Disorder effects in focused-ion-beam-deposited Pt contacts on GaN nanowires

The current-bias (I-V) characteristics at various temperatures, T, of focused-ion-beam (FIB)-deposited Pt contacts on GaN nanowires evolves from low-resistance ohmic (linear I-V) to rectifying as the diameter increases, and both exhibit strongly nonmetallic T-dependence. The small-diameter (66 nm) T-dependent resistance is explained by two-dimensional variable range hopping with a small characteristic energy, ensuring low resistance at 300 K. For large diameters (184 nm), back-to-back Schottky barriers explain the nonlinear I-V at all T values and permit an estimate of doping concentration from the bias-dependent barrier height. Both behaviors can be understood by accounting for the role of FIB-induced amorphization of GaN underneath the contact, as confirmed by cross-sectional transmission electron microscopy.

The effect of a training course in aggression management on mental health nurses' perceptions of aggression: a cluster randomised controlled trial

Nurses' attitudes towards patient aggression may influence their behaviour towards patients. Thus, their enhanced capacity to cope with aggressive patients may nurture more positive attitudes and alleviate adverse feelings emanating from patient aggression. This cluster randomised controlled trial conducted on six psychiatric wards tested the hypotheses that a 5 day training course in aggression management would positively influence the following outcome measures: Nurses' perception and tolerance towards patient aggression and resultant adverse feelings. A repeated measures design was employed to monitor change. No effect was found. The short time frame between the training course and the follow up measurement or non-responsiveness of the measurement instruments may explain this finding.

The effectiveness of two interventions in the management of patient violence in acute mental inpatient settings: report on a pilot study

Systematic risk assessment and training courses have been suggested as interventions to deal with patient violence in psychiatric institutions. A dual centre prospective feasibility study was conducted on two Swiss psychiatric admission wards to test the hypothesis that such interventions will reduce the frequency and severity of violent events and coercion. A systematic aggression risk assessment, in combination with a standardized training course in aggression management was administered and the frequency and severity of aggressive incidents and the frequency of coercive measures were registered. The incidence rates of aggressive incidents and attacks showed no significant reduction from the baseline through risk prediction and staff training, but the drop in coercive measures was highly significant. A 'ward effect' was detected with one ward showing a decline in attacks with unchanged incidence rates of coercion and the other ward showing the opposite. The severity of the incidents remained unchanged whilst the subjective severity declined after the training course. We conclude that a systematic risk assessment and a training course may assist in reducing the incidence rate of coercive measures on psychiatric acute admission wards. Further testing of the interventions is necessary to measure the effect of the training alone and to counteract 'ward effects'.

Monocyte proinflammatory cytokine release is higher and glucocorticoid sensitivity is lower in middle aged men than in women independent of cardiovascular risk factors

OBJECTIVE

To investigate whether stimulated monocyte cytokine release and its inhibition by glucocorticoids differs between men and women.

DESIGN

In vitro monocyte interleukin 6 (IL-6) and tumour necrosis factor alpha (TNFalpha) release after lipopolysaccharide stimulation were assessed with and without co-incubation with increasing doses of dexamethasone and hydrocortisone separately. Glucocorticoid sensitivity was defined as the amount of a particular glucocorticoid required to inhibit lipopolysaccharide stimulated monocyte cytokine release by 50%. The established cardiovascular risk factors of age, body mass index, number of cigarettes smoked daily, low density cholesterol to high density cholesterol ratio, systolic and diastolic blood pressure, and haemoglobin A1c were used as covariates.

SETTING

Aircraft manufacturing plant in southern Germany.

PATIENTS

269 middle aged male and 36 middle aged female employees.

RESULTS

Release of monocyte IL-6 and TNFalpha (each p = 0.001) was higher in samples from men than in those from women. Inhibition of lipopolysaccharide stimulated IL-6 and TNFalpha release by either glucocorticoid was less pronounced in samples from men than in those from women (IL-6: dexamethasone p = 0.033, hydrocortisone p = 0.029; TNFalpha: dexamethasone p < 0.001, hydrocortisone p = 0.089).

CONCLUSIONS

The finding suggests that proinflammatory activity of circulating monocytes is higher in men than in women independent of cardiovascular risk factors, thereby providing one explanation for the relatively greater coronary risk in men.

Predicting inpatient violence in acute psychiatric wards using the Brøset-Violence-Checklist: a multicentre prospective cohort study

The Norwegian Brøset-Violence-Checklist (BVC) is one of the few instruments that is suitable for short-term prediction of violence of psychiatric inpatients by nursing staff in routine care. The instrument assesses the presence or absence of six behaviours or states frequently observed before a violent incident. We conducted a study to elucidate whether the predictive properties of the BVC are retained in other psychiatric settings than the original north-Norwegian validation dataset. During their admission period, 219 consecutive patients admitted to six acute psychiatric wards were assessed as to the risk for attack using a German version of the BVC (BVC-G). Data on preventive measures were concurrently collected. Aggressive incidents were registered using an instrument equivalent to the Staff Observation of Aggression Scale (SOAS-R). Fourteen attacks towards staff were observed with incident severity ranging from 5 to 18 of a possible 22 points. BVC-G sensitivity was 64.3%, the specificity 93.9%, the positive predictive value 11.1%, and the area under the receiver operating characteristic curve 0.88. In some false positive cases intense preventive measures had been implemented. The predictive accuracy of the BVC-G proved consistent with the Norwegian original.

The perception of aggression by nurses: psychometric scale testing and derivation of a short instrument

Patient aggression is a serious problem in psychiatric nursing. Nurses' attitudes towards aggression have been identified as mediating the choice of nursing interventions. To date, investigations are lacking which elucidate the stability of one of the few scales for measuring the attitude of aggression. This study aimed to investigate the test-retest stability of the Perception of Aggression Scale and to derive a shortened version. In order to test the reliability of the Perception of Aggression Scale items, three groups of psychiatric nurses were requested to fill in the Perception of Aggression Scale twice (30 student nurses after 4 days, 32 qualified nurses after 14 days and 36 qualified nurses after 70 days). We derived the shortened version from an independent data set obtained from 729 psychiatry nurses using principal component analysis, aiming to maximize parsimony and Cronbach's alpha. Amongst competing short versions, we selected those with the highest reliability at 70 or 14 day retest. A scale using 12 of the original 32 items was derived yielding alphas of r = 0.69 and r = 0.67 for the two POAS factors with retest reliabilities of r = 0.76 and r = 0.77. The shortened scale offers a practical and viable alternative to the longer version.

Arbeit, Stress und kardiovaskuläre Erkrankungen

Klassische Risikofaktoren wie Rauchen, erhöhter Blutdruck oder Cholesterinspiegel erklären nur einen Teil der Varianz des kardiovaskulären Risikos. Arbeitsbedingte psychosoziale Belastungen wie etwa hoher Termindruck, geringer Entscheidungsspielraum, ungünstiges Betriebsklima bestehen oft über lange Zeit. Arbeitsbedingte Belastungen könnten über die biologische Stressreaktion direkt biologische Risikofaktoren wie etwa Blutdruck verändern oder aber indirekt über eine Modifikation des Gesundheitsverhaltens. Epidemiologische Untersuchungen legen eine Assoziation zwischen berufsbedingten Belastungen und dem Risiko kardiovaskulärer Erkrankungen nahe. Das allgemeine Stressmodell von Allostase und allostatischer Last unterscheidet die nützliche akute Anpassungsreaktion zur Vorbereitung auf Kampf oder Flucht (Allostase) und die biologischen Folgen wiederholter oder fehlregulierter Anpassungsreaktionen (allostatische Last). Das Modell erlaubt, sowohl die Wirkung arbeitsbedingter psychosozialer Belastungen auf die primäre Stressreaktion zu untersuchen (Abnahme des vagalen Tonus, Aktivierung von Symphatikus und Cortisolsekretion) als auch die von der Anpassungsreaktion regulierten biologischen Prozesse. Erste Longitudinalstudien zeigen einen Zusammenhang zwischen hoher allostatischer Last und ungünstigem Outcome.

Raman spectroscopy and structure of crystalline gallium phosphide nanowires

Gallium phosphide nanowires with a most probable diameter of approximately 20.0 nm and more than 10 microns in length have been synthesized by pulsed laser vaporization of a heated GaP/5% Au target. The morphology and microstructure of GaP nanowires have been investigated by scanning electron microscopy and transmission electron microscopy. Twins have been observed along the crystalline nanowires, which have a growth direction of [111]. Raman scattering shows a 4 cm-1 downshift of the longitudinal optical phonon peak in the nanowire with respect to the bulk; the transverse optical phonon frequency and line width are, however, the same as in the bulk. The quantum confinement model first proposed by Richter et al. cannot explain the observed behavior of the Raman modes.

Neuromotor development from kindergarten age to adolescence: developmental course and variability

The normal course of neuromotor development is described from 5 to 18 years of age. The data have been collected by use of the Zurich Neuromotor Assessment, a standardized testing procedure in which distinct motor tasks are judged with regard to timed performance and movement quality (associated movements of the contralateral and ipsilateral extremity, face, head and body). In the Zurich Growth and Development Studies, norms for these motor tasks have been established in 662 children and adolescents from middle class families. Neuromotor development is not a phenotypic entity, but evolves from motor functions of different complexity. With regard to timed performance and movement quality developmental course, gender differences and laterality vary considerably over age and among motor tasks. Thus, for a reliable assessment of the neuronotor developmental status in children, a standardized test instrument, well-trained examiners and normative data are required.

Neuromotor development from kindergarten age to adolescence: developmental course and variability

The normal course of neuromotor development is described from 5 to 18 years of age. The data have been collected by use of the Zurich Neuromotor Assessment, a standardized testing procedure in which distinct motor tasks are judged with regard to timed performance and movement quality (associated movements of the contralateral and ipsilateral extremity, face, head and body). In the Zurich Growth and Development Studies, norms for these motor tasks have been established in 662 children and adolescents from middle class families. Neuromotor development is not a phenotypic entity, but evolves from motor functions of different complexity. With regard to timed performance and movement quality developmental course, gender differences and laterality vary considerably over age and among motor tasks. Thus, for a reliable assessment of the neuronotor developmental status in children, a standardized test instrument, well-trained examiners and normative data are required.

Thermoelectric power of p-doped single-wall carbon nanotubes and the role of phonon drag

We measured thermoelectric power S of bulk single-wall carbon nanotube materials p doped with acids. In contrast to oxygen-exposed or degassed samples, S is very small at the lowest temperatures, increases superlinearly above a characteristic and sample-dependent T, and then levels off. We attribute this unusual behavior to 1D phonon drag, in which the depression of the Fermi energy cuts off electron-phonon scattering at temperatures below a characteristic T0. This idea is supported by a model calculation in which the low temperature behavior of phonon drag is specifically related to the one-dimensional character of the electronic spectrum.

Production and characterization of polymer nanocomposites with highly aligned single-walled carbon nanotubes

We report the production and characterization of polymer nanocomposites with single-walled carbon nanotubes having improved mechanical properties and exceptional nanotube alignment. High-pressure carbon monoxide nanotubes (HiPco) were efficiently distributed in polystyrene (PS) and polyethylene (PE) with a twin-screw compounder. Nanotube concentrations were 1, 5, 10, and 20 wt% in PE composites and 0.7 wt% in PS composites. PE composites were melt-spun into fibers to achieve highly aligned nanotubes. Polarized Raman spectroscopy shows that the degree of alignment increases with decreasing fiber diameter and decreases with increasing nanotube loading. The orientation distribution function of a 1 wt% HiPco/PE composite had a full width at half-maximum of approximately 5 degrees. The elastic modulus increases up to 450% relative to PE fibers for 20 wt% nanotube loading at an intermediate fiber diameter of 100 microns.

Coercive procedures and facilities in Swiss psychiatry

BACKGROUND

Coercive measures in psychiatry,although in many cases effective in violence management and injury reduction, have been criticised from a consumerist point of view.

METHOD

A questionnaire regarding coercive facilities and procedures was dispatched to the charge nurses of 86 acute psychiatric admission wards in German speaking Switzerland covering a catchment area of 75% of the Swiss population.

RESULTS

95% of all wards responded rendering the survey representative. The majority of wards have seclusion rooms and 55% of charge nurses perceive seclusion facilities as adequate. Two to twenty staff members are involved in overwhelming dangerous patients and some discontent is expressed at the haphazard fashion in which such events occur. Almost 70% of the wards use a form for reporting, 42 % of wards keep statistics on violent incidents and 17% of wards have access to these data. Of all wards 84% register injections against patients' will, 83% seclusion, and 78% mechanical restraint and a minority of wards register the coercive administration of oral medication, forced nutrition, threats of coercive measures in case of pharmacological non-compliance.

DISCUSSION

Isolation, the coercive administration of medicine and restraint techniques are sensitive forms of treatment. Deficits reported by the charge nurses point to the need for enhanced facilities and improved forms of coercion management such as training in the use of mechanical restraints and the overwhelming of dangerous patients.

CONCLUSION

The data show considerable differences in the facilities, the use, and the recording of coercive measures in the area under scrutiny.

Coercive procedures and facilities in Swiss psychiatry

BACKGROUND

Coercive measures in psychiatry,although in many cases effective in violence management and injury reduction, have been criticised from a consumerist point of view.

METHOD

A questionnaire regarding coercive facilities and procedures was dispatched to the charge nurses of 86 acute psychiatric admission wards in German speaking Switzerland covering a catchment area of 75% of the Swiss population.

RESULTS

95% of all wards responded rendering the survey representative. The majority of wards have seclusion rooms and 55% of charge nurses perceive seclusion facilities as adequate. Two to twenty staff members are involved in overwhelming dangerous patients and some discontent is expressed at the haphazard fashion in which such events occur. Almost 70% of the wards use a form for reporting, 42 % of wards keep statistics on violent incidents and 17% of wards have access to these data. Of all wards 84% register injections against patients' will, 83% seclusion, and 78% mechanical restraint and a minority of wards register the coercive administration of oral medication, forced nutrition, threats of coercive measures in case of pharmacological non-compliance.

DISCUSSION

Isolation, the coercive administration of medicine and restraint techniques are sensitive forms of treatment. Deficits reported by the charge nurses point to the need for enhanced facilities and improved forms of coercion management such as training in the use of mechanical restraints and the overwhelming of dangerous patients.

CONCLUSION

The data show considerable differences in the facilities, the use, and the recording of coercive measures in the area under scrutiny.

Long-term evaluation of extended thymectomy with anterior mediastinal dissection for myasthenia gravis

BACKGROUND

Thymectomy for the treatment of myasthenia gravis (MG) is well established. The extent of resection, however, remains a source for debate. Outcomes for newer surgical techniques need to be compared to more extensive procedures.

METHODS

A retrospective review was done of 64 consecutive patients who underwent transsternal thymectomy with extended anterior mediastinal dissection for MG between 1979 and 2000 and who were operated on by a single surgeon.

RESULTS

Fifty-six patient charts were available, providing 58 operative procedures. Three patients had died of unrelated causes. The mean age of symptom onset was 36.0 +/- 2.5 years, with a mean duration of 3.3 +/- 0.5 years until surgery was undertaken. The mean length of follow-up was 6.8 +/- 0.8 years. Operative procedures were associated with a 10.3% major morbidity rate and no mortality. Drug-free remission was achieved in 50.0% of the patients, and symptoms were absent or improved in 76.8% of the patients. Patients followed up long-term (>10 years) achieved the greatest remission rate (71.4%) and symptomatic improvement (85.7%). After thymectomy, the mean dosages of prednisone and Mestinon decreased by 69.3% and 58.8%, respectively.

CONCLUSIONS

Extended thymectomy provides excellent overall symptom improvement, which is enhanced over time. This review provides a basis for long-term comparison with other less invasive and perhaps less extensive procedures.

Use of angulated video-intubation laryngoscope in children undergoing manual in-line neck stabilization

Laryngeal views obtained during direct laryngoscopy with and without manual in-line neck stabilization (MILNS) and during video-assisted intubation with MILNS using the angulated video-intubation laryngoscope were assessed in 100 paediatric patients (aged 0.25-17.3 yr). Visualization of the larynx (Cormack and Lehane score) as well as time taken for video-assisted tracheal intubation by six nurses and four resident anaesthetists not experienced in the technique were recorded. Cormack and Lehane scores were significantly worse during direct laryngoscopy when MILNS was applied. Video-assisted visualization of the larynx during MILNS produced scores, which were as good or better than those observed during direct laryngoscopy alone. Intubation times ranged from 19-75 s (mean 35 (SD 13.4); median 32).

Adrenergic blockade reduces skeletal muscle glycolysis and Na(+), K(+)-ATPase activity during hemorrhage

BACKGROUND

Recent evidence suggests that hyperlactatemia in shock may reflect accelerated aerobic glycolysis linked to activity of the Na(+), K(+)-ATPase rather than hypoxia. Epinephrine stimulates glycolysis in resting muscle largely by stimulating Na(+), K(+)-ATPase activity. This study evaluates the effects of hemorrhagic shock, with and without combined alpha- and beta-adrenergic receptor blockade, on lactate production, glycogenolysis, Na(+)-K(+) pump activity, and high-energy phosphates in rat skeletal muscle.

METHODS

Male Sprague-Dawley rats in four treatment groups were studied: unhemorrhaged control not receiving blockers (CN), controls receiving blockers (CB), shocked animals not receiving blockers (SN), and shocked rats receiving blockers (SB). Shocked rats (SN and SB) were bled to a MAP of 40 mm Hg, maintained for 60 min. Blocker groups (CB and SB) received propranolol and phenoxybenzamine. Arterial blood was drawn for plasma lactate, epinephrine, norepinephrine, and gas analysis. Lactate, glycogen, glucose 6-phosphate, ATP, phosphocreatine, and intracellular Na(+) and K(+) were determined in extensor digitorum longus and soleus muscles. For comparison, muscles were exposed to epinephrine and/or ouabain in vitro.

RESULTS

With the exception of P(a)CO(2), HCO(3), and base excess in the SN group, no significant differences in arterial blood gas parameters were noted. Adrenergic blockade significantly reduced plasma lactate concentration. In shocked rats, adrenergic blockade significantly reduced muscle lactate and glucose 6-phosphate accumulation. Intracellular Na(+):K(+) ratio was decreased in SN rats, implying increased Na(+)-K(+) pump activity. Adrenergic blockade raised the intracellular Na(+):K(+) ratio in shocked animals, implying decreased pump activity. Epinephrine exposure in vitro stimulated muscle lactate production, raised glucose 6-phosphate content, and significantly reduced soleus phosphocreatine stores.

CONCLUSIONS

Neither hypoxia nor defective oxidative metabolism appeared responsible for increased glycolysis during hemorrhagic shock. Adrenergic blockade concurrently reduced plasma lactate, muscle levels of lactate and glucose 6-phosphate, and muscle Na(+)-K(+) pump activity during shock. Rapid skeletal muscle aerobic glycolysis in response to increased plasma epinephrine levels may be an important contributor to increased glycolysis in muscle and increased plasma lactate during hemorrhagic shock.

Always flush the sampling port before flushing the arterial cannula in pediatric patients

BACKGROUND

Blood sampling from arterial lines is a frequent event in anesthesia and critical care. To avoid clot formation, both the stopcock outlet and the cannula must be flushed after sampling. We investigated in a bench experiment whether fluid flow through the cannula is affected by the sequence of flushing procedures.

METHODS

Continuity of fluid delivery from a vascular cannula was gravimetrically determined using two different flushing techniques with either a syringe pump flush system or a bag flush system. The procedures comprised first flushing the stopcock towards the cannula and then towards the stopcock sampling outlet or the reverse order. Experiments were repeated in triplicate and two sets for each flushing system at hydrostatic pressures of 37 mm Hg and 74 mm Hg.

RESULTS

The main finding of the study was that flushing the stopcock towards the outlet after flushing the cannula resulted in considerable retrograde aspiration volumes and zero flow times, in particular in combination with syringe pump flush systems. At a hydrostatic pressure of 74 mm Hg, the observed zero flow time at the cannula tip amounted to (mean+/-SD) 0.1+/-0.01 min with the bag flush system and 7.7+/-0.5 min with the syringe pump flush system. The related retrograde aspiration volumes were 2.2+/-0.7 microl with the bag system and 30.0+/-2.0 microl with the syringe pump system. No backflow was recorded when the stopcock was first flushed to ambient pressure and then afterwards towards the cannula.

CONCLUSION

Opening a flush system to ambient pressure affects the continuity of fluid delivery, particularly when using syringe pump flush systems. After blood sampling, the stopcock outlet should be flushed first followed by cannula flushing.

Use of the Internet by medical doctors in Switzerland

QUESTIONS UNDER STUDY

To investigate the utilisation of the Internet by primary care physicians for medical purposes during their daily practice, and to clarify the reasons for use or non-use of this technology.

METHODS

Cross-sectional postal survey in German-speaking Switzerland employing a purpose-designed pre-validated 69-item questionnaire. A random sample of 2009 primary care physicians participated in the investigation.

MAIN OUTCOME MEASURES

Number of primary care physicians with access to the Internet; reasons for using the Internet during consultations; sources of information in solving medical problems arising from concurrent patient care.

RESULTS

55% of the physicians returned the completed questionnaire. 75% of respondents reported access to the Internet. Only 7% use the Internet during patient consultations. The main reasons for not using the Internet were time pressure and concerns about potential negative interaction with physician-patient communication. To solve patient-specific problems arising during daily practice, 59% of the practitioners consult text-books or colleagues. Only 14% of respondents report regularly finding useful information on the Internet. Internet users assess information quality by checking on authorship, institution, publishing company, or whether the information is sponsored by a third party with a potential conflict of interest.

CONCLUSIONS

Access to the Internet is widespread amongst German-speaking Swiss primary care physicians. Only a small minority use the Internet for information retrieval during consultation hours. Electronic information systems need to be tailored to the needs of primary care physicians.

Use of the Internet by medical doctors in Switzerland

QUESTIONS UNDER STUDY

To investigate the utilisation of the Internet by primary care physicians for medical purposes during their daily practice, and to clarify the reasons for use or non-use of this technology.

METHODS

Cross-sectional postal survey in German-speaking Switzerland employing a purpose-designed pre-validated 69-item questionnaire. A random sample of 2009 primary care physicians participated in the investigation.

MAIN OUTCOME MEASURES

Number of primary care physicians with access to the Internet; reasons for using the Internet during consultations; sources of information in solving medical problems arising from concurrent patient care.

RESULTS

55% of the physicians returned the completed questionnaire. 75% of respondents reported access to the Internet. Only 7% use the Internet during patient consultations. The main reasons for not using the Internet were time pressure and concerns about potential negative interaction with physician-patient communication. To solve patient-specific problems arising during daily practice, 59% of the practitioners consult text-books or colleagues. Only 14% of respondents report regularly finding useful information on the Internet. Internet users assess information quality by checking on authorship, institution, publishing company, or whether the information is sponsored by a third party with a potential conflict of interest.

CONCLUSIONS

Access to the Internet is widespread amongst German-speaking Swiss primary care physicians. Only a small minority use the Internet for information retrieval during consultation hours. Electronic information systems need to be tailored to the needs of primary care physicians.

[Tests and criteria in diagnosis of chronic hypotension--a systematic review]

The diagnosis of hypotensive circulatory disorders is based on a variety of criteria and classifications. This paper aims to provide a systematic review of published definitions and diagnostic criteria for hypotensive disorders. Searches for relevant papers were undertaken in Medline, Winspirs version (January 1966 to December 1999) and in textbooks of internal medicine. References of all identified articles were also searched. Publications in English, French, German and Italian were included. In 47 articles, 56 different reference were made to definitions and diagnostic criteria for hypotension. At present there is no uniform definition of hypotension and there are no clear, standardized criteria on which to base a diagnosis. Basically, one distinguishes between two schools of thought. The Anglo-American literature describes hypotensive disorders in terms of orthostatic dysregulation in the presence of an underlying primary condition, whereas the German-speaking countries use mixed approaches. On the one hand, the questionable pathological value of essential/primary hypotension is discussed; on the other hand, tests for orthostatic circulatory function, like the Schellong test, appear to have become established. Neither resting blood pressure limits nor a drop in blood pressure during orthostatic challenge can be used to diagnose hypotension. The orthostatic test is a better diagnostic tool than resting blood pressure. Hypotension is probably difficult to classify in simple terms because it is usually a symptom of numerous disorders hallmarked by a variety of pathophysiological mechanisms. Hypotension should indeed be understood as a secondary symptom of a primary disease. Accordingly, the primary aim of diagnostic efforts should be to uncover the underlying condition. The studies included were of insufficient methodological quality. Moreover, the heterogeneity among the individual studies made pooled analysis impossible. This systematic review revealed a marked lack of studies with valid results.