The amount of information and the volume of ‘information tare’

A distinction is suggested between the notions ‘information tare’, the role of which is played by the signals or letters forming the message, and ‘information’, which may be contained in such messages. It is shown that Shannon's definition of the amount of information is, in fact, the definition of the volume of information tare, whereas the amount of information itself may be measured as the volume of information tare of the maximally compact message used for its recording. This allows one to express both the volume of information tare, H, and the amount of information, B, in the same units of measurement–bits–and for any message B≤H. Some consequences of these views are analysed.     

Unsupervided pattern recognition for the classification of EMG signals

The shapes and firing rates of motor unit action potentials (MUAP's) in an electromyographic (EMG) signal provide an important source of information for the diagnosis of neuromuscular disorders. In order to extract this information from EMG signals recorded at low to moderate force levels, it is required: i) to identify the MUAP's composing the EMG signal, ii) to classify MUAP's with similar shape, and iii) to decompose the superimposed MUAP waveforms into their constituent MUAP's. For the classification of MUAP's two different pattern recognition techniques are presented: i) an artificial neural network (ANN) technique based on unsupervised learning, using a modified version of the self-organizing feature maps (SOFM) algorithm and learning vector quantization (LVQ) and ii) a statistical pattern recognition technique based on the Euclidean distance. A total of 1213 MUAP's obtained from 12 normal subjects, 13 subjects suffering from myopathy, and 15 subjects suffering from motor neuron disease were analyzed. The success rate for the ANN technique was 97.6% and for the statistical technique 95.3%. For the decomposition of the superimposed waveforms, a technique using crosscorrelation for MUAP's alignment, and a combination of Euclidean distance and area measures in order to classify the decomposed waveforms is presented. The success rate for the decomposition procedure was 90%.     

A study of injected dose for brain mapping on the ECAT HR+: activation maps for a parametric verbal working memory task

The success of the 15O-water PET technique to localize statistically significant changes in regional cerebral blood flow is dependent on factors such as the activity level injected and the magnitude of the flow change. Undetectable changes may occur if insufficient activity is injected leading to high levels of statistical noise or the task performed results in only small changes in blood flow. To explore the relationship between injected activity and statistical significance, we performed a series of studies with the ECAT EXACT HR+, a high resolution PET tomograph. A parametric verbal working memory task (the N-back task) was selected to examine the relationship between regional cerebral blood flow and working memory load across a range of injected doses of 15O-water. At each activity level the volunteers were required to perform four different levels of the N-back task, a task in which a letter displayed on a monitor is matched with the letter displayed N letters previously. With increasing N, this task places increased load on working memory. For this study, 5, 10, and 15 mCi of 15O-water were injected into nine normal volunteers. The complete sequence of four tasks (N = 0, 1, 2, and 3) at three activity levels was repeated twice, for a total of 24 injections of 15O-water. We show that the peak count rate performance for the HR+ is approached at injected activity levels of 15O-water around 15 mCi. For this particular choice of N-back task, robust activation maps can nevertheless be obtained with as little as 5 mCi injected dose.     

Aberrant methylation of p16INK4a and deletion of p15INK4b are frequent events in human esophageal cancer in Linxian, China

Esophageal transit scintigraphy seems to be a valid methodology to assess impaired esophageal motility in early stages of disease. The purpose of this study was to discriminate patients with primary Raynaud's phenomenon (RP) and patients with systemic sclerosis (SSc) from healthy subjects by esophageal scintigraphy with a semisolid meal. METHODS: We studied 32 patients with primary RP, 18 with SSc and 13 healthy subjects. Dysphagia, acid regurgitation and heartburn were scored. After an overnight fast, all subjects underwent esophageal scintigraphy, using a semisolid orally ingested bolus (10 mL apple puree) labeled with 99mTc-sulfur colloid. Esophageal transit and emptying time and integral value were evaluated with the subjects in the upright (sitting) and supine positions. Transit time was defined as the time from the entry of 50% of radioactivity into the upper esophagus until the clearance of 50% of the bolus from the whole esophagus. Emptying time was defined as the time from the entry of 50% of radioactivity into the upper esophagus, until the clearance of 100% of the bolus from the whole esophagus. Integral value was defined as the total counts under the time-activity curve normalized to the maximum. RESULTS: Esophageal transit and emptying time and integral value, evaluated in both positions, were significantly higher in patients with SSc than in healthy subjects and than in patients with RP. Moreover, patients with RP had all three parameters, assessed in supine position, significantly longer compared to healthy subjects. Clinical scores regarding dysphagia, acid regurgitation and heartburn were not significantly different between patients with RP and SSc. CONCLUSION: Esophageal transit and emptying time and integral value appear to be able to discriminate patients with primary RP from patients with SSc and patients with RP from healthy subjects, suggesting an early mild esophageal dysfunction in RP.     

Thermal denaturation of Escherichia coli thioredoxin studied by hydrogen/deuterium exchange and electrospray ionization mass spectrometry: monitoring a two-state protein unfolding transition

Thermally denatured oxidized Escherichia coli thioredoxin (TRX) in 2% acetic acid was examined by electrospray ionization mass spectrometry (ESI-MS) and circular dichroism. Conformational dynamics during thermal unfolding were probed by hydrogen/deuterium (H/D) exchange-in experiments. ESI-MS was used to determine the H/D ratios. TRX shows only a marginal change in negative ellipticity at 222 nm during thermal unfolding, but in the near-UV circular dichroism (240-350 nm) a clear transition is observed (Tm = 61 degrees C), and unfolding goes to completion. ESI mass spectra were recorded as a function of temperature, and the observed bimodal charge state distributions were analyzed assuming a two-state unfolding mechanism which allowed an estimation of the midpoint temperature, Tm = 64 degrees C. Under conditions at which the compact, folded conformational state is only marginally stable (80 degrees C, 2% acetic acid-d1), H/D exchange-in experiments in combination with ESI-MS resulted in mass spectra differing in the number of incorporated deuteriums which indicates the presence of two distinct populations of molecules after short incubation periods. As the exchange-in time increases, the population representing the unfolded state increases and the population which is protected against exchange decreases. The rate of conversion was used to estimate the rate constant of unfolding which was 2.1 +/- 0.2 min-1. The results presented here indicate that thermally denatured TRX under the conditions used may represent a collapsed unfolded state with properties often attributed to molten globule-like states, such as pronounced secondary structure but absence of rigid tertiary structure and, hence, lack of protection against H/D exchange.     

厌氧胶：可靠且节约成本紧固件的锁紧和密封

当机械设备发生故障时，厌氧螺纹锁固剂便可发挥作用。正如赛车的特滑层有助于确保车辆在赛道的抓地力，螺纹锁固剂有助于保证紧固件螺纹的夹持力。根据厌氧技术，这些金属胶粘剂可以实现机械辅助措施无法实现的功能：它们可完全填满连接螺纹之间的微小间隙。使用螺纹锁固剂固定的螺栓可以提供比机械装置更好的夹紧力。专用螺母或垫圈的价格是液体螺纹锁固剂的5倍以上。采用液体螺纹锁固剂可降低库存成本。在选择螺纹锁固复合物时，有一些关键因素需要考虑：抗剪强度、固化速度、间隙填充能力和工作环境。     

Amifostine protects normal tissues from paclitaxel toxicity while cytotoxicity against tumour cells is maintained

The objectives of this study were to evaluate the protective effects of amifostine against paclitaxel-induced toxicity to normal and malignant human tissues. Haematopoietic progenitor colony assays were used to establish the number of CFU-GEMM and BFU-E colonies after incubation with WR-1065 alone, Amifostine alone, paclitaxel (2.5 or 5 microM) +/- WR-1065 or amifostine. MTT and alkaline elution assays evaluated the in vitro growth inhibitory and DNA damaging effects, respectively, of paclitaxel with or without amifostine against normal human fibroblasts and human non-small cell lung cancer (NSCLC) cells. This combination was also evaluated in vivo using severe combined immune deficient (scid) mouse models of early (non-palpable tumours) and advanced (palpable tumours) human ovarian cancer. Human 2780 ovarian cancer cells were inoculated subcutaneously while paclitaxel and amifostine were administered intraperitoneally. A brief exposure (15 min) to amifostine not only protected human haematopoietic progenitor colonies from paclitaxel toxicity, but stimulated the growth of CFU-GEMM and BFU-E beyond control values. Amifostine protected normal human lung fibroblasts from paclitaxel-induced cytotoxicity and DNA single-strand breaks. However, paclitaxel cytotoxicity and DNA single-strand breaks were actually enhanced by pretreatment with amifostine in the NSCLC model. Importantly, amifostine did not interfere with paclitaxel antitumour activity even with prolonged exposure (24.5 h) of the lung cancer cells to high concentrations (1.2 mM) in vitro or following five repetitive high doses (200 mg/kg) given to scid mice with human ovarian cancer xenografts. Indeed, under certain circumstances, amifostine resulted in sensitisation of tumour cells to paclitaxel. Our results confirm previous reports of the ability of amifostine to protect normal tissues from the toxic effects of chemotherapy drugs and now extend these observations to paclitaxel.     

Intravascular lymphomatosis: a case presenting with encephalomyelitis and reactive haemophagocytic syndrome diagnosed by renal biopsy

OBJECTIVE: To determine the frequency of characteristics associated with unprotected heterosexual intercourse in HIV infected adults in an urban area. DESIGN: Retrospective comparison of sexual risk transmission behaviour between HIV infected men and women from a drug treatment site and between women from the drug site and HIV infected women from an urban medical centre. METHODS: HIV infected women and men were asked questions on sexual behaviour for a 1 year period before enrollment. The outcome variable was heterosexual risk behaviour (HRB) defined as having vaginal sex at least once in the previous year and not always using condoms. RESULTS: 73% of the drug clinic females, 72% of the drug clinic males, and 42% of the medical centre female engaged in HRB. Using logistic regression analysis, women and men in drug treatment engaged in similar rates of HRB; however, women in drug treatment were four times (95% CI = 2.0-8.3) more likely to engage in HRB risk behaviour than women from the medical centre. CONCLUSION: The data suggest that a surprisingly large portion of HIV infected patients under treatment engaged in HRB, especially former drug users. Without specifically targeted interventions, the heterosexual spread of HIV in urban areas will continue to be a serious problem.