

Naringenin is a flavonoid compound with antioxidant effects. It is used to treat oxidative stress-related diseases, but its mechanism is unclear. In this experiment, we explored whether naringenin can increase the expression of superoxide dismutase 1(SOD1), reduce the oxidative stress of PC12 cells induced by homocysteine (Hcy), and decrease the apoptosis of PC12 cells induced by Hcy by inhibiting the expression of mir-224-3p. Different concentrations of Hcy (1, 3, 5, 8, and 10 mmol/L) was used to analyze effect of homocysteine on PC12 cells. A total of 5 mmol/L Hcy was used to induce the excitatory and neurotoxicity model of PC12 cells in vitro. The cells were divided into normal control, Hcy induction, Hcy + Naringenin (25 μM), Hcy + Naringenin (50 μM), Hcy + Naringenin (75 μM), Hcy + Naringenin (100 μM), and Hcy + Naringenin (150 μM) groups. The relative survival rate and activities of the PC12 cells were determined by the MTT method, and the apoptosis rate of the PC12 cells was determined by using flow cytometry. The Western blot method was used to determine the expressions of SOD1, Bax, Caspase-3, Caspase-8, and Bcl-2 in the PC12 cells induced by Hcy. The expressions of SOD1 mRNA and miR-224-3p in the Hcy-induced PC12 cells were determined by RT-PCR. Results found that Hcy increased the expression of miR-224-3p in a dose-dependent manner but decreased that of SOD1 mRNA and protein. Hcy also increased oxidative stress in the PC12 cells and the proapoptotic proteins Bax, Caspase-3, and Caspase-9. Furthermore, it decreased the expression of anti-apoptotic protein Bcl-2 and the activity and survival rate of the HT22 cells, but it increased the apoptosis of the PC12 cells. The treatment of Hcy-induced PC12 cells with different concentrations of naringenin for 24 h decreased the expression of miR-224-3p in a dose-dependent manner and increased the expressions of SOD1 mRNA and protein. The treatment also decreased the oxidative stress in the PC12 cells and the expressions of pro-apoptotic proteins Bax, Caspase-3, and Caspase-9; increased the expression of anti-apoptotic protein Bcl- 2; decreased the apoptosis of the PC12 cells; and increased the PC12 cells.The results suggest that Naringenin can decrease the apoptosis and oxidative stress of PC12 cells induced by Hcy and increase the activities and survival rates of PC12 cells. The mechanism may be related to naringenin decreasing the expression of miR-224-3p in PC12 cells induced by Hcy and increasing the expressions of SOD1 mRNA and protein.

Three-Dimensional Molybdenum Diselenide Helical Nanorod Arrays for High-Performance Aluminum-Ion Batteries

The rechargeable aluminum-ion battery (AIB) is a promising candidate for next-generation high-performance batteries, but its cathode materials require more development to improve their capacity and cycling life. We have demonstrated the growth of MoSe₂ three-dimensional helical nanorod arrays on a polyimide substrate by the deposition of Mo helical nanorod arrays followed by a low-temperature plasma-assisted selenization process to form novel cathodes for AIBs. The binder-free 3D MoSe₂-based AIB shows a high specific capacity of 753 mAh g^-1 at a current density of 0.3 A g^-1 and can maintain a high specific capacity of 138 mAh g^-1 at a current density of 5 A g^-1 with 10 000 cycles. Ex situ Raman, XPS, and TEM characterization results of the electrodes under different states confirm the reversible alloying conversion and intercalation hybrid mechanism during the discharge and charge cycles. All possible chemical reactions were proposed by the electrochemical curves and characterization. Further exploratory works on interdigital flexible AIBs and stretchable AIBs were demonstrated, exhibiting a steady output capacity under different bending and stretching states. This method provides a controllable strategy for selenide nanostructure-based AIBs for use in future applications of energy-storage devices in flexible and wearable electronics.

Nanoprobing of MoS2 by Synchrotron Radiation When van der Waals Epitaxy Is Locally Invalid

In this work, we demonstrated nano-scaled Laue diffractions by a focused polychromatic synchrotron radiation beam to discover what happens in MoS₂ when van der Waals epitaxy is locally invalid. A stronger exciton recombination with a local charge depletion in the density of 1 × 10¹³ cm^-2, extrapolated by Raman scattering and photoluminescence, occurs in grains, which exhibits a preferred orientation of 30° rotation with respect to the c-plane of a sapphire substrate. Else, the charge doping and trion recombination dominate instead. In addition to the breakthrough in extrapolating mesoscopic crystallographic characteristics, this work opens the feasibility to manipulate charge density by the selection of the substrate-induced disturbances without external treatment and doping. Practically, the 30° rotated orientation in bilayer MoS₂ films is promoted on inclined facets in the patterned sapphire substrate, which exhibits a periodic array of charge depletion of about 1.65 × 10¹³ cm^-2. The built-in manipulation of carrier concentrations could be a potential candidate to lateral and large-area electronics based on 2D materials.

High-Performance Rechargeable Aluminum-Selenium Battery with a New Deep Eutectic Solvent Electrolyte: Thiourea-AlCl3

Aluminum-sulfur batteries (ASBs) have attracted substantial interest due to their high theoretical specific energy density, low cost, and environmental friendliness, while the traditional sulfur cathode and ionic liquid have very fast capacity decay, limiting cycling performance because of the sluggishly electrochemical reaction and side reactions with the electrolyte. Herein, we demonstrate, for the first time, excellent rechargeable aluminum-selenium batteries (ASeBs) using a new deep eutectic solvent, thiourea-AlCl₃, as an electrolyte and Se nanowires grown directly on a flexible carbon cloth substrate (Se NWs@CC) by a low-temperature selenization process as a cathode. Selenium (Se) is a chemical analogue of sulfur with higher electronic conductivity and lower ionization potential that can improve the battery kinetics on the sluggishly electrochemical reaction and the reduction of the polarization where the thiourea-AlCl₃ electrolyte can stabilize the side reaction during the reversible conversion reaction of Al-Se alloying processes during the charge-discharge process, yielding a high specific capacity of 260 mAh g^-1 at 50 mA g^-1 and a long cycling life of 100 times with a high Coulombic efficiency of nearly 93% at 100 mA g^-1. The working mechanism based on the reversible conversion reaction of the Al-Se alloying processes, confirmed by the ex situ Raman, XRD, and XPS measurements, was proposed. This work provides new insights into the development of rechargeable aluminum-chalcogenide (S, Se, and Te) batteries.

Direct Synthesis of Large-Scale Multilayer TaSe2 on SiO2/Si Using Ion Beam Technology

The multilayer 1T-TaSe₂ is successfully synthesized by annealing a Se-implanted Ta thin film on the SiO₂/Si substrate. Material analyses confirm the 1T (octahedral) structure and the quasi-2D nature of the prepared TaSe₂. Temperature-dependent resistivity reveals that the multilayer 1T-TaSe₂ obtained by our method undergoes a commensurate charge-density wave (CCDW) transition at around 500 K. This synthesis process has been applied to synthesize MoSe₂ and HfSe₂ and expanded for synthesis of one more transition-metal dichalcogenide (TMD) material. In addition, the main issue of the process, that is, the excess metal capping on the TMD layers, is solved by the reduction of thickness of the as-deposited metal thin film in this work.

[Construction of mouse CCR3 gene RNAi lentivirus vector and its expression on mast cells]

Objective:The aim of this study is to screen the targeting chemokine receptor 3-RNA interference (CCR3-RNAi) lentiviral expression vector, infect mouse mast cells,observe the expression of this gene in mast cells and the interference efficiency of the virus vector.The pathogenesis of allergic rhinitis lays the foundation.Method:Three pairs of CCR3-shRNA sequences were constructed,and three pairs of double-stranded shRNA oligo were inserted into shRNA lentiviral vectors to construct three shRNA lentiviral recombinant plasmids.The recombinant vector and virus-packed auxiliary plasmids were co-transfected into 293T cells to obtain lentiviral plasmids.The lentiviral plasmids were then transfected into mouse bone marrow-derived mast cells in vitro and purified. The expression level of CCR3 mRNA in mast cells was verified by qRT-PCR,and the expression level of CCR3 protein in mast cells was detected by Western Blot.Result: It was confirmed by sequencing that the lentiviral vector of CCR3 shRNA was successfully constructed, transfected into 293T cells and packaged with virus. Finally the high purity PDSO19-PL-CCR3 lentiviral plasmid was obtained with a virus titer of 3.7×10⁸TU/ml.The lentiviral plasmid was used to infect mouse mast cells.RT-PCR and Western Blot detection assay showed that CCR3shRNA reduced the expression of CCR3 gene in mouse mast cells at the level of mRNA and protein.Conclusion: The CCR3 gene RNAi lentivirus expression vector was successfully constructed.It was found that it downregulated the expression level of CCR3 gene mRNA and protein in mouse mast cells,which laid the foundation for further research on its role in the pathogenesis of allergic rhinitis.

3D CoMoSe4 Nanosheet Arrays Converted Directly from Hydrothermally Processed CoMoO4 Nanosheet Arrays by Plasma-Assisted Selenization Process Toward Excellent Anode Material in Sodium-Ion Battery

In this work, three-dimensional (3D) CoMoSe4 nanosheet arrays on network fibers of a carbon cloth denoted as CoMoSe4@C converted directly from CoMoO4 nanosheet arrays prepared by a hydrothermal process followed by the plasma-assisted selenization at a low temperature of 450 °C as an anode for sodium-ion battery (SIB) were demonstrated for the first time. With the plasma-assisted treatment on the selenization process, oxygen (O) atoms can be replaced by selenium (Se) atoms without the degradation on morphology at a low selenization temperature of 450 °C. Owing to the high specific surface area from the well-defined 3D structure, high electron conductivity, and bi-metal electrochemical activity, the superior performance with a large sodium-ion storage of 475 mA h g-1 under 0.5-3 V potential range at 0.1 A g-1 was accomplished by using this CoMoSe4@C as the electrode. Additionally, the capacity retention was well maintained over 80 % from the second cycle, exhibiting a satisfied capacity of 301 mA h g-1 even after 50 cycles. The work delivered a new approach to prepare a binary transition metallic selenide and definitely enriches the possibilities for promising anode materials in SIBs with high performances.

Enhanced Photocarrier Generation with Selectable Wavelengths by M-Decorated-CuInS2 Nanocrystals (M = Au and Pt) Synthesized in a Single Surfactant Process on MoS2 Bilayers

A facile approach for the synthesis of Au- and Pt-decorated CuInS₂ nanocrystals (CIS NCs) as sensitizer materials on the top of MoS₂ bilayers is demonstrated. A single surfactant (oleylamine) is used to prepare such heterostructured noble metal decorated CIS NCs from the pristine CIS. Such a feasible way to synthesize heterostructured noble metal decorated CIS NCs from the single surfactant can stimulate the development of the functionalized heterostructured NCs in large scale for practical applications such as solar cells and photodetectors. Photodetectors based on MoS₂ bilayers with the synthesized nanocrystals display enhanced photocurrent, almost 20-40 times higher responsivity and the On/Off ratio is enlarged one order of magnitude compared with the pristine MoS₂ bilayers-based photodetectors. Remarkably, by using Pt- or Au-decorated CIS NCs, the photocurrent enhancement of MoS₂ photodetectors can be tuned between blue (405 nm) to green (532 nm). The strategy described here acts as a perspective to significantly improve the performance of MoS₂ -based photodetectors with the controllable absorption wavelengths in the visible light range, showing the feasibility of the possible color detection.

Non-layered Ti2N synthesized by plasma process for the anodes of lithium-ion batteries

ε-Ti₂N synthesized by an N₂ plasma-assisted process is first applied to lithium-ion batteries with good performance.

[The state-of-the-art development in research on oral mucositis induced by chemotherapy]

Chemotherapy is one of the effective methods to treat cancer. However, the chemotherapy agents may cause a series of adverse reactions due to the nonselective characteristics that affect not only tumor cells, but also normal cells. Oral mucositis induced by chemotherapy is a common oral complication caused by chemotherapy in clinic. It brings great suffering to the patients and also interferes with the procedure of chemotherapy. Because of its high incidence in patients receiving chemotherapy and the significant influence, there are more researches on oral mucositis induced by chemotherapy which let us have further understanding of it. This review article will introduce the pathogenesis, risk factors, clinical manifestations, assessments, treatment and prevention of oral mucositis induced by chemotherapy.

The effect of aminoguanidine (AG) and pyridoxamine (PM) on ageing human cortical bone

OBJECTIVES

Advanced glycation end-products (AGEs) are a post-translational modification of collagen that form spontaneously in the skeletal matrix due to the presence of reducing sugars, such as glucose. The accumulation of AGEs leads to collagen cross-linking, which adversely affects bone quality and has been shown to play a major role in fracture risk. Thus, intervening in the formation and accumulation of AGEs may be a viable means of protecting bone quality.

METHODS

An in vitro model was used to examine the efficacy of two AGE-inhibitors, aminoguanidine (AG) and pyridoxamine (PM), on ageing human cortical bone. Mid-diaphyseal tibial cortical bone segments were obtained from female cadavers (n = 20, age range: 57 years to 97 years) and randomly subjected to one of four treatments: control; glucose only; glucose and AG; or glucose and PM. Following treatment, each specimen underwent mechanical testing under physiological conditions via reference point indentation, and AGEs were quantified by fluorescence.

RESULTS

Treatment with AG and PM showed a significant decrease in AGE content versus control groups, as well as a significant decrease in the change in indentation distance, a reliable parameter for analyzing bone strength, via two-way analysis of variance (ANOVA) (p < 0.05).

CONCLUSIONS

The data suggest that AG and PM prevent AGE formation and subsequent biomechanical degradation in vitro. Modulation of AGEs may help to identify novel therapeutic targets to mitigate bone quality deterioration, especially deterioration due to ageing and in AGE-susceptible populations (e.g. diabetics).Cite this article: Bone Joint Res 2018;7:105-110.

Impact of individual behaviour change on the spread of emerging infectious diseases

Human behaviour plays an important role in the spread of emerging infectious diseases, and understanding the influence of behaviour changes on epidemics can be key to improving control efforts. However, how the dynamics of individual behaviour changes affects the development of emerging infectious disease is a key public health issue. To develop different formula for individual behaviour change and introduce how to embed it into a dynamic model of infectious diseases, we choose A/H1N1 and Ebola as typical examples, combined with the epidemic reported cases and media related news reports. Thus, the logistic model with the health belief model is used to determine behaviour decisions through the health belief model constructs. Furthermore, we propose 4 candidate infectious disease models without and with individual behaviour change and use approximate Bayesian computation based on sequential Monte Carlo method for model selection. The main results indicate that the classical compartment model without behaviour change and the model with average rate of behaviour change depicted by an exponential function could fit the observed data best. The results provide a new way on how to choose an infectious disease model to predict the disease prevalence trend or to evaluate the influence of intervention measures on disease control. However, sensitivity analyses indicate that the accumulated number of hospital notifications and deaths could be largely reduced as the rate of behaviour change increases. Therefore, in terms of mitigating emerging infectious diseases, both media publicity focused on how to guide people's behaviour change and positive responses of individuals are critical.

[Effect of simulating leg length inequality on spinal and pelvic posture in the elderly]

Objective: To study the effects of simulating leg length inequality on the spine and pelvic posture in standing and walking states and to explore their compensatory laws. Methods: From January to April, a total of 44 healthy volunteers were rasterstereographically examined for spine and pelvis in Institute of Digitized Medicine, Wenzhou Medical University and Department of Orthopaedics, First Affiliated Hospital of Wenzhou Medical University.Volunteers wore uniform shoes, and single 5 mm thick insoles were customized.The simulating leg length inequalities (5-30 mm) were artificially created by increasing insole height.The parameters of 3D body surface parameters and 4D dynamic parameters of the pelvic and spine were measured and statistically analyzed in standing and walking states. Results: In the static standing state, with the increase of the difference of both lower extremities, coronal plane pelvic tilt and sagittal plane pelvic torsion also increased[the maximum value about (10.6±4.3) mm and (3.3±3.5)°], as well as the frontal deviation of the spine [the maximum value about (11.1±17.9) mm]. But the pelvic rotation, vertebral surface rotation angle (rms) and spine sagittal plane deviation were no obvious changes.In the walking state, with the difference between lower extremities increased, the maximum angles of vertebral surface rotation to the left and right and pelvic rotation to the left and right were no obvious changes, but (coronal) spinal maximum offset distance to left and right increased [the maximum value about (9.8±5.1), (10.4±6.9) mm]. Conclusion: The effect of the leg length discrepancy on the pelvic coronal plane and the sagittal plane changes are obvious, but little effect has on the pelvic cross section.The pelvis is compensated by the increase of the inclination of the coronal plane and the sagittal angle at first order.Similarly, the effect on the coronal plane of the spine is more markedly, but the changes of sagittal and cross-section of the spine is less affected, the spine is mainly compensated by the coronal plane bending at second order.

Diabetes incidence and prevalence in Hong Kong, China during 2006-2014

AIMS

To estimate recent secular changes in the incidence and prevalence of diabetes and pre-diabetes among Hong Kong Chinese adults, and thus show possible future trends for developing mainland China.

METHODS

Based on a complete census of the public sector health records of 6.4 million people from 2006 to 2014, diabetes cases were ascertained using different methods including the World Health Organization (WHO) 2011 guidelines (HbA_1c , fasting plasma glucose and glucose tolerance test), American Diabetes Association (ADA) 2015 guidelines (plus random plasma glucose), and additionally recorded diagnosis codes and medication dispensation. Pre-diabetes was defined using ADA 2015 guidelines.

RESULTS

We identified 697 201 people with diabetes (54.2% were incident cases); and 1 229 731 people with diabetes or pre-diabetes. In 2014, the overall incidence of diabetes was 9.46 per 1000 person-years [95% confidence interval (CI): 9.38 to 9.54], and overall prevalence was 10.29% (95% CI: 10.27% to 10.32%). Incidence of diabetes decreased significantly from 2007 to 2014 (quadratic trend, P < 0.001). From 2006 to 2014, the prevalence of diabetes increased significantly in both sexes and across all age groups (quadratic trend, P < 0.001). The overall incidence of pre-diabetes in 2014 was 18.88 per 1000 person-years (95% CI: 18.76 to 18.99), and the overall prevalence of pre-diabetes was 8.90% (95% CI: 8.87% to 8.92%).

CONCLUSIONS

Similar to other developed western and Asian populations, diabetes (and pre-diabetes) incidence in Hong Kong Chinese appeared to have stabilized and there have been small declines during the period of observation. Ageing and survivorship will likely drive a continued increase in the prevalence of diabetes and pre-diabetes, albeit with a decelerating growth rate if past trends persist.

Assessment of collagen quality associated with non-enzymatic cross-links in human bone using Fourier-transform infrared imaging

Aging and many disease conditions, most notably diabetes, are associated with the accumulation of non-enzymatic cross-links in the bone matrix. The non-enzymatic cross-links, also known as advanced glycation end products (AGEs), occur at the collagen tissue level, where they are associated with reduced plasticity and increased fracture risk. In this study, Fourier-transform infrared (FTIR) imaging was used to detect spectroscopic changes associated with the formation of non-enzymatic cross-links in human bone collagen. Here, the non-enzymatic cross-link profile was investigated in one cohort with an in vitro ribose treatment as well as another cohort with an in vivo bisphosphonate treatment. With FTIR imaging, the two-dimensional (2D) spatial distribution of collagen quality associated with non-enzymatic cross-links was measured through the area ratio of the 1678/1692cm^-1 subbands within the amide I peak, termed the non-enzymatic crosslink-ratio (NE-xLR). The NE-xLR increased by 35% in the ribation treatment group in comparison to controls (p<0.005), with interstitial bone tissue being more susceptible to the formation of non-enzymatic cross-links. Ultra high-performance liquid chromatography, fluorescence microscopy, and fluorometric assay confirm a correlation between the non-enzymatic cross-link content and the NE-xLR ratio in the control and ribated groups. High resolution FTIR imaging of the 2D bone microstructure revealed enhanced accumulation of non-enzymatic cross-links in bone regions with higher tissue age (i.e., interstitial bone). This non-enzymatic cross-link ratio (NE-xLR) enables researchers to study not only the overall content of AGEs in the bone but also its spatial distribution, which varies with skeletal aging and diabetes mellitus and provides an additional measure of bone's propensity to fracture.

Genetic rearrangements of variable di-residue (RVD)-containing repeat arrays in a baculoviral TALEN system

Virus-derived gene transfer vectors have been successfully employed to express the transcription activator-like effector nucleases (TALENs) in mammalian cells. Since the DNA-binding domains of TALENs consist of the variable di-residue (RVD)-containing tandem repeat modules and virus genome with repeated sequences is susceptible to genetic recombination, we investigated several factors that might affect TALEN cleavage efficiency of baculoviral vectors. Using a TALEN system designed to target the AAVS1 locus, we observed increased sequence instability of the TALE repeat arrays when a higher multiplicity of infection (MOI) of recombinant viruses was used to produce the baculoviral vectors. We also detected more deleterious mutations in the TALE DNA-binding domains when both left and right TALEN arms were placed into a single expression cassette as compared to the viruses containing one arm only. The DNA sequence changes in the domains included deletion, addition, substitution, and DNA strand exchange between the left and right TALEN arms. Based on these observations, we have developed a protocol using a low MOI to produce baculoviral vectors expressing TALEN left and right arms separately. Cotransduction of the viruses produced by this optimal protocol provided an improved TALEN cleavage efficiency and enabled effective site-specific transgene integration in human cells.

[Interaction of DAXX and human papillomavirus type 16 E2 protein]

The aim of the study was to explore the interactions of human papilloma virus 16 (HPV16) E2 protein and Daxx. The location or co-localization of PML and E2 with Daxx in Caski cells was observed by indirect immunofluorescence test. The interaction of E2 and Daxx was analyzed by co-immunoprecipitation, Western-blot and yeast-two hybrid assay. In Caski cells the fluorescence of Daxx or PML was mainly distributed in the cytoplasm or nucleus, respectively, and in the align image their signals did not overlapped. However, when the red signal of HPV16 E2 and the green signal of Daxx in cyto- plasm of Caski cells were merged, the yellow signals appeared. The yeast co-transformed with pGBKT7/Daxx and pGADT7/E2 or pGADT7/E2 TAD can grow onto SD/-Trp-Leu-His and SD/-Trp-Leu-His-Ade plates. So Daxx wasn't co-located with PML but with HPV16 E2 mainly in the cytoplasm of Caski cells. On the base of the results one can propose that HPV16 E2, in particularly its transcription-activity domain (TAD), interacts with Daxx.

How tough is brittle bone? Investigating osteogenesis imperfecta in mouse bone

The multiscale hierarchical structure of bone is naturally optimized to resist fractures. In osteogenesis imperfecta, or brittle bone disease, genetic mutations affect the quality and/or quantity of collagen, dramatically increasing bone fracture risk. Here we reveal how the collagen defect results in bone fragility in a mouse model of osteogenesis imperfecta (oim), which has homotrimeric α1(I) collagen. At the molecular level, we attribute the loss in toughness to a decrease in the stabilizing enzymatic cross-links and an increase in nonenzymatic cross-links, which may break prematurely, inhibiting plasticity. At the tissue level, high vascular canal density reduces the stable crack growth, and extensive woven bone limits the crack-deflection toughening during crack growth. This demonstrates how modifications at the bone molecular level have ramifications at larger length scales affecting the overall mechanical integrity of the bone; thus, treatment strategies have to address multiscale properties in order to regain bone toughness. In this regard, findings from the heterozygous oim bone, where defective as well as normal collagen are present, suggest that increasing the quantity of healthy collagen in these bones helps to recover toughness at the multiple length scales.

Local tissue properties of human osteoarthritic cartilage correlate with magnetic resonance T(1) rho relaxation times

The objective of this study is to examine the local relationship between T(1ρ) relaxation times and the mechanical behavior of human osteoarthritic articular cartilage using high-resolution magnetic resonance imaging (MRI) and local in situ microindentation. Seven human tibial plateaus were obtained from patients who underwent total knee arthroplasty due to severe osteoarthritis (OA). Three to six sites were selected from each sample for visual classification using the ICRS Outerbridge scale (a total of 36 sites). Samples were imaged by MR, and the local distribution of T(1ρ) relaxation times were obtained at these selected sites. The elastic and viscoelastic characteristics of the tissue were quantified nondestructively using dynamic microindentation to measure peak dynamic modulus, energy dissipation, and phase angle. Measured Outerbridge scores, MR T(1ρ) relaxation times, and mechanical properties were highly heterogeneous across each cartilage surface. Site-specific measures of T(1ρ) relaxation times correlated significantly with the phase angle (p < 0.001; R = 0.908), a viscoelastic mechanical behavior of the cartilage. The novel combination of high-resolution MR imaging and microindentation allows the investigation of the local relationship between quantitative MRI and biomechanical properties in highly heterogeneous OA cartilage. These findings suggest that MRI T(1ρ) can provide a functional assessment of articular cartilage.

The relative contributions of non-enzymatic glycation and cortical porosity on the fracture toughness of aging bone

The risk of fracture increases with age due to the decline of bone mass and bone quality. One of the age-related changes in bone quality occurs through the formation and accumulation of advanced glycation end-products (AGEs) due to non-enzymatic glycation (NEG). However as a number of other changes including increased porosity occur with age and affect bone fragility, the relative contribution of AGEs on the fracture resistance of aging bone is unknown. Using a high-resolution nonlinear finite element model that incorporate cohesive elements and micro-computed tomography-based 3d meshes, we investigated the contribution of AGEs and cortical porosity on the fracture toughness of human bone. The results show that NEG caused a 52% reduction in propagation fracture toughness (R-curve slope). The combined effects of porosity and AGEs resulted in an 88% reduction in propagation toughness. These findings are consistent with previous experimental results. The model captured the age-related changes in the R-curve toughening by incorporating bone quantity and bone quality changes, and these simulations demonstrate the ability of the cohesive models to account for the irreversible dynamic crack growth processes affected by the changes in post-yield material behavior. By decoupling the matrix-level effects due to NEG and intracortical porosity, we are able to directly determine the effects of NEG on fracture toughness. The outcome of this study suggests that it may be important to include the age-related changes in the material level properties by using finite element analysis towards the prediction of fracture risk.

The effect of dichloroacetate on health- and lifespan in C. elegans

Aging is associated with increased vulnerability to chronic, degenerative diseases and death. Strategies for promoting healthspan without necessarily affecting lifespan or aging rate have gained much interest. The mitochondrial free radical theory of aging suggests that mitochondria and, in particular, age-dependent mitochondrial decline play a central role in aging, making compounds that affect mitochondrial function a possible strategy for the modulation of healthspan and possibly the aging rate. Here we tested such a "metabolic tuning" approach in nematodes using the mitochondrial modulator dichloroacetate (DCA). We explored DCA as a proof-of-principle compound to alter mitochondrial parameters in wild-type animals and tested whether this approach is suitable for reducing reactive oxygen species (ROS) production and for improving organismal health- and lifespan. In parallel, we addressed the potential problem of operator bias by running both unblinded and blinded lifespan studies. We found that DCA treatment (1) increased ATP levels without elevating oxidative protein damage and (2) reduced ROS production in adult C. elegans. DCA treatment also significantly prolonged nematode health- and lifespan, but did not strongly impact mortality doubling time. Operator blinding resulted in considerably smaller lifespan-extending effects of DCA. Our data illustrate the promise of a "metabolic tuning" intervention strategy, emphasize the importance of mitochondria in nematode aging and highlight operator bias as a potential confounder in lifespan studies.

Changes in non-enzymatic glycation and its association with altered mechanical properties following 1-year treatment with risedronate or alendronate

SUMMARY

One year of high-dose bisphosphonate (BPs) therapy in dogs allowed the increased accumulation of advanced glycation end-products (AGEs) and reduced postyield work-to-fracture of the cortical bone matrix. The increased accumulation of AGEs in these tissues may help explain altered bone matrix quality due to the administration of BPs in animal models

INTRODUCTION

Non-enzymatic glycation (NEG) is a posttranslational modification of the organic matrix that results in the formation of advanced glycation end-products (AGEs). In bone, the accumulation of AGEs play an important role in determining fracture resistance, and elevated levels of AGEs have been shown to adversely affect the bone's propensity to brittle fracture. It was thus hypothesized that the suppression of tissue turnover in cortical bone due to the administration of bisphosphonates would cause increased accumulation of AGEs and result in a more brittle bone matrix.

METHODS

Using a canine animal model (n = 12), we administered daily doses of a saline vehicle (VEH), alendronate (ALN 0.20, 1.00 mg/kg) or risedronate (RIS 0.10, 0.50 mg/kg). After a 1-year treatment, the mechanical properties, intracortical bone turnover, and the degree of nonenzymatic cross-linking of the organic matrix were measured from the tibial cortical bone tissue of these animals.

RESULTS

There was a significant accumulation of AGEs at high treatment doses (+49 to + 86%; p < 0.001), but not at doses equivalent to those used for the treatment of postmenopausal osteoporosis, compared to vehicle. Likewise, postyield work-to-fracture of the tissue was significantly reduced at these high doses (-28% to -51%; p < 0.001) compared to VEH. AGE accumulation inversely correlated with postyield work-to-fracture (r (2) = 0.45; p < 0.001), suggesting that increased AGEs may contribute to a more brittle bone matrix.

CONCLUSION

High doses of bisphosphonates result in the accumulation of AGEs and a reduction in energy absorption of cortical bone. The increased accumulation of AGEs in these tissues may help explain altered bone matrix quality due to the administration of BPs in animal models.

Changes in Nutritional, Functional Status and Quality of Life of COPD Out-patients after a Pulmonary Rehabilitation Programme in HUKM: a Pilot Study

This quasi-experimental study was carried out to evaluate the effectiveness of an eight-week multi-disciplinary pulmonary rehabilitation programme in improving nutritional and functional status and quality of life of COPD out patients at Hospital Universiti Kebangsaan Malaysia. A total of 9 COPD outpatients aged 40 years and above (6 men and 3 women) completed at least 50% of 16 sessions of an eight-week pulmonary rehabilitation programme. Their nutritional and functional status and rating of quality of life were measured at baseline (0 day) and after 8 weeks and these were compared to those of the control group matched for age, comprising 13 subjects (11 men and 2 women). Nutritional status was determined using anthropometry, body composition (Bioelectrical Impedance Analysis) and three-day food record. Assessment of appetite for food was also carried out using the Simplified Nutritional Assessment Questionnaire (SNAQ). Functional status was assessed using the Pulmonary Functional Status and Dyspnea Questionnaire-modified version(PFSDQ-M). The handgrip strength was also measured using handgrip dynamometer. The SF36 questionnaire was used to measure the quality of life of the subjects. There was a reduction in dyspnea (-49.0%, p<0.05) and fatigue (-47.8%, p<0.05) in men after the intervention programme, as compared to their controls (dyspnea -2.9% and fatigue 8.9%). Quality of life in this group was also significantly improved by 31.8% (p<0.05) as compared to their controls (-3.0%,p>0.05). Similar trends were noted for the women, although the difference was not significant. No significant changes were seen in nutritional status assessed by anthropometry, dietary intake and appetite. However, there was a trend of increased nutrient intake and SNAQ score in the intervention group as compared to control. An eight-week pulmonary rehabilitation programme was effective in improving the functional status particularly in men, by reducing dyspnea and fatigue; and also improving their quality of life, but was not effective in changing the nutritional status.

A non-invasive in vitro technique for the three-dimensional quantification of microdamage in trabecular bone

An accurate analysis and quantification of microdamage is critical to understand how microdamage affects the mechanics and biology of bone fragility. In this study we demonstrate the development and validation of a novel in vitro micro-computed tomography (microCT) method that employs lead-uranyl acetate as a radio-opaque contrast agent for automated quantification of microdamage in trabecular bone. Human trabecular bone cores were extracted from the femoral neck, scanned via microCT, loaded in unconfined compression to a range of apparent strains (0.5% to 2.25%), stained in lead-uranyl acetate, and subsequently re-scanned via microCT. An investigation of the regions containing microdamage using the backscatter mode of a scanning electron microscope (BSEM) showed that the lead-uranyl sulfide complex was an effective contrast agent for microdamage in bone. Damaged volume fraction (DV/BV), as determined by microCT, increased exponentially with respect to applied strains and proportionately to mechanically determined modulus reduction (p<0.001). Furthermore, the formation of microdamage was observed to occur before any apparent stiffness loss, suggesting that the localized tissue yielding occurs prior to the structural yielding of trabecular bone. This non-invasive in vitro technique for the detection of microdamage using microCT may serve as a valuable complement to existing morphometric analyses of bone.

Parallelisation and application of a multi-layer atmospheric transport model to quantify dispersion and deposition of ammonia over the British Isles

An atmospheric transport model, FRAME (Fine Resolution AMmonia Exchange), has been used to model the spatial pattern of ammonia concentrations and deposition over the British Isles for the first time. The model uses a multi-layer approach with diffusion through 33 layers to describe vertical concentration profiles in the atmosphere explicitly. Together with the necessary description of atmospheric reactions with sulphur and oxidised nitrogen, this imposes a major computational requirement, with the model having a run-time of 8.5 days on a mid-range workstation. Improvement in the model run-time was sought by developing a parallel implementation coded in a data-parallel approach using High Performance Fortran. Running the code on a Cray T3E with 128 processors provided a speedup by a factor of 69. The code's portability, its validation with measurements and new maps of its application to the British Isles, are presented. Good agreement is found with measured NH3 concentrations, while wet de-position is underestimated. In addition to model uncertainties, this may be due to an underestimation of the NH3 emissions input data.

[Applying photocclusion method to study occlusion mechanics on wedge shaped teeth defect with computer assisting]

OBJECTIVE

Study the occlusal force of wedge shaped teeth defect and its relation with the clinical condition.

METHODS

Use the method of clinical examination and plaster model measurement to decide the parameters of axial gradient degree of the teeth, abrasion index, missing teeth number and so on; Adopt the computer image processing technology and program to analyse the photocclusion sheet, take the date and image information of occlusion force, areas, and occlusal stress of wedge shaped teeth defect.

RESULTS

The occlusion contact data and graph of wedge-shaped teeth defect had the features of trauma occlusion. 42.97% of them has the larger axial gradient degree, 96.09% of them has abration in different classes, 46.29% missing the front teeth and 57.03% missing the buccal teeth. Occlusal contact force increase took up 78.91% in the wedge shaped teeth defect.

CONCLUSION

It can be concluded that the not uniformly distributed occlusal force produced from the larger axial gradient degree, the defect of dentition, and the abrasion of teeth, may be the important factors which cause wedge shaped teeth defect.

Synthesis and diversity analysis of lead discovery piperazine-2-carboxamide libraries

A Lead Discovery Library of piperazine-2-carboxamide derivatives was produced for general screening. This paper discloses two novel solid phase synthetic routes used to produce 15,000 single compounds via the Irori directed sorting technique. Computational methods such as reagent clustering and library profiling were used to maximize reagent diversity and optimize pharmacokinetic parameters. The results of a four center pharmacophore analysis revealed the added diversity gained by using two independent synthetic routes.

Solid-phase synthesis of an arylsulfone hydroxamate library

Synthesis of an arylsulfone hydroxamate lead optimization library is presented. Biological activity of representative examples is given to demonstrate the value of this approach for lead optimization.

Interpreter services in healthcare. Policy recommendations for healthcare agencies

The author discusses the need for interpreter services for delivering effective healthcare in a country such as Canada, which is made up of people from diverse ethnocultural and linguistic backgrounds. As well as examining the complexity of allocation decisions and policy implementation, the author proposes policy recommendations for healthcare agencies to set up an integrated system of interpreter services based on cost-effective and equitable use of finite resources and partnership between agencies.

Human agency and the process of healing: lessons learned from women living with a chronic illness--'re-writing the expert'

In this paper we examine the notion of human agency in the context of women experiencing a chronic illness. Based on two qualitative studies conducted with Canadian women of Chinese- and Anglo-descent living with diabetes, we unmask the complex power relations inherent in patient-practitioner interactions, and problematize the privileging of healthcare providers as knowers and experts on the patient's body. Specifically, we analyse the meanings that women ascribe to their illness experience. We discuss how women experience the loss of agency in healthcare encounters, how they resist patienthood by reclaiming agency, and how healthcare providers foster agency in their interactions with women. Rather than suggesting that biomedical experts should be 'written out', we propose to rewrite healthcare providers as 'reflexive practitioners' through the construction of transformative knowledge. We argue that praxis-oriented practice, which is based on transformative knowledge, will provide the space for women and healthcare providers to enter into a new dialogue and a relation in which women can sustain a sense of self, and begin the journey of healing.

Application of evaporative light scattering detection to the characterization of combinatorial and parallel synthesis libraries for pharmaceutical drug discovery

The advent of combinatorial and parallel synthesis methodologies in drug discovery have necessitated the development of analytical techniques which permit high throughput quantitative analysis of mixtures of small organic molecules. High pressure liquid chromatography with evaporative light scattering detection has become the major tool for this task. In this article we briefly review the theory of evaporative light scattering detection and the design of commercial instruments, as well as discuss the operational constraints imposed by the exigency of analyzing en masse the product libraries generated by these new drug discovery methods. The application of evaporative light scattering detection to library analysis is illustrated using examples from our library synthesis program. Complemented by ultraviolet absorbance detection for purity assessment and mass spectrometry for product identification, evaporative light scattering detection is the only technique affording sufficient accuracy and sensitivity for high throughput library analysis.

Degradation pathways of salmon calcitonin in aqueous solution

Salmon calcitonin (sCT), a 32-amino-acid peptide, is the active component in many pharmaceuticals used for the management of bone diseases. The degradation pathways of sCT were determined, and the structures of the major degradation products were identified. Aqueous solutions of sCT at pH values of 3, 4, 5, and 6 were degraded, and the major degradation products were detected using reversed phase and size-exclusion high-performance liquid chromatography (HPLC). The degradation rate and pathways of sCT are strongly dependent on pH in the pH range between 3 and 6. The major degradation products were isolated by semipreparative HPLC and identified using a variety of spectroscopic and bioanalytical techniques. The results show that sCT can undergo hydrolyses resulting in cleavage of the 1-2 amide bond and deamidation of the Gln14 and Gln20 residues, sulfide exchange that leads to an unusual trisulfide derivative, and dimerization to reducible and nonreducible dimers. The mechanisms for the pathways can be rationalized from known degradation pathways of peptide and proteins.

[Clinical application of inspiring psychological nursing in vaginal delivery]

A new nursing method named Inspiring Psychological Nursing was initiated and applied to 176 primigravida undergoing vaginal delivery from Jan. to Jun. 1994. 202 primigravida who received general medical care during vaginal delivery from Jan. to Jun. 1993 was served as control group. No significant differences were found between the two groups regarding to age, gestational weeks, times of pregnancy, fetal position and newborn's weight. However significant differences were found regarding the duration of the second stage of labor and incidence of newborn asphyxia. Primigravida in the control group usually delivered after 60 min. and carried a higher incidence of newborn asphyxia, being 6.7%. It's concluded that Inspiring Psychological Nursing could significantly improve pregnancy outcome.

Enzyme inhibition during the conversion of squalene to cholesterol

Two separate enzymatic assays were developed in order to test the selectivity of inhibitors in cholesterol biosynthesis. One assay detects inhibition of delta 5.7-sterol delta 7-reductase, the enzyme involved in the conversion of 7-dehydrocholesterol to cholesterol. Delta 5.7-Sterol delta 7-reductase was inhibited by both RPR 101821, a protonated cyclohexylamine, and BM 15.766, a piperazine derivative, with IC50 values of 1 microM. The second assay detects accumulation of any of five intermediates (squalene oxide, squalene dioxide, lanosterol, desmosterol, and 7-dehydrocholesterol) upon inhibition of enzymes catalyzing reactions in the conversion of squalene to cholesterol. In this assay, inhibition data were most accurate when control assays exhibited a conversion of squalene to cholesterol in the order of 50%. The time required to attain 50% conversion of squalene to cholesterol was 6 h. Given a high inhibitor to substrate concentration ratio and the possible values of Ki, kon, and koff for the reaction between enzymes and inhibitor to form enzyme-inhibitor complexes, it was predicted that in the presence of inhibitors, intermediate accumulation could still be observed after 6 h incubation. The experimental results were in agreement with this prediction.

Primary structure control of recombinant proteins using high-performance liquid chromatography, mass spectrometry and microsequencing

The conformity of two recombinant proteins (a von Willbrand factor fragment and human serum albumin, consisting of respectively 289 and 585 amino acids) has been examined by HPLC combined with mass spectrometry and microsequencing, on both intact material and fragment peptides obtained by proteolytic cleavage. These studies confirmed that the primary structure of the recombinant proteins corresponds to that predicted from their gene, particularly the integrity of their N and C termini, and, in the case of albumin, the agreement between the observed disulfide bond pattern and the published model. Furthermore, the structure of an albumin-related compound could be elucidated. Application of LC-MS for batch-to-batch quality control is also under discussion.

Thiamin requirement of juvenile shrimp (Penaeus monodon)

In a 9-wk feeding trial, juvenile shrimp (Penaeus monodon) were fed semipurified diets containing seven levels (0, 20, 40, 60, 80, 160 and 320 mg/kg diet) of supplemental thiamin hydrochloride. The dietary thiamin level required for optimal growth in P. monodon was found to be approximately 14 mg/kg diet based on hemolymph (blood) thiamin analysis. The minimum dietary thiamin level that produced substantial shrimp growth was approximately 13 mg/kg diet. Shrimp fed unsupplemented diets (thiamin content of 0.12 mg/kg diet) did not demonstrate specific deficiency signs, except those universal signs such as retarded growth, poor food conversion and low survival rates.

Analysis of duodenal bile acids by high performance liquid chromatography in infants with cholestasis

Non-sulfated bile acid levels including cholic acid (CA), chenodeoxycholic acid (CDCA), deoxycholic acid (DCA), lithocholic acid (LCA), ursodeoxycholic acid (UDCA), five taurine conjugates, and five glycine conjugates in duodenal juice were measured in 50 Chinese infants with cholestasis to test their diagnostic value. All 17 with biliary atresia (BA) cases, 11 out of 26 neonatal hepatitis (NH) cases and one case with paucity of the interlobular bile duct were without detectable bile acids. In those NH patients with detectable bile acids, the major components were conjugated forms of CA and CDCA, which was similar to all 6 cases of the comparison group with other diseases. The minor bile acid components identified in them were glycine conjugated UDCA, free CDCA, free CA, and free and conjugated DCA. Only one patient with NH had taurine conjugated LCA. The mean total duodenal bile acid level in 15 patients with NH was significantly lower than that in the 6 patients of the comparison group. Most patients with NH had a CDCA/CA ratio of less than one, indicating that cholic acid is the predominant form in their bile. Glycine conjugated bile acids were the predominant bile acids present in 11 out of 15 patients with NH and 4 out of 6 of the comparison group patients. The results suggest that the detection of duodenal bile acids by a sensitive HPLC method is of limited value in making a differential diagnosis between BA and NH.(ABSTRACT TRUNCATED AT 250 WORDS)