Analysis of the linear oscillation dynamics of Fluidyne engines.

A Fluidyne engine is a liquid piston Stirling engine that uses thermally induced self-sustained oscillations of water and air that are filled in a looped tube and tuning column. It presents high potential for use as a low-temperature-difference Stirling engine with a simple structure. This study analyzes the linear oscillation dynamics of the Fluidyne from a thermoacoustic point of view, with particular emphasis on the local specific acoustic impedance of the working gas, which is given by the ratio of the complex amplitudes of the pressure and velocity oscillations in the regenerator of the Fluidyne. The frequency dependence of the specific acoustic impedance indicates that the gas in the regenerator region undergoes a thermodynamic cycle equivalent to the Stirling cycle when the oscillation frequency is equal to the natural oscillation frequency of the U-shaped liquid column in the Fluidyne. The analysis of the natural oscillation modes determined two key parameters for the desired specific acoustic impedance: the tuning column length and the connecting position to the loop. Experimental verification was achieved via measurements of the onset temperature ratio and acoustic field of a prototype Fluidyne engine.

Metastasis of breast carcinoma to mandibular gingiva.

Metastatic tumours to the oral region are rare but more often involve the jaws rather than the oral soft tissues. In this report, an infiltrative ductal carcinoma of the breast that metastasised to the mandibular gingiva is presented. The patient consulted her dentist for what she thought was a dental abscess in the bicuspid region of the lower left jaw. However, her dentist referred her for a specialist opinion of the lesion. The patient's medical history revealed that she had undergone a breast 'lumpectomy' 1 year previously. A provisional diagnosis of primary or metastatic malignancy was made, and a biopsy was performed. Microscopically, the lesion showed features of a poorly differentiated infiltrative ductal carcinoma. Subsequent microscopic review of the primary lesion also showed a poorly differentiated infiltrating ductal carcinoma of the breast identical to the features observed in the metastatic lesion.

HIV infection in patients of liver cirrhosis.

A total of 130 patients of liver cirrhosis (97 males, 33 females; aged 9-70 yr) of various etiologies were subjected to anti HIV antibodies testing by ELISA and supplementary Western Blot (WB) tests. Eleven patients were positive by ELISA. Of these 11 patients, 5 were WB positive, 4 were WB negative and 2 were indeterminate. Of the 5 WB positive patients none had received blood transfusions and one was a homosexual. These results indicate that HIV infection was present in 3.8 per cent patients of liver cirrhosis. Further studies are required on a large number of patients to recommend HIV testing routinely in cirrhotic patients.

PIP: Health workers took blood examples from 130 9-70 year old patients with liver cirrhosis admitted to the Department of Gastroenterology at BYL Nair Hospital in Bombay, India, between January 1990 and February 1992. Since patients with liver cirrhosis tend to undergo many blood transfusions in emergency situations, because of vomiting blood, researchers wanted to determine whether an association exists between HIV infection and liver cirrhosis. Laboratory personnel tested the samples for anti-HIV antibodies using first the ELISA and then confirming positive samples with the Western Blot (WB) test. The ELISA revealed 11 positive samples (5 were WB positive; 4 were WB negative, and 2 had indeterminate results) and the WB confirmed 5 HIV positive cases (all being 20 to 50 year old males). Thus, the HIV seroprevalence was 3.8% among the liver cirrhosis cases. 1 HIV-positive patient had earlier engaged in homosexual intercourse, 2 others had had multiple sexual partners. 4 HIV=positive patients had chronic alcoholism. 1 HIV-positive patient suffered from extensive intra abdominal tuberculosis and died during his hospital stay. None of the HIV-positive patients had earlier undergone a blood transfusion. The researchers called for more studies to confirm a relationship between HIV infection and liver cirrhosis with or without alcoholism.

Malignant transformation rate in oral submucous fibrosis over a 17-year period.

Sixty-six patients with oral submucous fibrosis were followed-up for a period of 17 yr (median observation 10 yr) in Ernakulam District, Kerala, India. Oral cancer developed in five (7.6%) patients. The malignant transformation rate in the same sample was 4.5% over a 15-yr observation period (median 8 yr). These findings impart a high degree of malignant potential to this condition.

Regional variations in oral submucous fibrosis in India.

Regional variations in the characteristics of submucous fibrosis were studied in two districts in India. In Pune district this condition involved soft palate, uvula and retromolar areas significantly more often than in Ernakulam district. The tongue, floor of the mouth and the hard palate were not involved in Pune. The age of the patients in Pune district was lower than in Ernakulam district. Associated oral cancer, leukoplakia and petechiae were observed solely among patients in Ernakulam. The most important etiologic factor for submucous fibrosis is the chewing of areca nut, and in both areas studied all patients chewed areca nut. In Pune, cured areca nut without other ingredients was chewed by 66% and in Ernakulam, raw areca nut was chewed as an ingredient of pan with tobacco by 100%. Thus in Ernakulam, the juice and the quid were mostly spat out, whereas in Pune they were swallowed. The regional variations in the characteristics of submucous fibrosis could be related to the differences in the areca nut chewing habit between the two areas.

Effects of storage, time, temperature, and composition of containers on biologic components of human milk.

Effects of steel and glass storage containers, duration of storage up to seven hours, and storage temperature on the concentration of humoral and cellular factors in 357 samples of human breastmilk were examined. Leukocytic functions were estimated by E-rosetting of sheep RBCs by T-lymphocytes and phagocytosis of S. cerevisieae by phagocytes. Immunoglobulin (Ig) levels were studied by single radial immunodiffusion technique (SRID). Viability and cell counts reduced during the storage period, but were greater than 60 percent of baseline values. IgG, IgA, and IgM levels in milk did not show significant decline after storage (p > 0.01). Milk stored in glass yielded a greater number of functional cells after storage at 4 degrees C.

An epidemiological study of tori among 667 dental outpatients in Trinidad & Tobago, West Indies.

AIM: To study the prevalence of tori amongst dental outpatients, the ethnic and sex variations in their distribution, and their clinical features. SETTING: The School of Dentistry, St. Augustine, Trinidad & Tobago. PARTICIPANTS: 667 consecutive dental outpatients representing three different ethnic groups of the country. METHODS: Clinical examination for and recording of tori indicating their location, extent and clinical features and the age, sex and ethnic grouping of the patient. RESULTS: The overall prevalence of tori was 12.3 per cent. CONCLUSIONS: There were no significant differences in the prevalence among the African, Indian or mixed ethnic groups of patients examined. There seemed to be strong link between the coexistence of palatal and mandibular tori.

Prevalence of delta virus infection in high risk population and hepatitis B virus related liver diseases.

Two hundred and fifty four high risk persons or patients with hepatitis B virus related liver disease (209 men, 45 women; age range 1-78 years) were tested for anti-delta antibody and IgM anti-HBc to determine the prevalence of delta agent coinfection and superinfection. The prevalence of delta infection was as follows: acute viral hepatitis 23/148 (16%) and chronic liver disease 17/92 (19%), and asymptomatic HBsAg carriers 1/6 (17%). In the high risk population, the delta antibody prevalence was as follows: multiple transfusion recipients 3/8 (38%), patients with chronic renal failure 1/5 (20%) and medical professionals 2/7 (29%). Of 44 patients (34 men, 10 women; age 3-63 years) with delta infection, 26 (59%) had coinfection and 18 (41%) had superinfection. Six patients with anti-delta antibody had received blood transfusion(s) and six others gave history of parenteral exposure.

Frequency of hepatitis B, C and D and human immunodeficiency virus infections in multi-transfused thalassemics.

Of forty multi-transfused thalassemia patients (26 males, 14 females; mean age 8.1 +/- 5.3 years, range 1-35) with no clinical or biochemical evidence of liver disease, HBsAg, anti-hepatitis C virus and anti-human immunodeficiency virus antibodies were present in 18 (45%), 7 (17.5%) and 1 (2.5%) cases respectively. Three of the 18 (16.7%) HBsAg positive patients were anti-delta antibody positive. Our results indicate that more than 50% of multi-transfused thalassemia patients show serological evidence of one or more of hepatitis B, C and D and human immunodeficiency virus infection.

PIP: Transfusion of whole blood or blood components is the mainstay of treatment in patients with beta-thalassemia and hemophilia. Owing to the scarcity of reports regarding the frequency of transfusion-transmitted hepatitis virus infections in thalassemia patients, the frequency of such infections was studied in India in 40 multi-transfused thalassemia patients (26 males, 14 females; mean age 8.1 +or- 5.3 years, range 1-35) with no clinical or biochemical evidence of liver disease. The enzyme-linked immunosorbent assay (ELISA) technique (Abbott) was used for all tests. The patients had received an average of 80 units (range 10-250) of blood. A majority of these units had been screened for hepatitis B surface antigen (HBsAg) using RPHA. HBsAg antibodies were present in 18 (45%), antihepatitis C virus (HCV) in 7 (17.5%), and antihuman immunodeficiency virus in 1 (2.5%) case, respectively. Of 18 HBsAg positive patients, antidelta and anti-HCV antibodies were present in 3 and 4 patients, respectively; 1 patient had both the antibodies. 4 of 40 (10%) patients had evidence of both hepatitis B virus (HBV) and HCV infection. In a US study, the frequencies of HBsAg and anti-HBs positively among thalassemics were 4.5% and 43.5%, respectively. In contrast, 90% of hemophiliacs show serological evidence of HBV infection. Routine screening of blood donors by CEP or RPHA technique was started in the hospital blood bank 7 years ago. The sensitivity of these techniques is much lower than that of RIA and ELISA and a majority of the patients has received initial blood transfusions before HBsAg screening was started. The study indicated that more than 50% of multi-transfused thalassemia patients showed serological evidence of one or more HBV, HCV, HDV, and HIV infection. Thus, screening of blood units for HBV, HCV, and HIV infections to be used for thalassemic patients and vaccination of thalassemic patients against hepatitis B is imperative.

Hepatitis C virus infection in chronic liver disease in Bombay.

To find out the prevalence of antibody of hepatitis C virus (anti-HCV) in patients with chronic liver disease in Bombay, sera from 126 patients (93 men, 33 women; aged 9-70 years, mean 39.7) with chronic liver disease (cirrhosis 103, cirrhosis with hepatocellular carcinoma 3, chronic active hepatitis 20) were tested for HBsAg and anti-HCV antibody. HBsAg positive sera were tested for anti-delta antibody and IgM anti-HBc. All the tests were carried out by ELISA. Of 126 patients, 51 (40.5%) were HBsAg positive, 49 (38.8%) alcoholic and 21 (16.6%) anti-HCV positive. The prevalence of anti-HCV in HBsAg positive, alcoholic and cryptogenic (HBV negative and no alcohol) liver disease patients was 13.7%, 14.7% and 20.5% respectively. Of 21 anti-HCV antibody positive patients, 8 (38%) had received blood transfusions previously. HCV is present in 15-20% of patients with chronic liver disease in Bombay.

Serological characterisation of Neisseria gonorrhoeae by co-agglutination technique.

Antibiotic susceptibility pattern in cases of acute gonococcal urethritis, was studied by single disc diffusion technique and minimum inhibitory concentration (MIC) by agar dilution technique were determined for 5 antibiotics, viz penicillin, ampicillin, tetracycline, gentamicin and norfloxacin. All the penicillinase producing Neisseria gonorrhoeae (PPNG) and non-PPNG strains were sensitive to norfloxacin. 72% of the isolates belonged to serogroup WII/WIII by co-agglutination technique.

Mono and dual therapy for Helicobacter pylori associated gastritis.

Sixty patients with Helicobacter Pylori positive non ulcer dyspepsia were randomly allocated to one of the following treatment groups: Group I--norfloxacin 400 mg bid for 10 days, Group II--amoxycillin 500 mg bid plus tinidazole 500 mg bid for 15 days, Group III--colloidal bismuth subcitrate (CBS) 240 mg bid for 4 weeks. H pylori elimination was achieved in 14%, 81%, and 62% in Groups I, II and III respectively. Eradication of H pylori was not observed in Groups I and II, but was achieved in 25% of patients in Group III. Antral gastritis improved in 69% in Group II and 50% in Group III. We conclude that norfloxacin is not effective in H pylori infection. A combination of amoxycillin and tinidazole is highly effective in H pylori elimination with improvement in associated gastritis, but H pylori eradication is not observed with this therapy. CBS is also effective in H pylori elimination though H pylori eradication is achieved in only 25%.

Accidental implantation of a bur tip in the elbow of a dentist. A possible pathway for inoculation with deadly infectious agent.

The most common source of occupational injury to dentists is percutaneous puncture of the hands from "sharps". We report a percutaneous injury involving a dentist where the tip of a dental bur became implanted in his elbow. The dentist had been vaccinated against Hepatitis B and both the patient and dentist were Hiv and Hepatitis B seronegative immediately after the incident. Surgical exploration of the dentist's elbow the following day was unsuccessful in locating the bur tip. The dentist remains healthy and is not incapacitated as a result of the injury, despite retention of the bur tip. This accident has implications for modifying the design of present and future dental units. We are not aware of a previous report of this type of injury.

Salmonella phage types in Bombay from 1983 to 1987.

A total of 156 strains of Salmonella isolated at T.N. Medical College and B.Y.L. Nair Ch. Hospital, Bombay over a period of 5 years from 1983 to 1987 were subjected to Phage Typing. Out of the 111 Salmonella typhi strains, phage type A was found in highest proportion (45.95%), followed by phage type E1 (15.32%), 0(9.91%), Deg. Vi. (9.91%) and C5(5.41%). Salmonella paratyphi A had phage type pattern of 1(60.0%), 2(22.86%) and Untypable (14.29%). Majority of the Salmonella typhimurium isolates (90.0%) were untypable.

Case reports of chromomycosis.

Two cases of chromomycosis were diagnosed in B.Y.L. Nair Charitable Hospital during the years 1980-1989. Isolates were identified as Fonsecea compactum.

A bacteriological study of purulent meningitis in children.

There was an increase in incidence of meningitis in children within the last three years at the Bai Yamunabai Laxman Rao Nair Charitable Hospital in Bombay. Out of 270 purulent samples, 60 (22.22 percent) were culture positive. Neisseria meningitidis showed an increase from one case in 1985 to 11 cases by the end of 1987. Staphylococcus aureus was isolated from 6 percent cases, Streptococcus pneumoniae 15 percent, and Gram negative bacilli were predominant, isolation rate being 57 percent. Salmonella species were isolated from 6 (10 percent) cases. They were multidrug resistant type, some belonging to the rare zoonotic species.

Rising incidence of oral cancer in Ahmedabad city.

CONTEXT: In 1999, an increase in mouth cancer incidence among young men (< 50 years) in urban Ahmedabad was reported to be occurring along with decreasing mouth cancer incidence in older age groups and increasing oral submucous fibrosis incidence associated with areca nut consumption among young men in Gujarat. The aim was to investigate whether the increase in the incidence mouth cancer that had started among young men in the 1990 s was continuing. SETTINGS AND DESIGN: Ahmedabad urban population, comparison of reported mouth cancer cases in the population across four time period. METHODS: Age-specific incidence rates of mouth cancer (International Classification of Diseases [ICD]-9:143-5; ICD-10:C03-06) in five year age groups among men aged ≥ 15 years for the city of Ahmedabad for years 1985, 1995, 2007 and 2010 were extracted from published reports. For comparison, lung cancer (ICD-9:169; ICD-10:C33-C34) rates were also abstracted. STATISTICAL ANALYSIS USED: A cohort approach was used for further analysis of mouth cancer incidence. Age adjusted incidence rates of mouth and lung cancer for men aged ≥ 15 years were calculated and compared. RESULTS: The age specific incidence rates of mouth cancer among men increased over the 25-year period while lung cancer rates showed a net decrease. Using a cohort approach for mouth cancer, a rapid increase in younger age cohorts was found. CONCLUSIONS: Mouth cancer incidence increased markedly among men in urban Ahmedabad between 1985 and 2010, apparently due to increasing consumption of areca nut products, mawa and gutka. Gutka has now been banned all over India, but a more vigorous implementation is necessary.