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Tin oxide is one of the most promising anode materials for lithium-ion batteries (LIBs) due to its high capacity and easy availability. However, its application is often hampered by the severe volume expansion during lithiation and delithiation process, causing a lower capacity retention rate. In this work, C@SnO2 core–shell nanostructure was constructed by using one-step hydrothermal method. In this nano-architecture, SnO2 nanoparticles are trapped and supported by carbon via the interfacial coupling effect. Benefiting from the structure and compositional characteristics, C@SnO2 electrodes display excellent lithium storage performance, when used as anode material for lithium-ion battery. It delivers a high initial discharge capacity of 1420 mA h g−1 and maintains a discharge capacity of 541 mA h g−1 after 150 cycles at the current density of 100 mA g−1, which is superior to the SnO2 and carbon electrodes. The enhanced electrochemical performance can be attributed to the construction of core–shell structure; the C@SnO2 has numerous void spaces and good electrical conductivity. It can effectively prevent the aggregation of SnO2 nanoparticles and shorten the diffusion path during electrochemical cycles, leading to the excellent lithium storage performance. This work provides a simple strategy to construct improved transition metal oxide electrodes for energy storage.

Laser peening has an extensive application in traditional manufacturing industry. However, in additive manufacturing, the initial stresses on the parts often reduce the effects of laser peening and make it hard to achieve a desirable residual stress distribution. In this investigation, the interaction of initial residual stress and laser peening-induced stress was studied through numerical simulation and experimental tests. A finite element model (FEM) model was built to predict the stress distribution on laser-deposited sample, and its changed state is affected by laser peening. The microstructure and mechanical properties were also characterized experimentally. The result turned out that the thermal-induced tensile residual stress in laser-deposited sample can affect the laser peening result in both horizontal and longitudinal directions. Some mechanical properties of the LAMed sample were changed after LSP treatment. The hardness on the surface and 1-mm depth have been increased by 7% and 22%, respectively, and the yield strength was increased by 16%, while there is no significant change in the tensile strength and elongation rate.

We report the properties of more than 600 bursts (including cluster-bursts) detected from the repeating fast radio burst (FRB) source FRB 20201124A with the Five-hundred-meter Aperture Spherical radio Telescope (FAST) during an extremely active episode on UTC September 25-28, 2021, in a series of four papers. The observations were carried out in the band of 1.0 - 1.5 GHz by using the center beam of the L-band 19-beam receiver. We monitored the source in sixteen 1-hour sessions and one 3-hour session spanning 23 days. All the bursts were detected during the first four days. In this first paper of the series, we perform a detailed morphological study of 624 bursts using the 2-dimensional frequency-time ``waterfall'' plots, with a burst (or cluster-burst) defined as an emission episode during which the adjacent emission peaks have a separation shorter than 400 ms. The duration of a burst is therefore always longer than 1 ms, with the longest up to more than 120 ms. The emission spectra of the sub-bursts are typically narrow within the observing band with a characteristic width of $\sim$277 MHz. The center frequency distribution has a dominant peak at about 1091.9 MHz and a secondary weak peak around 1327.9 MHz. Most bursts show a frequency-downward-drifting pattern. Based on the drifting patterns, we classify the bursts into five main categories: downward drifting (263) bursts, upward drifting (3) bursts, complex (203), no drifting (35) bursts, and no evidence for drifting (121) bursts. Subtypes are introduced based on the emission frequency range in the band (low, middle, high and wide) as well as the number of components in one burst (1, 2, or multiple). We measured a varying scintillation bandwidth from about 0.5 MHz at 1.0 GHz to 1.4 MHz at 1.5 GHz with a spectral index of 3.0., Comment: Accepted by Research in Astronomy and Astrophysics (RAA)

Fast radio bursts (FRBs) are highly dispersed millisecond-duration radio bursts. Recent observations of a Galactic FRB suggest that at least some FRBs originate from magnetars, but the origin of cosmological FRBs is still not settled. Here we report the detection of 1863 bursts in 82 hr over 54 days from the repeating source FRB~20201124A. These observations show irregular short-time variation of the Faraday rotation measure (RM), which probes the density-weighted line-of-sight magnetic field strength, of individual bursts during the first 36 days, followed by a constant RM. We detected circular polarisation in more than half of the burst sample, including one burst reaching a high fractional circular polarisation of 75%. Oscillations in fractional linear and circular polarisations as well as polarisation angle as a function of wavelength were detected. All of these features provide evidence for a complicated, dynamically evolving, magnetised immediate environment within about an astronomical unit (au; Earth-Sun distance) of the source. Our optical observations of its Milky-Way-sized, metal-rich host galaxy reveal a barred spiral, with the FRB source residing in a low stellar density, interarm region at an intermediate galactocentric distance. This environment is inconsistent with a young magnetar engine formed during an extreme explosion of a massive star that resulted in a long gamma-ray burst or superluminous supernova., Comment: 28 pages, 10 figures, updated to match the published version

The dispersive sweep of fast radio bursts (FRBs) has been used to probe the ionized baryon content of the intergalactic medium, which is assumed to dominate the total extragalactic dispersion. While the host galaxy contributions to dispersion measure (DM) appear to be small for most FRBs, in at least one case there is evidence for an extreme magneto-ionic local environment and a compact persistent radio source. Here we report the detection and localization of the repeating FRB 20190520B, which is co-located with a compact, persistent radio source and associated with a dwarf host galaxy of high specific star formation rate at a redshift $z=0.241\pm0.001$. The estimated host galaxy DM $\approx 903^{+72}_{-111}$ pc cm$^{-3}$, nearly an order of magnitude higher than the average of FRB host galaxies, far exceeds the DM contribution of the intergalactic medium. Caution is thus warranted in inferring redshifts for FRBs without accurate host galaxy identifications., Accepted, Version 3

The event rate, energy distribution, and time-domain behaviour of repeating fast radio bursts (FRBs) contains essential information regarding their physical nature and central engine, which are as yet unknown. As the first precisely-localized source, FRB 121102 has been extensively observed and shows non-Poisson clustering of bursts over time and a power-law energy distribution. However, the extent of the energy distribution towards the fainter end was not known. Here we report the detection of 1652 independent bursts with a peak burst rate of 122~hr^{-1}, in 59.5 hours spanning 47 days. A peak in the isotropic equivalent energy distribution is found to be ~4.8 x 10^{37} erg at 1.25~GHz, below which the detection of bursts is suppressed. The burst energy distribution is bimodal, and well characterized by a combination of a log-normal function and a generalized Cauchy function. The large number of bursts in hour-long spans allow sensitive periodicity searches between 1 ms and 1000 s. The non-detection of any periodicity or quasi-periodicity poses challenges for models involving a single rotating compact object. The high burst rate also implies that FRBs must be generated with a high radiative efficiency, disfavoring emission mechanisms with large energy requirements or contrived triggering conditions., 69 pages, 14 figures, 2 tables; Updates for author correction

Ketamine is a non-competitive channel blocker of N-methyl-D-aspartate (NMDA) receptors1. A single sub-anaesthetic dose of ketamine produces rapid (within hours) and long-lasting antidepressant effects in patients who are resistant to other antidepressants2,3. Ketamine is a racemic mixture of S- and R-ketamine enantiomers, with S-ketamine isomer being the more active antidepressant4. Here we describe the cryo-electron microscope structures of human GluN1-GluN2A and GluN1-GluN2B NMDA receptors in complex with S-ketamine, glycine and glutamate. Both electron density maps uncovered the binding pocket for S-ketamine in the central vestibule between the channel gate and selectivity filter. Molecular dynamics simulation showed that S-ketamine moves between two distinct locations within the binding pocket. Two amino acids-leucine 642 on GluN2A (homologous to leucine 643 on GluN2B) and asparagine 616 on GluN1-were identified as key residues that form hydrophobic and hydrogen-bond interactions with ketamine, and mutations at these residues reduced the potency of ketamine in blocking NMDA receptor channel activity. These findings show structurally how ketamine binds to and acts on human NMDA receptors, and pave the way for the future development of ketamine-based antidepressants.

To explore the effect of carbachol on myocardial injury in septic rats, and to further study its influence on the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway.A total of 48 healthy male Sprague-Dawley rats were randomly divided into sham group (n=16), model group (n=16), and carbachol group (n=16). The rat model of sepsis was established via cecal ligation and puncture. Carbachol was intraperitoneally injected (10 μg/kg) immediately after operation in carbachol group, and no cecal ligation was performed in sham group. At 48 h after operation, the survival rate of rats in each group was recorded, the activity of plasma creatine kinase-MB (CK-MB) was detected, and the cardiac function in each group was determined. Moreover, the heart was isolated, and the myocardial tissues were taken to detect the apoptosis level using the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) apoptosis kit. The content of inflammatory factors in myocardial tissues was determined using enzyme-linked immunosorbent assay (ELISA) kits, and the expression levels of apoptosis-related proteins and the PI3K/AKT signaling pathway-related proteins were detected via Western blotting.Carbachol could significantly raise the survival rate of septic rats (p0.01), remarkably decrease the activity of CK-MB (p0.01), markedly reduce the left ventricular internal diameter at end-systole (LVIDs), and markedly increase the left ventricular ejection fraction (LVEF, %) and left ventricular fractional shortening (LVFS, %). Besides, carbachol could evidently lower the apoptosis level of myocardial cells of septic rats (p0.01), reduce the content of inflammatory factors including tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß) and IL-6 (p0.01), notably decrease the expression of Caspase-3 in myocardial tissues (p0.01), remarkably increase the expression of Bcl-2/Bax (p0.01), and distinctly inhibit the expressions of phosphorylated (p-)PI3K, p-AKT, Nod-like receptor protein 3 (NLRP3), and Caspase-1 (p0.01).Carbachol can reduce the release of inflammatory factors in myocardial cells, the expression of apoptotic proteins and the apoptosis of myocardial cells, and improve the cardiac function and survival rate of septic rats by inhibiting the PI3K/AKT signaling pathway.

Background The One-Child Policy led to the imbalance of the sex ratio at birth (SRB) in China. After that, Two-Child Policy was introduced and gradually liberalized at three stages. If both the husband and wife of one couple were the only child of their parents, they were allowed to have two children in policy (BTCP). If only one of them was the only child, they were allowed to have two children in policy (OTCP). The Universal Two-Child Policy (UTCP) allowed every couple to have two children. The objective of this study was to explore the changing trend of SRB at the stages of Two-Child Policy, to analyze the effect of population policy on SRB in terms of maternal age, delivery mode, parity, maternal education, delivery hospital, and to figure out what factors have greater impact on the SRB. Methods The data of the study came from Hebei Province Maternal Near Miss Surveillance System, covered the parturients delivered at 28 gestation weeks or more in 22 hospitals from January 1, 2013 to December 31, 2017. We compared the SRB at different policy stages, analyzed the relationship between the SRB and population policy by logistic regression analysis. Results Total 270,878 singleton deliveries were analyzed. The SRB, 1.084 at BTCP, 1.050 at OTCP, 1.047 at UTCP, declined rapidly (χ2 = 15.97, P χ2 = 44.49, P Conclusions The SRB has declined to normal level with the gradually liberalizing of Two-Child Policy in China. Advanced maternal age, cesarean delivery, multiparous women, middle level education, rural hospital are the main factors of effect on the decline of the SRB.

In order to avoid the damage of membrane structure caused by snow load, a new type of intelligent snow removal device is proposed based on the principle of micro-spray irrigation and the dual control of pressure and temperature. The determination method of construction parameters such as pressure critical value, snow area, sprinkler size and number of the device is expounded. Finally, taking a Shanghai membrane structure project as an example, the snow area of the project was determined. Considering the size of snow area and the sprinkler spraying area, the number and construction location of the sprinklers on the membrane surface were finally determined.

Introduction: Three main contradictions that accompany the urbanization process: population explosion and food demand, urban expansion and production space, production mode and energy consumption. The pressure of urbanization has caused a huge mismatch between production and consumption in space and mode. Analysing the status and trends of urban food system planning show that sustainable consumption and production are closely related to their spatial layout. Method: Take a simulated urban community sustainable food system as an example. Based on local production and consumption, distributed layout and resource recycling system. The model formulates a reasonable spatial planning strategy based on urban agriculture of different scales, technologies and efficiencies, quantifies the indicators of the productive community to suit different scales, and uses a python algorithm to simulate a spatial model with adjustable parameters. Results: Through the comparison and optimization of multi-plan spatial patterns, a sustainable consumption and production-oriented planning decision was formed, which was finally used to guide the productive community spatial planning project. Discussion: This model is only a preliminary attempt at food system planning, but ‘theory-simulation-design’ has proved the feasibility of productive community spatial planning and explored the path of sustainable urban communities that support sustainable consumption and production.

目的 比较IPI、美国国家综合癌症网络IPI（NCCN-IPI）及年龄调整的IPI（aa-IPI）三种预后分层模型在弥漫大B细胞淋巴瘤（DLBCL）患者中的预后分层能力。 方法 回顾性分析2003年1月至2012年12月311例初治DLBCL患者资料，根据治疗方案将患者分为CHOP（环磷酰胺、多柔比星、长春新碱、泼尼松）方案及利妥昔单抗（R）-CHOP方案组，分别采用IPI、NCCN-IPI及aa-IPI对DLBCL患者进行危险度分层。采用Harrell's C统计评价不同模型的预后分层能力。 结果 ①311例患者中接受CHOP方案治疗者128例，接受R-CHOP方案治疗者183例。②CHOP方案组患者的5年总生存（OS）率结果显示，aa-IPI（71.0%对25.0%，P

To reduce defects and improve the quality of laser drilling, the electric and magnetic (EM) field-assisted laser drilling has been tested. For different industrial applications, we performed microlaser drilling and macro-through-hole drilling under different EM fields using two different lasers (ns and ms). Drilling was performed on a custom apparatus that can produce static and rotating EM fields. The motion of the plasma strongly affected the drilling quality. In an EM field, both the ns and ms lasers produced holes with smaller diameters, better surface quality, and fewer hole wall defects. The drilling defects were mainly caused by the plasma-based multi-shock effect. The EM field can influence the motion of the plasma and minimize defects.

To investigate the correlation of type 2 diabetes mellitus (DM) complicated with osteoporosis with lipid metabolism, adipokines and inflammatory factors, and to define the risk factors via the multivariate regression analysis.A total of 80 patients with DM admitted into our hospital from November 2015 to November 2016 were enrolled, including 40 patients complicated with osteoporosis and 40 patients not complicated with osteoporosis. The levels of blood lipid, adipokines and inflammatory factors were compared; the correlations between bone mineral density (BMD) and total cholesterol (TC), adiponectin and tumor necrosis factor-α (TNF-α) were analyzed; and multivariate Logistic regression analysis was performed for osteoporosis, hyperlipidemia, abnormal adipokine levels and body's inflammatory response.The levels of serum lipid indexes, total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C), in patients without complicating osteoporosis were significantly lower than those in patients complicated with osteoporosis. The level of high-density lipoprotein cholesterol (HDL-C) was significantly higher than that in patients complicated with osteoporosis. The levels of adipokines, adiponectin and visfatin, in patients without complicating osteoporosis were significantly lower than those in patients complicated with osteoporosis. The levels of inflammatory factors, TNF-α, interleukin-6 (IL-6) and C-reactive protein (CRP), in patients without complicating osteoporosis were significantly lower than those in patients complicated with osteoporosis. There were negative correlations between BMD and TC, adiponectin and TNF-α. Abnormal blood lipid, abnormal adipokine levels and elevated inflammatory factor levels were independent risk factors for osteoporosis.Enhanced inflammatory response, abnormal blood lipid metabolism and abnormal changes in adipokines may increase the risk of osteoporosis in patients with diabetes mellitus.

Peritrophic membrane proteins are important components of the insect peritrophic membrane. A novel cDNA gene encoding a chitin-binding protein, named secbp66, was identified by immunization screening of the cDNA library of Spodoptera exigua. The full length of secbp66 is 1806 bp, which encodes 602 amino acids. The predicted weight of the protein is 64.2 kDa. Bioinformatic analysis showed that a signal peptide composed of 17 amino acids located at the N-terminal of SeCBP66 contained seven tandem putative Type-II functional chitin-binding domains and five potential N-glycosylation sites, but no O-linked glycosylation sites. To study the properties of SeCBP66, recombinant SeCBP66 was successfully expressed in the insect cell line BTI-Tn-5B1-4 with a Bac-to-Bac expression system. A chitin binding experiment showed that the recombinant SeCBP66 protein could bind to chitin strongly. This study of the novel chitin-binding protein SeCBP66 provides a basis for developing new control targets for S. exigua.

Abnormal expression of microRNA-135a (miR-135a) is closely associated with oncogenesis. However, the relationship between serum miR-135a levels and the clinical parameters and prognosis of non-small cell lung cancer (NSCLC) remain unclear. The study aimed to investigate the clinical significance of serum miR-135a expression in patients with NSCLC. miR-135a expression was analyzed by real-time PCR and its correlation with NSCLC was determined by various statistical methods for 104 NSCLC patients and 40 healthy volunteers. The serum miR-135a level was significantly lower in NSCLC patients than in healthy control subjects (P < 0.01), and was closely related to distant metastasis (P < 0.015), lymphatic metastasis (P = 0.000), TNM (tumor node metastasis) stage (P = 0.001), and pathological stage (P = 0.021) of NSCLC. The five year overall survival was significantly lower in patients with low miR-135a expression than that in patients with high serum miR-135a levels (P = 0.010). Multivariate analysis showed that serum miR-135a level could be treated as an independent risk factor for NSCLC prognosis (P = 0.011). In conclusion, the serum miR-135a level was downregulated in NSCLC patients, and was associated with poor prognosis. Additionally, it can be used as a biomarker for NSCLC prognosis.

Cu–Co alloys of bulk compositions Cu75Co25 and Cu84Co16 were undercooled and solidified using electromagnetic levitation. Microstructure of the samples was characterized using optical microscopy, scanning electron microscopy, energy dispersive spectrometry, and micro X-ray diffraction analysis. It was found that besides a bimodal size distribution, droplets of the Co-rich L1 phase resulting from liquid phase separation have a broad composition distribution. The bimodal size distribution of the droplets is more pronounced for the Cu75Co25 sample than for the Cu84Co16 sample, whilst the composition distribution of the droplets is broader in the Cu75Co25 sample than in the Cu84Co16 sample. The droplets were found to also have different types of substructures in the two samples. The results provide novel insight into microstructural evolution of phase-separated alloys under influence of forced convection.

As a bioactive signal, nitric oxide (NO) is involved in multiple plant physiological responses, especially under some abiotic stress. Here, we investigated the effects of exogenous nitric oxide on both the reactive oxygen species (ROS) scavenging metabolism and regulating functions of plasma membrane and tonoplast in tomato plants treated with 50µM CuCl 2 . Copper stress induced significant accumulation of H 2 O 2 , led to serious lipid peroxidation, and finally markedly decreased shoot height and fresh weight of tomato plants. The application of 100µM sodium nitroprus side (SNP – NO donor) promoted some antioxidant enzymes, reduced accumulation of H 2 O 2 , and adjusted the activity of H + -ATPase and H + -PPase in plasma membrane or tonoplast, and significantly alleviated the growth inhibition induced by copper toxicity. On the other hand, the application of sodium ferrocyanide (an analog of SNP) and sodium nitrate or nitrite (the decomposition product of NO or its donor SNP) which did not release NO, did not show the effects of SNP. Furthermore, the effects of SNP were reverted by addition of hemoglobin (an NO scavenger). Therefore, these results indicated that exogenous NO could effectively assuage copper toxicity by physiological and biochemical response so as to maintain normal growth. Keyword: nitric oxide (NO); copper toxicity; tomato; enzyme activity; plasma membrane; tonoplast

In May 2016, some irregular pink spots with gray necrosis in the center and a yellow halo around the edge were found to develop on rubber (Hevea brasiliensis) leaves in a nursery in Jinghong, Yunnan. Some infected leaves were washed with tap water, dried and sterilized with 75% alcohol for 30 s, and subsequently dried and cut into pieces of 0.2 to 0.3 cm. Finally, the heathy pieces neighbor to symptomatic leaf tissues were placed on potato dextrose agar (PDA) medium at 25°C for 5 days. Then some pure cultures identical to the colony and spores could be obtained after transferring several times. After 15 days, healthy leaves of three plants were selected for pathogenic tests in the nursery. Spore suspension (1 × 10⁶ spores/ml) was made from a pure culture 10 days after inoculation on PDA. Spore suspension (10 ml per leaf) was sprayed on the surface of the selected 10 leaves per plant; in the meantime, an equal amount of sterilized water was sprayed on another 15 healthy leaves as the controls, and then all leaves were covered respectively with a fresh bag to remain moisturize for 3 days. All the bags were removed on the 4th day after inoculation. Some light yellow spots developed, turned into red on the 7th day, and then turned into pink on 10th day. The symptoms of inoculation were consistent with those of collection in the field but not on the controls. The fungus identical to the previous colony and conidia could be reisolated from the symptomatic leaves but not from the controls. The mycelium cultured at 25°C for 5 days is light and yellow on the back, and ascospores began to appear in the colonies after 2 days. Ascus, dark brown to black, superficial, elliptic or subglobose, approximately 151 to 316 × 142 to 312 μm, the ascomal hair, setaceous, apex acuminate, separated, unbranched, brown, with smooth surface; lateral hairs are shorter, setaceous, brown, unbranched, apically acuminate, with gradually shallow color; ascus wall dispels in early stage, ascospore is brown, oval shaped to elliptic, with the size of 4.8 to 5.7 × 3.2 to 5.5 μm, one end slightly pointed with a top bud hole, flat on both sides. The internal transcribed spacer (ITS) sequence was extracted and was amplified by the primers ITS1 and ITS4, and the 563-bp product of the ITS (GenBank accession no. KX869740) showed 100% sequence identity to Chaetomium funicola (GenBank accession no. KR909159.1). Therefore, both molecular and morphological observations indicated that the pathogenic fungus was mostly similar to C. funicola (Zhang 2013). C. funicola was reported to cause chromoblastomycosis on a man’s skin in western Panama (Piepenbring et al. 2007). Chaetomium globosum could cause leaf spot on pomegranate in Yunnan, China (Guo et al. 2016). As far as the authors know, this is the first report of rubber leaf spot caused by Chaetomium sp. in Yunnan, China, as well as in the world.

The influence of gradient magnetic field on the undercooling behavior of glass-fluxed pure Sb melts was investigated using a superconducting magnet. It was found that under a positive gradient magnetic field, the mean undercooling of pure Sb melts increased with increasing magnetic field intensity. However, under a negative gradient magnetic field, the mean undercooling showed a decreasing tendency following an initial increase with increasing magnetic field intensity. The results were discussed by considering the Lorentz force and the magnetization force imposed by the gradient magnetic field.

Electromagnetically levitated Cu-Cr alloy melts containing 5-70 at.% Cr were splat-quenched onto a chill substrate. The microstructure of the solidified alloys was investigated by scanning electron microscopy. The alloys containing 5-60 at.% Cr showed a droplet-shaped microstructure consisting of Cr-rich spheroids or and dendrites in a Cu-rich matrix, whereas those containing 65 and 70 at.% Cr showed a banded microstructure consisting of alternative Cu-rich and Cr-rich bands. Both types of microstructure presented evidence for metastable phase separation in Cu-Cr alloy compositions, thus verifying the existence of a broad miscibility gap in the undercooled liquid. However, the results suggested that the miscibility gap has a Cr-rich critical composition and a skewed geometry.

Grain yield presents a complex nonlinear relationship with variables, and takes on randomness and mutability. It is hard to describe the prediction model with traditional linear model. Grey model can be used to process samples with great stochastic volatility. In this paper, we propose to use the grey neural network to predict the grain yield. Experiments are carried out on the beans yield, rice yield and corn yield respectively to evaluate the prediction performance. The promising experimental results validate the effectiveness of our prediction model. Keywords-grey neural network; grey model; grain yield prediction

An important necessary condition for transverse phase space damping in the optical stochastic cooling with transit-time method is derived. The longitudinal and transverse damping dynamics for the optical stochastic cooling is studied. The authors also obtain an optimal laser focusing condition for laser-beam interaction in the correction undulator. The amplification factor and the output peak power of the laser amplifier are found to differ substantially from earlier publications. The required power is large for hadron colliders at very high energy.

Advances in nonaqueous capillary electrophoresis are reviewed with 71 references in this paper. Capillary electrophoresis is generally performed in aqueous buffer. In fact, it can provide some advantages to use organic solvent as a separation medium instead of water. The choice of organic solvent and electrolyte, the detection mode and solute-additive interactions are summarized. Furthermore, the separation of inorganic ions, neural compounds, organic acids, pharmaceuticals, metabolites and chiral substance is also described.

A new method for predicting the retention time of solutes under linear gradient elution has been established. In this method, the migration distance of solutes in column and the mobile phase gradient were modified simultaneously according to the distribution of mobile phase in column. The prediction results of retention time of both weakly and strongly retentive solutes were accurate in different instrumental systems using this method. In order to test and verify this method, the retention time of fifteen amino acids and eight homologous compounds of benzene were predicted. The predicted results were compared with those predicted by the method in common use. The relative average errors between predicted and experimental values were 3.70% and 4.90% for the weakly retentive solutes, far smaller than those obtained by the reference method (23.61% and 31.16%). For the strongly retentive solutes, the relative average errors were 0.21% and 6.01% respectively, slightly smaller than those obtained by the reference method (0.81% and 6.69%). It is seen that this new method has many advantages.

This report covers developments in chromatography and related techniques in China during the period of 1998-1999. The papers published in 23 domestic and a few foreign periodicals which are closely related to chromatography, and presented at 1999 Beijing Conference and Exhibition on Instrumental Analysis and the 12th National Symposium of Chromatography are reviewed. Specific topic areas covered include gas chromatography (GC), high performance liquid chromatography (HPLC), capillary electrophoresis (CE) and capillary electrochromatography (CEC), solid phase extraction (SPE) and solid phase microextraction (SPME).

To review the spatiotemporal behaviours of central otolith neurons in decerebrate animals.Laboratory of Neurophysiology, Department of Physiology, Faculty of Medicine, The University of Hong Kong.Results of key research findings from 1992 to 1997.With constant velocity colckwise (CW) and counterclockwise (CCW) off-vertical axis rotations as stimuli to the otolith organs, neurons in the vestibular nuclei and medullary reticular formation showed characteristic spatiotemporal behavious. One-dimensional neurons showed symmetric and stable bidirectional response sensitivities (delta) to change in velocity while two-dimensional neurons showed asymmetric and variable delta to velocity. This CW-CCW asymmetry to bidirectional rotations may provide directional coding in the modulation of neural signals. Vestibular nuclear neurons also displayed distinct spontaneous discharge patterns at the stationary and earth-horizontal position, indicating that one- and two-dimensional neurons belong to physiologically distinct etities. These spatiotemporal behavious of the vestibular nuclear neurons were also shown to be precisely controlled by imputs from the vestibulocerebellum and/or bilateral otoliths. In both the vestibular nucleus and the reticular formation, the best response orientations of one-dimensional neurons and the orientations of the maximum response vector of two-dimensional neurons were found to point in all directions close to the horizontal plane, indicating that all head orientations on this plane are encoded across an ensemble of neurons.Otolith-evoked behaviours of the one-dimensional and two-dimensional neurons constitute an important element for the recognition of the direction and orientation of head motion in space.

Trente-deux chameaux de Bactriane eleves dans des conditions traditionnelles d'elevage ont ete suivis pour etudier leur croissance post-natale et leur profil de developpement. Treize mesures corporelles lineaires ont ete faites a trente jours d'intervalle depuis la naissance jusqu'au 420 eme jour. Les taux moyens de croissance pour la hauteur, le tour de poitrine, la longueur, la circonference de l'os canon, la profondeur et la largeur du poitrail, la longueur et la largeur de la croupe, la longueur des pattes, la longueur et la largeur de la tete et la longueur du cou ont ete evalues. Les resultats ont montre que, dans une large mesure, les differentes dimensions corporelles avaient un profil de maturite uniforme et que leur hierarchie tendait a rester constante pendant toute la periode d'observation. Les taux de croissance rapide correspondaient a un allaitement maternel satisfaisant. Le profil de croissance du poids vif suivait la courbe de la plupart des mammiferes. Cependant la croissance a ete plus rapide au cours des sept premiers mois et le gain de poids moyen quotidien (gmq) le plus important a ete constate au cours du 3e mois, avec une moyenne de 0,782 ± 0,349 kg. Un gmq negatif a ete observe entre le 1Oe et le 11e mois avec une moyenne de -0,1677 ± 0,19 kg pour les mâles et de -0,006 ± 0,24 kg pour les femelles, lorsque la mere entrait en periode de reproduction et que la production laitiere chutait. Le gmq moyen sur 420 jours a ete de 0,3846 ± 0,2895 kgd-1. Les courbes de croissance standardisees ont permit de deduire le degre de maturite en termes de poids vif et d'âge. (Resume d'auteur)