Conductivity control of as-grown branched indium tin oxide nanowire networks.

Branched indium tin oxide (ITO) nanowire networks are promising candidates for transparent conductive oxide applications, such as optoelectronic electrodes, due to their high porosity. However, these branched networks also present new challenges in assessing conductivity. Conventional four-point probe techniques cannot separate the effect of porosity on the long-range conductivity from the intrinsic material conductivity. Here we compare the average nanoscale conductivity within the film measured by terahertz time-domain spectroscopy (THz-TDS) to the film conductivity measured by four-point probe in a branched ITO nanowire network. Both techniques report conductivity increases with deposition flux rate from 0.5 to 3.0 nm s(-1), achieving a maximum of ~ 10 (Ω cm)(-1). Modeling the THz-TDS conductivity data using the Drude-Smith model allows us to distinguish between conductivity increases resulting from morphological changes and those resulting from the intrinsic properties of the ITO. In particular, the intrinsic material conductivity within the nanowires can be extracted, and is found to reach a maximum of ~ 3000 (Ω cm)(-1), comparable to bulk ITO. To determine the mechanism responsible for increasing conductivity with flux rate, we characterize dopant concentration and morphological changes (i.e., to branching behavior, nanowire diameter and nucleation layers). We propose that changes in the electron density, primarily due to changes in O-vacancy concentration at different flux rates, are responsible for the observed conductivity increase. This understanding will assist balancing structural and conductivity requirements in applications of transparent conductive oxide networks.

Indium tin oxide nanowhisker morphology control by vapour-liquid-solid glancing angle deposition.

A new growth technique for indium tin oxide nanowhiskers with increased control over feature size and spacing is reported. The technique is based on a unique combination of self-catalysed vapour-liquid-solid (VLS) growth and glancing angle deposition (GLAD). This VLS-GLAD technique provides enhanced control over nanowhisker morphology as the effect of typical VLS growth parameters (e.g. flux rate, temperature) is amplified at large deposition angles characteristic of GLAD. Spatial modulation of the collimated growth flux controls trunk width, number and orientation of branches, and overall nanowhisker density. Here we report the influence of growth conditions (including deposition angle, flux rate, nominal pitch and substrate temperature) on nanowhisker morphology, with specific focus on the effect of large deposition angles. Sheet resistance and transmission of the films were measured to characterize their performance as transparent conductive oxides. Hybrid nanostructured films grown in this study include high surface area nanowhiskers protruding from a conductive film, ideal for transparent conductive electrode applications.

Human metapneumovirus infection in adults with community-acquired pneumonia and exacerbation of chronic obstructive pulmonary disease.

We tested nasopharyngeal aspirate specimens by real-time polymerase chain reaction assays and paired serum samples by enzyme-linked immunosorbent assays. Acute human metapneumovirus infections were identified in 6 (4.1%) of 145 adult patients who presented to the emergency department for pneumonia or acute exacerbation of chronic obstructive pulmonary disease during 2 winter/spring seasons in Quebec, Canada.

Treatment of community-acquired pneumonia in the elderly: the role of cefepime, a fourth-generation cephalosporin.

In a prospective, multicentre double-blind trial, 151 patients over the age of 65 years were randomly assigned to receive either cefepime 2 g every 12 h for a minimum of 3 days and up to 14 days or ceftriaxone 1 g every 12 h for a minimum of 3 days and up to 14 days. Antibiotics were maintained until 48 h after fever had resolved; no other antibiotics were permitted. The average age in each group exceeded 77 years and significant co-morbidity was found in the majority of patients. The mean total duration of therapy was 5.8+/-2.4 days for the cefepime group and 6.7+/-2.7 days for the ceftriaxone group (P = 0.06). The clinical success rate at the end of therapy was 79.1% with cefepime and 75.4% with ceftriaxone (P = 0.62). At the end of follow-up, 91.7% of the cefepime-treated patients and 86.5% of the ceftriaxone patients had a satisfactory clinical response (P = 0.38). In 35 bacteriological evaluable patients, potential pathogens were eradicated in all but one patient receiving cefepime. Seven patients in each group died during the study period but in each case the death was unrelated to study drug. The commonest side-effect was diarrhoea (cefepime, five patients; ceftriaxone, two patients). The clinical and microbiological efficacy of cefepime is similar to that of ceftriaxone in elderly patients with community-acquired pneumonia requiring hospitalization. Cefepime is an appropriate choice for the treatment of community-acquired respiratory tract infections in the elderly.

A 1-year community-based health economic study of ciprofloxacin vs usual antibiotic treatment in acute exacerbations of chronic bronchitis: the Canadian Ciprofloxacin Health Economic Study Group.

OBJECTIVE: To evaluate the costs, consequences, effectiveness, and safety of ciprofloxacin vs standard antibiotic care in patients with an initial acute exacerbation of chronic bronchitis (AECB) as well as recurrent AECBs over a 1-year period. DESIGN: Randomized, multicenter, parallel-group, open-label study. SETTING: Outpatient general practice. PATIENTS: A total of 240 patients, 18 years or older with chronic bronchitis, with a history of frequent exacerbations (three or more in the past year) presenting with a type 1 or 2 AECB (two or more of increased dyspnea, increased sputum volume, or sputum purulence). MAIN OUTCOME MEASURES: The assessment included AECB symptoms, antibiotics prescribed, concomitant medications, adverse events, hospitalizations, emergency department visits, outpatient resources such as diagnostic tests, procedures, and patient and caregiver out-of-pocket expenses. Patients completed the Nottingham Health Profile, St. George's Respiratory Questionnaire, and the Health Utilities Index. The parameters were recorded with each AECB and at regular quarterly intervals for 1 year. These variables were compared between the ciprofloxacin-treated group and the usual-care-treated group. RESULTS: Patients receiving ciprofloxacin experienced a median of two AECBs per patient compared to a median of three AECBs per patient receiving usual care. The mean annualized total number of AECB-symptom days was 42.9+/-2.8 in the ciprofloxacin arm compared to 45.6+/-3.0 days in the usual-care arm (p=0.50). The overall duration of the average AECB was 15.2+/-0.6 days for the ciprofloxacin arm compared to 16.3+/-0.6 days for the usual-care arm. Treatment with ciprofloxacin tended to accelerate the resolution of all AECBs compared to usual care (relative risk=1.20; 95% confidence interval [CI], 0.91 to 1.58; p=0.19). Treatment assignment did not affect the interexacerbation period but a history of severe bronchitis, prolonged chronic bronchitis, and an increased number of AECBs in the past year were associated with shorter exacerbations-free periods. There was a slight, but not statistically significant, improvement in all quality of life measures with ciprofloxacin over usual care. The only factors predictive of hospitalization were duration of chronic bronchitis (odds ratio=4.6; 95% CI, 1.6, 13.0) and severity of chronic bronchitis (odds ratio=4.3; 95% CI, 0.8, 24.6). The incremental cost difference of $578 Canadian in favor of usual care was not significant (95% CI, -$778, $1,932). The cost for the ciprofloxacin arm over the usual care arm was $18,588 Canadian per quality-adjusted life year gained. When the simple base case analysis was expanded to examine the effect of risk stratification, the presence of moderate or severe bronchitis and at least four AECBs in the previous year changed the economic and clinical analysis to one favorable to ciprofloxacin with the ciprofloxacin-treated group having a better clinical outcome at lower cost ("win-win" scenario). CONCLUSIONS: Treatment with ciprofloxacin tended to accelerate the resolution of all AECBs compared to usual care; however, the difference was not statistically significant. Further, usual care was found to be more reflective of best available care rather than usual first-line agents such as amoxicillin, tetracycline, or trimethoprim-sulfamethoxazole as originally expected. Despite the similar antimicrobial activities and broad-spectrum coverage of both ciprofloxacin and usual care, the trends in clinical outcomes and all quality of life measurements favor ciprofloxacin. In patients suffering from an AECB with a history of moderate to severe chronic bronchitis and at least four AECBs in the previous year, ciprofloxacin treatment offered substantial clinical and economic benefits. In these patients, ciprofloxacin may be the preferred first antimicrobial choice.

Clarithromycin versus cefaclor in lower respiratory tract infections. The Canadian Bronchitis Study Group.

A randomized study was done to compare the efficacy of clarithromycin 250 mg or 500 mg b.i.d., vs. cefaclor 250 mg or 500 mg t.i.d. for 7-14 d in 197 evaluable patients with lower respiratory tract infection. Ninety-five patients received clarithromycin, 88 with acute bronchitis or exacerbation of chronic bronchitis, and 7 with pneumonia. One hundred and two patients received cefaclor, 86 with bronchitis and 16 with pneumonia. Ten patients (10.5%) in the clarithromycin group did not complete the trial, 5 (5.3%) because of adverse event, and 3 (3.2%) because of clinical failure. Similarly, 11 patients (10.8%) did not complete cefaclor, 2 (2%) because of adverse event, and 7 (6.9%) because of clinical failure. Clinical cure or improvement was observed in 90 (94.7%) of patients on clarithromycin vs. 92 (90.2%) on cefaclor, p = 0.66. Bacteriologic cure was seen in 26/36 patients (72.2%) on clarithromycin vs. 28/40 patients (70%) on cefaclor, p = 0.28. Clarithromycin is just as effective as cefaclor for lower respiratory tract infections and is well tolerated.

Influence of continuous positive airway pressure on sleep apnea-related desaturation in sleep apnea patients.

To investigate the influence of nasal continuous positive airway pressure (CPAP) on apnea-related desaturation, we compared the sleep apnea-related desaturations obtained during a polysomnographic study before and during nasal CPAP in 15 sleep apnea patients. An individual desaturation curve was determined with a regression analysis by plotting the lowest SaO2 value reached during each apnea against its duration; these data were collected throughout the night. At baseline, we only considered the apneas with a preapneic SaO2 value greater than 90% and a minimal SaO2 value above or equal to 60%. For the CPAP study, the preapneic SaO2 value also had to be within 2% the baseline value for the apneas to be retained. Due to the restriction criteria imposed to characterize apnea-related SaO2 falls, residual apneas still had to be recorded with CPAP. These data were analyzed separately for obstructive apnea for non-rapid eye movement (REM) and REM sleep stages. A desaturation curve was obtained from 10 sec to a variable upper limit that corresponded to the longest apnea duration commonly reached during both baseline and CPAP for a given apnea-type and sleep stage. The individual apnea-related SaO2 fall was characterized by measuring a desaturation area corresponding to the area under the curve. It was expressed in % SaO2/sec of apnea. CPAP reduced the number of apneas per hour of sleep from 37.5 +/- 6.5 (mean +/- SEM) to 14.3 +/- 3.7 (p = 0.001), and improved the whole night SaO2 level as estimated by a cumulative SaO2 curve. The mean apnea duration was reduced from 22.9 +/- 1.5 sec at baseline to 16.8 +/- 0.5 sec during CPAP therapy (p = 0.005). The preapneic SaO2 value was 94.8 +/- 0.3% at baseline and 95.5 +/- 0.2% during CPAP (p = 0.5). The desaturation area decreased from 267 +/- 48% SaO2/sec at baseline to 152 +/- 41% SaO2/sec during CPAP (p less than 0.001). We conclude that CPAP improves the apnea-related desaturation independently of the shortening of apneas and of any difference in the preapneic SaO2 value.

[Obstructive sleep apnea syndromes]. / Le syndrome des apnées obstructives du sommeil.

Obstructive sleep apnea syndrome was first described 200 years ago but the definition of the syndrome was only developed during the last ten years (snoring, apneas during the night, somnolence, high blood pressure, changes of personality). The frequency of the syndrome is not known exactly but the pathophysiology, the morbidity and the mortality associated with the syndrome is facilitating by application of a positive airway pressure (CPAP) at the nose. Good compliance and rapid improvement of the symptomatology with practically no complications make that CPAP is the first choice for the physician in 1991.

Phase I/II trial of recombinant gamma-interferon in patients with renal cell carcinoma: immunologic and biologic effects.

Thirteen patients with metastatic renal cell carcinoma were entered on a Phase I/II trial of recombinant gamma-interferon (gamma-IFN). Patients (3) were entered on escalating dose levels, and each patient was escalated to the next dose until an individual maximum tolerated treatment dose (MTD) was established. Multiple parameters of biologic response were measured. Patients were studied twice baseline and at frequent intervals after the initial treatment and every treatment until the patient's individual MTD was reached. The MTD for most patients was less than 75 X 10(6) U/m2. Small, but statistically significant, enhancement of monocyte antibody-dependent cellular cytotoxicity and mononuclear cell inhibition of MBL-2 growth were noted in vitro at gamma-IFN concentrations greater than 250 U/ml. Clinically obvious biologic effects were observed: fever, chills, hypotension, and malaise. However, laboratory assays of peripheral blood mononuclear cell natural killer cell activity, tumor (MBL-2) growth inhibition, antibody-dependent cellular cytotoxicity, lymphoblastic T-cell subsets, and 2'5'-oligonucleotide synthetase were not altered in vivo.

Phase I/II trial of interferon-beta-serine in patients with renal cell carcinoma: immunological and biological effects.

Interferon-beta-serine (IFN-beta ser) is a recombinant genetically altered interferon with extensive in vitro antiproliferative, antiviral, and immunological effects. We undertook a Phase I/II trial of this agent in patients with untreated metastatic renal cell carcinoma with good performance status. IFN-beta ser was given twice weekly (Monday/Thursday) by a 4-h i.v. infusion. Three patients were entered at increasing drug levels until the maximum tolerated dose was determined. Moreover, if individual patients tolerated the initial IFN treatment, the dose was escalated one level at the next treatment. Preliminary studies with normal donor cells demonstrated that IFN-beta ser in vitro enhanced activity in a mononuclear-MBL-2 growth inhibition, NK-cell, and monocyte antibody-dependent cellular cytotoxicity assay. Therefore, prior to therapy these in vitro tests were performed utilizing each patient's mononuclear cells in an attempt to predict tumor response with in vitro immunological response to IFN. In general, there was no difference in IFN responsiveness in vitro between patients who developed tumor response (3) and those who did not (12). After initiation of treatment blood was taken from patients at frequent intervals for assessment of biological response. The following parameters were not altered at any dose or time interval: T-cell number, T-H/S ratio, % Leu 11a-positive cells, percentage or intensity of staining with anti-HLA-DR, and concanavalin A driven T-cell proliferation. Monocyte antibody-dependent cellular cytotoxicity was significantly depressed 4 h after doses of 30-150 million units/m2 but returned to base line at 24 h. Activity in three assays was significantly increased in patients receiving therapy: MBL-2/growth inhibition assay, NK-cell, and 2',5' oligonucleotide synthetase activity. In general changes in these assays were observed at low levels of IFN-beta ser, increased at 4-48 h, then returned toward base line. We conclude that IFN-beta ser is an active biological agent in vitro and significantly modulated the biological responses in patients with renal cell carcinoma.

Phase II trial of MVE-II in metastatic malignant melanoma.

MVE-II, a low molecular weight fraction of pyran copolymer was utilized in a Phase II trial in patients with metastatic malignant melanoma. A total of 15 patients were investigated and no clinical responses or immunologic responses were observed. We concluded that MVE-II is not an active agent in malignant melanoma.

Diagnosis and long-term follow-up of major bronchial disruptions due to nonpenetrating trauma.

From 1966 through 1978, 13 patients were treated for major bronchial disruptions due to nonpenetrating trauma. In 10 patients the diagnosis was made early, and operation was carried out in all of them. Four of the 6 patients with main bronchus avulsion had primary repair and all 4 patients with lobar rupture underwent lobectomy. One patient had a pneumonectomy. There was 1 operative death. In 3 patients the diagnosis was made more than a month after the injury. A bronchoplastic repair was done in every patient. All 7 patients who had repair of a transected main bronchus were assessed 2 to 14 years after operation (average, 7 1/2 years). Flow-volume curves on air and air-helium were normal, indicating no major airway obstruction; this finding was confirmed by clinical and bronchoscopic examinations. Pulmonary diffusing capacity for carbon monoxide was also normal in all patients. Volume measurements by closed circuit method and by body plethysmography showed restriction in 1 patient but no major air trapping. Perfusion/ventilation scans showed homogeneous distribution of air and blood flow in the lung.