Improved regression in ratio type estimators based on robust M-estimation.

In this article, a new robust ratio type estimator using the Uk's redescending M-estimator is proposed for the estimation of the finite population mean in the simple random sampling (SRS) when there are outliers in the dataset. The mean square error (MSE) equation of the proposed estimator is obtained using the first order of approximation and it has been compared with the traditional ratio-type estimators in the literature, robust regression estimators, and other existing redescending M-estimators. A real-life data and simulation study are used to justify the efficiency of the proposed estimators. It has been shown that the proposed estimator is more efficient than other estimators in the literature on both simulation and real data studies.

Rapid analysis of sugars in honey by processing Raman spectrum using chemometric methods and artificial neural networks.

The aim of this study was to quantify glucose, fructose, sucrose and maltose contents of honey samples using Raman spectroscopy as a rapid method. By performing a single measurement, quantifications of sugar contents have been said to be unaffordable according to the molecular similarities between sugar molecules in honey matrix. This bottleneck was overcome by coupling Raman spectroscopy with chemometric methods (principal component analysis (PCA) and partial least squares (PLS)) and an artificial neural network (ANN). Model solutions of four sugars were processed with PCA and significant separation was observed. This operation, done with the spectral features by using PLS and ANN methods, led to the discriminant analysis of sugar contents. Models/trained networks were created using a calibration data set and evaluated using a validation data set. The correlation coefficient values between actual and predicted values of glucose, fructose, sucrose and maltose were determined as 0.964, 0.965, 0.968 and 0.949 for PLS and 0.965, 0.965, 0.978 and 0.956 for ANN, respectively. The requirement of rapid analysis of sugar contents of commercial honeys has been met by the data processed within this article.

Serum levels of alpha-tocopherol, vitamin C, beta-carotene, and retinol in malignant pleural mesothelioma.

The aim of this study was to investigate the possible relationship between antioxidant vitamin levels and malignant pleural mesothelioma (MPM). For this purpose, we measured the serum levels of 4 antioxidant vitamins, ß-carotene, α-tocopherol, retinol, and ascorbic acid, in patients with environmentally induced MPM and in healthy controls from one tremolite village (Kureysler), the biggest erionite village (Tuzkoy) and Ankara. A total of 160 subjects were enrolled in the study, 42 (26.3%) diagnosed with MPM and 118 (73.7%) healthy subjects. A comparison was made between the MPM group and three control groups of which two were exposed and one was unexposed to mineral fibers. The study population consisted of 82 males (51%) and 78 females (49%) with a mean of age of 44.8±14 years (range; 20-65 years). Lowest levels of ß-carotene, ascorbic acid, and α-tocopherol were found in MPM patients (MPM vs control groups combined, p<0.0001 for each antioxidant vitamin), without any relation to age or sex. There was no significant difference between the antioxidant levels of healthy controls of Tuzkoy and Ankara. In conclusion; our findings suggested an increased risk of MPM being associated with low levels of α-tocopherol and ascorbic acid in patients with MPM.

Prognostic significance of Bax and Fas ligand in erionite and asbestos induced Turkish malignant pleural mesothelioma.

Environmentally exposed erionite is a potent and unique inducer of malignant pleural mesothelioma (MPM) in Central Anatolia in Turkey. Previous studies have shown that erionite induced MPM has different biological behavior than asbestos induced MPM. Although impaired apoptosis has been implicated in tumor biology, the relationship between the type of environmental exposure and apoptosis has not yet been evaluated in MPM. The purpose of this study was to determine the expression of apoptosis regulating proteins and their prognostic significance in erionite and asbestos induced MPM. Thirty-five patients with MPM (16 erionite and 19 asbestos induced), and 17 patients with adenocarcinoma were comparatively evaluated. Expression of Bcl-2, Bax, Fas and Fas Ligand, were assessed by immunohistochemistry. Bcl-2 and Fas did not stain in almost all specimens. The staining extension of Bax was 13.75 +/- 19.27%, 5.89 +/- 14.51% and 7.38 +/- 14.53% for erionite and asbestos induced MPM and adenocarcinoma, respectively (p = 0.566). The staining extension of Fas Ligand was 26.87 +/- 31.87%, 46.10 +/- 37.30% and 26.47 +/- 23.23% for erionite and asbestos induced MPM, and adenocarcinoma, respectively (p = 0.123). Bax negative patients in erionite group had longer survival than Bax positive patients (18 months versus 14 months) (p = 0.06). Fas Ligand positive patients showed statistically better survival than Fas Ligand negative patients in all MPM group (15 months versus 12 months) (p = 0.05). Although all proteins expressed in similar extension in all samples, Bax staining displayed an inverse relation with survival in erionite group. This may implicate a difference in Bax functioning in erionite induced MPM. However, Fas Ligand may be functionally intact to reduce tumor survival.

Management of recurrent malignant pleural effusion with chemical pleurodesis.

PURPOSE: Malignant pleural effusion is a common complication of primary and metastatic pleural malignancies. It is usually managed by drainage and pleurodesis, but there is no consensus as to the best method of pleurodesis. We compared the effectiveness, side effects, and cost of different chemical pleurodesis agents used in patients with malignant pleural effusion. METHODS: Between January 1990 and December 2001, 108 patients with malignant pleural effusion underwent chemical pleurodesis in our department. Thoracoscopy was performed in 64 patients (59%), a minithoracotomy in 18 (17%), tube thoracostomy in 11 (10%), and a small-bore catheter was inserted in 15 (14%). Talc was used in 68 (63%) patients, tetracycline in 26 (24%), and bleomycin in 14 (13%). Talc was instilled by insufflation during surgery after drainage, whereas tetracycline and bleomycin were instilled via tube or catheter for pleural analgesia. RESULTS: Talc resulted in significantly earlier tube and catheter removal, after an average 4.1 days versus 5.1 days after tetracyline, and 6.3 days after bleomycin (P = 0.026, P = 0.001, respectively). A significantly lower reaccumulation ratio in 90 days was achieved by the talc group, with nine (13.2%) patients, representing an 86.8% success rate, than in the tetracyline and bleomycin groups, with seven (26.7%) and five (35.7%) patients, respectively, representing 73.8% and 64.3% success rates (P = 0.04). CONCLUSIONS: Talc resulted in the earliest expansion, minimal drainage, and the earliest tube and catheter removal.