LONG TERM STORAGE STABILITY OF MIDDLE DISTILLATE FUELS FROM A CHEMICAL MECHANISTIC POINT OF VIEW. PART 2.

The objective of this review is to (i) articulate the current level of understanding of the types of “reactive molecules” intimately involved in the long term oxidative storage instability of middle distillates, (11) review the types of chemical reaction mechanisms most likely involved in the “oxidative phase” of insoluble formation, (iii) review the postulated chemical mechanisms of stabilizer (additive) operation, and (iv) discuss future research areas that must be explored if a greater understanding and control of middle distillate instability is to be realized.     

A comparative study of human skin thermal response to sapphirecontact and cryogen spray cooling

Surface cooling, in conjunction with various thermally mediated therapeutic procedures, can provide a means to protect superficial tissues from injury while achieving destruction of deeper targeted structures. We have investigated the thermal response of in-vivo human skin to: (1) contact cooling with a sapphire window (6-12°C); and (2) spray cooling with a freon substitute cryogen [tetrafluoroethane; boiling point ≈-26°C at 1 atmospheric pressure (atm)]. Measurements utilizing infrared radiometry show surface temperature reductions from 30°C to 14-19°C are obtained within approximately is in response to sapphire contact cooling. Surface temperature reductions to values between 5°C and -9°C are obtained in response to 20-100-ms cryogen spurts. Computational results, based on fitting the measured radiometric surface temperature to estimate heat transfer parameters, show: (1) temperature reductions remain localized to approximately 200 μm of superficial tissue; and (2) values of heat flux and total energy removed per unit skin surface area at least doubled when using cryogen spray cooling     

High-transconductance n-type Si/SiGe modulation-doped field-effecttransistors

The authors report on the fabrication and the resultant device characteristics of the first 0.25-μm gate-length field-effect transistor based on n-type modulation-doped Si/SiGe. Prepared using ultrahigh vacuum/chemical vapor deposition (UHV/CVD), the mobility and electron sheet charge density in the strained Si channel are 1500 (9500) cm²/V-s and 2.5×10¹² (1.5×10¹² ) cm^-2 at 300 K (77 K). At 77 K, the devices have a current and transconductance of 325 mA/mm and 600 mS/mm, respectively. These values far exceed those found in Si MESFETs and are comparable to the best results achieved in GaAs/AlGaAs modulation-doped transistors     

When is less treatment better? The role of social anxiety in matching methadone patients to psychosocial treatments.

In response to a need to match drug users to the most appropriate and cost-effective level of care, it was hypothesized that socially anxious methadone-maintained patients would attain greater benefit from coping skills training provided in the context of a low-intensity enhanced standard methadone maintenance intervention (E-STD) than in the context of a high-intensity, socially demanding day treatment program (DTP). Social anxiety was assessed in 307 methadone-maintained patients using the Social Anxiety and Distress Scale prior to randomization to either E-STD or DTP. The hypothesis was supported: Socially anxious patients were drug free longer during treatment, were more likely to be abstinent at treatment completion, and had greater reductions in HIV risk behaviors if assigned to the lower intensity intervention, which was provided at ? the cost of the DTP. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assessment of pseudarthrosis in pedicle screw fusion: a prospective study comparing plain radiographs, flexion/extension radiographs, CT scanning, and bone scintigraphy with operative findings

Tribal warfare is a way of life in the highlands of Papua New Guinea. In earlier times direct confrontation with bushknives and axes, and shooting with bows and arrows were common. In recent years there have not been as many instances of direct confrontation with bushknives and axes, but the use of bows and arrows is on the rise. Since 1993, guns have been increasingly used, with devastating results. In 1993, 18 deaths were reported from tribal warfare in one area of the Southern Highlands Province, especially from gunshots, while in 1994, 24 deaths were reported from another area. A five-year review of tribal fight admissions to Mendi Hospital, from 1990 to 1994, showed an increase in the number and proportion of gunshot wounds; there were none in 1990-1992 but they constituted 18% of tribal fight injuries in 1993 and 33% in 1994.     

A novel four-point bend test for strength measurement of opticalfibers and thin beams. II. Statistical analysis

In the first part of this work, a novel implementation of the well-known four-point bend test is described that determines the strength of thin beams and optical fibers by measuring the loading pin displacement, rather than the applied load. This paper extends the analysis of the nonlinear bending behavior to account for the stochastic nature of strength. A statistical analysis is presented that determines the effective tested length in bending and the tension to bending strength ratio. Results are given for both surface and volume flaws as well as for specimens of both circular and rectangular section. Strength measurements on a deliberately weakened silica optical fiber are consistent with the predictions of the analysis     

Poststress effects of danger and safety signals on gastric ulceration in rats.

Gastric ulceration of rats stressed by restraint in 19°C water for 75 min was markedly increased by allowing a 75-min postrestraint room-temperature rest period during which the rat was exposed to cues that had previously been associated with the delivery of 80 5-s uncontrollable electric shocks distributed over four sessions. This effect obtained equally without regard to whether "danger cues" were punctate signals or constant contextual cues or whether contextual ones were interrupted by punctate safety signals. The experimental treatments used were unusual in that they equated the groups on their total conditioning history and thus allowed a more pure look at the poststress effect than heretofore. Other groups provided controls for prior shocks, rest, and their interaction as well as handling. Analyses of corticosterone after the stress or stress-rest cycle revealed only a general decline in corticosterone levels with rest undifferentiated across groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A prospective study of the efficacy of the physician order form for life-sustaining treatment

OBJECTIVES: The Physician Orders for Life-Sustaining Treatment (POLST), a comprehensive, one-page order form, was developed to convey preferences for life-sustaining treatments during transfer from one care site to another. This study examined the extent to which the POLST form ensured that nursing home residents' wishes were honored for Do Not Resuscitate (DNR) and requests for transfer only if comfort measures fail. DESIGN: The study used chart record data to follow prospectively a sample of nursing home residents with the POLST. SETTING: Eight geographically diverse, long-term, adult-care facilities in Oregon in which the POLST was in use. PARTICIPANTS: Nursing home residents (n = 180), who had a POLST recording DNR designation and who indicated a desire for transfer only if comfort measures failed, were followed for 1 year. MEASUREMENTS: For all subjects: treatment and disposition after significant health status changes; orders for narcotics and for provision or limitation of aggressive interventions. For hospitalized subjects: diagnosis, medical interventions, and DNR orders. For those who died: cause and location of death, life-sustaining treatments attempted, and comfort measures provided. RESULTS: No study subject received CPR, ICU care, or ventilator support, and only 2% were hospitalized to extend life. Of the 38 subjects who died during the study year, 63% had an order for narcotics, and only two (5%) died in an acute care hospital. A total of 24 subjects (13%) were hospitalized during the year. Hospitalized subjects' mean length of stay was 4.9 days, and the mean rate of hospitalizations for all subjects was 174 per 1000 resident years. In 85% of all hospitalizations, patients were transferred because the nursing home could not control suffering. In 15% of hospitalizations (n = 4), the transfer was to extend life, overriding POLST orders. CONCLUSIONS: POLST orders regarding CPR in nursing home residents in this study were universally respected. Study subjects received remarkably high levels of comfort care and low rates of transfer for aggressive life-extending treatments.