The use of sinusoidally changing workloads as an aid to identify dynamic properties of physiological systems

Summary The methodology of using frequency analysis in order to identify types of system(s) is discussed. A number of models with their characteristic Nyquist plots are presented graphically, to facilitate the identification of various types of systems by pattern recognition. A small series of measurements of oxygen consumption and heart rate has been carried out to illustrate the possibilities and limitations of the use of frequency analysis in exercise physiology. With a step function method one can only establish whether a system has multiple components in parallel or not, but with the frequency analysis method one can identify whether a system has multiple components in parallel or in series. It was found that under moderate exercise, the response of oxygen consumption to exercise is a system with multiple components in series, but the response of heart rate to exercise is a system with multiple components in parallel. The data that were obtained are in agreement with those produced by other authors, but the curves to fit the observed data were obtained using second order linear transfer functions.     

Distributed computer system for capture,analysis and display of biological data

A distributed real-time computer system has been developed to automate the collection, analysis and display of biological (pharmacological) data. It comprises a series of laboratory interface devices (CED 1401/1609) connected to a micro-VAX II via multiple IEEE-488 buses. The micro-VAX II is integrated to the main site computers using Ethernet running DECnet. The micro-VAX II system supports a multi-user, multipreparation and multitasking, environment and it provides rapid transfer, storage, analysis and display of data. The system saves the pharmacologists from the manual analysis of their data, typically saving them four days of analysis per experiment and has improved both the quality of data detected and their subsequent analysis. Also, the development of a standard data capture procedure on common hardware along with the modular design of application software has almost quartered project development times.     

Theoretical implications of the application of polymorphic protein systems to gene location on a trisomic chromosome, and its application to the haptoglobin phenotype frequencies in Down''s syndrome

In this, the first of a series of communications on the application of the study of polymorphic enzyme and protein systems to gene location on a trisomic chromosome, the theoretical implications are considered. Mathematical models for the expected phenotype shift have been examined, and have been expanded to include a three-allele locus and a three-allele locus with one allele being of the 'silent' variety. Some modifications in the existing mathematical models were necessary due to possible failure of electrophoretic and immuno-electrophoretic separations to differentiate between some heterozygote forms. The mathematical models have been applied to a series of hi-allelic polymorphic systems and one tri-allelic system to determine the minimum number of subjets with trisomy that would be required to establish the presence or absence of a phenotype shift. The additional use of the techniques for estimating the position of the gene with respect to the centromere, and estimating the timing of the non-disjunction are discussed.
The application of Haldane's log ratio test (1956) involving the combining of the homozygous Corms is considered and applied to the phenotype data on the serum haptoglobins of 254 subjects with Down's syndrome and 853 mentally retarded control subjects.     

脑电的非线性动力学高维特性及研究现状与展望

80年代以来 ,脑电 (EEG)一直被视为低维混沌信号 ,关于脑电混沌性的检验及对其低维混沌性的质疑 ,是近年来国际学术界的研究热点。目前的研究基本上认证了 EEG的非线性和混沌性 ,却否定了它是源于低维的混沌系统。因此 ,用经典的低维混沌理论和算法去分析研究高维 EEG的适用性和适用条件 ,必须进行探讨和论证。本文简要介绍了近年来的研究现状 ,其中着重介绍了EEG低维简化模型法 ,最后展望了研究的发展前景。     

计数型模拟量及人体血管壁动态信息多道遥测电脑系统的研制

提出了计数型模拟量新概念，该量同时具有模拟量和数字量的某些特征或者说具有二重性特征。通过分析找到两种计数型模拟量：调宽计数脉冲串和调频计数脉冲串，并阐述了它的产生方法，同时验证了它的二象性特征。利用计数型模拟量，无须使用A／D转换芯片，即可方便地实现单道或多道模数A／D转换。为了验证其可行性，本文给出了计数型模拟量在医学上的应用范例“人体血管壁动态信息多道遥测电脑系统”。通过该范例清楚地表明：计数型模拟量不仅应用方法简单可行，而且应用前景也很广阔。     

Neurotensin,a Novel Messenger to Cross-Link Inflammation and Tumor Invasion via Epithelial-Mesenchymal Transition Pathway

Multiple cytokines and growth factors are critical for the prognosis of cancer which has been regarded as a worldwide health problem. Recently, neuropeptides, soluble factors regulating a series of functions in the central nervous system, have also been demonstrated to stimulate the proliferation and migration of tumor cells. Among these signaling peptides, the role of neurotensin (NTS) on malignancy procession has become a hot topic. The effects of NTS on tumor growth and its antiapoptosis role have already been identified. Subsequently, studies demonstrated the impact of NTS on the migration and invasion, but the molecular mechanisms involved are still unclear at present. Recently, some reports indicated that NTS could induce expression and secretion of interleukin-8 (IL-8) to promote local imflammatory response which might participate in epithelial-mesenchymal transition (EMT)-related tumor migration. In present review, we highlight the process of tumor EMT induced by NTS through stimulating IL-8 and the significance of NTS/IL-8 pathway in clinical application prospect.     

干细胞治疗神经系统疾病现状的思考：是希望还是炒作？

背景：干细胞研究已50年,干细胞体外分离、培养、纯化和鉴定技术已经相对成熟,干细胞替代治疗神经系统疾病已在临床开展,但在缺少统一应用规范的情况下不免出现一些负面报道和夸大宣传,面对这些很多医生、患者出现了迷惘。 目的：探讨干细胞治疗神经系统疾病到底是希望？还是炒作？ 方法：通过①对人民日报近期发表的两篇影响较大的干细胞临床应用相关报道的思考。②结合作者自身多年开展干细胞治疗神经系统疾病的一些经验。③参考国内外一些研究文献等多条线索进行剖析。以“干细胞”、“动物模型”、“神经”等检索词变换组合检索万方数据库和Pubmed全文数据库1999年1月至2012年4月相关资料,获得文献阅读后进一步剔除。 结果与结论：在动物实验方面,神经干细胞对于神经系统损伤及退行性变有一定治疗作用。在干细胞的临床应用研究方面,受到很多限制。面对阻力,一些国家已经从国家层面展开具有一定规模的临床试验,大多已进入临床Ⅱ、Ⅲ期。美国代表性产品Prochymal成为全球首个获准用于临床治疗人体疾病的干细胞药物。产业化的干细胞成品具有巨大的研究价值和应用前景。但在疗效不确切的情况下,暂不主张在临床上大规模推广应用,更不主张以盈利为目的、夸大其词的商业化宣传     

Case-based retrieval to support the treatment of end stage renal failure patients

OBJECTIVE: In the present paper, we describe an application of case-based retrieval to the domain of end stage renal failure patients, treated with hemodialysis. MATERIALS AND METHODS: Defining a dialysis session as a case, retrieval of past similar cases has to operate both on static and on dynamic features, since most of the monitoring variables of a dialysis session are time series. Retrieval is then articulated as a two-step procedure: (1) classification, based on static features and (2) intra-class retrieval, in which dynamic features are considered. As regards step (2), we concentrate on a classical dimensionality reduction technique for time series allowing for efficient indexing, namely discrete Fourier transform (DFT). Thanks to specific index structures (i.e. k -d trees), range queries (on local feature similarity) can be efficiently performed on our case base, allowing the physician to examine the most similar stored dialysis sessions with respect to the current one. RESULTS: The retrieval tool has been positively tested on real patients' data, coming from the nephrology and dialysis unit of the Vigevano hospital, in Italy. CONCLUSIONS: The overall system can be seen as a means for supporting quality assessment of the hemodialysis service, providing a useful input from the knowledge management perspective.     

Algorithm for Vector Autoregressive Model Parameter Estimation Using an Orthogonalization Procedure

We review the derivation of the fast orthogonal search algorithm, first proposed by Korenberg, with emphasis on its application to the problem of estimating coefficient matrices of vector autoregressive models. New aspects of the algorithm not previously considered are examined. One of these is the application of the algorithm to estimate coefficient matrices of a vector autoregressive process with time-varying coefficients when multiple realizations of the said process are available. Computer simulations were also performed to characterize the statistical properties of the estimates. The results show that even for shorter time series the algorithm works well and obtains good estimates of the time-varying parameters. Statistical characterization indicates that the standard deviation of the estimates decreases as being the length of the time series), a typical behavior of least-squares estimators. Another key aspect of the approach, which has previously been considered, is its direct extension to the parameter estimation of vector nonlinear autoregressive models. Nonlinear terms can be added to the model and the same algorithm can be applied to effectively estimate their associated parameters. Using chaotic time series generated from the Lorenz equations, the algorithm produces a model that captures the nonlinear structure of the data and exhibits the same chaotic attractor as that of the original system. © 2002 Biomedical Engineering Society. PAC2002: 8710+e, 0210Yn, 0230Lt     

基于时间序列分析方法的胆囊炎发病率预测

目的探讨时间序列分析方法在时间序列资料中的应用,建立海西州地区胆囊炎发病率的预测模型。方法在时间序列分析方法理论的基础上,通过时间序列模型对海西州地区的胆囊炎发病率进行实证研究,建立了相应的ARMA模型和ARCH模型并进行预测和评价。结果 ARCH模型的预测结果较ARMA模型理想,适合描述海西州地区胆囊炎发病率的变动趋势。结论 ARMA(4,2)-ARCH(2)模型可作为海西州地区胆囊炎发病率的预测模型。     

Lactobacilli - bacteria-host interactions with special regard to the urogenital tract

Lactobacilli are part of the commensal human mucosal flora. Their application as probiotics in dairy products such as yoghurt has increased during the last century since a health promoting effect has been reported. Much work has been done to study the effects of these bacteria on the immune system and epithelial cells, mainly focused on the intestinal mucosa as the field of first contact. This review is aimed to present and discuss results concerning interactions of lactobacilli and immune system or epithelial cells with focus to urogenital mucosa.     

Digital TV tomography: description and physical assessment

A digital TV tomography system, capable of retrospective reconstruction of multiple digital tomographic images, has been developed and its basic physical characteristics have been evaluated. The multiple tomographic images were formed through retrospective reconstruction of digital data acquired on a linear tomographic x-ray unit and an image intensifier-television system. Digital data were obtained with a series of 30 pulsed exposures during linear motion of the system. A distortion correction algorithm for the convex surface of the image intensifier was developed in order to reduce image distortion. A phantom study showed that the square-wave response at the fulcrum plane was slightly inferior to that in conventional tomography. There was also a slight decrease in the square-wave response away from the fulcrum plane and upon application of a correction algorithm, as compared with the response of the original reconstructed image at the fulcrum plane. The exposure dose for a single image was approximately half that in conventional tomography. Because of many advantages, including low exposure, short examination time, digital image manipulation, and applicability to picture archiving and communication systems, this is likely to become an important method in radiology when further technical refinements have been made.     

The Aberdeen Mark II single-photon-emission tomographic scanner: specification and some clinical applications

The construction, operation and physical characteristics of a single-section multi-detector single-photon-emission scanner are described. The machine has 24 detectors arranged along the sides of a square. Movements and data collection are under the control of a series of distributed microprocessors. Both head and trunk tomograms can be produced. The spatial resolution at the collimator focus is 9 mm in the transverse plane, and the effective slice thickness is 14 mm. The volume sensitivity is 300 counts/s kBq ml with a 20 cm diameter cylindrical phantom filled with 99Tcm solution. The application of this machine to the examination of the brain, liver and heart has been found to be clinically useful.     

Introduction and some problems of the rapid time series laboratory reporting system]

We introduced an on-line system of biochemical, hematological, serological, urinary, bacteriological, and emergency examinations and associated office work using a client server system NEC PC-LACS based on a system consisting of concentration of outpatient blood collection, concentration of outpatient reception, and outpatient examination by reservation. Using this on-line system, results of 71 items in chemical serological, hematological, and urinary examinations are rapidly reported within 1 hour. Since the ordering system at our hospital has not been completed yet, we constructed a rapid time series reporting system in which time series data obtained on 5 serial occasions are printed on 2 sheets of A4 paper at the time of the final report. In each consultation room of the medical outpatient clinic, at the neuromedical outpatient clinic, and at the kidney center where examinations are frequently performed, terminal equipment and a printer for inquiry were established for real-time output of time series reports. Results are reported by FAX to the other outpatient clinics and wards, and subsequently, time series reports are output at the clinical laboratory department. This system allowed rapid examination, especially preconsultation examination. This system was also useful for reducing office work and effectively utilize examination data.     

桥接组合式内固定系统的应用及研究进展

桥接组合式内固定系统是根据BO理念设计的一套独立的内固定系统，具备生物力学及微创特性，集钉板系统、髓内钉系统及外固定支架优势于一体，自推广应用以来，已经得到许多骨科医师认可，其优异的疗效被大量临床实践所证实，是目前单系统适应证最广的内固定产品。本文从桥接组合式内固定系统的结构组成、生物力学特性及优势、生物力学基础研究、临床应用、并发症、展望等方面进行综述。     

Online measurement of cardiac indices from frequency transformed TAV Doppler ultrasound signals

A system is described for the analysis of blood flow signals in the aortic artery which enables indices of stroke volume and cardiac output to be derived. A commercial Doppler ultrasound monitor is used, the demodulated return signals are digitised, and frequency analysis is performed in real time using an FFT signal processing circuit. A Z-80 microprocessor controls the synchronisation of the data acquisition, transformation and display of the signals. Algorithms have been developed to identify the maximum velocity profile of each heartbeat and perform the necessary calculations to produce indices of stroke volume and cardiac output. The system has been evaluated against an existing offline method for a series of recordings on normal subjects and has demonstrated good repeatability. It has also been used in a clinical study on the effects of anaesthesia on chronic spinal injury patients. The results have shown that the system can be used to follow serial changes in cardiac performance within individual subjects.     

Numerical investigations of the loading behaviour of a prefabricated non-rigid bar system

The aim of this study has been to systematically evaluate the loading behaviour of a novel pre-fabricated chair-side SFI-Bar^® bar system supported by two implants using finite element (FE) analysis. Two series of FE models were created of the bar placed on two idealised implants and embedded in idealised bone segments using CAD data. In the first series, the inter-implant distance varied from 10 to 26 mm; the second series consisted of a bar with a fixed implant distance of 26 mm and varying horizontal fitting inaccuracy from 0.0 to 0.3 mm. The bar was loaded vertically at 500 N. In all simulations, the regions with the greatest amount of stress were concentrated on the connecting elements of the bar and the bar itself. A slight increase in stress was observed with decreasing inter-implant distance. With a non-zero fitting inaccuracy, no clear correlation was observed between the amount of play and the stress distribution in the system. For a perfect fit, an obvious increase in stress was found in the implant and strain in the implant bed. With respect to the excessive static loading performed in our simulations and the resulting loading behaviour, we conclude that the SFI-Bar is a system suitable for clinical application.     

NF2 gene in neurofibromatosis type 2 patients

Neurofibromatosis type 2 (NF2) is an autosomal dominant disorder that predisposes to nervous system tumors. The schwannomin (also termed merlin) protein encoded by the NF2 gene shows a close relationship to the family of cytoskeleton-to-membrane proteins linkers ERM (ezrin- radixin-moesin proteins). Even though penetrance of the disease is >95% and no genetic heterogeneity has been described, point mutations in the NF2 gene have been observed in only 34-66% of the screened NF2 patients, depending on the series. In order to generate tools that would enable an exhaustive alteration screening for the NF2 gene, we have deduced its entire genomic sequence. This knowledge has provided the delineation of a mutation screening strategy which, when applied to a series of 19 NF2 patients, has revealed a high recurrence of large deletions in the gene and has raised the efficiency of mutation detection in NF2 patients to 84% of the cases in this series. The remaining three patients who express two functional NF2 alleles are all sporadic cases, an observation compatible with the presence of mosaicism for NF2 mutation.      

A clinical review of bioabsorbable interference screws and their adverse effects in anterior cruciate ligament reconstruction surgery

Bioabsorbable material screws are widely used in various surgical specialties. One popular application is their use as interference screws in anterior cruciate ligament (ACL) reconstruction surgery. Despite their routine use, a major concern with bioabsorbable materials in surgery has been the incidence of adverse events. Various case reports, series reports and studies in the past years have reported complications specific to the use of bioabsorbable interference screws intra operatively and at different time periods post operatively. The aim of this literature review is to summarize the clinical studies where bioabsorbable screws have been used in ACL reconstruction surgery and in particular to highlight any specific complications and adverse effects related to the use of these materials.