Studies on the encapsulation of F- in single walled nanotubes of different chiralities using density functional theory calculations and Car-Parrinello molecular dynamics simulations.

In this study, the encapsulation of F(-) in different nanotubes (NTs) has been investigated using electronic structure calculations and Car-Parrinello molecular dynamics simulations. The carbon atoms in the single walled carbon nanotube (CNT) are systematically doped with B and N atoms. The effect of the encapsulation of F(-) in the boron nitride nanotube (BNNT) has also been investigated. Electronic structure calculations show that the (7,0) chirality nanotube forms a more stable endohedral complex (with F(-)) than the other nanotubes. Evidence obtained from the band structure of CNT calculations reveals that the band gap of the CNT is marginally affected by the encapsulation. However, the same encapsulation significantly changes the band gap of the BNNT. The density of states (DOS) derived from the calculations shows significant changes near the Fermi level. The snapshots obtained from the CPMD simulation highlight the fluctuation of the anion inside the tube and there is more fluctuation in BNNT than in CNT.

Role of encapsulation of Na+ and F- ions on the Diels-Alder reactivity of C32.

The density functional theory (DFT)-based Becke's three parameter hybrid exchange functional and Lee-Yang-Parr correlation functional (B3LYP) calculations have been performed to understand the role of encapsulation of Na(+) and F(-) ions on the Diels-Alder reactivity of C(32). In this context, C(32) has been taken as the dienophile and cis-1,3-butadiene has been considered as diene. Results obtained from the calculations on the Na(+)@C(32) and F(-)@C(32) have also been compared with that of C(32). It is found from the results that encapsulated Na(+) ion acts as a catalyst, whereas the encapsulated F(-) does not accelerate the reaction between C(32) and cis-1,3-butadiene. Thus, the reactivity of F(-)@C(32) is less than that of free C(32) and Na(+)@C(32). Formation of adduct involving [5,5]-B bond is preferred over other bonds. The energy decomposition analysis has been applied to understand the role of confinement on an encaged ion. The part played by the charge transfer interaction is evident from the NBO analysis. The frontier orbital analysis points out that the reaction is driven by the normal electron demand.

Psychometric validation of a knowledge questionnaire on micronutrients among adolescents and its relationship to micronutrient status of 15-19-year-old adolescent boys, Hyderabad, India.

OBJECTIVE: To develop a psychometrically valid questionnaire for testing knowledge on micronutrients and to assess the relationship between knowledge and biomarkers of micronutrient status among adolescents. DESIGN: Cross-sectional, institution-based, validity and reliability study. SETTING: Seven higher secondary schools were covered in the limits of Greater Hyderabad Municipal Corporation, Hyderabad, India. SUBJECTS: Students aged 15-19 years, n 92 for the pre-test, n 108 for test-retest and n 109 for studying the relationship between knowledge and biomarkers of Fe, retinol, ascorbic acid, α-tocopherol, folic acid and vitamin B12 status. RESULTS: From an item pool of 106, thirty-one items were selected based on content validity. Statistical tools to obtain a valid and reliable questionnaire among adolescent boys and girls resulted in eighteen items with a difficulty index of 0·11-0·86, discrimination index of 0·20-0·72 and validity index (point bi-serial correlation) of 0·10-0·62. Reliability as measured by Cronbach's α was 0·71 and the intra-class correlation coefficient was 0·80. A Bland-Altman plot showed good agreement between test and retest scores. The mean response score to the eighteen-item questionnaire was 5·2 (sd 2·68). The mean values of serum retinol were significantly different (P = 0·022) between groups below (24·8 (sd 6·64) µg/dl) and above (28·0 (sd 7·67) µg/dl) the 50th percentile of knowledge score. The relationship persisted after controlling for economic status as a covariate using analysis of covariance (P = 0·018). Other micronutrients did not show any significant relationship. CONCLUSIONS: A valid and reliable eighteen-item knowledge questionnaire was constructed and found to have a significant positive relationship with plasma retinol status alone.

Substitution effects of diborane on the interaction with borazine (inorganic benzene).

The gas phase interaction between borazine (IBz) and diborane (DB) has been investigated using MP2/6-311++G** and M05-2X/6-311++G** methods. The calculations have also been carried out at the same levels on the intermolecular complex formed between benzene (Bz) and DB to compare the modes of interaction. The complexation pattern found in IBz...DB is similar to that of Bz...DB due to their structural similarity. The calculated stabilization energies (SEs) at the MP2/6-311++G** level of theory for IBz...DB and Bz...DB complexes are 1.67 and 3.06 kcal/mol, respectively. The corresponding values obtained from the M05-2X/6-311++G** level of calculation are 2.55 and 3.43 kcal/mol. The variation in the SEs between IBz...DB and Bz...DB is due to the differences in the pi-electron distributions of IBz and Bz rings. Since, DB contains a three center-two electron (3c-2e) electron deficient bond, the substitution of nonbridge hydrogen atoms (H) by different functional groups may influence the nature of interaction between the DB and IBz. Thus, the nonbridge H atom in DB has been substituted by electron withdrawing (CN and Cl) and electron donating (CH(3)) groups. The interaction between substituted DBs and IBz has also been investigated using CCSD(T), MP2, and M05-2X methods. Results reveal that the substitution of the nonbridge H atom of DB by a cyano group significantly influences the calculated stabilization energies (SEs) and geometrical parameters whereas substitution by Cl and CH(3) groups marginally affects the stabilities and geometrical parameters of the substituted complexes. The calculated SEs of various substituted DB and IBz complexes range from 1.87 to 7.91 kcal/mol. Furthermore, evidence shows that SEs vary linearly with the number of substituents present in the complexes. The energy decomposition analysis using the density functional theory-symmetry adopted perturbation theory (DFT-SAPT) method confirms the predominant role played by the dispersion interaction in the stabilization of the various complexes when compared to the electrostatic interaction.

Frontal sinus pneumocoele: a rare cause of orbital emphysema.

Sudden onset nonaxial proptosis and diplopia is alarming and orbital haemorrhage or a rapidly expanding orbital tumour should be excluded. We present a case of a young man aged 15 years who attended the Accident and Emergency Department with a 6-h history of sudden onset proptosis and diplopia in whom the aetiology was orbital emphysema.

Alcohol delamination of the corneal epithelium for recalcitrant recurrent corneal erosion syndrome: a prospective study of efficacy and safety.

AIM: To investigate the safety and efficacy of alcohol delamination of the corneal epithelium for recalcitrant recurrent corneal erosion syndrome (RCE) in a prospective non-comparative interventional case series. METHODS: Patients with RCE who remained symptomatic despite topical lubrication and 3-month use of an extended wear (bandage) contact lens were included. The intensity of pain on a scale of 1 to 10, and duration and frequency of attacks were recorded. Patients were treated with alcohol delamination and followed up at 1 week, 1 month and then at 12 months, which was the minimum follow up time. Success was defined as a resolution of symptoms after 1 month of treatment, and partial success as a significant reduction in symptoms manageable with topical lubricants, and failure where symptoms were unchanged or worsened. RESULTS: 20 eyes of 20 patients with RCE caused by trauma (n = 14), anterior basement membrane dystrophy (n = 5) or idiopathic (1) were studied. The mean age of patients was 44 years and mean follow-up 24 months. Two eyes were lost to follow-up. 15 (83%) eyes were qualified as successes, 3 as partial successes and no failures were seen. No intraoperative complications were observed. 1 patient developed transient subepithelial haze that resolved with topical steroid, 1 had a change in refraction and 1 developed herpetic stromal keratitis 2 months postoperatively, which was successfully treated. No loss of vision was observed in any of the patients. CONCLUSION: Alcohol delamination of the corneal epithelium is a safe and effective method for treating patients with recalcitrant RCE.

Scedosporium prolificans sclerokeratitis 10 years after pterygium excision with adjunctive mitomycin C.

Scedosporium prolificans is an unusual infection, especially following pterygium surgery. A 63-year-old man who developed an uncomfortable, red right eye 10 years after pterygium surgery with adjunctive mitomycin C is described. To the best of the authors' knowledge, this is the first reported case of S. prolificans sclerokeratitis following pterygium surgery with adjunctive mitomycin C.

Gastric asthma: a clinical update for the general practitioner.

Asthma is an inflammatory disease of the airways characterized by increased airway reactivity with airflow obstruction. It is exacerbated by multiple triggers, and one common, often overlooked trigger is gastroesophageal reflux (GER). The prevalence of GER in asthmatics is estimated at between 34% and 80%. Up to 24% of asthmatics may have silent GER without the classic reflux symptoms (heartburn, acid regurgitation, and dysphagia). Since most patients are initially seen at the primary care level, it is essential for the primary physicians to recognize the underlying cause of the disease. This review briefly discusses the pathogenesis and clinical features of gastric (reflux-triggered) asthma and provides clues for its diagnosis in primary care practice. The current diagnostic approach to such patients and its management relevant to general practitioners is also discussed.

Alcohol consumption, hepatic iron load and the risk of amoebic liver abscess: a case-control study.

OBJECTIVE: It is unknown why most amoebic liver abscess (ALA) cases occur in alcohol drinkers. In experimental studies, the presence of 'iron' potentiates the in-vitro growth of Entamoeba histolytica (E. histolytica), and is also known to increase its in-vivo invasiveness in animal infections. Chronic alcoholism increases the hepatic iron deposition. We hypothesized that ALA occurs more commonly in livers with a high iron load as in alcoholics. To test this hypothesis we compared the levels of iron between ALA and non-ALA cases belonging to alcoholic and non-alcoholic groups. METHODS: Out of a total of 48 ALA cases, 34 (70%) were alcoholics and 14 (30%) were non-alcoholics. After applying exclusion criteria, serum iron and liver iron stores were quantified in 20 ALA cases (10 alcoholic and 10 non-alcoholics) and compared with 20 non-ALA cases (10 alcoholics and 10 non-alcoholics). RESULTS: All patients of ALA had serum iron values within the normal range but higher than non-ALA cases. In the liver tissue, most patients with ALA had higher (grade II or III) iron deposition, than non-ALA cases (mostly grade I). Thus, patients with ALA, with or without alcohol indulgence, had higher iron levels when compared to the non-ALA cases. CONCLUSION: It appears that the higher incidence of ALA in alcoholic livers is possibly due to their higher iron content.

Self-referral to specialists--a dodgy proposition.

Patients are often ill-equipped to know which speciality to choose for their health problem. Especially in the presence of non-specific symptoms, choosing the right specialist might not be so obvious. In such cases, misdirected self-referrals by patients to self-chosen specialists can sometimes lead to misdiagnosis resulting in unwarranted delays in getting the right treatment. The general physicians, on the other hand, are in a unique position to oversee the big picture of patients' health, and are therefore better equipped to identify and sort out their individual health problems. Hence instead of a specialist if the first place of contact for patients is a general physician, they are likely to be guided along the right path of treatment for their various health problems. Such a system will minimize errors on the part of the patients by making certain that they are referred to the appropriate specialists.

Hypertriglyceridemia-induced acute pancreatitis--treatment with heparin and insulin.

Heparin and insulin stimulate lipoprotein lipase and are known to decrease serum triglyceride levels. However, their efficacy in hypertriglyceridemia-induced acute pancreatitis is not well documented. We report a 51-year-old man in whom treatment with heparin and insulin was accompanied by reduction in serum triglyceride levels and resolution of pancreatitis.

Serum transferrin receptor in children with respiratory infections.

OBJECTIVE: To study the effect of infection on iron status in children suffering from acute, mild or severe respiratory infections and to determine the nature of anemia in infection using serum transferrin receptor (sTfR) levels. DESIGN: Forty-three children aged between 3 and 5 y with no evidence of infection and receiving iron supplements in the preceding 100 days served as controls. Twenty-one children with mild upper respiratory infection and 94 children hospitalized for acute pneumonia constituted the experimental group. Hemoglobin (Hb), sTfR and serum ferritin were estimated in all the children at the time of diagnosis and again on the 15th and 30th days after the infection in those who were available for follow-up. RESULTS: Mean (95% CI) sTfR was 6.08 (5.1-7.1) mg/l in healthy non-anemic children. Upper respiratory infection had no impact on Hb or sTfR but it significantly elevated serum ferritin levels. Eighty-three percent of the children with pneumonia had Hb less than 110 g/l at the time of diagnosis and had elevated mean sTfR, 18.0 (15.7-20.3) mg/l. There was a decline in mean sTfR by the 15th day of infection to 14.3 (11.3-17.4) mg/l with further rise to 22.9 (13.0-31.9) mg/l by 30 days. Serum ferritin was significantly elevated at the time of diagnosis (85.9; 71.1-100.8 micro g/l) as well as at 15 days (89.1; 68-110.1 micro g/l) with a decline by 30 days. CONCLUSIONS: Severe lower respiratory infection exaggerates iron-deficient erythropoiesis by blocking release of iron from the storage pools. sTfR may not be a sensitive and specific tool of assessing true iron status of children exposed to severe infections.

Palmar erythema and hoarseness: an unusual clinical presentation of sarcoidosis.

Palmar erythema is a very unusual manifestation of sarcoidosis. We report on a patient whose presenting features of sarcoidosis were palmar erythema and a hoarse voice. The diagnosis was confirmed by palmar skin biopsy and the patient responded well to treatment with prednisolone.

Burning feet syndrome. A clinical review.

BACKGROUND: Burning pain in the feet has been known to occur as a distinct clinical symptom for almost two centuries. Despite being a common and fascinating clinical entity, this syndrome has received scant attention in the medical literature and has been described only in anecdotal reports. OBJECTIVE: This article describes and discusses the various aspects of this intriguing syndrome. DISCUSSION: Burning feet syndrome (BFS) is a common disorder especially among the elderly and is frequently encountered in general practice. There is no specific aetiology and it can occur as an isolated symptom or as part of a symptom complex in a variety of clinical settings. In contrast to the presence of distressing subjective symptoms, the physical examination is marked by a paucity of objective signs. The pathophysiology of BFS is not very clear and treatment varies depending on the aetiology.

Sleep-disordered Breathing in Neuromuscular Disease.

Patients with neuromuscular disorders involving respiratory muscles (upper airway muscles, respiratory accessory muscles, diaphragm, even abdominal muscles that stabilize the chest) have more significant problems with breathing during sleep, especially during REM sleep, than during wakefulness. There are means of appropriately treating sleep disordered breathing and improving the quality of life of these patients. Treatment helps to avoid daytime symptoms and additional autonomic nervous system dysfunction. The treatment involves support of breathing during sleep. It must be adjusted to the severity of the problem during sleep, which implies systematic investigation and treatment based on polygraphic recordings during sleep. Patients, even when stable, need to be monitored during sleep at least once a year and more often if symptomatic, ie, appearance of any daytime symptom or frequent upper respiratory infection or indication of daytime CO(2) retention.

Urinary hydatid antigen detection by coagglutination, a cost-effective and rapid test for diagnosis of cystic echinococcosis in a rural or field setting.

We describe here coagglutination (Co-A), a rapid slide agglutination test for the detection of hydatid antigen in the urine for the diagnosis of cystic echinococcosis (CE). Paired urine and serum samples were collected from 16 patients with surgically confirmed CE, 10 patients with ultrasound-proven CE, 14 patients with clinically diagnosed CE, 24 patients with various parasitic diseases other than CE, and 25 healthy control subjects. Co-A detected excreted hydatid antigen in the concentrated urine of 7 of 16 (43.75%) surgically confirmed cases, 6 of 10 (60%) ultrasound-proven cases, and 8 of 14 (57.14%) clinically diagnosed cases of CE. A false-positive reaction was observed with 12.50% of control urine specimens from patients with parasitic diseases other than CE and 12% of urine samples from healthy controls. The circulating antigen was detected in the serum in 13 of 16 (81.25%) surgically confirmed cases, 6 of 10 (60%) ultrasound-proven cases, and 13 of 14 (92.86%) clinically diagnosed cases of CE. False-positive reactions were observed with three sera (12.5%) from controls with other parasitic diseases. The low sensitivity of Co-A for detection of antigen in the urine of a patient whose serum was positive for the antigen is possibly due to low levels of antigen in the urine. Unlike the collection of blood for serum, which is an invasive procedure and also requires technical expertise and disposable syringes, urine can be collected easily and frequently without causing any inconvenience to the patient. Urine as a clinical specimen alternative to serum would be immensely useful in the diagnosis of CE, particularly in a rural or field setting. In such situations as well as in poorly equipped laboratories, Co-A has the potential to be used as a simple, rapid, and economical slide agglutination test for detection of urinary hydatid antigen in the diagnosis of CE.

Biological efficacy and plasma norethisterone levels of orally administered norethisterone enanthate in rat and hamster.

Norethisterone enanthate (NET-En) is a well known intramuscular contraceptive drug. The long acting nature of this preparation when administered orally was evaluated in female rats and hamsters using fertility inhibition test and from the plasma levels of norethisterone (NET). An oral dose of 20-60 mg NET-En was administered to random groups of six female rats and hamsters and were mated after five and ten days with males of proven fertility. The fertility inhibition rate was determined from vaginal delivery. A dose-dependent reduction in fertility was seen in rats 5 days after oral administration of NET-En. This effect was found to be less pronounced and not significant 10 days after administration of similar doses of NET-En. In hamsters, a similar but less pronounced effect was noted. The decrease in fertility was significant only at the 60 mg dose. The plasma levels of NET estimated by RIA over a period of 15 days, in a different set of treated rats, suggested rapid absorption of NET-En within a day, and drug concentration decreased slowly, the levels on the 4th day ranged from 0.9-2.3 with the 10 mg and 1.0-4.0 ng/ml with the 20 mg dose. Detection of adequate levels of NET in plasma during the estrous cycle in rats, and the fertility inhibition observed in female rats and at higher doses in hamsters, suggest that NET-En is orally active.

Evaluation of human hydatid disease before and after surgery and chemotherapy by demonstration of hydatid antigens and antibodies in serum.

This study was performed to differentiate serologically between patients with hydatid disease which is active, and which has been successfully cured. A total of 18 cases was included. Pre-treatment serum samples were collected before surgery or chemotherapy. Post-treatment serum samples were collected at various intervals (3 days, 7 days, 1 month, 6 months, 1 year and 2 years) after surgery or chemotherapy. These sera were tested for the presence of circulating hydatid antigen (CAg) by bacterial co-agglutination (Co-A) and counter-current immunoelectrophoresis (CIEP) tests, and for circulating hydatid antibodies (CAb) by indirect haemagglutination assay (IHA). Ten and eight sera, respectively, were positive out of 11 pre-operative and pre-chemotherapeutic sera tested for CAg by the Co-A and CIEP tests. Post-operative sera collected from these cases did not show any CAg by the CIEP test. However, CAg was detected by Co-A in three and four serum samples collected on the third and seventh day, respectively, after surgical removal of the cyst. However, the CAg levels in these post-operative sera showed a gradual decline by the seventh day and were completely absent in the serum specimens collected 1 month after surgery and 6 months after chemotherapy. All the post-operative serum samples except two, collected 2 years after surgical removal of the cyst, in seven cases of old hydatid disease, were negative for CAg by both the CIEP and Co-A tests. Unlike the CAg profile, no marked differences were noted between the CAb profile of the pre- and post-treatment sera, as shown by the IHA test. Even 1 year after surgery or chemotherapy, two sera showed a marginal decrease in their CAb titre. CAb at varying titres was still detectable in all seven serum samples from old cases of hydatid disease, even 2 years after surgical removal of the cyst. This study shows the value of serial pre- and post-operative or chemotherapy estimation of CAg by Co-A and CIEP as an index of cure or of continuing hydatid infection.