Cadmium Chloride Assisted Re-Crystallization of CdTe: The Effect of Varying the Annealing Time

Although the cadmium chloride treatment is an essential process for high efficiency thin film cadmium telluride photovoltaic devices, the precise mechanisms involved that improve the cadmium telluride layer are not well understood. In this investigation we apply advanced micro-structural characterization techniques to study the effect of varying the time of the cadmium chloride annealing treatment on the micro-structure of cadmium telluride solar cells deposited by close spaced sublimation (CSS) and relate this to cell performance. A range of techniques has been used to observe the morphological changes to the micro-structure as well as the chemical and crystallographic changes as a function of treatment parameters. Electrical tests that link the device performance with the micro-structural properties of the cells have also been undertaken. Techniques used include Transmission Electron Microscopy (TEM) for sub-grain analysis and XPS for composition-depth profiling. The study provides a new insight in to the mechanisms involved in the initiation and the subsequent complete re-crystallization of the cadmium telluride layer.

Picosecond time resolved opto-acoustic imaging with 48 MHz frequency resolution

A compact femtosecond dual-oscillator pump-probe setup with 48 MHz-repetition rate, relying on asynchronous optical sampling, is presented. The relative timing jitter between both lasers over the whole pump-probe delay range is of the order of or lower than 500 fs. We demonstrate that both a picosecond temporal resolution and a 48 MHz spectral resolution combined with the fast acquisition rate inherent to the asynchronous optical sampling allow performing broadband opto-acoustic imaging with a spectrum covering more than two decades from 300 MHz to 150 GHz. As an illustration, the opto-acoustic response of a supported thin film is investigated, revealing high frequency acoustic echoes close to the epicenter as well as low GHz surface acoustic waves propagating up to 40μm away from the epicenter. Semi-analytical calculations have been carried out and perfectly reproduce the dispersion of the surface acoustic waves experimentally observed.

A ring calcified benign thymoma in a patient with asbestos exposure

The differential diagnosis of a mediastinal mass with ring calcification on chest X-ray includes thymoma,dermoid tumour, teratoma, neurogenic tumours and lymphadenopathy. Cross-sectional imaging via CT can aid diagnosis. This case may also demonstrate an association between asbestos exposure and thymoma calcification.

Modified prone position to dissect the popliteal fossa

Introduction

Traditionally, the prone position is used for dissecting the popliteal fossa, which requires endotracheal intubation. Access to the airway in this position is limited, hence the complications. It is not surprising that the prone position is not favoured by the anaesthetists, especially in patients with a high body mass index. We describe a safe and novel alternative to the prone position.

Methods

The modified prone position (MPP) is described as an alternative position that facilitates access to the airway.

Results

Between October 2007 and May 2010, 12 patients underwent popliteal fossa dissection using the MPP. All patients had general anaesthesia using a laryngeal mask airway with the exception of one, who had an epidural anaesthesia. There were no airway or haemodynamic complications. The surgical access to the popliteal fossa was as good as with the traditional prone position.

Conclusions

The MPP was satisfactory for both the surgeon and the anaesthetists. The authors now use this position routinely for dissecting the popliteal fossa.

Cell-cycle characteristics - alterable determinants of remission duration in a study of 179 standard risk newly diagnosed patients with acute myeloid-leukemia

Prognostic factors were related to remission duration among 179 standard risk newly diagnosed acute myeloid leukemia (AML) patients who received identical induction and consolidation therapies. Following a bromodeoxyuridine infusion, labeling indices of bone marrow aspirate/biopsy, durations of S-phase and cell cycle (Tc) were determined. Patients with slowly cycling myeloblasts had longer remissions (Log rank p=0.03) than those with rapidly cycling myeloblasts. Multivariate analysis demonstrated that both WBC and Tc contributed to remission duration (p=0.01 and 0.005 respectively). Patients with slowly proliferating leukemias have longer remissions probably due to slower regrowth of leukemia between chemotherapy courses.

Novel cellular markers in breast cancer

Epidemiological studies have revealed that Parsi women have a higher incidence of breast cancer than non-Parsis and that they are more susceptible to breast cancer. We have studied the cellular distribution of two prosomal proteins p23K in parallel to the p30.33K and proliferation marker Ki-67 as potential markers to identify high risk population for breast cancers. Flow cytometry data demonstrated that the Parsi benign and non-Parsi malignants have a higher number of cells labelled with these two prosomal protein antibodies than the non-Parsi benign and European 'normals'. Using immunohistochemical methods, p23 K was found to be significantly higher in Parsi and non-Parsi malignants as well as in non-Parsi benigns. In our FCM analysis, intergroup comparison showed, interestingly, a significantly higher expression of both p23K and p30.33K in Parsi benigns as compared to non-Parsis, raising the possibility that benign tumors of Parsis represent already premalignant lesions. The present study, in addition, proposes the prosomal antigens as likely cell proliferation markers comparable to Ki-67.