Perturbation of Copper Substitutional Defect Concentrations in CdS/CdTe Heterojunction Solar Cell Devices

The efficacy of implementing terrestrial-based photovoltaics is dictated by trade-offs in device performance, cost, and reliability. Presently, the highest efficiency polycrystalline CdS/CdTe superstrate solar cells utilize back contacts containing copper as an intentional dopant. Accelerated stress data correlates copper diffusion from this contact with performance degradation. Degradation at the device level exhibits two characteristic modes that are influenced by CdTe surface treatments prior to contacting. Rapid degradation associated with a rapidly decreasing open-circuit voltage can occur in cases where processing favors stoichiometric CdTe surfaces. Slower degradation associated with roll-over is typified by treatments favoring the presence of Te at the back contact. The chemical composition and extent of Te-rich contact interfaces is revealed by transmission electron microscopy. Deep-level transient spectroscopy of NP etched and non-etched devices show Te-rich conditions are necessary for the detection of deep-acceptor CuCd defect levels at (Ev +0.28 to 0.34 eV). Low keV cathodoluminescence measurements show that these defects can be found localized at the back surface of CdS/CdTe devices.

Dietetic guidelines on food and nutrition in the secondary prevention of cardiovascular disease ? evidence from systematic reviews of randomized controlled trials (second update, January 2006)

AIM

To update dietetic guidelines based on systematic review evidence on dietary advice to prevent further events in people with existing cardiovascular disease (CVD) (secondary prevention).

METHODS

The Cochrane Library, MEDLINE and EMBASE were comprehensively searched to January 2005 for systematic reviews on aspects of diet and heart health. Reviews were included if they searched systematically for randomized controlled trials relating to diet and secondary prevention of CVD. Each review was critically appraised by at least two members of the UK Heart Health and Thoracic Dietitians Group. The quality and results of each review were discussed and summarized at a group meeting.

RESULTS

Evidence-based strategies that reduce cardiovascular events in those with CVD include reduction in saturated fat and substitution with unsaturated fats. Individuals who have suffered a myocardial infarction may also benefit from adopting a Mediterranean type diet and increasing intake of omega 3 fats, but it is not clear whether they are beneficial for all patients with CVD. There is no systematic review evidence to support the use of antioxidant vitamins supplements, low glycaemic index diets, or homocysteine lowering therapies in this group.

CONCLUSION

There remains good evidence that reducing saturated fat reduces morbidity in patients with CVD. This advice is consistent for most manifestations of CVD, with the addition of Mediterranean dietary advice and increased omega 3 fats for those who have had a myocardial infarction.

Deposition pattern of radiolabeled salbutamol inhaled from a metered-dose inhaler by means of a spacer with mask in young children with airway obstruction

BACKGROUND

The exact amount of drug deposited in the respiratory and gastrointestinal tract in children with airway obstruction, when delivered from a metered-dose inhaler (MDI) via a spacer with mask, and its distribution in children with airway obstruction, are unknown.

METHODS

We studied 15 children, using salbutamol labeled with technetium 99m. Each patient was imaged with a gamma-camera immediately after one puff of labeled salbutamol was administered via a spacer with mask. Drug deposition was then analyzed to measure the distribution of the labeled spray in the oropharynx, the lungs, the stomach, and the spacer with mask (Aerochamber) itself.

RESULTS

Fifteen infants and children (mean age, 21 months (range, 3 months to 5 years); mean weight, 9.3 kg (range, 3.2 to 15 kg)) were studied. Mean aerosol deposition was 1.97% +/- 1.4% in the lungs, 1.28% +/- 0.77% in the oropharynx, and 1.11% +/- 2.4% in the stomach. The remainder was trapped in the spacer. Lung imaging after inhalation from an MDI via a spacer showed widespread deposition of the drug in central and peripheral intrapulmonary airways. In two adult volunteers the deposition after one puff of the same radiolabeled drug, inhaled from an MDI via a spacer with a mouthpiece, was 19% in the lungs and 2% in the stomach.

CONCLUSIONS

Infants and toddlers with obstructive lung disease can be reliably and safely treated with inhaled medication administered with an MDI via a spacer with mask. The doses of a drug given from an MDI to infants and toddlers when a spacer with mask is used are not yet well defined but should be higher than the currently recommended doses, perhaps as much as an adult dose.

Potential antisecretory antidiarrheals. 2. Alpha 2-adrenergic 2-[(aryloxy)alkyl]imidazolines

Lofexidine, an alpha 2-agonist, has central hypotensive activity and peripheral intestinal antisecretory activity. Analogues were synthesized with increased polarity in an attempt to prevent penetration of the blood-brain barrier. The compounds were evaluated in the cholera toxin treated ligated jejunum of the rat and in the Ussing chamber with a rabbit ileum preparation. Active compounds were determined to be alpha 2-adrenergic agonists by yohimbine reversals of their Ussing chamber activities. The 2,6-dimethyl derivative of lofexidine, 4a, was as active as lofexidine in vivo, but derivatives with 2,6-substituents larger than ethyl were inactive. (Aryloxy)alkyl derivatives which have an imidazoline and a methyl or larger group as part of the alkyl exhibited the best antisecretory activity. Compounds with substituents in the para position of the phenyl ring were generally inactive. 3-Amino-2,6-dimethyl derivative 21 was twice as active as 4a. A 2-methyl substituent is required in the 3-amino series to retain good activity. 2-Methyl derivative 12a had activity comparable to that of 4a, while 6-methyl derivative 12f was inactive. Substituents on the 3-amino group did not affect the activity, but substituting a hydroxyl for the amino group produced an inactive compound. Replacing the phenyl moiety with a 4-indole resulted in retention of activity, but other heterocycles were inactive. Compound 12a was resolved and d isomer 32 was five times more potent than l isomer 33. The more active compounds in the rat cholera toxin assay (RCTA), when evaluated in the dog, exhibited antisecretory activity but also exhibited central nervous system (CNS) effects, sedation and ataxia, at 10 mg/kg, and in spontaneously hypertensive rats at 50 mg/kg. A measure of polarity, log P, was calculated for the (aryloxy)alkyl groups. Regression analysis showed no correlation of antisecretory ED50 to the calculated log P. The active compounds did not show a separation of the central CNS effects from the peripheral antisecretory activity by increasing the polarity.

Potential antisecretory antidiarrheals. 1. Alpha 2-adrenergic aromatic aminoguanidine hydrazones

Guanabenz, a centrally acting antihypertensive agent, has been shown to have intestinal antisecretory properties. A series of aromatic aminoguanidine hydrazones was made in an effort to separate the antisecretory and cardiovascular activities. Benzaldehyde, naphthaldehyde, and tetralone derivatives were synthesized. The compounds were evaluated in the cholera toxin treated ligated jejunum of the rat and in the Ussing chamber using a rabbit ileum preparation. A number of compounds, including members of each structural class, were active upon subcutaneous administration in the rat. Active compounds were determined to be alpha 2-adrenergic agonists by yohimbine reversals of their Ussing chamber activities. The compound displaying the best separation of activities was the aminoguanidine hydrazone of 2,6-dimethyl-4-hydroxybenzaldehyde (20).

110 bullet wounds to the neck

Selective management of 110 patients with bullet wounds to the neck resulted in 31 explored and 79 observed. There was an overall mortality rate of 2.7%, well within that reported in the literature, which ranges from 2 to 6%. At our institution, it is believed that a substantial number of patients can be selectively managed, depending on the signs and symptoms, the site and direction of the trajectory, and whether the interval of time between injury and entrance to the hospital is longer than 6 hours. Patients who are stable and lack physical signs of obvious major neck injury are evaluated by diagnostic radiologic and endoscopic techniques. If no significant injury is found, they are admitted for observation. The efficacy of this mode of management is strengthened by savings in the costs of hospitalization, risks of undergoing an additional operation, overall negative exploration rate in the mandatory exploration studies, and our own results of selective management. We do not recommend this form of management for all institutions. It has been found that in this well-staffed teaching hospital with an extensive trauma service, experienced personnel doing careful and repeated physical examinations, in addition to 24-hour availability of radiologic and endoscopic modalities, the policy of selective management of bullet wounds to the neck can be adhered to. Further studies need to be done into the various mechanisms of penetrating neck trauma, separating each mechanism into morbidity, mortality, and treatment.

The safety of cement fixation in the cervical spine. Studies of a rabbit model

Immediate postoperative ambulation of patients with terminal neoplastic disease of the cervical spine can be permitted by vertebral stabilization with wire reinforced with polymethylmethacrylate. Precautions are necessary to avoid a temperature rise during cement polymerization and prevent vasular or nerve damage. Experiments on 20 rabbits and 2 human cadavers indicate that temperature at the cement-lamina interface can rise as high as 90 degrees while temperature under the intact lamina measures only 50 degrees. Precooling and insulation with Gelfoam may prevent heat injury to spinal cord.

Evidence of lack of passage of human prolactin through human placental membranes

Human prolactin (hPRL) derived from either amniotic fluid (AF) or pituitary was tested for its passage capability through amniotic and chorionic membranes placed in an in vitro perfusion chamber. The passage of both 'cold' and labelled prolactin were investigated using intact monomeric iodinated hPRL isolated from amniotic fluid which also served as a tracer in a homologous double antibody radioimmunoassay used for prolactin determinations. Throughout 4 h incubation period at 37 degrees C, there was no passage of 'cold' hPRL from either of the sources across either direction. Also, in contrast to free iodine ions, there was no passage of intact labelled prolactin in either direction. Decomposition of labelled prolactin occurred only in the chorionic side, and only decomposed labelled prolactin molecules passed into the amniotic side. These became detectable 1 h after commencement of incubation. These results may explain the long half-life and the high concentration of hPRL in amniotic fluid, and also suggest that the source of AF hPRL is not maternal.