Biodegradation Behavior of Starch in Simulated White Water System of Old Corrugated Cardboard Pulping Process

Considering the serious barriers/issues induced by the accumulated starch generated in white water system of old corrugated cardboard(OCC)pulping process,large amounts of accumulated starch in white water would be decomposed by microorganisms and could not be utilized,thereby resulting in severe resource wastage and environmental pollution.This study mainly explored the effects of biodegradation/hydrolysis conditions of the two types of starch substrates(native starch and enzymatically(α-amylase)hydrolyzed starch),which were treated via microorganism degradation within the simulated white water from OCC pulping system and their biodegradation products on the key properties were characterized via X-ray diffraction(XRD),Fourier-transform infrared spectroscopy(FT-IR),and gel permeation chromatography(GPC)technologies.The effects of system temperature,pH value,starch concentration,and biodegradation time on starch biodegradation ratio and the characteristics of obtained biodegradated products from the two types of starches were studied.In addition,the effect ofα-amylase dosage on the biodegradation ratio of enzymatically hydrolyzed starch and its properties was investigated.It was found that the native starch presented a maximal degradation ratio at a system temperature of 55℃and pH value range of 5-7,respectively,the corresponding starch concentration within simulated white water system was 200 mg/L.Whereas the enzymatically hydrolyzed starch exhibited a highest degradation ratio at a system temperature of 50℃and pH value of 5.5,respectively,and the corresponding starch concentration within simulated white water system was 100 mg/L.It was verified that native starch is more readily bio-hydrolyzed and biodegradation-susceptive by microorganisms in simulated white water system of OCC pulping process,while the enzymatically hydrolyzed starch exhibits better biodegradation/hydrolysis resistance to the microbial degradation than that of native starch.This study provides a practical and interesting approach to investigate the starch hydrolysis or biodegradation behaviors in white water system of OCC pulping process,which would greatly contribute to the full recycling and valorized application of starch as a versatile additive during paperboard production.

Uncovering the degradation mechanism induced by ion-diffusion kinetics in large-format lithium-ion pouch cells

Battery electrochemistry in an actual cell is a complicated behavior influenced by the current density,uniformity,and ion-diffusion distance,etc.The anisotropism of the lithiation/delithiation degree is usually inevitable,and even worse,due to a trend of big-size cell design,typically such as 4680 and blade cells,which accelerated a battery failure during repeat lithiation and delithiation of cathodes.Inspire by that,two big-size pouch cells with big sizes,herein,are selected to reveal the ion-diffusion dependency of the cathodes at different locations.Interestingly,we find that the LiCoO_(2) pouch cell exhibits ~5 A h loss after 120 charge-discharge cycles,but a 15 A h loss is verified in a LiNixMnyCO_(1-x)-yO_(2)(NCM) cell.Synchrotron-based imaging analysis indicates that higher ion-diffusion rates in the LiCoO_(2)than that in the LiNixMnyCO_(1-x)-yO_(2)is the determined factor for the anisotropic cathode fading,which is responsible for a severe mechanical issue of particle damage,such as cracks and even pulverization,in the cathode materials.Meanwhile,we verify the different locations at the near-tab and bottom of the electrode make it worse due to the ion-diffusion kinetics and temperature,inducing a spatially uneven electrochemistry in the big-size pouch cell.The findings give an in-depth insight into pouch cell failure and make a guideline for high-energy cell design and development.

Progress and Achievements of Multi-sensor Fusion Navigation in China during 2019—2023

Global Navigation Satellite System(GNSS)can provide all-weather,all-time,high-precision positioning,navigation and timing services,which plays an important role in national security,national economy,public life and other aspects.However,in environments with limited satellite signals such as urban canyons,tunnels,and indoor spaces,it is difficult to provide accurate and reliable positioning services only by satellite navigation.Multi-source sensor integrated navigation can effectively overcome the limitations of single-sensor navigation through the fusion of different types of sensor data such as Inertial Measurement Unit(IMU),vision sensor,and LiDAR,and provide more accurate,stable and robust navigation information in complex environments.We summarizes the research status of multi-source sensor integrated navigation technology,and focuses on the representative innovations and applications of integrated navigation and positioning technology by major domestic scientific research institutions in China during 2019—2023.

Optimal Maintenance Modeling for Systems with Multiple Non-Identical Units Using Extended DSSP Method

In the optimal maintenance modeling, all possible maintenance activities and their corresponding probabilities play a key role in modeling. For a system with multiple non-identical units, its maintenance requirements are very complicated, and it is time-consuming, even omission may occur when enumerating them with various combinations of units and even with different maintenance actions for them. Deterioration state space partition (DSSP) method is an efficient approach to analyze all possible maintenance requirements at each maintenance decision point and deduce their corresponding probabilities for maintenance modeling of multi-unit systems. In this paper, an extended DSSP method is developed for systems with multiple non-identical units considering opportunistic, preventive and corrective maintenance activities for each unit. In this method, different maintenance types are distinguished in each maintenance requirement. A new representation of the possible maintenance requirements and their corresponding probabilities is derived according to the partition results based on the joint probability density function of the maintained system deterioration state. Furthermore, focusing on a two-unit system with a non-periodical inspected condition-based opportunistic preventive-maintenance strategy;a long-term average cost model is established using the proposed method to determine its optimal maintenance parameters jointly, in which “hard failure” and non-negligible maintenance time are considered. Numerical experiments indicate that the extended DSSP method is valid for opportunistic maintenance modeling of multi-unit systems.

An Incidental Detection of Nutcracker Phenomenon in an Adolescent with Transient High Blood Pressure: A Case Report

Nutcracker phenomenon (NCP) is caused by a compression of left renal vein between aorta and superior mesenteric artery. The traditional clinical manifestations of nutcracker syndrome is usually accompanied with abdominal pain, hematuria, orthostatic proteinuria, and varicocele formation, however, hypertension is rarely reported as main clinical feature. We describe a male adolescent with manifestation of hypertension who was identified as NCP. Renal ultrasound and computed tomography angiography have provided evidences of left renal vein dilatation, probably due to the compression through the decreased angle between aorta and superior mesenteric artery. There were no other signs for secondary hypertension for the blood levels of renin and aldosterone being between normal limits and urinalysis being negative of hematuria and proteinuria. This patient was conservatively observed without any anti-hypertensive drugs and was asked for appropriately putting on weight. Three months later, the hypertension symptom was alleviated. In conclusion, although there were no established direct pathogenetic links between hypertension and NCP, no other definite etiology was shown to be the cause of this main manifestation. Thus we speculate that the NCP might be the main cause of hypertension in this patient.

导热绝缘有机硅复合材料的制备与性能

以氧化锌(Zn O)粒子负载在还原氧化石墨烯(RGO)表面,制备出一种以石墨烯为基体的导热绝缘混合填料粒子(Zn O-RGO)。分别采用傅里叶变换红外光谱、X射线衍射、扫描电子显微镜、热重分析方法进行测试,结果表明Zn O成功地负载在RGO上。将制得的Zn O-RGO粒子掺入有机硅中,制备复合有机硅橡胶,当Zn O-RGO掺量仅为1%(质量分数)时,复合硅橡胶的体积电阻率为1. 1×1014Ω·cm,热导率为0. 325 W/(m·K),相对于纯硅橡胶基体,热导率提升80. 5%,同时复合有机硅的力学性能也得到提升,拉伸强度提高了143. 7%,断裂伸长率提升了123. 8%,硬度由39提高到50。

The mechanism of astragaloside Ⅳ promoting sciatic nerve regeneration

3-O-beta-D-xylopyranosyl-6-O-beta-D-glucopyranosyl-cycloastragenol (astragaloside Ⅳ), the main active component of the traditional Chinese medicine astragalus membranaceus, has been shown to be neuroprotective. This study investigated whether astragaloside Ⅳ could promote the repair of injured sciatic nerve. Denervated sciatic nerve of mice was subjected to anastomosis. The mice were intraperitoneally injected with 10, 5, 2.5 mg/kg astragaloside Ⅳ per day for 8 consecutive days. Western blot assay and real-time PCR results demonstrated that growth-associated protein-43 expression was upregulated in mouse spinal cord segments L4-6 after intervention with 10, 5, 2.5 mg/kg astragaloside Ⅳ per day in a dose-dependent manner. Luxol fast blue staining and electrophysiological detection suggested that astragaloside Ⅳ elevated the number and diameter of myelinated nerve fibers, and simultaneously increased motor nerve conduction velocity and action potential amplitude in the sciatic nerve of mice. These results indicated that astragaloside Ⅳ contributed to sciatic nerve regeneration and functional recovery in mice. The mechanism underlying this effect may be associated with the upregulation of growth-associated protein-43 expression.

Promoter methylation of Wnt/β-Catenin signal inhibitor TMEM88 is associated with unfavorable prognosis of nonsmall cell lung cancer

Objective:Recent research has indicated that altered promoter methylation of oncogenes and tumor suppressor genes is an important mechanism in lung cancer development and progression.In this study,we investigated the association between promoter methylation of TMEM88,a possible inhibitor of the Wnt/β-Catenin signaling,and the survival of patients with nonsmall cell lung cancer(NSCLC).Methods:Twelve pairs of tumor and adjacent non-tumor samples were used for microarray analyses of DNA methylation and gene expression.For validation,more than two hundred additional samples were analyzed for methylation using bisulfite pyrosequencing and for gene expression using q RT-PCR.Then the cell function were tested by wound healing,transwell,CCK8 and cell cycle assay.Results:Our analysis of patient specimens showed that TMEM88 methylation was higher in NSCLC tumors(82.2%±10.3,P<0.01)compared with the adjacent normal tissues(65.9%±7.2).The survival analysis revealed that patients with high TMEM88methylation had a shorter overall survival(46 months)compared with patients with low TMEM88 methylation(>56 months;P=0.021).In addition,we found that demethylation treatment could inhibit tumor cell proliferation,migration,and invasion,which was supportive of an association between methylation and survival.Conclusions:Based on these consistent observations,we concluded that TMEM88 may play an important role in NSCLC progression and that promoter methylation of TMEM88 may serve as a biomarker for NSCLC prognosis and treatment.

Knockdown of long non-coding RNA LCPAT1 inhibits autophagy in lung cancer

Objective: Long non-coding RNAs(lnc RNAs) are involved in numerous biological processes in lung cancer cells. In our previous studies, we identified a lnc RNA, ENST00000439577, which is highly expressed in lung carcinomas, and termed it lung cancer progression-associated transcript 1(LCPAT1). To characterize the role of LCPAT1 in lung cancer, we conducted the current study.Methods: Expression of LCPAT1 and autophagy-associated markers in tumor tissues and lung cancer cell lines was determined by real-time quantitative polymerase chain reaction(q PCR). Hematoxylin and eosin(HE) staining, q PCR, Western blot, and immunohistochemistry were performed to evaluate xenografted tumor tissues. Autophagy induced by rapamycin was detected by Western blot and immunofluorescence in lung cancer cell lines.Results: Expression of LCPAT1 and microtubule-associated protein 1 light chain 3 beta(LC3B) was positively correlated in lung cancer. Knockdown of LCPAT1 inhibited tumor growth and suppressed cell autophagy in vivo. Moreover, LCPAT1 knockdown in lung cancer cell lines resulted in decreased autophagy-associated gene expression and alleviated the cell autophagy induced by rapamycin.Conclusions: We speculate that LCPAT1 plays a crucial role in regulating autophagy in lung cancer.

Phase 1 studies comparing safety, tolerability, pharmacokinetics and pharmacodynamics of HLX01(a rituximab biosimilar) to reference rituximab in Chinese patients with CD20-positive B-cell lymphoma

Objective: This study aimed to compare the pharmacokinetic, pharmacodynamic and safety profiles of HLX01(a rituximab biosimilar) and reference rituximab sourced from China(Mab Thera?;rituximab-CN).Methods: Here we report the results of two phase 1 studies. In the phase 1 a, open-label, dose-escalation study(NCT03218072, CTR20140400), eligible patients received 250, 375 and 500 mg/m^(2) HLX01 sequentially at 7-day intervals, after confirming no dose-limiting toxicity(DLT). In the phase 1 b, double-blind study(NCT02584920,CTR20140764), eligible patients were given a single dose of 375 mg/m^(2) HLX01 or rituximab-CN. The primary endpoints included safety and tolerability parameters for the phase 1 a and the area under the plasma concentrationtime curve from time zero to day 91(AUC0-91 d) for the phase 1 b study. Equivalence was concluded if 90%confidence interval(90% CI) for the geometric least squares mean ratio(GLSMR) fell in the pre-specified equivalence criteria(80%-125%).Results: Between June 20, 2014 and January 5, 2015, 12 patients were enrolled in the phase 1 a study. The pharmacokinetics of HLX01 showed dose proportionality and accumulation to steady state. HLX01 was well tolerated, with no serious adverse events(AEs), discontinuations or DLTs. Between November 8, 2014 and August13, 2015, 87 eligible patients were enrolled in the phase 1 b study, including 43 who received HLX01 and 44 who were treated with rituximab-CN. The equivalence endpoint was met with GLSMR for AUC0-91 d being 89.6%(90% CI: 80.4%-99.8%). AEs, anti-drug antibodies, and CD19+ and CD20+ B lymphocyte counts were similar between the HLX01 and rituximab-CN treatment groups.Conclusions: Treatment with HLX01 was safe and well tolerated in Chinese patients with B-cell lymphoma.HLX01 and rituximab-CN have similar pharmacokinetic, pharmacodynamic and safety profiles.

ICU护士自尊、工作满意度与主观幸福感的相关性研究

目的探讨ICU护士的自尊、工作满意度和主观幸福感状况,并分析3者之间的相关关系。方法选取天津市5所教学医院的224名ICU护士进行横断面调查。使用自尊量表(Self-EsteemScale,SES)、护士工作满意度量表(Nurse's working Satisfaction Scale)及主观幸福感量表(Subjective Well-Being Scale,SWB)进行调查,并采用Pearson相关分析方法探讨3者之间的关系。结果ICU护士的SES得分为(27.67±3.41)分,处于低水.平;护士工作满意度量表得分为(43.57±9.04)分,处于中等水平;SWB得分为(69.73±11.60)分,处于低水平。主观幸福感量表得分与自尊量表(r=0.454,P<0.01)和护士工作满意度量表得分(r=0.584,P<0.01)呈显著正相关。结论ICU护士自尊和工作满意度越高,其主观幸福感越强。在ICU护士工作压力暂时不能缓解的情况下,护理管理者和护士自身应采取积极策略加强心理建设,提高自尊水平及工作满意度,从而提高护士主观幸福感水平。

Precise Orbit Determination for the FY-3C Satellite Using Onboard BDS and GPS Observations from 2013, 2015, and 2017

Using the FengYun-3C(FY-3C)onboard BeiDou Navigation Satellite System(BDS)and Global Positioning System(GPS)data from 2013 to 2017,this study investigates the performance and contribution of BDS to precise orbit determination(POD)for a low-Earth orbit(LEO).The overlap comparison result indicates that code bias correction of BDS can improve the POD accuracy by 12.4%.The multi-year averaged one-dimensional(1D)root mean square(RMS)of the overlapping orbit differences(OODs)for the GPS-only solution is 2.0,1.7,and 1.5 cm,respectively,during the 2013,2015,and 2017 periods.The 1D RMS for the BDS-only solution is 150.9,115.0,and 47.4 cm,respectively,during the 2013,2015,and 2017 periods,which is much worse than the GPS-only solution due to the regional system of BDS and the few BDS channels of the FY-3C receiver.For the BDS and GPS combined solution(also known as the GC combined solution),the averaged 1D RMS is 2.5,2.3,and 1.6 cm,respectively,in 2013,2015,and 2017,while the GC combined POD presents a significant accuracy improvement after the exclusion of geostationary Earth orbit(GEO)satellites.The main reason for the improvement seen after this exclusion is the unfavorable satellite tracking geometry and poor orbit accuracy of GEO satellites.The accuracy of BDS-only and GC combined solutions have gradually improved from 2013 to 2017,thanks to improvements in the accuracy of International GNSS Service(IGS)orbit and clock products in recent years,especially the availability of a high-frequency satellite clock product(30 s sampling interval)since 2015.Moreover,the GC POD(without GEO)was able to achieve slightly better accuracy than the GPS-only POD in 2017,indicating that the fusion of BDS and GPS observations can improve the accuracy of LEO POD.GC combined POD can significantly improve the reliability of LEO POD,simply due to system redundancy.An increased contribution of BDS to LEO POD can be expected with the launch of more BDS satellites and with further improvements in the accuracy of BDS satellite products in the near future.

Controlled Growth of Large-Area Aligned Single-Crystalline Organic Nanoribbon Arrays for Transistors and Light-Emitting Diodes Driving

Organic field-effect transistors(OFETs) based on organic micro-/nanocrystals have been widely reported with charge carrier mobility exceeding 1.0 cm^2V^(-1)s^(-1), demonstrating great potential for high-performance, low-cost organic electronic applications. However, fabrication of large-area organic micro-/nanocrystal arrays with consistent crystal growth direction has posed a significant technical challenge. Here, we describe a solution-processed dip-coating technique to grow large-area, aligned 9,10-bis(phenylethynyl) anthracene(BPEA) and 6,13-bis(triisopropylsilylethynyl) pentacene(TIPSPEN) single-crystalline nanoribbon arrays. The method is scalable to a 5 9 10 cm^2 wafer substrate, with around 60% of the wafer surface covered by aligned crystals. The quality of crystals can be easily controlled by tuning the dip-coating speed. Furthermore, OFETs based on well-aligned BPEA and TIPS-PEN single-crystalline nanoribbons were constructed.By optimizing channel lengths and using appropriate metallic electrodes, the BPEA and TIPS-PEN-based OFETs showed hole mobility exceeding 2.0 cm^2V^(-1)s^(-1)(average mobility 1.2 cm^2V^(-1)s^(-1)) and 3.0 cm^2V^(-1)s^(-1)(average mobility2.0 cm^2V^(-1)s^(-1)), respectively. They both have a high on/off ratio(I_(on)/I_(off))>10~9. The performance can well satisfy the requirements for light-emitting diodes driving.

Short-term Prediction of Ionospheric TEC Based on ARIMA Model

In order to achieve high short-term prediction accuracy of ionospheric TEC,first,we transform a seasonal time series for ionospheric Total Electron Content (TEC) into a stationary time series by seasonal differences and regular differences with a full consideration of the Multiplicative Seasonal model.Next,we use the Autoregressive Integrated Moving Average (ARIMA) model taken from time series analysis theory for modeling the stationary TEC values to predict the TEC series.Using TEC data from 2008 to 2012 provided by the Center for Orbit Determination in Europe (CODE) as sample data,we analyzed the precision of this method for prediction of ionospheric TEC values which vary from high to low latitudes during both quiet and active ionospheric periods.The effect of the TEC sample’s length on the predicted accuracy is analyzed,too.Results from numerical experiments show that during the ionospheric quiet period the average relative prediction accuracy for a six day time span reaches up to 83.3% with average prediction residual errors of about 0.18±1.9 TECu.During ionospheric active periods it changes to 86.6% with an average prediction residual error of about 0.69±2.6 TECu.For the quiet periods,above 90% of predicted residual is less than ±3 TECu while during active periods,it is only about 81%.The two periods show that that the higher the latitude,the higher the absolute precision,and the lower the predicted relative accuracy.In addition,the results show that prediction accuracy will improve with an increase of the TEC sample sequences length,but it will gradually reduce if the length exceeds the optimal length,about 30 days.On the other hand,with the same TEC sample,as the predicted days increase,the predictive accuracy decreases.Athough the predictive accuracy is not apparent at the beginning,it will be significantly reduced after 30 days.

基于ZigBee组网控制的温室大棚环境监控系统

针对温室大棚在农业领域越来越得到广泛推广,数字化采集环境因素需求越来越得到重视,设计了基于ZigBee组网控制的温室大棚环境监控系统。系统主要由温湿度采集电路、光强传感器电路、ZigBee无线传输电路、电源管理电路、GSM数据传输电路等组成。通过SHT20温湿度采集传感器以及BH1750光强传感器采集环境因素,将各节点的环境因素通过ZigBee无线传感网络汇总处理,并永久保存至云端服务器,用户通过智能手机终端可以实时监测各项数据。测试结果表明,系统实现了对大棚内环境参数的采集、处理、传输、保存功能,具有低功耗、操作简便、体积小等特点,对用户在日常大棚中环境因素的采集起到方便管理以及便于维护的功能。

Clinical features of progressive supranuclear palsy in 105 Chinese patients

OBJECTIVE:To thoroughly investigate clinical characteristics of progressive supranuclear palsy(PSP)in a Chinese population.METHODS:Computer-based online searches through China National Knowledge Infrastructure and Weipu Periodical Database were performed to collect case reports of PSP published between 1980 and 2009.Clinical characteristics were analyzed.RESULTS:A total of 58 studies comprising 105 patients(76 males and 29 females)were included.All cases were sporadic and free of family history.The mean age at onset was 60.6±9.1 years,and the mean course from onset of symptoms to diagnosis was 3.4±2.4 years.The male-to-female ra-tio was approximately 3:1.Onset was characterized by akinetic-rigid features and accounted for 34.3%of all cases,followed by early postural instability(25.5%),pseudobulbar palsy(9.8%),cogni-tive impairment(9.8%),and vertical supranuclear ophthalmoplegia(7.8%).With disease progres-sion,vertical supranuclear ophthalmoplegia was reported in 95.1%of cases,followed by aki-netic-rigid features(83.3%),pseudobulbar palsy(82.4%),axial dystonia(75.5%),cognitive impair-ment(72.5%),and early postural instability(69.6%).A total of 70.5%of patients exhibited abnormal electroencephalograms,and 21.4%exhibited mild abnormalities in cerebrospinal fluid.Brain CT scanning results of 37 patients showed 37.8%with midbrain and concurrent cerebral hemisphere atrophy,and 5.4%and 24.3%with midbrain and cerebral hemisphere atrophy,respectively.Brain MRI scanning results of 55 patients revealed a total of 16.4%patients with midbrain atrophy,23.6% with midbrain and concurrent cerebral hemisphere atrophy,32.7%with cerebral hemisphere atrophy,and 11%with brainstem atrophy.The percentage of midbrain atrophy revealed by MRI was greater than by CT.All 11 patients subjected to Mini-Mental State Examination scored<23.A total of 10 patients underwent brain electrophysiological examination,and 80%presented with abnormalities of cerebral-evoked potential.A total of 33.3%patients presented with neurogenic damage of anal sphincter electromyography.Nine cases were neuropathologically diagnosed,and all displayed tau-positive argyrophilic globous neurofibrillary tangles,tuft-shaped astrocytes,and coiled bodies.Gene diagnosis was not performed.A total of 40 patients were misdiagnosed,including 23(58%)as Parkinson's disease and seven(18%)as Parkinsonism;44 patients were treated by madopar,ar-tane,or amantadine,and only seven(16%)improved in movement.No patients exhibited improved eye movement.Of 4 patients treated with madopar and dopa agonists,2 improved in movement.In addition,movement improved in 3 patients treated with madopar and monoamine oxidase B.CONCLUSION:PSP is a sporadic disease that often strikes middle or elderly individuals.There are no significant differences in age of onset between male and female patients,although disease pro-gression is more rapid in female patients,likely because the time from symptom onset to disease diagnosis in females is less than in male.Akinetic-rigid features and early postural instability are the most common symptoms of onset.With disease progression,the incidence of vertical supranuclear ophthalmoplegia and akinetic-rigid features increases.MRI is a common,sensitive,and noninva-sive supplemental test.However,PSP is frequently misdiagnosed as Parkinson's disease or Park-insonism during the early stage,and anti-Parkinson treatments remain ineffective.

Flame-retarding battery cathode materials based on reversible multi-electron redox chemistry of phenothiazine-based polymer

Polymeric organic battery materials are promising alternatives to the transition-metal-based ones owing to their enriched chemistries. However, the flammability of organic compounds brings in serious concern on battery safety. In addition to use flame-retarding electrolyte/electrolyte additives or battery separators,flame retardancy can readily be achieved through the integration of flame-retarding unit into the polymer backbone, imparting the flame retardancy permanently. The as-designed polymer based on phenothiazine shows significantly shortened self-extinguished time without deteriorating its intrinsic thermodynamic and electrochemical properties. Moreover, two electron per phenothiazine molecule is realized for the first time in a highly reversible manner with discharge voltages of 3.52 V and 4.16 V versus Li+/Li and an average capacity of ca. 120 mAh g-1 at a current rate of 2 C. The origin of the reversibility is investigated through density functional theory(DFT) calculations. These findings address the importance of molecular design for safer and more stable organic materials for batteries.

Progress in Chemical Synthesis of Peptides and Proteins

For the proteins that cannot be expressed exactly by cell expression technology(e.g., proteins with multiple posttranslational modifications or toxic proteins), chemical synthesis is an important substitute. Given the limited peptide length offered by solid-phase peptide synthesis invented by Professor Merrifield, peptide ligation plays a key role in long peptide or protein synthesis by ligating two small peptides to a long one. Moreover, high-molecularweight proteins must be synthesized using two or more peptide ligation steps, and sequential peptide ligation is such an efficient way. In this paper, we reviewed the development of chemical protein synthesis, including solid-phase peptide synthesis, chemical ligation, and sequential chemical ligation.

The tidal signals extraction from GPS data on the Amery Ice Shelf, Antarctica

Tidal motion is the source of short-term vertical motion that an ice shelf experiences, and hence has a significant impact on ice shelves. During the 2003/2004 Austral summer season, five days of GPS measurements were carried out on the front of the Amery Ice Shelf (AIS), East Antarctica, by the 20th Chinese National Antarctica Research Expedition (CHINARE). The GPS data was processed using GAMIT/GLOBK software with 2-hour static data segment and the vertical precision is less than 0.18 m. To verify our results for the vertical component, we compare the ice shelf GPS tidal signal with a tidal result derived from tide gauge measurements at China's Zhongshan Station on Antarctica. Comparison of the GPS results with the tide gauge were in good agreement in amplitude at the few cm level, which indicates that the tide under the front of Amery Ice Shelf is irregular semidiurnal tide, the maximal tidal differences is approximately 2 m. GPS data can be used to validate the ocean tide model around the Antarctic area and such studies are important to improve our knowledge of the Antarctic ice shelf mass balance and dynamical models of ice sheet/ocean interaction.

Virus DNA Detection of Herpes Simplex Keratitis by PCR

HSV-DNA of seven corneal lesions suspected with herpessimplex keratitis (HSK) and nine normal human donor corneas weredetected by PCR,Five out of seven diseased corneas showed positiveresults,and the other two diseased corneas and nine.normal corneasnegative.The results suggest the PCR may be useful as a rapid andsensitive method for diagnosing HSK.Eye Science 1993;9:126-128.