Integrating sphere based reflectance measurements for small-area semiconductor samples.

This article describes a method that enables reflectance spectroscopy of small semiconductor samples using an integrating sphere, without the use of additional optical elements. We employed an inexpensive sample holder to measure the reflectance of different samples through 2-, 3-, and 4.5-mm-diameter apertures and applied a mathematical formulation to remove the bias from the measured spectra caused by illumination of the holder. Using the proposed method, the reflectance of samples fabricated using expensive or rare materials and/or low-throughput processes can be measured. It can also be incorporated to infer the internal quantum efficiency of small-area, research-level solar cells. Moreover, small samples that reflect light at large angles and develop scattering may also be measured reliably, by virtue of an integrating sphere insensitive to directionalities.

First Report of Cassava Common Mosaic Potexvirus Infecting Chaya (Cnidoscolus chayamansa) in Tuvalu.

Chaya (Cnidoscolus chayamansa McVaugh) was introduced into Tu-valu as a leaf vegetable in the early 1990s (1) with the primary objective of alleviating vitamin A and C deficiencies, which at that time were prevalent throughout the population. Although there are no definitive quarantine records, we believe that the crop originated from vegetative cuttings introduced into Funafuti atoll from Kiribati. In the years following its introduction, chaya was distributed as cuttings taken from the original, introduced germplasm, to other islands and atolls of Tuvalu. The occurrence of yellow patches on the mature leaves of chaya cultivated in Funafuti had previously been attributed to iron deficiency, which was the inevitable consequence of growing the crop on coral atoll soils that are well known to be poor sources of metallic ions, notably iron, zinc, and copper. Following heavy cyclonic rains in March 1997, young, emerging chaya leaves were noted to exhibit an angular mosaic of the leaf lamina, characteristic of virus infections. Negatively stained sap from mosaic-affected leaves, when examined in the transmission electron microscope, was found to contain many rod-shaped virus particles similar in morphology to those of the Potexviridae (approximately 510 × 15 nm). The virus was transmitted mechanically to Chenopodium amaranticolor, in which it induced local lesion symptoms. The virus was found to be more closely related serologically to cassava common mosaic potexvirus (CsCMV) from Brazil than to that from Colombia, by immunosorbent electron microscopy with antisera kindly provided by F. Morales. Recently, CsCMV particles have been found in mosaic-affected chaya derived from the original Funafuti mother plants on Vaitupu Island. Similar symptoms have been observed on chaya being cultivated in Nui and Nanumaga islands. We conclude that CsCMV must now have been distributed throughout the atolls and islands of Tuvalu by infected planting material. We believe this to be the first report of the occurrence of CsCMV outside Central America and the first record of a plant virus from Tuvalu. Reference: (1) C. Howells and M. Bainbridge. 1996. South Pacific Commission, Pacific Island Forests and Trees. Page 10.

First Report of Hibiscus Chlorotic Ringspot Carmovirus in Tuvalu.

In September 1997, plants of Hibiscus manihot (locally called nambele) were observed on Vaitupu Island, Tuvalu, exhibiting an angular leaf mosaic and chlorosis that was not always clearly discernible. Electron microscopy of negatively stained sap from affected leaves revealed the presence of numerous isometric virus particles 28 nm in diameter. Poly-acrylamide gel electrophoresis of purified virus gave a single protein band of Mr 38,000 similar to that of the carmoviruses. Immunosorbent electron microscopy tests with antisera kindly provided by N. Spence showed the virus to be hibiscus chlorotic ringspot carmovirus (HCRSV) (1). This virus is also reported from El Salvador, the U.S., Australia, Thailand, Malaysia, Fiji, the Solomon Islands, and Vanuatu. It is not known how the virus reached Tuvalu but we suspect it was via infected cuttings, which were imported for the production of food supplements to combat acute deficiencies of vitamins A and C in the population. The virus is most likely to have been disseminated throughout the islands and atolls of Tuvalu through infected cuttings. Local spread within fields could occur through contaminated hands and cutting implements because of the ease with which the virus is mechanically transmitted. Reference: (1) H. E.Waterworth et al. Phytopathology 66:570, 1976.

A double blind, placebo-controlled study to assess the effect of famciclovir on virus replication in patients with chronic hepatitis B virus infection.

This is the first double-blind controlled study of famciclovir, an oral antiviral agent, as potential therapy for chronic hepatitis B virus (HBV) carries. A fall of more than 90% in HBV DNA levels was noted in six of 11 evaluable patients treated with a 10 day course of oral famciclovir. Further studies with more prolonged therapy are ongoing.

Serum zinc, sodium, calcium, magnesium and potassium levels and standard diet in leprosy patients.

Serum zinc levels were estimated in different types of leprosy by means of the atomic absorption spectrophotometry method in 64 leprosy patients, comprising of tuberculoid tuberculoid (TT) (5), borderline tuberculoid (BT) (6), borderline borderline (BB) (10), borderline lepromatous (BL) (13), lepromatous lepromatous (LL) (14) and burnt-out leprosy (BO) (16). These findings were evaluated in comparison to 86 normal control subjects who were served the same standard diet. Serum zinc levels were significantly low in the total leprosy group. The findings of this study are of clinical importance as zinc deficiency can be one of the factors involved in suppression of cell-mediated immunity (CMI) in lepromatous leprosy. This again has a bearing on the management of wounds and wound healing. This study also reveals that altered levels of the serum elements (eg. calcium and sodium) have a direct association with the disease and not with food deprivation.

Human fight-bite injuries of the hand. A study of 100 cases within 18 months.

100 consecutive patients whose finger had been bitten by another person, or who had cut it on a tooth in a fight, have been studied. 82 healed completely but 18 eventually needed amputation. Early and thorough debridement is required, plus a suitable mixture of antibiotics. Once infection is established in bone or tendon sheath, amputation is often needed, but most infected joints can be saved.

Outbreak of Salmonella food poisoning amongst delegates at a medical conference.

An outbreak of Salmonella typhimurium DT9 food poisoning due to contaminated chicken pieces affected at least 196 delegates at a medical conference. Twelve per cent of the cases reported suffering parasthaesiae. Nine reported serious complications of infection which included rectal prolapse and perianal abscess. Antibiotic therapy did not measurably reduce the duration or severity of diarrhoea. Over 1,600 doctor-days were lost to the NHS. Most doctors sought expert infection control advice before returning to work but the advice given differed between hospitals.

Legionella pneumophila in coal miners.

Legionnaires' disease was diagnosed in three mineworkers at a colliery. Investigation of water samples from various sites at the colliery did not discover a source of the infection. Results of serological surveys undertaken on the workmates of the patients and other miners showed only one additional positive Legionella indirect fluorescent antibody test. There was, therefore, no justification for any alteration in the water supply or the ventilation at the colliery.

Relation between the mucosal flora and Paneth cell population of human jejunum and ileum.

The Paneth cell population in surgically resected human jejunum and ileum was estimated using image analysis of the granule area in patients who had not received antibiotics. The mucosa was cultured aerobically and anaerobically. In the jejunum 22 samples were sterile and five yielded bacteria; in the ileum four were sterile and three were non-sterile. The mean Paneth cell granule area in the sterile jejunum was 122.7 +/- 37.2 micron2 and in the non-sterile samples 67.2 +/- 36.6 micron2 (p less than 0.006). The corresponding values for the ileum were 137.9 +/- 109.8 and 100.5 +/- 9.1 (NS). Thus an increase in the Paneth cell population may occur in response to changes in the intestinal luminal environment. Failure of this response and resultant Paneth cell deficiency may lead to bacterial overgrowth.

Mucosal flora of the small intestine and the effect of preoperative antibiotics.

Samples of mucosa from the small intestines of 100 patients undergoing intestinal surgery were examined bacteriologically. Sixty four patients had received chemotherapy, 12 for more than 24 h before operation. Most of the jejunal samples were sterile unless there was a carcinoma, previous surgery, or potential intestinal stasis. Ileal mucosa was more likely to contain intestinal organisms. Most of the strains isolated were sensitive in vitro to the antibiotics given in vivo, but short term treatment may not have allowed sufficient time for the treatment to have become effective. The findings suggest that antibiotics are not needed for most operations on the duodenum or jejunum but may be required for operations on the ileum.

Urethral syndrome: a self limiting illness.

Thirty nine adult women who were not pregnant and had the urethral syndrome in a general practice underwent detailed microbiological investigations. Patients monitored their own symptoms, and those with persisting symptoms were entered into a randomised controlled trial of treatment with doxycycline and placebo. Chlamydia trachomatis and Neisseria gonorrhoeae were not isolated and fastidious organisms were not causally associated with the urethral syndrome. Treatment with doxycycline showed no benefit; each episode of the urethral syndrome was short and self limiting and there were no recurrences in a median observation period of 12 months.

A comparative trial of pivmecillinam/pivampicillin and amoxycillin/clavulanate in the therapy of urinary tract infection in a general practice population.

Fifty-eight patients seen in general practice presenting with symptoms of acute urinary tract infection were entered consecutively into an open randomized trial of 200 mg pivmecillinam plus 250 mg pivampicillin twice daily or 250 mg amoxycillin plus 125 mg clavulanate 3-times daily for 5 days. The results were analyzed in 41 patients with significant bacteriuria (23 on pivmecillinam/pivampicillin and 18 on amoxycillin/clavulanate). Both antibiotic combinations produced good overall bacteriological cure, but there were a considerable number of persisting symptoms despite the absence of significant bacteriuria. Eight patients in the pivmecillinam/pivampicillin group and 5 in the amoxycillin/clavulanate group had side-effects, principally thrush, vomiting and abdominal pain, and 1 patient from each group ceased treatment for this reason. Sensitivity profiles of urinary isolates (41 trial, 135 non-trial) to both combinations and to ampicillin and mecillinam showed that the majority were fully sensitive to amoxycillin/clavulanate and to a lesser extent to pivmecillinam/pivampicillin; resistance was highest to ampicillin.

A survey of nasal Streptococcus pneumoniae in children.

Nasal swabs were taken from 369 four-year-old children in two South Wales towns and cultured for Streptococcus pneumoniae. The organism was isolated in 34% of the specimens, similar rates being found in boys and girls in the two towns. The children were swabbed again a year later, when the prevalence of nasal pneumococci had fallen to 25%. There was no association between the presence of the organism on the two occasions. Types 6 and 23 were most often isolated. After excluding children who had received an antibiotic, the proportion carrying a pneumococcus was higher in those who had recently had a respiratory infection than in the rest, although the difference was not quite statistically significant. There was a significant negative association between the presence of Staphylococcus aureus and Strep. pneumoniae.

Nasal staphylococci in children--a follow-up study.

Nasal carriage of Staphylococcus aureus was studied in a cohort of infants born to the residents of two towns in South Wales. The children were followed up to the ge of 5 years, nasal swabs being taken annually after a more detailed survey during the first year. The carriage-rate of S. aureus reached a minimum of 10-15% at one year and then rose steadily to 41% at five years. From the age of two years about 90% of the organisms isolated were resistant to penicillin. There was a marked tendency for children to carry the same strains from year to year, but carriage during the first year of life did not predict carriage at the age of five.