Terahertz oscillations in ultra-thin n-In(0.53)Ga(0.47)As ungated channels

Using a self-consistent Monte Carlo simulator we investigate the spectrum of voltage fluctuations of an n-type InGaAs two-terminal layer of variable thickness W in the range 1-100 nm and variable length L in the range 0.01-10 µm embedded in an external dielectric medium. Calculations are performed at T = 300 K for different dopings and in the presence of an external bias of increasing strength. When the bias is well below the threshold for the Gunn effect the spectrum peaks at the plasma oscillations of the electron gas. For W≥100 nm and carrier concentrations of 10(17)-10(18) cm(-3) the peaks are in good agreement with the standard three-dimensional (3D) expression of the plasma frequency. For W≤10 nm the results exhibit a plasma frequency that depends on the length of the layer, thus implying that the oscillation mode is dispersive. The corresponding frequency covers a wide range of values 0.1-10 THz and is in agreement with the two-dimensional (2D) expression of the plasma frequency obtained for a collisionless regime within the in-plane approximation for the electric field. A region of cross-over between the 2D and 3D behaviours of the plasma frequency is shown for W>10 nm. When the bias is above the threshold for the Gunn effect, we observe the washing out of the plasma peak and the onset of a frequency peak associated with the transit time of the Gunn domain located in the sub-terahertz frequency region.

Cyclophilin and the regulation of symbiosis in Aiptasia pallida

The sea anemone Aiptasia pallida, symbiotic with intracellular dinoflagellates, expresses a peptydyl-prolyl cis-trans isomerase (PPIase) belonging to the conserved family of cytosolic cyclophilins (ApCypA). Protein extracts from A. pallida exhibited PPIase activity. Given the high degree of conservation of ApCypA and its known function in the cellular stress response, we hypothesized that it plays a similar role in the cnidarian-dinoflagellate symbiosis. To explore its role, we inhibited the activity of cyclophilin with cyclosporin A (CsA). CsA effectively inhibited the PPIase activity of protein extracts from symbiotic A. pallida. CsA also induced the dose-dependent release of symbiotic algae from host tissues (bleaching). Laser scanning confocal microscopy using superoxide and nitric oxide-sensitive fluorescent dyes on live specimens of A. pallida revealed that CsA strongly induced the production of these known mediators of bleaching. We tested whether the CsA-sensitive isomerase activity is important for maintaining the activity of the antioxidant enzyme superoxide dismutase (SOD). SOD activity of protein extracts was not affected by pre-incubation with CsA in vitro.

Envelope protein Us9 is required for the anterograde transport of bovine herpesvirus type 1 from trigeminal ganglia to nose and eye upon reactivation

In this study, the authors examined the role of bovine herpesvirus type 1 (BHV-1) Us9 in the anterograde transport of the virus from trigeminal ganglia (TG) to nose and eye upon reactivation from latency. During primary infection, both BHV-1 Us9-deleted and BHV-1 Us9-rescued viruses replicated efficiently in the nasal and ocular epithelium. However, upon reactivation from latency, only the BHV-1 Us9-rescued virus could be isolated in the nasal and ocular shedding. By real-time polymerase chain reaction, comparable DNA copy numbers were detected in the TGs during latency and reactivation for both the viruses. Therefore, Us9 is essential for reactivation of the virus in the TG and anterograde axonal transport from TG to nose and eye.

Physical activity and nutrition knowledge and preferences in kindergarten children

The aim of the present study was to determine physical activity and nutritional knowledge and preferences in kindergarten children. Following height and weight measurement, and age and gender adjusted BMI percentile calculation, 202 kindergarten children (4 - 6.5 yr) completed twice in a random order, a photo-pair food and exercise questionnaire. Knowledge was determined by asking the child to choose food/activity that would make a selected doll healthier, while preferences where determined by the child's own choise. Nutritional knowledge score was higher than the physical activity knowledge score (73.4 +/- 1.5 vs. 67.5 +/- 1.9 %, p < 0.006), while the nutrition preference score was lower than the physical activity preference score (42.2 +/- 1. 8 vs. 66.5 +/- 1.6 %, p < 0.0001). There was a difference between nutrition knowledge and preferences (73.4 +/- 1.5 vs. 42.2 +/- 1.8 %, p < 0.0001). No differences were found between physical activity knowledge and preferences. No differences were found between overweight and normal weight kindergartners. Female kindergartners had higher nutrition knowledge and preference scores, but lower physical activity preference scores compared to male kindergartners. Our data suggest that in developing health promotion programs for kindergarten children, an effort should be made to increase physical activity knowledge and to improve nutritional preferences.

Outcome of bilateral hip hemiarthroplasty for displaced fracture of the hip

Our aim was to evaluate the outcome in patients with bilateral non-simultaneous hip fracture treated with hemiarthroplasty at our institution between 1997 and 2003. We looked for any important modification factor that could change the devastating functional and social results. Twenty-two patients with a mean age of 79 at the initial fracture and 82 at the subsequent fracture were evaluated; all were Garden grade III-IV. The second fracture happened a mean of 28 months after the first one. The outcome measurement was the incidence of hip pain, recovery of pre-injury level of ambulation and activities of daily living at a minimum follow-up of one year. Following the first hemiarthroplasty patients deteriorated in their walking capacity and other activities of daily life, and this happened to an even greater extent after the second operation. With respect to walking ability (measured in metres) we concluded that it improved if a modular hemiarthroplasty was used after both fractures (p<0.05) and that worse functional outcomes were observed when different kinds of hemiarthroplasties were used in the same patient.;

The significance of Acinetobacter baumannii bacteraemia compared with Klebsiella pneumoniae bacteraemia: risk factors and outcomes

Risk factors and outcomes for patients with nosocomial Acinetobacter baumannii bacteraemia were compared with those for patients with nosocomial Klebsiella pneumoniae bacteraemia in a single centre in Israel between 2000 and 2003. Data were collected retrospectively through patient chart review. In total, 112 patients with A. baumannii bacteraemia and 90 patients with K. pneumoniae bacteraemia were identified. A. baumannii was significantly associated with poorer performance status, mechanical ventilation, presence of devices, prior treatment with carbapenems, pneumonia as the source of infection and inappropriate empirical antibiotic treatment. All-cause 30-day mortality was higher for A. baumannii bacteraemia compared with K. pneumoniae bacteraemia (61.6% vs 38.9%, P=0.001). Variables significantly associated with mortality at the univariate level (P<0.1) were entered into a multi-variable logistic regression model for mortality. A. baumannii remained significantly associated with mortality when adjusted for all other risk factors (odds ratio 3.61, 95% confidence interval 1.55-8.39). This result did not change when the analysis was repeated for subgroups of less severely ill patients, i.e. those who were not ventilated and those who did not present with septic shock. These results support the view that nosocomial bacteraemia due to A. baumannii is associated with increased mortality.

Functional analysis of bovine herpesvirus 1 (BHV-1) genes expressed during latency

Bovine herpes virus 1 (BHV-1) establishes latency in sensory neurons of trigeminal ganglia (TG), and germinal centers of pharyngeal tonsil. Periodically BHV-1 reactivates from latency, virus is shed, and consequently virus transmission occurs. Two transcripts, the latency related (LR) RNA and ORF-E, are abundantly expressed in TG of latently infected cattle. A LR mutant strain of BHV-1 was constructed that contains stop codons near the beginning of the LR-RNA. The LR mutant virus does not express two proteins encoded by the LR gene, or reactivate from latency suggesting that LR protein expression regulates the latency-reactivation cycle. Higher levels of apoptosis occur in TG of calves infected with the LR mutant versus wild type BHV-1 indicating that the anti-apoptotic properties of the LR gene regulate the latency-reactivation cycle. The LR gene also inhibits bICP0 expression and mammalian cell growth, but these functions do not require LR protein expression. In contrast, the ability of the LR gene to inhibit apoptosis appears to require LR protein expression. A small open reading frame (ORF-E) that is located within the LR promoter is expressed in the nucleus of neuroblastoma cells. We predict that the LR gene and ORF-E regulate the BHV-1 latency-reactivation cycle.

Characteristics of candidaemia with Candida-albicans compared with non-albicans Candida species and predictors of mortality

Candidaemia due to non-albicans Candida species is increasing in frequency. We describe 272 episodes of candidaemia, define parameters associated with Candida albicans and other Candida species, and analyse predictors associated with mortality. Patients with C. albicans (55%) had the highest fatality rate and frequently received immunosuppressive therapy, while patients with Candida parapsilosis (16%) had the lowest fatality and complication rates. Candida tropicalis (16%) was associated with youth, severe neutropenia, acute leukaemia or bone marrow transplantation, Candida glabrata (10%) was associated with old age and chronic disease, and Candida krusei (2%) was associated with prior fluconazole therapy. The overall fatality rate was 36%, and predictors of death by multi-variate analysis were shock, impaired performance status, low serum albumin and congestive heart failure. Isolation of non-albicans Candida species, prior surgery and catheter removal were protective factors. When shock was excluded from analysis, antifungal therapy was shown to be protective. Unlike previous concerns, infection with Candida species other than C. albicans has not been shown to result in an increased fatality rate.

Ocular penetration of grepafloxacin after intravitreal administration in albino and pigmented rabbits

Ocular penetration of grepafloxacin into several ocular tissues was determined in albino and pigmented rabbits following a single intravitreal administration. After administration, grepafloxacin was detected in all ocular tissues studied in both breeds of rabbits. The superior mean penetration ratios were found in the chorioretina and lens of albino rabbits, and in the chorioretina, iris and lens of pigmented rabbits. A significantly greater penetration of grepafloxacin was found in the chorioretina and iris of the pigmented rabbits than in those of the albino rabbits. As a final conclusion, grepafloxacin detected in different ocular structures could attain therapeutic concentrations against a variety of ocular conditions.

Multicenter evaluation of a new screening test that detects Clostridium difficile in fecal specimens

Clostridium difficile causes approximately 25% of nosocomial antibiotic-associated diarrheas and most cases of pseudomembranous colitis. We evaluated C. DIFF CHEK, a new screening test that detects glutamate dehydrogenase of C. difficile. Our results showed that this test was comparable to PCR in sensitivity and specificity and outperformed bacterial culture.

Two-step (culture and PCR) diagnostic approach for differentiation of non-T. foetus trichomonads from genitalia of virgin beef bulls in Argentina

Preputial fluids from 567 virgin Angus and Hereford bulls, 1-2 years old, were inoculated into Sutherland medium, and approximately 8.4% produced cultures with a protozoan suggestive of Tritrichomonas foetus. Under brightfield microscopy, large numbers of single-celled motile organisms with multiple anterior flagellae, a posterior flagellum, axostyle, and a visible undulating membrane were detectable. Motility was jerky and rolling, as described for T. foetus. Air-dried smears of cultures stained with Giemsa or Diff-Quick + iodine revealed an organism similar to T. foetus, although somewhat more rounded. Several organisms appeared to have four anterior flagellae. Scanning electron microscopy (5000x) of representative samples revealed four anterior flagellae on most organisms, and an axostyle that was consistently longer than that seen in T. foetus. Using pan-trichomonal primers and T. foetus-specific primers in a polymerase chain reaction (PCR) assay, amplification products of 372bp were detected in all virgin bull isolates, but only with the pan-trichomonal primers. Positive control isolates of T. foetus yielded amplification products of the expected size (372 and 347bp) with the two sets of primers, respectively. We conclude that these protozoa are not T. foetus, and note the similarity of these findings with those reported earlier in North American beef cattle. Because in several countries there is no legal treatment for bovine trichomonosis, veterinarians recommend slaughter of bulls with positive preputial cultures. The existence of easily mis-identified non-T. foetus trichomonads in the bovine prepuce suggests that the current "gold standard" diagnostic test (culture of preputial scrapings or washings) should be augmented with a more specific confirming test, such as the PCR employed in this study.

Pharmacokinetics and ocular penetration of grepafloxacin in albino and pigmented rabbits

The pharmacokinetics of grepafloxacin were determined in albino and pigmented rabbits following a single 10 mg/kg intravenous administration. The penetration of grepafloxacin into various ocular tissues was also determined after continuous intravenous infusion in both types of animal. Grepafloxacin showed a bicompartmental model of distribution in both pigmented and albino rabbits with significant differences in the pharmacokinetics between the two types of animal. After continuous intravenous infusion, significantly greater penetration of grepafloxacin was found in the iris, cornea and chorioretina of pigmented rabbits compared with albino rabbits.