Propagation of amorphous oxide nanowires via the VLS mechanism: growth kinetics.

This work reports the growth kinetics of amorphous nanowires (NWs) developed by the vapour-liquid-solid (VLS) mechanism. The model presented here incorporates all atomistic processes contributing to the growth of amorphous oxide NWs having diameters in the 5-100 nm range. The steady state growth condition has been described by balancing the key atomistic process steps. It is found that the 2D nano-catalyst liquid and NW solid (L-S) interface plays a central role in the kinetic analysis. The balance between the 2D Si layer crystallization and oxidation rate is quantitatively examined and compared with experimental values. The atomistic process dependencies of the NW growth rate, supersaturation (C/C 0), desolvation energy (Q D) barrier and NW diameter have been analyzed in detail. The model successfully predicts the reported NW growth rate to be in the range of 1-10 µm s-1. A novel seed/catalyst metal-based synthesis strategy for the preparation of amorphous silica NWs is reported. A nickel thin film on Si is used as a seed metal for the Au assisted VLS growth of silica NWs. The experimental results provide evidence of the creation of SiO under the given conditions followed by Si injection in the Au-Si nano-catalyst solution. The usage of seed metal was observed to reduce the growth temperature compared to the methods reported in the literature and obtain similar growth rates. The technique presented here holds promise for the synthesis of sub-100 nm diameter NWs.

Comparative evaluation of serum fluoride levels in patients with and without chronic abdominal pain.

BACKGROUND: Fluorosis ranks high among the major environmental health problems in India. Non-ulcer dyspeptic complaints are common in humans and it is a known fact that fluoride in drinking water, food and other items can cause these symptoms. METHODS: Fifty adult outpatients (mean age: 35.2±12.7 y) with chronic abdominal pain of unexplained origin were tested for their serum, urinary, and drinking water fluoride (F) concentrations. These concentrations were compared with those of 50 asymptomatic outpatients (mean age: 37.4±11.5 y) and analysed statistically. RESULTS: Serum F concentrations were higher than normal in 62% of the study group I and in 42% of the control group II with a mean of 0.065±0.03 ppm (range: 0.010-0.421) in the former and 0.023±0.028 ppm in the latter. Statistical analysis of the data by Student's t-test (unpaired) revealed a significant correlation (p<0.05) between chronic abdominal pain and elevated serum F. Urinary fluoride concentrations in group I were 0.87±1.67 (0.01-3.7) ppm. Seventy-three percent of the patients examined for urinary fluoride concentrations were having higher values than normal, whereas 27% patients had normal range urinary fluoride concentrations despite raised serum fluoride concentrations. CONCLUSIONS: In the cases of chronic pain abdomen, chronic fluoride ingestion from drinking water and other sources can be the cause and should be evaluated in patients in which other parameters are normal.

How important is history of unconsciousness in head injury patients?

A total of 100 patients of head injury were studied. They all underwent thorough clinical and neurological examination, skull radiography and CT scan of head. And with the help of all these parameters an evaluation was done to find out the importance of history of unconsciousness on risk of intracranial complications. A lot of controversies exist about detection of factors that make a patient of head injury a high risk candidate for developing intracranial complications. Young active population was the most commonly affected group in head injury with male preponderance at all ages. Roadside accident found to be the main cause of head trauma in adults while fall from height in paediatric age group. Although Glassgow Coma Index (GCI) was found to be a good predictor for intracranial complications as well as final outcome in patients with total score of 12 or less but it was not equally good in patients of minor head injury (GCI = 13-15). Similarly history of unconsciousness was not found to be correlating well with risk of intracranial complications but longer duration of unconsciousness was found to be a poor prognostic index.

Malignant fibrous histiocytoma of peritoneum presenting as intestinal obstruction.

Malignant fibrous histiocytoma (MFH) is a high-grade soft-tissue sarcoma of fibroblast-cell origin with a propensity for metastasis and recurrence. Primary MFH of the peritoneum is rare. We report a 60-year-old man with MFH of the peritoneum presenting with obstructive symptoms. Complete surgical excision of the tumor was done, and he is well six months later.

Coronary angioplasty versus repeat coronary artery bypass grafting for patients with previous bypass surgery.

OBJECTIVES: We attempted to determine the relative risks and benefits of percutaneous transluminal coronary angioplasty (PTCA) and repeat coronary artery bypass grafting (re-CABG) in patients with previous coronary bypass surgery (CABG). BACKGROUND: Due to an expanding population of patients with surgically treated coronary artery disease and the natural progression of atherosclerosis, an increasing number of patients with previous CABG require repeat revascularization procedures. Although there are randomized comparative data for CABG versus medical therapy and, more recently, versus PTCA, these studies have excluded patients with previous CABG. METHODS: We retrospectively analyzed data from 632 patients with previous CABG who required either elective re-CABG (n = 164) or PTCA (n = 468) at a single center during 1987 through 1988. The PTCA and re-CABG groups were similar with respect to gender (83% vs. 85% male), age > 70 years (21% vs. 23%), mean left ventricular ejection fraction (46% vs. 48%), presence of class III or IV angina (70% vs. 63%) and three-vessel coronary artery disease (77% vs. 74%). RESULTS: Complete revascularization was achieved in 38% of patients with PTCA and 92% of those with re-CABG (p < 0.0001). The in-hospital complication rates were significantly lower in the PTCA group: death (0.3% vs. 7.3%, p < 0.0001) and Q wave myocardial infarction (MI) (0.9% vs. 6.1%, p < 0.0001). Actuarial survival was equivalent at 1 year (PTCA 95% vs. re-CABG 91%) and 6 years (PTCA 74% vs. re-CABG 73%) of follow-up (p = 0.32). Both procedures resulted in equivalent event-free survival (freedom from dealth or Q wave MI) and relief of angina; however, the need for repeat percutaneous or surgical revascularization, or both, by 6 years was significantly higher in the PTCA group (PTCA 64% vs. re-CABG 8%, p < 0.0001). Multivariate analysis identified age > 70 years, left ventricular ejection fraction < 40%, unstable angina, number of diseased vessels and diabetes mellitus as independent correlates of mortality for the entire group. CONCLUSIONS: In this nonrandomized series of patients with previous CABG requiring revascularization, an initial stategy of either PTCA or re-CABG resulted in equivalent overall survival, event-free survival and relief of angina. PTCA offers lower procedural morbidity and mortality risks, although it is associated with less complete revascularization and a greater need for subsequent revascularization procedures.

Sigmoido-rectal intussusception.

Sigmoido-rectal intussusception is the least common type of intussusception seen in infants and children and is therefore usually misdiagnosed as rectal prolapse. Delay in diagnosis and treatment is due to lack of its awareness amongst surgeons, incomplete assessment of the prolapsed bowel at the anal orifice, and absence of classical traid of intussusception i.e. palpable abdominal mass, colicky abdominal pain, and bleeding per rectum.

Ultrasonography versus roentgenography in suspected cases of cholecystolithiasis.

The present study was carried out to evaluate the relative merits of ultrasonography and roentgenography in 50 cases of suspected cholecystolithiasis. The accuracy rate with roentgenography (plain X-ray abd, OCG and IVC) in the diagnosis of cholecystolithiasis was 92.5% where as it was 95% with ultrasonography. Oral cholecystography should be done in patients with normal ultrasound examination if the symptoms are strongly suggestive of cholecystolithiasis.

Enumeration of total coliforms, fecal coliforms, and Escherichia coli in foods by hydrophobic grid membrane filter: collaborative study.

A collaborative study was conducted in 18 laboratories to assess the performance of the hydrophobic grid membrane filter method against that of the AOAC official first action method 46.013-46.016 for enumerating total and fecal coliforms and Escherichia coli. The study was carried out on frozen breaded fish, raw comminuted poultry, unroasted walnut pieces, ground black pepper, and cheddar cheese. The hydrophobic grid membrane filter method recovered significantly larger numbers of target bacteria in 7 of the food/analysis combinations: fecal coliforms in fish; E. coli in poultry; fecal coliforms and E. coli in walnuts; and total coliforms, fecal coliforms and E. coli in black pepper. Random error (Sr2) associated with the hydrophobic grid membrane filter method was significantly lower than that of the reference method in over 30% of the paired sample series. The hydrophobic grid membrane filter method for total coliform, fecal coliform, and E. coli enumeration in foods has been adopted official first action.

Cervicoauricular fistula.

(I) A rare case of cervicoauricular fistula with a review of available literature has been presented. (2) The cephalic end of a fistulous tract showing elevations and depressions probably represents the duplication of tubercles taking part in the formation of external ear.