Quasi One-Dimensional Metal-Semiconductor Heterostructures.

The band offsets occurring at the abrupt heterointerfaces of suitable material combinations offer a powerful design tool for high performance or even new kinds of devices. Because of a large variety of applications for metal-semiconductor heterostructures and the promise of low-dimensional systems to present exceptional device characteristics, nanowire heterostructures gained particular interest over the past decade. However, compared to those achieved by mature two-dimensional processing techniques, quasi one-dimensional (1D) heterostructures often suffer from low interface and crystalline quality. For the GaAs-Au system, we demonstrate exemplarily a new approach to generate epitaxial and single crystalline metal-semiconductor nanowire heterostructures with atomically sharp interfaces using standard semiconductor processing techniques. Spatially resolved Raman measurements exclude any significant strain at the lattice mismatched metal-semiconductor heterojunction. On the basis of experimental results and simulation work, a novel self-assembled mechanism is demonstrated which yields one-step reconfiguration of a semiconductor-metal core-shell nanowire to a quasi 1D axially stacked heterostructure via flash lamp annealing. Transmission electron microscopy imaging and electrical characterization confirm the high interface quality resulting in the lowest Schottky barrier for the GaAs-Au system reported to date. Without limiting the generality, this novel approach will open up new opportunities in the syntheses of other metal-semiconductor nanowire heterostructures and thus facilitate the research of high-quality interfaces in metal-semiconductor nanocontacts.

Nucleation of Ga droplets on Si and SiOx surfaces.

We report on gallium droplet nucleation on silicon (100) substrates with and without the presence of the native oxide. The gallium deposition is carried out under ultra-high vacuum conditions at temperatures between 580 and 630 °C. The total droplet volume, obtained from a fit to the diameter-density relation, is used for sample analysis on clean silicon surfaces. Through a variation of the 2D equivalent Ga thickness, the droplet diameter was found to be between 250-1000 nm. Longer annealing times resulted in a decrease of the total droplet volume. Substrate temperatures of 630 °C and above led to Ga etching into the Si substrates and caused Si precipitation around the droplets. In contrast, we obtained an almost constant diameter distribution around 75 nm over a density range of more than two orders of magnitude in the presence of a native oxide layer. Furthermore, the droplet nucleation was found to correlate with the density of surface features on the 'epi-ready' wafer.

Sustained brain activation supporting stop-signal task performance.

Stop-signal paradigms operationalize a basic test of goal-directed behaviour whereby an overarching stop goal that is performed intermittently must be maintained throughout ongoing performance of a reaction time go task (go goal). Previous studies of sustained brain activation during stop-signal task performance in humans did not observe activation of the dorsolateral prefrontal cortex (DLPFC) that, in concert with the parietal cortex, is known to subserve goal maintenance. Here we explored the hypothesis that a DLPFC and parietal network has a key role in supporting ongoing stop-signal task performance. We used a blocked functional magnetic resonance imaging design that included blocks of trials containing typical stop-signal paradigm stimuli that were performed under three conditions: Stop condition, which required reaction time responding to go stimuli and inhibition of cued responses upon presentation of a stop signal; Go condition, identical except that the tone was ignored; and Passive condition, which required only quiescent attention to stimuli. We found that, whereas a distributed corticothalamic network was more active in Stop compared with Go, only the right DLPFC and bilateral parietal cortex survived after masking that contrast with Stop compared with Passive. These findings indicate that sustained activation of a right dominant frontoparietal network supports stop goal processes during ongoing performance of the stop-signal task.

How COVID-19 impacted people with disabilities: A qualitative study in Delaware.

Objectives: The COVID-19 pandemic created unprecedented challenges for people with disabilities and their caregivers and service providers. An assessment of how the COVID-19 pandemic, and the public health response to it, inequitably impacted the health and well-being of people with disabilities is needed to improve preparedness for future public health emergencies. Interviews were conducted with the goal of documenting the impacts of COVID-19 on community-dwelling individuals in Delaware. Study design: Qualitative interviews using a structured interview guide. Methods: In November and December 2022, interviews were conducted with individuals with disabilities, their caregivers, governmental and non-profit service providers, and elected representatives in Delaware. Interviews focused on obtaining information related to COVID-related threats to maintaining good health, affordable and accessible housing, work, educational opportunities, transportation, and community belonging during the pandemic. Interview transcripts were inductively analyzed. Results: Five themes were identified including changes to, or loss of, home-based medical and other services, changes in daily routines that impacted access to work and education, limits on access to transportation, financial strains and housing issues, and mental health concerns. Conclusions: The COVID-19 pandemic impacted nearly all aspects of the lives of people with disabilities. COVID-19 presented long-term, existential threats to progress made toward independent living, meaningful work, and financial, health, and educational equity for people with disabilities.

The World Rugby and International Rugby Players Contact Load Guidelines: From conception to implementation and the future.

Managing training load in rugby union is crucial for optimising performance and injury prevention. Contact training warrants attention because of higher overall injury and head impact risk, yet players must develop physical, technical, and mental skills to withstand the demands of the game. To help coaches manage contact loads in professional rugby, World Rugby and International Rugby Players convened an expert working group. They conducted a global survey with players to develop contact load guidelines. This commentary aims to describe the contact load guidelines and their implementation, and identify areas where future work is needed to support their evolution.

Beneficial effects of androgen-primed chemotherapy in the Dunning R3327 G model of prostatic cancer.

The objective of this study was to test the hypothesis that androgen administration prior to chemotherapy (androgen priming) may potentiate tumor cytotoxicity in hormone-responsive prostate cancer. Accordingly, six groups of Copenhagen rats bearing small (i.e., 40-mm3 median volume) Dunning R3327 G tumors were left untreated or received castration, chemotherapy, or a combination of the two, with or without androgen priming. Groups without priming included: intact untreated, castrate alone, intact plus chemotherapy, and castrate plus chemotherapy (cyclophosphamide, 30 mg/kg/day, for 2 days, with repeat cycle in 24 days) (Cx). To specifically evaluate the effect of androgen priming on Cx cytotoxicity, two additional castrate groups were studied. One received testosterone propionate (4 mg/kg/day) for 2 days prior to Cx and the other after Cx. Treatment effect was evaluated by quantitating tumor volume as well as animal survival to an ethically allowable, maximal tumor burden. As expected, castration and Cx produced a retardation of tumor growth and prolongation of survival when compared to untreated animals. The addition of androgen priming prior to but not after Cx enhanced the degree of tumor suppression. Specifically, 26 days after the second Cx cycle, all androgen-primed tumors had regressed; 70% of tumors had disappeared and those remaining were barely palpable. At this same time point, tumors in all the other groups were actively growing and had volumes greater than initial values (P less than 0.01). Although tumor regrowth occurred, median survival for the androgen-primed group was significantly prolonged, to 186 days versus 39 days (P less than 0.01) for untreated animals and 153 days for the non-primed castrate plus Cx animals (P less than 0.01). These data suggested that androgen priming potentiates the effects of Cx in castrate animals bearing R3327 G tumors.

Kinetic and morphometric responses of heterogeneous populations of experimental breast cancer cells in vivo.

Although the hormone responsiveness of some breast cancers is well known, the differential sensitivity of tumor cell subpopulations to hormonal effects is not well established. These experiments were designed to address this issue using the hormone-responsive N-nitrosomethylurea-induced rat mammary tumor. Rats bearing these tumors were randomly assigned to no treatment, 7-day castration, and 7-day castration followed by 1-, 3-, 7-, and 10-day treatment with estradiol benzoate (5 micrograms) and perphenazine (1 mg) to stimulate prolactin release. Under these conditions, the proportion of different cell populations was estimated with morphometric analysis, while their replicative activity was assessed using [3H]thymidine autoradiography. In tumors of intact rats the fractions of glandular epithelial, myoepithelial, and nonepithelial cells were 88.2%, 3.8%, and 8.0%, respectively. All cell types manifested a similar kinetic response to our hormonal treatments characterized by a drastic decline in the labeling index after castration followed by a progressive increase with hormone repletion which peaked on Day 7 of treatment. The magnitude of the response was, however, greater in the epithelial components of the tumor (glandular and myoepithelial cells), where the peak labeling indices significantly exceeded those observed in the tumors of control intact rats. Castration reduced the proportion of glandular cells while increasing the fractions of myoepithelial and nonepithelial cells. Furthermore, castration reduced the volume of the glandular-epithelial cells by 35%, which accounted for approximately half of the overall tumor volume reduction induced by ovariectomy. These alterations in tumor morphology were partially reversed by hormone repletion. These results underscore the exquisite hormonal sensitivity of different cellular counterparts of this experimental breast cancer with regard to both kinetic and morphological characteristics. They also provide support for stromal-epithelial interaction in the hormonal modulation of breast cancer growth.

Relative effectiveness of the implantable cardioverter-defibrillator and antiarrhythmic drugs in patients with varying degrees of left ventricular dysfunction who have survived malignant ventricular arrhythmias. AVID Investigators. Antiarrhythmics Versus Implantable Defibrillators.

OBJECTIVES: We sought to assess the effect of baseline ejection fraction on survival difference between patients with life-threatening ventricular arrhythmias who were treated with an antiarrhythmic drug (AAD) or implantable cardioverter-defibrillator (ICD). BACKGROUND: The Antiarrhythmics Versus Implantable Defibrillators (AVID) study demonstrated improved survival in patients with ventricular fibrillation or ventricular tachycardia with a left ventricular ejection fraction (LVEF) < or =0.40 or hemodynamic compromise. METHODS: Survival differences between AAD-treated and ICD-treated patients entered into the AVID study (patients presenting with sustained ventricular arrhythmia associated with an LVEF < or =0.40 or hemodynamic compromise) were compared at different levels of ejection fraction. RESULTS: In patients with an LVEF > or =0.35, there was no difference in survival between AAD-treated and ICD-treated patients. A test for interaction was not significant, but had low power to detect an interaction. For patients with an LVEF 0.20 to 0.34, there was a significantly improved survival with ICD as compared with AAD therapy. In the smaller subgroup with an LVEF <0.20, the same magnitude of survival difference was seen as that in the 0.20 to 0.34 LVEF subgroup, but the difference did not reach statistical significance. CONCLUSIONS: These data suggest that patients with relatively well-preserved LVEF (> or =0.35) may not have better survival when treated with the ICD as compared with AADs. At a lower LVEF, the ICD appears to offer improved survival as compared with AADs. Prospective studies with larger patient numbers are needed to assess the effect of relatively well-preserved ejection fraction (> or =0.35) on the relative treatment effect of AADs and the ICDs.

In-hospital versus out-of-hospital presentation of life-threatening ventricular arrhythmias predicts survival: results from the AVID Registry. Antiarrhythmics Versus Implantable Defibrillators.

OBJECTIVES: This study describes the outcomes of patients from the Antiarrhythmics Versus Implantable Defibrillators (AVID) Study Registry to determine how the location of ventricular arrhythmia presentation influences survival. BACKGROUND: Most studies of cardiac arrest report outcome following out-of-hospital resuscitation. In contrast, there are minimal data on long-term outcome following in-hospital cardiac arrest. METHODS: The AVID Study was a multicenter, randomized comparison of drug and defibrillator strategies to treat life-threatening ventricular arrhythmias. A Registry was maintained of all patients with sustained ventricular arrhythmias at each study site. The present study includes patients who had AVID-eligible arrhythmias, both randomized and not randomized. Patients with in-hospital and out-of-hospital presentations are compared. Data on long-term mortality were obtained through the National Death Index. RESULTS: The unadjusted mortality rates at one- and two-year follow-ups were 23% and 31.1% for patients with in-hospital presentations, and 10.5% and 16.8% for those with out-of-hospital presentations (p < 0.001), respectively. The adjusted mortality rates at one- and two-year follow-ups were 14.8% and 20.9% for patients with in-hospital presentations, and 8.4% and 14.1% for those with out-of-hospital presentations (p < 0.001), respectively. The adjusted long-term relative risk for in-hospital versus out-of-hospital presentation was 1.6 (95% confidence interval [CI] 1.3-1.9). CONCLUSIONS: Compared with patients with out-of-hospital presentations of life-threatening ventricular arrhythmias not due to a reversible cause, patients with in-hospital presentations have a worse long-term prognosis. Because location of ventricular arrhythmia presentation is an independent predictor of long-term outcome, it should be considered as an element of risk stratification and when planning clinical trials.

Relation of circadian ventricular ectopic activity to cardiac mortality. CAST Investigators.

The relation between the circadian occurrence of ventricular premature depolarizations (VPD) and sudden arrhythmic death was examined in a subset of patients entered into the Cardiac Arrhythmia Suppression Trial (CAST). Ambulatory electrocardiographic recordings with hourly measurement of VPD frequency were available in 357 patients. Forty percent of the patients (142 of 357) demonstrated circadian variation in VPD frequency between 6:00 A.M. and 9:59 A.M. that was significantly higher (p < 0.05) than what could randomly be expected from an overall 24-hour average for that patient. The only baseline characteristics in patients with circadian VPDs were age (p < 0.04), history of cardiac arrest (p < 0.01), presence of higher frequency of VPDs (p < 0.002), more frequent episodes of ventricular tachycardia (p < 0.04), and more frequent episodes of slow runs (p < 0.04). There was no difference in mortality in patients with or without circadian VPD variation; drug treatment did not effect mortality. These data indicate that the presence of circadian VPDs is not a predictor of sudden arrhythmic death in patients with a high frequency of VPDs.

Lisinopril. A preliminary review of its pharmacodynamic and pharmacokinetic properties, and therapeutic use in hypertension and congestive heart failure.

Lisinopril is an orally active angiotensin-converting enzyme (ACE) inhibitor which at dosages of 20 to 80 mg once daily is effective in lowering blood pressure in all grades of essential hypertension. It is at least as effective as usual therapeutic dosages of hydrochlorothiazide, atenolol, metoprolol and nifedipine while direct comparisons with other ACE inhibitors have not been reported. Many patients achieve an adequate blood pressure reduction with lisinopril alone, and in those who do not, most will with the addition of hydrochlorothiazide; lisinopril also attenuates hypokalaemia induced by thiazide diuretics. In patients with congestive heart failure resistant to conventional therapy, lisinopril 2.5 to 20 mg once daily improved indices of cardiac function and appeared to produce greater benefit than captopril in one controlled study. Lisinopril is well tolerated, with few serious adverse effects being reported. Thus, lisinopril is a suitable treatment for essential hypertension and shows promise in the treatment of congestive heart failure. If additional studies confirm these preliminary findings, then lisinopril will have a similar profile of indications to other ACE inhibitors, and like some other drugs in this class it offers the convenience of once daily administration.

Bisoprolol. A preliminary review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy in hypertension and angina pectoris.

Bisoprolol is a beta 1-adrenoceptor antagonist with no partial agonist (intrinsic sympathomimetic) activity or membrane stabilising (local anaesthetic) activity. The oral bioavailability of bisoprolol is high (90%) and the drug has a long elimination half-life which allows once-daily administration; in addition, it is hepatically and renally cleared in equal proportions. In non-comparative studies, and comparative trials, bisoprolol proved effective, and as efficacious as atenolol, low doses of metoprolol, diuretics and nifedipine SR in hypertension, and atenolol and verapamil in stable angina pectoris. Bisoprolol has been well tolerated in most patients. Thus, bisoprolol is an effective alternative to other beta-adrenoceptor antagonists in patients with mild to moderate essential hypertension or stable angina pectoris. Furthermore, its unique pharmacokinetic properties may offer advantages in selected patients. However, the results of further comparative studies with established agents in the treatment of hypertension and angina pectoris are still awaited so that a final assessment of the relative place in therapy of bisoprolol in these disease states may be made.

Dothiepin. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy in depressive illness.

Dothiepin is a tricyclic antidepressant that is structurally related to amitriptyline. It appears that the antidepressant activity of dothiepin is mediated through facilitation of noradrenergic neurotransmission by uptake inhibition and possibly also by enhancement of serotoninergic neurotransmission. The overall therapeutic efficacy of dothiepin is very similar to that of amitriptyline. In addition, dothiepin appears to be comparable to imipramine, doxepin, maprotiline, mianserin, fluoxetine, fluvoxamine and trazodone. Dry mouth is the most commonly reported side effect of therapeutic doses but the incidence of this and other anticholinergic side effects is less among patients treated with dothiepin than with amitriptyline. However, the sedative/anxiolytic activity of dothiepin is similar to that of amitriptyline. Dothiepin has not been associated with cardiotoxicity at therapeutic doses. Thus, many years of extensive clinical use have shown that dothiepin is now an established and effective antidepressant in both inpatients and outpatients with depressive symptoms of varying severity and coexisting anxiety. Its therapeutic equivalence to other tricyclics ensures its place as a treatment alternative in these disorders.

Lofepramine. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy in depressive illness.

Lofepramine is a tricyclic antidepressant that is structurally similar to imipramine and is extensively metabolised to desipramine. In the absence of other major pharmacological effects it appears that its antidepressant activity stems from the facilitation of noradrenergic neurotransmission by uptake inhibition, and possibly by the additional facilitation of serotoninergic neurotransmission. The overall therapeutic efficacy of lofepramine is comparable to that of imipramine, amitriptyline, clomipramine, maprotiline and mianserin in patients with depression of varying severity, and coexisting anxiety. Dry mouth is the most commonly reported side effect of usual therapeutic doses of lofepramine, but the incidence of this and other anticholinergic side effects is less among patients treated with lofepramine than with imipramine. Lofepramine has not been associated with adverse effects on cardiac function even in cases of attempted suicide by overdose. Thus, providing its apparent favourable side effect profile is confirmed in practice, lofepramine may be a valuable alternative for treatment of the depressed patient where a tricyclic is indicated.

A surface polysaccharide forms when gonococci are converted to serum resistance by cytidine 5'-monophospho-N-acetyl neuraminic acid.

A serum-susceptible, guinea-pig chamber-passaged, laboratory strain (BS4 (agar)) of Neisseria gonorrhoeae was converted to serum resistance by incubation with cytidine 5-monophospho-N-acetyl neuraminic acid (CMP-NANA) and examined by electron microscopy after staining with ruthenium-red. In contrast to serum susceptible gonococci incubated without CMP-NANA, the majority (60-70%) of the serum resistant organisms showed a surface accumulation of polysaccharide. This surface polysaccharide was enhanced on all the resistant gonococci after incubation with fresh human serum. Control susceptible gonococci were devoid of the polysaccharide after incubation with heated human serum. Identical results were obtained with a fresh gonococcal isolate which had lost serum resistance on subculture but which, in common with 3 other isolates, was restored to serum resistance by incubation with CMP-NANA.

A comparison of the efficacy and tolerability of two recombinant human follicle-stimulating hormone preparations in patients undergoing in vitro fertilization-embryo transfer.

OBJECTIVE: To compare the efficacy and tolerability of two recombinant human FSH (r-hFSH) preparations, follitropin-alpha (Gonal-F; Ares Serono, Geneva, Switzerland) and follitropin-beta (Puregon; Organon, Oss, the Netherlands), for superovulation in patients undergoing IVF-ET. DESIGN: Randomized, parallel-group, assessor-blind, single-center trial. SETTING: Outpatient tertiary referral center for assisted reproductive techniques. PATIENT(S): Forty-four infertile women undergoing IVF-ET. INTERVENTION(S): After down-regulation with buserelin acetate, patients were randomized to receive follitropin-alpha or follitropin-beta, 150 IU/d for 6 days; after that, dosages were adjusted according to the ovarian response. MAIN OUTCOME MEASURE(S): Cumulative dose of r-hFSH; duration of r-hFSH treatment; number of follicles of > or =11 mm and of 14 mm on day 7 of r-hFSH treatment and on the day of hCG administration; number of oocytes retrieved; number of viable embryos; and number of pregnancies (biochemical, ectopic, miscarried) and clinical pregnancies. RESULT(S): There were no statistically significant differences in any efficacy measures between the two preparations. The incidence of systemic adverse events was comparable in the two groups. Local reactions at the injection site were significantly more common and more severe with follitropin-beta than with follitropin-alpha CONCLUSION(S): Follitropin-alpha and follitropin-beta have comparable efficacy in patients undergoing IVF-ET.

Closed interlocking nailing of the femur complicated by an intramedullary calcified lesion.

The interlocking intramedullary nail has greatly expanded the indications for closed intramedullary nailing of the femur. We describe a complication caused by the presence of a calcified lesion located at the proximal metaphyseal-diaphyseal junction of the femur. This lesion could not be penetrated by hand reamers. We used a long 3.5-mm drill bit to place a hole in the infarct, which then allowed passage of the hand reamer. The operation then proceeded in the standard fashion without complications.

The analysis of lysergide (LSD): the development of novel enzyme immunoassay and immunoaffinity extraction procedures together with an HPLC-MS confirmation procedure.

A forensic procedure for the screening and confirmation of the presence of lysergide (lysergic acid diethylamide, LSD) in urine is described together with the evaluation of a novel enzyme immunoassay (EIA) and immunoaffinity extraction procedure. Following initial screening using either an established radioimmunoassay (RIA) or a novel EIA procedure, a quantitative estimate is established using a conventional high performance liquid chromatography-fluorescence (HPLC) technique following solid phase extraction. Final confirmation and quantitation, without derivatization, is established using HPLC in combination with electrospray ionization (ESI) mass spectrometry using methysergide as an internal standard. The detection limit of LSD in urine is 0.5 ng/mL. A blind trial confirmed the validity of the results. The choice of internal standard is discussed. Consideration is given to the photosensitivity of LSD solutions. A study of potential interferants in the HPLC-MS confirmation of LSD is presented and shows that for the wide range of compounds studied, there are none that would interfere with this confirmation technique. A comparison is shown between solid phase and immunoaffinity extraction/clean up procedures, and between RIA and EIA screening procedures.

Predictors of depression in female adolescents.

Depression during adolescence has been associated with a number of factors, including failure to individuate (Blos, 1968), insecure attachments (Armsden, McCauley, Greenberg, Burke, & Mitchell, 1990), negative parental representations, and object relations that lack self-other differentiation (Blatt, Wein, Chevron, & Quinlan, 1979). The present study examined factors associated with symptoms of depression in 59 nonclinical female adolescents. Specifically, the relationship between a number of theoretically related measures-separation-individuation, interpersonal concerns, self-critical concerns, attachment style, parental representations-and symptoms of depression was investigated. The model developed was able to explain the interrelationships of the variables involved in the psychological process of adolescence, and their demonstrated ability to predict symptoms of depression in normal female adolescents.

Subtalar dislocations: a prognosticating classification.

A review of the literature and analysis of eight cases of subtalar dislocations was undertaken to correlate our experience with others and to determine a classification for prognostication. Our findings corresponded with those found by others. A 75% incidence of associated injuries was present in our series and these represented a continuum of varying degrees of complication. A new system was devised whereby increasing severity of associated injuries correlated with increasing rate of complications, including loss of motion, arthritis, pain and avascular necrosis. Dislocations were classified according to: no associated injuries, those with soft tissue injuries, extra-articular fractures, intra-articular fractures and those prone to development of avascular necrosis, ie, open dislocations and fractures of the body of the talus. It was found that associated fractures increased the immobilization period as well as the incidence of complications. Intra-articular fractures have demonstrated increased rates of arthroses in the subtalar joint. Avascular necrosis, an infrequent but devastating complication, is primarily associated with open dislocations and dislocations with concomitant fractures of the body of the talus. Our series had two open subtalar dislocations, neither of which developed avascular necrosis.