57Fe internal field nuclear magnetic resonance and Mössbauer spectroscopy study of Li-Zn ferrites.

We report the internal field nuclear magnetic resonance (IFNMR) and Mössbauer spectroscopy study of Li-Zn ferrites at RT. The results were supported by the IFNMR data measured at 77 K. As Zn concentration increases the IFNMR echo amplitude decreases and below certain Zn concentration no signal was detected. At RT the echo amplitude vanishes at a lower Zn concentration, whereas at 77 K, the echo amplitude does not vanish completely (except for pure Zn-ferrite). However, in Mössbauer spectroscopy at RT, we have observed magnetically ordered state of all the Li-Zn ferrite samples. This discrepancy could be related to the difference between the time scale of detection of the spins by Mössbauer spectroscopy (10-7-10-10 s) and NMR spectroscopy (10-6 s). Hence, sensitivity of zero-field NMR depends on the magnetic hyperfine field, temperature and abundance of the magnetic cations at the lattice of the spinel ferrites. We have demonstrated that the 'two-equal-pulses' sequence leads to higher echo signal than the spin echo pulse sequence due to the presence of distribution of internal magnetic fields throughout the material. We obtained a limiting value for the fraction of spins needed to produce an echo signal at a particular temperature and at a particular site of the Li-Zn ferrite spinels that can be sensitively detected by pulsed IFNMR technique.

Draft whole genome sequence of groundnut stem rot fungus Athelia rolfsii revealing genetic architect of its pathogenicity and virulence.

Groundnut (Arachis hypogaea L.) is an important oil seed crop having major biotic constraint in production due to stem rot disease caused by fungus, Athelia rolfsii causing 25-80% loss in productivity. As chemical and biological combating strategies of this fungus are not very effective, thus genome sequencing can reveal virulence and pathogenicity related genes for better understanding of the host-parasite interaction. We report draft assembly of Athelia rolfsii genome of ~73 Mb having 8919 contigs. Annotation analysis revealed 16830 genes which are involved in fungicide resistance, virulence and pathogenicity along with putative effector and lethal genes. Secretome analysis revealed CAZY genes representing 1085 enzymatic genes, glycoside hydrolases, carbohydrate esterases, carbohydrate-binding modules, auxillary activities, glycosyl transferases and polysaccharide lyases. Repeat analysis revealed 11171 SSRs, LTR, GYPSY and COPIA elements. Comparative analysis with other existing ascomycotina genome predicted conserved domain family of WD40, CYP450, Pkinase and ABC transporter revealing insight of evolution of pathogenicity and virulence. This study would help in understanding pathogenicity and virulence at molecular level and development of new combating strategies. Such approach is imperative in endeavour of genome based solution in stem rot disease management leading to better productivity of groundnut crop in tropical region of world.

Ultrasound enhances lipase-catalyzed synthesis of poly (ethylene glutarate).

The present work explores the best conditions for the enzymatic synthesis of poly (ethylene glutarate) for the first time. The start-up materials are the liquids; diethyl glutarate and ethylene glycol diacetate, without the need of addition of extra solvent. The reactions are catalyzed by lipase B from Candida antarctica immobilized on glycidyl methacrylate-ter-divinylbenzene-ter-ethylene glycol dimethacrylate at 40°C during 18h in water bath with mechanical stirring or 1h in ultrasonic bath followed by 6h in vacuum in both the cases for evaporation of ethyl acetate. The application of ultrasound significantly intensified the polyesterification reaction with reduction of the processing time from 24h to 7h. The same degree of polymerization was obtained for the same enzyme loading in less time of reaction when using the ultrasound treatment. The degree of polymerization for long-term polyesterification was improved approximately 8-fold due to the presence of sonication during the reaction. The highest degree of polymerization achieved was 31, with a monomer conversion of 96.77%. The ultrasound treatment demonstrated to be an effective green approach to intensify the polyesterification reaction with enhanced initial kinetics and high degree of polymerization.

Ultrasound assisted synthesis of methyl butyrate using heterogeneous catalyst.

Ultrasound assisted esterification of butyric acid with methanol was investigated in an ultrasound irradiated isothermal batch reactor using acid ion-exchange resin (amberlyst-15) as a catalyst. Effect of parameters such as temperature (323-353 K), catalyst loading (0-8.5%w/w), alcohol to acid ratio, M (2-6), ultrasound power (0-145 W), duty cycle (0-85%) and amount of molecular sieves added (0-11%w/w) on the rate of reaction was studied. At optimized parameters, a maximum conversion of 91.64% was obtained in 120 min in presence of ultrasound. Experimental kinetic data were correlated by using Eley-Rideal (ER) and Langmuir-Hinshelwood-Hougen-Watson (LHH W) models taking into account reverse reaction. Studies showed that single site LHHW with reactants and products both adsorbing on catalyst surface was most suited for the obtained experimental data. Activation energy determined based on heterogeneous kinetics was in the range 49.31-57.54 kJ/mol while it was 18.29 kJ/mol using homogeneous model.

Recidivas después de la quimioterapia en la lepra / No disponible

No disponible

Evaluation of anti-Candida potential of geranium oil constituents against clinical isolates of Candida albicans differentially sensitive to fluconazole: inhibition of growth, dimorphism and sensitization.

Fluconazole (FLC) susceptibility of isolates of Candida spp., (n = 42) and efficacy as well as mechanism of anti-Candida activity of three constituents of geranium oil is evaluated in this study. No fluconazole resistance was observed among the clinical isolates tested, however 22% were susceptible-dose-dependent (S-DD) [minimal inhibitory concentration (MIC) ≥ 16 µg ml(-1)] and a standard strain of C. albicans ATCC 10231 was resistant (≥ 64 µg ml(-1)). Geraniol and geranyl acetate were equally effective, fungicidal at 0.064% v/v concentrations i.e. MICs (561 µg ml(-1) and 584 µg ml(-1) respectively) and killed 99.9% inoculum within 15 and 30 min of exposures respectively. Citronellol was least effective and fungistatic. C. albicans dimorphism (Y → H) was highly sensitive to geranium oil constituents tested (IC50 approximately 0.008% v/v). Geraniol, geranyl acetate and citronellol brought down MICs of FLC by 16-, 32- and 64-fold respectively in a FLC-resistant strain. Citronellol and geraniol arrested cells in G1 phase while geranyl acetate in G2-M phase of cell cycle at MIC(50). In vitro cytotoxicity study revealed that geraniol, geranyl acetate and citronellol were non-toxic to HeLa cells at MICs of the C. albicans growth. Our results indicate that two of the three geranium oil constituents tested exhibit excellent anti-Candida activity and significant synergistic activity with fluconazole.

Effect of water extract of the bark of Buchanania lanzan linn. on behaviour and chromatophores of a fresh water fish, Labeo rohita.

Fish exposed to 150 ppm and 250 ppm doses saparately, showed eratic swimming with hyper-excitability, spiralling, convulsion and mortality. However at 350 ppm dose fish became lethargic and steady at the bottom of aquarium. This behaviour appears to be due to sedative effects of fish implicating the phychoactive nature of the plant B. Ianzan. At 150 ppm to 350 ppm doses, fish scale changed from reticulate to punctate chromatophores; and treated fish when transferred to fresh water, were slowly regained to normal behaviour after 96 h exposure. Hence doses regaining from 150 ppm to 350 ppm is considered to be psychoative in nature. In higher doses 450 ppm and 550 ppm fish could survive only 76 h and 4.30 h respectively and then died indicating toxicity of plant for the said doses. It is found that scale present on its body is most suitable test system for the study of psychoactivity and toxicity of plant extracts on fish, Labeo rohita.

Biotechnological production of oil: fatty acid composition of microbial oil.

The fatty acid profile and the fatty acid composition of microbial lipids obtained from molds revealed that oil from Aspergillus sydowii, Fusarium oxysporum and F. equisetti had a high percentage of unsaturated fatty acids, particularly oleic acid, and had a similarity to the edible oils, groundnut and palm oil. This study sheds light on the possibilities of exploring the use of these oils as supplement to other edible fats and for other non-edible industrial purposes.

Stent retriever for dilation of pancreatic and bile duct strictures. brand@uke.uni-hamburg.de.

BACKGROUND AND STUDY AIMS: Dilation of high grade strictures of pancreatic or biliary ducts using dilating or balloon catheters may fail. We evaluated the efficacy of the 7-Fr Soehendra Stent Retriever used as a dilator. PATIENTS AND METHODS: Following sphincterotomy, the stricture was first negotiated with a 260 cm long 0.032-inch J-type Terumo wire. Dilation was then attempted using a 7-Fr dilating catheter. If the stricture could not be traversed, the 7-Fr Stent Retriever was inserted over the Terumo wire to dilate the stricture. Between May 1996 and January 1997, the Stent Retriever was used for dilation in 32 patients with biliary or pancreatic duct strictures. RESULTS: The indication for therapeutic endoscopic retrograde cholangiopancreatography (ERCP) was symptomatic chronic pancreatitis in 21 patients (twelve men, nine women; mean age 45.7, range 26-70). The mean length (+/-SD) of the pancreatic duct strictures was 20mm+/-10 (range 3-55) with a prestenotic ductal diameter of 9mm+/-2 (range 2-15). Out of 21 patients, nine suffered from pancreaticolithiasis and were treated with extracorporeal shock wave lithotripsy. All but three patients underwent successful stenting in the same session. Another 11 patients (four men, seven women; mean age 67.4, range 47-85) had cholestasis because of benign or malignant bile duct strictures. The mean length of the strictures was 20mm+/-5 (range 3-40), and the mean prestenotic diameter was 10mm+/-5 (range 4-21). Stenting was easily done in all of these patients in the same session. Symptom relief was observed within the first week after stenting in all patients with a biliary or pancreatic stricture. In seven cases, material for cytological examination was obtained from the bile duct, which revealed malignancy in two cases. There was no complication associated with the use of the Stent Retriever. One subcapsular liver perforation was caused by the guide wire and occurred prior to the use of the Retriever. CONCLUSIONS: Tight pancreatic and bile duct strictures can be dilated successfully with the Stent Retriever. The procedure is of low risk. In addition, tissue sampling is possible in some cases.

Improved endoscopic stenting for malignant dysphagia using Tygon plastic prostheses.

BACKGROUND AND STUDY AIMS: Endoscopic palliative treatment of malignant esophageal stenosis using conventional plastic stents has been reported to be associated with a considerable risk of perforation. Stenoses with a distance of less than 2cm from the upper esophageal sphincter (UES) have generally been excluded from treatment. Using self-expandable metal stents, procedure-related complications are rare. However, the rates of late complications necessitating retreatment appear to be as high as those of plastic stents. This study describes our stent placement technique and our results using a modified Tygon plastic stent. PATIENTS AND METHODS: Over a two-year period, 71 consecutive patients with incurable malignant esophageal stenosis were prospectively studied. Tygon plastic stents of diameter 9-14 mm were individually tailored according to length and location of the stenosis. Prior to stenting, stepwise bougienage was performed, if necessary over several sessions. After endoscopic placement of a guide wire, the stent was inserted over a bougie without fluoroscopic monitoring. RESULTS: A total of 71 patients (54 men and 17 women, median age 69, range 34-93), were treated with Tygon plastic stents (14 mm: 19 patients; 12 mm: 50 patients; 9 mm: 2 patients). Median length of the strictures and of the stents were 7 (range 2-18) and 10 (range 6-25) cm, respectively. Four patients had an associated esophago-respiratory fistula. After a median of 2 (range 1-5) bougienage sessions, stent insertion was technically successful in all patients. Forty-one stents were placed across the cardia, 13 were positioned 0.5-1 cm below the UES. Three patients had to undergo retreatment within 24 hours because of pain or stent migration and the stents were repositioned or exchanged. No procedure-related perforation, hemorrhage or respiratory problems were observed. During a median follow-up of 63 (range 2-388) days, 82% of the patients died. Improvement or stabilization of dysphagia allowing for oral nutrition could be achieved in 89%. Dislocation occurred in eight patients, bolus obstruction in five patients and tumor overgrowth in four patients. Three of the four fistulas could be covered by the stent. In one patient with a fistula located at the level of the UES, a stent was placed but migrated after 5 days. Overall, 27 patients (38%) required reinterventions, mainly for dysphagia or nutritional problems. CONCLUSIONS: In our experience, Tygon plastic stents with a diameter of 9-14 mm can be safely placed after stepwise, less extensive bougienage. Effective palliation is possible even for lesions located close to the UES. Perforation can be avoided. Reintervention rates seem to be comparable to those seen with self-expanding metal stents.

EUS-guided, fine-needle aspiration biopsy using a new mechanical scanning puncture echoendoscope.

BACKGROUND: A new mechanical sector scanning echoendoscope designed for EUS-guided, fine-needle aspiration biopsy (FNAB) was prospectively evaluated. The technical feasibility, safety, and histocytologic FNAB results are reported. METHODS: Eighty-six patients underwent 106 FNAB procedures. The new echoendoscope has a 2.8 mm accessory channel and an elevator. Target sites: pancreas 58, lymph nodes 43, and miscellaneous lesions 5. Lesions were punctured with a 0.7 mm needle and submitted for cytologic and histologic examination. Definitive diagnosis was by surgery or clinical follow-up. RESULTS: The wide scanning field (250 degrees) enabled easy sonographic orientation for FNAB. Longitudinal needle visibility was "good" in 93% and 71% of transesophageal and transgastric procedures, respectively, but were compromised during most transduodenal procedures. Needle penetration of indurated pancreatic lesions failed in two patients, and in four additional patients pancreatic sampling succeeded only after a second attempt using an automated spring-loaded device. The mean number of passes was three. Ten percent of FNAB specimens were "inadequate"; excluding these, the diagnostic accuracy rate was 97%; sensitivity for malignancy was 88.5% and specificity was 100%. CONCLUSION: EUS-guided FNAB is feasible, safe, and accurate using the new mechanical puncture echoendoscope. Needle visibility needs to be improved, particularly for transduodenal FNAB.

Endoscopic ultrasound-guided, 18-gauge, fine needle aspiration biopsy of the pancreas using a 2.8 mm channel convex array echoendoscope.

BACKGROUND: Previous studies have reported on endoscopic ultrasound-guided, fine needle aspiration biopsy using 22- to 25-gauge needles. We evaluated the histologic and cytologic yield of endoscopic ultrasound-guided, fine needle aspiration biopsy of the pancreas using an 18-gauge, Menghini-type core needle. METHODS: Fine needle aspiration biopsy was performed in conjunction with a prototype 2.8 mm channel convex array echoendoscope. The core specimen was placed in formalin for cell block, and residual material was expelled on slides for cytology. Definitive diagnosis was established by surgery or clinical follow-up. RESULTS: Of 45 patients who underwent fine needle aspiration biopsy, the needle failed to penetrate indurated pancreatic lesions in five. An average of 2.6 passes were performed in the remaining patients. Sufficient material for a histologic and/or cytologic diagnosis was obtained in 40 patients (histologic and cytologic yield of 68% and 75%, respectively). Combining the results of histology and cytology, the sensitivity and specificity for detection of malignancy was 76% and 100%, respectively. Histology confirmed the cytologic findings in 35 patients, providing additional tissue specific information. In three cases histology established a diagnosis of malignancy where cytology was not conclusively malignant. However, in three cases of surgically confirmed malignancy histology failed to detect malignancy, whereas cytology showed suspicious or malignant cells. The sensitivity of histology and cytology alone in detecting malignancy was 53% and 70%, respectively. Mild pancreatitis occurred after pancreatic fine needle aspiration biopsy in one patient. CONCLUSION: Core specimens for histology can be safely obtained using an 18-gauge needle. Histology provides tissue-specific information that complements cytology, but histology is less sensitive than cytology in detecting malignancy.

Endoscopic therapy of pancreatic strictures.

Over the past decade, endoscopic therapy has been increasingly used as a less invasive alternative to surgery for the treatment of pancreatic duct strictures. The therapeutic goal has been the palliative relief of severe pain associated with chronic pancreatitis. Studies from several centers have shown that endoscopic stenting results in pain relief for a high percentage of patients. Future investigation needs to focus on the refinement and standardization of basic techniques, and different strategies need to be compared in well-designed trials.

A theoretical model for pulsatile blood flow with applications to cerebrovascular diseases.

A solution for fully developed pulsatile flow of a couple stress fluid through a circular, rigid tube of infinite length has been obtained in the form of a Bessel-Fourier series. The velocity profiles and flow rates for different values of flow parameters have been shown graphically. It has been observed that velocity and flow rate are almost in phase with pressure gradient for low values of pulsatile Reynolds number alpha (alpha 2 = 0.1). For higher values of alpha(= 2) a phase difference of approximately 30 degrees between the velocity profile and pressure gradient has been observed. The obtained results are in good agreement with other theoretical and experimental results. The present analysis is valid for both values of alpha , i.e., alpha greater than or equal to 1 and alpha less than 1, whereas the existing analysis for pulsatile flow of couple stress fluid is valid for only alpha less than 1. The first, second, and third approximate solutions have been obtained and it is found that the convergence of the solutions is quite fast and the series could be terminated after the second term. This theoretical work could be useful in the measurement of blood flow rates, its apparent viscosity, and peripheral resistance of the circulatory system which, at present, are thought to be some of the main causes of many cerebrovascular diseases and stroke problems.U