Analytical Review of the Papers Presented at the International Scientific and Technical Symposium “Improving the Energy and Recourse Efficiency and Environmental Safety of Processes and Apparatuses in Chemical Industry and Allied Branches” Dedicated to the 110th Anniversary of A.N. Planovskii

Theoretical Foundations of Chemical Engineering - The papers analyzed here were presented in the reposts of leading scientists in the processes and apparatuses of chemical technology and published...     

Electrical and gas-sensitive properties of nanostructured SnO<Subscript>2</Subscript>:ZrO<Subscript>2</Subscript> semiconductor films

The results of a study of the effect of atomic composition of metal-oxide semiconductor composites SnO₂:ZrO₂ on the surface morphology, polycrystal grain size, resistivity, concentration, free-carrier mobility, and gas-sensitive properties of thin films (0.5–2.5 μm) are presented. Films SnO₂ with ZrO₂ additives (the Zr content was varied from 0.5 to 4.6 at %) are grown by reactive ion-beam sputtering of metal targets of different compositions in a controlled Ar + O₂ atmosphere. Using transmission electron microscopy, atomic-force microscopy, and high-resolution transmission electron microscopy, it is experimentally shown that, as the Zr content increases in the SnO₂:ZrO₂ film composition, the polycrystal grain size decreases from 45 to 10 nm, the free-carrier concentration decreases almost by four orders of magnitude and the mobility increases by approximately nine times. As the Zr content increases in the SnO₂:ZrO₂ film from 0.5 to 4.6 at %, the temperature of maximum gas sensitivity of films to such gases as ethanol, isopropyl alcohol, and acetone decreases by 100–190°C.     

Vitamin C stability in vitamin-fortified syrups]

Factors influencing ascorbic acid stability in syrups were studied. It has been found that the vitamin stability depends on its concentration and the syrup composition. It is shown that vitamin C stability can be increased in some syrups by substitution of ascorbic acid for sodium ascorbinate.     

Pelvic exenteration in gynecologic oncology: Experience at the Mount Sinai Center, 1975-1992

Thirty-nine patients underwent pelvic exenteration for gynecologic malignancies at The Mount Sinai Medical Center between 1975 and 1992. Surgical techniques, morbidity, survival, and other variables for patients so treated in two periods, 1975-1984 and 1985-1992, were compared. The primary cancer included squamous cell carcinoma of the cervix, 27; adenocarcinoma of the cervix, 1; squamous cell carcinoma of the vagina, 4; adenocarcinoma of the endometrium, 4; squamous cell carcinoma of the vulva, 2; and adenocarcinoma of the rectum, 1. Median survival was 23.1 months, with a median follow-up of 18 months. Survival was significantly related to status of the lymph nodes (p 0.0004) and surgical margins (p 0.0038). There were two postoperative mortalities, one due to pulmonary embolus and another to myocardial infarction. The ability in the second period analyzed, 1985-1992, to integrate a continent urinary reservoir and supralevator exenteration without colostomy yet not induce increased morbidity or decreased survival, has not been previously reported.     

Phospholipid degradation in hypoxic/reoxygenated cardiomyocytes in response to phospholipase C from Bacillus cereus

In the present study, we investigated possible mechanisms behind exogenous phospholipase C-induced glycerol production in irreversibly damaged myocytes. Rat ventricular myocytes were preincubated for 60 min in substrate-free Krebs-Henseleit bicarbonate buffer equilibrated with 95% N2-5% CO2 (37 degrees C, pH = 7.4), resulting in exhaustion of cellular high energy phosphates and loss of rod-shaped morphology. At the end of the preincubation period, the incubation vials were divided into two groups; one receiving 10 mU/ml phospholipase C (PC-PLC), whereas the other received an equivalent volume of buffer (control incubations). Incubation was then continued for another 60 min under 95% air-5% CO2 atmosphere. Samples for measurement of metabolite levels were taken immediately after cell isolation, at the end of the preincubation period and at the end of the normoxic incubation period. During the 60 min incubation period following reoxygenation, glycerol output was markedly higher from PC-PLC treated than from control myocytes. However, the elevated glycerol output from these cells was not accompanied by a simultaneous rise in glycerol-3-phosphate, nor was it inhibited by inclusion of pyruvate in the incubation buffer. On the other hand, glycerol output from PC-PLC treated myocytes was effectively inhibited by a diacylglycerol lipase inhibitor (U-57908, The Upjohn Company). Analysis of cellular lipids revealed a 22% reduction of phospholipid in PC-PLC treated myocytes (P < 0.02), while the content of triacylglycerol, diacylglycerol and unesterified fatty acids increased by 76, 261 and 103%, respectively (P < 0.02). No significant changes were observed for these parameters in control myocytes.(ABSTRACT TRUNCATED AT 250 WORDS)     

Mortality mapping in Hong Kong, 1979-83 and 1984-88: the patterns of major non-malignant diseases

In this study, human platelets were used as a cellular model for exploring cytosolic free Ca (Cai) regulation in non-insulin-dependent diabetes mellitus (NIDDM). Cai levels were monitored in resting and thrombin-stimulated platelets from obese females with NIDDM; obese, nondiabetic women, and nonobese, nondiabetic women. All subjects were black. Significant and marked elevation of basal Cai levels was observed in platelets from the diabetic subjects when no aspirin was used during platelet isolation. However, no significant differences were observed in Cai between aspirin-treated platelets from women with NIDDM and platelets from nondiabetic women. The rate of the Cai return to basal level after thrombin stimulation was significantly lower in platelets from the diabetic subjects, suggesting an abnormality in platelet Ca extrusion or sequestration in NIDDM. Platelet Cai levels positively correlated with low-density lipoprotein cholesterol/high-density lipoprotein cholesterol ratio (LDL/HDL) and fasting blood glucose. These findings suggest abnormalities in platelet Cai homeostasis in NIDDM that are influenced by the serum lipid profile and perhaps glucose.     

The preemptive effect of regional anesthesia on post-cesarean section pain

Chronologic age is an utmost important birth record in many industrialized Western countries. When the date of birth is unknown, there is a demand for establishing the chronologic age. Dental methods for age estimations are considered more reliable than most other methods by the majority of researchers and are among the most commonly used means to determine age. Traditionally, these methods have most often been based on subjectively estimated, radiographic stages of tooth development. In the present study metric measurements of the length of the forming root have been used and are compared with one standard method. The formed part of the root of the lower third molar as seen in a panoramic radiograph was digitized. Data were directly stored in a computer for subsequent statistical analysis. The technique of collecting data with the aid of a computer had some statistical advantages. The precision of age estimations was, however, slightly inferior to the standard method.