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Three patients were enrolled, two as hemophiliacs, and one with acute EBV infection. Serial serum samples of each patient were tested with at least 3 different HIV antibody EIA tests, an immunofluo-rescent test and two western blots (WB). In the third case, PCR and reverse transcriptase enzyme activity measurement were also done. One of the regularly checked serum samples of hemophiliac patients was reactive with different HIV screening and confirmatory assays. Their next blood samples, two weeks and one month later, respectively, were negative with the same tests. In Case 3. two and a half years after the first examination, the EIA tests results changed to negative, but the WB was still indeterminate. In the case of the two hemophiliac patients, the patients may have been exposed to HIV containing blood products (before 1985), but were not infected. Regular treatment with factor VIII concentrate, in which HIV antigens may be present, can boost the immune response and results in transient seropositivity. In the case of the EBV infected patient, the transient HIV seropositivity may be the consequence of EBV induced proliferation of anti-HIV-antibody producing B cell clones. During our ten year HIV confirmatory practice we tested more than 40000 samples, from which transient seropositivity were observed only in the three cases summarized in this paper.

Chlorinated hydrocarbons (CHCs) were monitored using a recently presented infrared fiber-optic physico-chemical sensor consisting of an MIR transparent, polymer coated, silver halide fiber coupled to a commercial FTIR spectrometer. The aim of this study was to test the performance of this new fiber optic sensing device with respect to temperature dependence, simultaneous detection of several CHCs, sensitivity and dynamic response behavior. In addition the diffusion process of the CHCs into the polymer was analyzed in order to better understand and evaluate the obtained results. During the investigation of the temperature dependence of the sensor response to real trend could be observed in the temperature range of 0 to 22°C. The dynamic response of the sensor is in the minute range when experiencing an increase in concentration of the analyte while with a decrease in concentration, the response is relatively slow. The sensor enabled the detection of 10 environmentally relevant CHCs at concentrations of 1 to 50ppm. The simulation of the experimental diffusion data revealed Fick's 1st law diffusion for CHCs into the polymer layers. Finally the sensing device was validated with head space-gas chromatography (HSGC) analyses and showed good agreement with these already established methods. This work shows the great potential of IR fiber optic sensors as early warning systems for a variety of CHCs in water (“threshold alarm sensor”)

A new method of optical gas sensing is presented which uses evanescent waves of optical fibers. Gas detection can be done in a simple, flexible, and possibly distributed way using a single optical fiber as both the sensor with an active element of 10 cm and the transmission line for optical signals. The detection of several single gaseous species — such as hexane, trichloro-trifluoro-ethane, methane, acetone, etc. — as well as gaseous mixtures in a concentration range of 1–10% could be achieved with an average reproducibility of 2–3% with a chalcogenide fiber optic coupled to an IFS 88 Bruker spectrometer.

The frequency of symptoms during panic attacks and anticipation of the panic consequences were compared in patients with the subtypes of panic disorder (PD). Patients with moderate and severe agoraphobic avoidance reported that they had experienced more symptoms than patients with an uncomplicated PD (without agoraphobia [AG]); they also experienced almost all of the symptoms more frequently, with the difference being significant for a quarter of the examined panic symptoms. Panic patients with moderate and severe AG were also significantly more concerned about the loss of control and social and physical consequences of panic attacks. Taken together, these findings suggest that the severity of panic attacks, defined as the number of panic symptoms, along with a variety of anticipatory fears about the consequences of the attacks may contribute to the development of AG in panic patients.

As the analysis of glucose and urea is of special interest in the field of clinical and process analysis, an enzymatic FIA-FTIR system is presented, based on the reactions of glucose to gluconic acid using glucose oxidase as well as of urea to ammonium carbonate catalyzed by urease. The method is tested with standard solutions, with samples simulating the blood composition and with a variety of fruit juices and soft drinks. Whereas the systematic error is within few percent, as concluded from the slope of the calibration graph, the reproducibility of the method is up to now not satisfactory for routine applications in process analysis and has to be improved.

The response behavior of a polymer-coated mid-infrared fiber optical sensor for chlorinated hydrocarbons in water is evaluated practically and theoretically. The sensor response to the target analytes tri- and tetrachloroethylene obtained in a muddy waste water sample is shown to be unaffected by other trace organic pollutants. A theoretical model is presented which can be used to predict the response of this sensing device. The use of this model allows to simulate the sensor response not only for increasing chlorinated hydrocarbon concentrations, but rather for any change in its concentration in the surrounding medium. In addition, the asymmetric sensor response, depending on the direction of the concentration change and the lag time after a concentration change can be explained by digital simulations and are shown to occur due to diffusion processes in the membrane.

An application of FTIR-microspectroscopy for the study of the homogeneity of chemisorbed, thin silane layers on IR-transparent fibers and ATR-elements is presented. Furthermore a calibration method for the layer thickness based on ellipsometry is established and theoretical considerations, which refer to the occuring signal enhancement in the fiber compared to a flat substrate, are explained.

In this paper the discovery is presented that FTIR microspectroscopy is also suitable for the micro-analysis of very thin organic layers in the range of 3.6 to 36 nm on chalcogenide fibers. Theoretical confirmation using the raytracing method is given and the observation of ultra-thin coatings on fibers is made possible by a signal enhancement compared to planar substrates due to the geometry of the fiber.

Twenty subjects with chronic nightmares for 17.2 years mean duration were randomly divided into two groups: Rehearsal and Recording. At inception, subjects in both groups were instructed to write down their nightmares for one month. The Recording group received no other intervention. Rehearsal subjects received a single treatment group session teaching an imagery rehearsal technique to reduce nightmare frequency. At inception and three months follow-up, both groups were compared for nightmare frequency and for self-rated distress with scales (Symptom Checklist and Symptom Questionnaire) measuring anxiety, depression, hostility, somatization and total distress. Nightmare frequency decreased significantly in both groups: Rehearsal group-7.2 per month to 2.0 per month (72% reduction) (p < 0.006); Recording group-9.4 per month to 5.0 per month (47% reduction) (p < 0.02). There were no statistically significant differences in the nightmare frequency reductions between groups. All anxiety, depression, somatization, hostility and total distress scores decreased substantially in the Rehearsal group. Most changes were significant. Changes in the Recording group were inconsistent and not significant. Two brief case histories are presented.

The stability of silver halide fibers in artificial sea water (ASW) with and without a protective polymer coating and the influence of high salt concentrations on the sensor response was investigated. In contrast to bare silver halide fibers, the polymer coated fibers remain stable in contact with chloride solutions. This enables the application of a recently presented mid-IR fiber evanescent wave spectroscopy (FEWS) sensor system for the quantitative detection of chlorinated hydrocarbons (CHC) also in sea water.

In the present work a silver-halide fiber was coated with low-density-polyethylene and used as a fiber optic Ir sensor for the detection of chlorinated hydrocarbons in water

The adsorption of 3-aminopropyltriethoxysilane (3-APTS) on germanium crystals was investigated using Attenuated Total Reflection (ATR) spectroscopy. Ethanol, which is produced by the hydrolysis of 3-APTS in water, adsorbs on germanium prior to 3-APTS. This can be checked by the CH3-modes at 1150 cm−1 and 2975 cm−1. The structure differences between chemisorbed and physisorbed 3-APTS can be observed by the shift of the Si-O-Si bands of the silane molecules. The asymmetric and symmetric stretch bands for chemisorbed 3-APTS occurs at 1096 cm−1 and 1022 cm−1, whereas, the bands for physisorbed 3-APTS are found at 1115 cm−1 and 1038 cm−1. The amino groups of physisorbed 3-APTS display two strong bands at 1566 cm−1 and 1485 cm−1 which result from amino groups strongly hydrogen bonded to free silanols. The deformation modes of the amino groups in chemisorbed layers can be found at 1609 cm−1 and 1512 cm−1, which is due to the deformation modes of the free amino groups. A controlled chemisorption is important for the development of chemical IR-sensors [15].

High levels of distress in medical students have been reported in several studies and have been attributed to the stresses of medical training. In order to compare the severity of distress in medical students to that of other students, we administered the Hopkins Symptom Checklist and the Symptom Questionnaire to 60 medical students (30 first-year and 30 third-year) and to matched law students. Law students reported significantly more depression and anger-hostility and less contentment and feelings of friendliness. Third-year students rated themselves as significantly more distressed than first-year students and females more distressed than males. Distress levels in medical students may be lower than those of other graduate students.