bluuebunny/crossref_metadata_2025 huggingface dataset:
Vancomycin resistance in Staphylococcus aureus may occur faster than expected
Authors: Tiwari Kiran Babu
Published: March 2010

Staphylococcus aureus, one notable example of nosocomial infections, has the characteristic ability to acquire antimicrobial resistance. Methicillin-resistant S. aureus have already become endemic worldwide, and vancomycin is the terminal antibiotic of choice for treatment of infections by these strains. Because of selection of vancomycin as the treatment option, n ow, the emergence of vancomycin resistance in S. aureus has been increasing elsewhere. Further, there is no consensus definition of minimum inhibitory concentration to determine the levels of vancomycin resistance in these strains making it difficult in interpretation and management of the resistant strains. As an intervention against cell wall physiology of the bacteria, vancomycin binds with terminal dipeptide of the peptidoglycan monomer. However, vancomycin-resistant strains possess a thickened cell wall with many free monomers capable of binding with the drug. The thickened cell wall not only traps more vancomycin molecules on the immediate cell surface, but also significantly impedes action of the drug towards inner layers of the peptidoglycan network on bacteria. Thus, the normal inner layers of peptidoglycan ensure the structural integrity of cell as a whole. Compounding with the stress selection of vancomycin-resistance in S. aureus, the novel mechanism allows the bacteria to reduce susceptibility to the drug easily; hence, emergence of vancomycin resistant strains in the hospital environment may occur faster than expected.  DOI: 10.3126/ijls.v3i0.2302
Plant Proteomics: Technologies, Strategies and Applications. Edited by Ganesh Kumar Agrawal and Radeep Rakwal
Authors: Agrawal Vishwanath P
Published: March 2010

DOI: 10.3126/ijls.v3i0.2371International Journal of Life Sciences Vol.3 2009 p.18
Sodium azide induced mutation of Actinomycetes I
Authors: Khatri Mamata , Rajbhandari Yurika , Regmi Shruti , Hamal Junu , Shrestha Upendra Thapa , Tiwari Kiran Babu
Published: March 2010

Sodium azide was employed to generate mutants of actinomycetes from Mount Everest region, viz. Sagarmatha National Park, Jorsale, Kalapatthar and Namche. Individual isolates of actinomycetes were inoculated on Starch Casein Agar plates containing 10, 50 and 100 ppm of sodium azide. Depending on complete inhibition of their growth , actinomycete isolates were categorized as highly sensitive , moderately sensitive and tolerant, respectively. Out of a total of 38 actinomycetes isolates, two (5.3%) were highly sensitive, 23 (60.5%) moderately sensitive and 13 (34.2%) tolerant. A total of 21 mutants were generated by treating 8 of the 23 moderately sensitive actinomycetes with 20, 30 and 40 ppm (sublethal concentrations ) of sodium azide and analyzed morphologically and biochemically. All mutants like wild strains were able to hydrolyse starch, Tween 20 and casein and utilize fructose and lactose. All were urease and catalase positive , but were different from wild strains in colony color or texture or both. Altogether nine (43 % ) mutants having negative mutation in loci of utilization of galactose or mannose (loss-of-function LOF, single mutants ) , two LOF double mutants in utilization of both galactose and arabinose , one gain-of-function (GOF) single mutant having positive mutation in the loci of utilization of galactose, one GOF double mutant in utilization of mannose and galactose and five double mutants (25%) having GOF ( arabinose or sucrose ) as well as LOF (mannose or galactose or arabinose) were obtained. Key words : Mt. Everest, Sagarmatha, actinomycetes, sodium azide, mutation, LOF, GOF  DOI: 10.3126/ijls.v3i0.2385
Characterization of Choreospondias axillaris (Lapsi) fruit protease
Authors: Prajapati Sabin , Sharma Samanta , Agrawal Vishwanath P
Published: March 2010

A catalytically powerful protease from Choreospondias axillaris (Lapsi) fruit has been reported. C. axillaris (Lapsi) is dioecious, deciduous fruit bearing tree. The protease extracted from the pulp of the fruit is highly thermo stable, autoclavable and extreme acidic and basic pH resistant. Its activity was retained even after multiple trichloro acetic acid (TCA) precipitation. The proteolytic activity of the protease increased linearly up to protein concentration of 62.28μg. It possesses a Km value of 13.09 μM and Vmax 15.87 pmoles/min for bovine serum albumin (BSA) as a substrate. Sodium Dodecyl Sulphate (SDS) activated the proteolytic activity.DOI: 10.3126/ijls.v3i0.2386Int J Life Sci Vol.3 2009 p.19-26
Differential responses of Plasmopara halstedii developmental forms to various steroid alkaloids
Authors: Oros Gyula
Published: March 2010

Significant differences were found in the sensitivity of various biotrophic and abiotrophic stages of Plasmopara halstedii to representative Solanum and Veratrum alkaloids and batrachotoxin with zoospores and cystospores being the most sensitive developmental forms. While Solanum alkaloids with pregnane skeleton inhibited the asexual spores without influencing biotrophic stages, Veratrum alkaloids that contain a highly hydroxylated C-nor-D-homosteroid skeleton inhibited both asexual spores and the systemic invasion of parasiting thallus. Cevagenine and 3-O-oleoylveracevine, the most active alkaloids, interrupted the life cycle of the fungus at several points: they influenced the parasiting thallus, delayed the zoosporogenesis and inhibited both zoospores and cystospores. The amphibian steroid alkaloid batrachotoxin affected asexual spores similarly. The zoospores responded rapidly to the alkaloid treatments; their motion was inhibited before the semipermeability of plasmalemma was completely lost. The antiperonospora efficacy of cevagenine and 3-O-oleoylveracevine was comparable to that of metalaxyl which inhibits only parasitic hyphae without affecting asexual spores. All alkaloids tested exhibited characteristic effect on the growth of the host plant, sunflower. These amphiphilic compounds are thought to act by direct incorporation into the fungal membrane thus disrupting its structural and functional integrity. Keywords: oomycota; sunflower; batrachotoxin; veratridine; solanine; tomatine; digitonin; tridemorphDOI: 10.3126/ijls.v4i0.2791 International Journal of Life Sciences Vol.4 2010 pp.1-15
Remarks on Certain Selected Fixed Point Theorems - II
Authors: Kumar Santosh
Published: March 2010

Recent common fixed point theorems due to Kumar et al and Jungck are used to derive two common fixed point theorems for four finite families of mappings in complete and compact metric spaces respectively. AMS (MOS) Subject Classification(2000) : Primary 54 H 25; Secondary 47 H 10. Key Words and phrases: Compatible mapping; coincidentally commuting mappings; coincidence point; fixed point; common fixed point. DOI: 10.3126/kuset.v3i2.2894 Kathmandu University Journal of Science, Engineering and Technology Vol.3, No.2, August 2007, pp 27-30
Radiation Measurement at X-Ray Centres of a few Hospitals in Kathmandu City, Nepal
Authors: Giri Karan , Giri Dhiraj , Murthy V Krishna
Published: March 2010

The ionizing radiation has hazardous health effects upon human exposure. Different types of cancers are reported to be arising on account of overt exposure to ionizing radiation like X-rays. This study reports occupational exposure as well as general exposure to the public and persons visiting radiology department in hospitals of Kathmandu city for diagnostic and therapeutic purposes. A portable environment radiation monitor was used to quantify the total radiation in places of work in the X-ray departments of 13 hospitals located in different parts of city. The findings show increased exposure and in some instances very high levels of unintentional exposure to radiation. DOI: 10.3126/kuset.v3i2.2895 Kathmandu University Journal of Science, Engineering and Technology Vol.3, No.2, August 2007, pp 31-34
Urban Environmental Quality Mapping: A Perception Study on Chittagong Metropolitan City
Authors: Majumder Ahmad Kamruzzaman , Hossain Md Eftekhar , Islam Md Nurul , Sarwar Md Iqbal
Published: March 2010

Urbanization is a global phenomenon. It is taking place at a faster pace in the less developed countries of the world like Bangladesh. The implication of such urbanization are manifested in mass poverty, gross inequality, high unemployment, crowded housing, proliferation of slums and squatters, deterioration in the environmental condition, highly inadequate supply of water, over crowding in schools and hospitals, increase in traffic jams, road accidents, crimes and social tensions. These features are the characteristics of nearly all urban centers of Bangladesh. The study has endeavored to analyze both the factual status and the perceptual pattern of the environmental quality of Chittagong Metropolitan City. The factual data have been collected from various secondary sources; while the perceptual data are based on a questionnaire survey of opinions of 492 respondents at the household level by city ward. Finally, it has been statistically justified by the use of a satisfaction index to know the degree of satisfaction of the respondents and chi-square test to examine the relationship between the income groups and degree of satisfaction. The study of perception residents f the different environmental aspects, show variation of degree of satisfaction by income groups and by groups of environmental features. The expected growth of population in Chittagong city will have adverse impact on the quality of urban environment. Key words: Environment; Chittagong; urban; environmental mapping DOI: 10.3126/kuset.v3i2.2896 Kathmandu University Journal of Science, Engineering and Technology Vol.3, No.2, August 2007, pp 35-48
Quality Assurance of Tomorrow's Doctor
Authors: Alam MT
Published: March 2010

DOI: 10.3329/jafmc.v5i2.4572JAFMC Bangladesh Vol.5(2) (December) 2009, pp.1-2
Lupus Nephritis - Past, Present and Future Management
Authors: Ahmed ZU
Published: March 2010

DOI: 10.3329/jafmc.v5i2.4573 JAFMC Bangladesh Vol.5(2) (December) 2009, pp.3-4
Present Status of Activities of Quality Assurance Scheme (QAS) in Medical and Dental Colleges of Bangladesh
Authors: Talukder MHK , Nargis T , Hossain MZ , Nazneen R
Published: March 2010

This cross-sectional study was conducted with the objective to assess the present status of activities related to quality assurance scheme (QAS) in medical and dental colleges of Bangladesh. The Principal or Vice principal or Academic coordinator was respondent and any one of them from each medical or dental college filled up a questionnaire. The study was conducted in 2008. Regarding the on going activities related to quality assurance scheme in their colleges, majority of the respondents mentioned that there are formal phase committees and course committee to run the quality assurance scheme, functioning faculty development and review scheme, continuing professional development activities like seminar etc., and mechanism to collect students' feedback through structured questionnaire. Majority of them also mentioned that phase committees & course committee meetings held regularly, academic coordinator regularly met with the phase coordinators, student outcome analyzed, annual sports and cultural functions held regularly and recently they have submitted a report on the status of QA scheme to the Director Medical Education and  Health Manpower Development (ME & HMPD). On the other hand most of them mentioned that the teachers of their respective medical colleges did not have adequate training on QAS, did not have adequate resources, designated staff for running QAS and functioning medical skill centre in the colleges and did not collect external examiners' report. Most of the respondents recommended that teachers should be adequately trained on QAS, staff should be designated to run QAS and adequate resources should be allocated to run QAS and activities should be monitored and evaluated regularly. Key words: Quality assurance, medical education. DOI: 10.3329/jafmc.v5i2.4574 JAFMC Bangladesh Vol.5(2) (December) 2009, pp.5-7
Cyclosporine & Mycophenolate Mofetil in the Treatment of Cyclophosphamide Refractory Class-IV Lupus Nephritis
Authors: Mostafi M , Rabbani MG , Hossain MR , Siddiqui AR , Rabbani SB
Published: March 2010

Class IV Lupus Nephritis is a difficult medical situation requiring aggressive management. Many patients do not respond to conventional cyclophosphamide (CPM) therapy. The aim of this study was to evaluate the effect of cyclosporine (CsA) and mycophenolate mofetil (MMF) in the treatment of CPM refractory class IV Lupus nephritis. The study was conducted at Combined Military Hospital (CMH) and Cantonment General Hospital (CGH) of Dhaka over a period of 8 years (from January 2000 till December 2008). CPM refractory Class IV Lupus nephritis patients were randomly assigned into 2 groups cyclosporine (4mg/kg/day) and mycophenolate mofetil (1000-2000mg/day). Thirty one patients completed at least one year follow up and were included in the study. Sixteen patients were included in cyclosporine group and 15 patients in mycophenolate mofetil group. CsA treated patients had a remission rate of 87.5% which was 80% in MMF group. The average remission time was 16.21 weeks in CsA and 20.91 weeks in MMF group. The urinary total protein(UTP) and creatinine clearance (CCr) values  were  similar in both groups, 0.54 gm vs 0.66 gm & 81 vs 86 ml/min. The systemic lupus erythematosus disease activity index (SLEDAI) was 9.56 and 9.2 in CsA and MMF group which came down to 1.92 and 1.83 in the same groups after remission. In this study It was found that both cyclosporine and mycophenolate mofetil were very effective in the treatment of CPM refractory class IV Lupus nephritis with slight better response with cyclosporine. Key words: Lupus Nephritis, mycophenolate mofetil, cyclosporine. DOI: 10.3329/jafmc.v5i2.4575 JAFMC Bangladesh Vol.5(2) (December) 2009, pp.8-13
Electrophysiological Changes of Motor Nerves in Patients with Type 2 Diabetes Mellitus
Authors: Sultana S , Begum N , Ali L , Hossain MM , Bhowmik NB , Parveen Z
Published: March 2010

Peripheral neuropathy is a common disabling complication in patients with diabetes and this complication is related to the duration of the disease process. Nerve conduction study is widely used for the assessment of diabetic polyneuropathy not only to evaluate the degree of abnormality but also to document serial changes in the clinical course of the disease. This study was designed to characterize motor nerve conduction abnormalities in subjects having relatively shorter and longer duration of type 2 diabetes mellitus and also to assess whether time related variable like duration of diabetes has any influence on motor nerve function of the subjects. Forty-four type 2 diabetic subjects were included in two groups:- Group B consisted of 23 diabetic subjects having duration of diabetes for 5-10 years (shorter duration) and Group C consisted of 21 diabetic subjects having duration of diabetes for 10-15 years (longer duration). Twenty-five age and BMI matched healthy subjects without family history of diabetes were included as Group A (non-diabetic) subjects. Motor nerve conduction velocities, action potential amplitudes and latencies of ulnar and peroneal nerves were measured by standard Nerve Conduction Velocity- Electromyography (NCV-EMG) equipment. Motor conduction parameters like ulnar compound muscle action potential (U CMAP), peroneal compound muscle action potential (P CMAP) and peroneal  nerve conduction velocity (P NCV) were found to be significantly reduced (p<0.001, <0.01, <0.01 respectively) in diabetic group with shorter duration of diabetes(Group B) in comparison to non-diabetic control group (Group A). In the diabetic group with relatively longer duration of diabetes (Group C) motor nerve conduction parameters like U CMAP and P NCV were significantly reduced (p<0.001, <0.01 respectively). The results showed that in the type 2 diabetic population, motor nerve conduction parameters were affected early and there was gradual deterioration of motor function as duration of diabetes increased. Though previous studies on diabetic neuropathy suggest that abnormalities of sensory nerve conduction are early features of diabetic nerve damage and sensory nerves are more susceptible to fall prey to metabolic assaults, the present study indicates that motor nerves are also involved and the neuropathic changes assessed by electro diagnostic methods in motor nerves may occur early in patients with type 2 diabetes mellitus. So, there may be some genetic and biochemical basis (other than hyperglycaemia) for early motor involvement in type 2 diabetic population of Bangladesh. Key words: Diabetic neuropathy, electrophysiology, nerve conduction, electromyography. DOI: 10.3329/jafmc.v5i2.4576 JAFMC Bangladesh Vol.5(2) (December) 2009, pp.14-17
Effect of Folic Acid Supplementation on Serum Homocystene and Lipid Profile in Acute Myocardial Infarction
Authors: Wahab MA , Zafreen F , Siddique MA , Akter Y , Parveen Z , Chowdhury NS , Parveen S , Arslan MI
Published: March 2010

This double blind randomized placebo controlled experimental study was carried out at the department of Biochemistry and Cardiology, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh over a period of one year. A total number of sixty (60) hospitalized acute myocardial infarction (AMI) patients of both sexes, age ranging 35 to 65 years, agreed after informed written consent, were included in the study. Cases were selected purposively on the basis of specified inclusion and exclusion criteria from hospitalized diagnosed patients of AMI. After detail history, clinical examination, physical and anthropometrics measurements study subjects were randomized into two groups and treated with 5 mg folic acid or placebo for 4 weeks. Fasting serum homocysteine (Hcy) and lipid profile of all the study subjects were estimated both before starting the drug and after completion of treatment, Hcy concentration was estimated by fluorescence polarization immunoassay (FPIA) method in 'AxSYM system' (Abbott, USA). Statistical analyses were done by using 'SPSS 12.0, continuous data were expressed as mean ± SEM and categorical data in percentage (%) and frequency. AMI patients Hcy concentration was higher than normal reference value (5 - 15 mmol/L). Folic acid supplementation decreased serum Hcy concentration very significantly (p<0.001) in drug group (from 25.92 ± 2.47 to 15.38 ± 0.68 mmol/L) but effect in placebo group was found no significant (p>0.05). In this study folic acid supplementation at a dose of 5 mg/day decreased Hcy concentration almost by 27%. Folic acid supplementation significantly (p<0.05) increased HDL concentration but shown no significant effect on other parameter of lipid profiles. Key words: Acute myocardial infarction (AMI), homocystein (Hcy), folic acid (Folate). DOI: 10.3329/jafmc.v5i2.4578 JAFMC Bangladesh Vol.5(2) (December) 2009, pp.21-23
Postmortem Study of Head Injury in Fatal Road Traffic Accidents
Authors: Ahmad M , Rahman FN , Chowdhury MH , Islam AKMS , Hakim MA
Published: March 2010

This study was conducted at the Dhaka Medical College (DMC) morgue among 100 postmortem cases of Road Traffic Accident (RTA) victims over a period of one year. The objective of this study was to find out incidences of head injury among the RTA victims along with other injuries and also to overview the present situation of RTA in the country. Out of 100 cases, 64% were male and 36% female. The highest incidence of RTA (28%) was observed among the age group 31 to 40 years. The highest number of victims were pedestrians (68%). Considering recorded causality by type of collision, hit pedestrian was the most common (39%), followed by head on collision (20%). Regarding injury pattern in different parts of body, all the victims had multiple abrasion and bruise, 90% had laceration, 78% had injury to brain and 77% victims had injury to abdominal organs like liver and spleen. In the skull, Linear/fissured fracture was the commonest type of fracture (36%), followed by comminuted fracture (18%). Temporal bone was observed most prone to be fractured (23%), followed by parietal bone (17%). Most of the victims had subdural haemorrhage (43%), followed by sub arachnoid haemorrhage (36%). Key words: Road traffic accident, head injury, postmortem. DOI: 10.3329/jafmc.v5i2.4579 JAFMC Bangladesh Vol.5(2) (December) 2009, pp.24-28
Sea Sickness in Naval Personnel
Authors: Malek MA , Maruf AA , Hossain MM
Published: March 2010

Seasickness can be a debilitating condition and can be dangerous if the naval personnel appointed in operational or key appointment in the ship during operation. The objective of this descriptive study was to report and evaluate the incidence, severity and effects of seasickness among naval personnel of Khulna Naval Base. The study was conducted over a period of 18 months. This study included 1293 healthy male sailors and aged ranges between 20 to 45 years. Data included sailor's demographics, duration at sea, types of symptoms, severity of seasickness, incidence of seasickness in relation to exposure, and sea condition. Total 785 (60.71%) sailors stayed less then 7 days, 311 (24.06%) from 7 to 14 days and 197 (15.23%) stayed more than 14 days. Total 523 (40.44%) sailors experienced seasickness; those were dizziness (18.32%), fatigue (17.09%), vertigo (11.36%), epigastric discomfort (9.74%), nausea (17.40%) and vomiting (6.57%). Majority were minor inconvenience, self limiting and did not require rest (78.78%).Excuse from duty for 24 hours was required in 101 (19.31%) cases and excused from duty for whole sea period in 10 (1.91%) cases. Incidence of seasickness observed in first exposure in 275 (52.59%) cases, after less than 10 exposure in 138 (26.39%) cases, after more than 10 exposure in 69 (13.18%) cases and always in 41 (7.84%) cases. Sailors had seasickness in calm sea (3.82%), in moderate sea (24.28%) and in rough sea (71.70%). No sailor required evacuation from sea to land for seasickness. Seasickness is troublesome for sailors, but majority of the symptoms were minor inconvenience and self-limiting without very few exceptions. For better confirmation and future prospect, study may be conducted in a larger aspect including both sexes.  Key words: Seasickness, sailor, naval person.
Acute Abdomen in a Peripheral Military Hospital
Authors: Matin MA , Siddiq AKMZ , Hasan MM
Published: March 2010

The term 'acute abdomen' is widely used but poorly defined. Essentially it represents a rapid onset of severe symptoms that may indicate a life threatening intra-abdominal pathology. This observational study was carried out at Combined Military Hospital (CMH) Ghatail (n=87) and CMH Momenshahi (n=63) from June 2006 to June 2007. A total of 150 patients admitted in the surgery ward clinically diagnosed as acute abdomen were studied. The goal of evaluating the patient with acute abdominal pain was to establish an early, efficient, and accurate diagnosis. When evaluating a patient with acute abdominal pain, the most important elements in making an accurate early diagnosis were the patient's history and physical examination. Acute abdominal pain was more common in the age group 21 to 30 years (50%) with female predominance (72.67%). Some patients presented without any associated symptoms other than abdominal pain, other presented with vomiting and fever in addition to abdominal pain. Sixty two (41.33%) patients had no positive findings in laboratory investigation; radiology and ultrasonography. Most of them did not require any surgical intervention. Large fraction of cases (40%) was diagnosed as non specific abdominal pain. Maximum patients (59.33%) responded with conservative management and 40.67% patient required operative treatment. Key words: Acute abdomen, conservative management, non specific pain abdomen. DOI: 10.3329/jafmc.v5i2.4582 JAFMC Bangladesh Vol.5(2) (December) 2009, pp.36-39
Adolescent Mycardial Infarction with Normal Coronary Artery: A Case Report
Authors: Malik FN , Ahmed MN , Ahmed N , Badiuzzaman M , Dutta AK , Banik D , Rahman MH , Huq TS , Kabiruzzaman M , Rashid TBA , Kalimuddin M , Ahmed S , Asaduzzaman M
Published: March 2010

Acute myocardial infarction may occur in adolescent with angiographically normal or near normal coronary arteries but the pathophysiology remain unclear. This mechanism includes in situ thrombosis or embolization with subsequent clot lysis and recanalization and vascular endothelial dysfunction, per se or combined. An one adolescent male having acute myocardial infarction (inferior with posterior with right ventricular infarction) was reported with no anomalous coronary artery nor history of risk factors for coronary artery disease and no history of drug abuse. He was thrombolysed in addition to per oral clopidegrol (600mg) and aspirin (300 mg) and other conventional anti-ischemic treatment. Two hours later the patient was pain free and there was complete resolution of ST segment. Five days later he was scheduled for coronary angiography. Key words: Adolescent myocardial infarction, coronary artery. DOI: 10.3329/jafmc.v5i2.4583 JAFMC Bangladesh Vol.5(2) (December) 2009, pp.40-43
Hydatid Cyst of Spleen
Authors: Bhuiyan MJH , Siddiq AKMZ , Akhter L
Published: March 2010

DOI: 10.3329/jafmc.v5i2.4584 JAFMC Bangladesh Vol.5(2) (December) 2009, pp.44-45
Preexcitation Syndrome Presented with Ventricular Tachycardia - A Case Report
Authors: Alam MR , Hussain SMB , Ahsan MN , Siraj SB
Published: March 2010

An adult unconscious patient was brought to intensive care unit (ICU) with impalpable peripheral pulse, non-recordable blood pressure (BP), gross pallor, cyanosis, sweating and gasping respiration along with very rapid and feeble carotid pulse. It revealed ventricular tachycardia on monitor and was revived successfully by immediate direct current (DC) cardioversion along with other resuscitative measures. There was no contributory past history. Subsequent electrocardiogram (ECG) on sinus rhythm was diagnosed as Wolff-Parkinson-White (WPW) syndrome, the most prominent manifestation of preexcitation syndrome, in which the most common tachyarrhythmia is atrio-ventricular reciprocating tachycardia (AVRT). It is classified as orthodromic (more common) or antidromic (less common). Antidromic AVRT is difficult to distinguish from ventricular tachycardia on ECG. Atrial flutter and fibrillation are less common but potentially more serious because they can result in rapid ventricular response rates and, in rare instances, ventricular fibrillation. However, any sustained symptomatic tachyarrhythmia warrants urgent resuscitative electrical and pharmacological maneuver and interventions to restore life, regarding which the health care providers should always remain familiar and updated by Continuing Medical Education (CME). Key words: Wolff-Parkinson-White syndrome, tachyzrrhythmia, preexicitation syndrome. DOI: 10.3329/jafmc.v5i2.4585 JAFMC Bangladesh Vol.5(2) (December) 2009, pp.46-48
In Vitro and In Vivo Evaluation of a Calcium Phosphate and Demineralized Bone Matrix Composite Biomaterial
Authors: Rosenberg A. , Tofighi Aliassghar , Camacho N. , Chang J.
Published: March 2010

A new class of osteoconductive and osteoinductive combination biomaterials composed of calcium phosphate cement (CPC), demineralized bone matrix (DBM) and a water-soluble viscosity modifier were prepared and characterized in-vitro and in-vivo. In previous studies, a range of combinations formulations were tested in order to compare their performance characteristic. In-vitro characterization results show that the mechanical strength is decreased when the amount of DBM increases. However, DBM does not affect the CPC’s ability to set hard and convert to nanocrystalline apatitic calcium phosphate, which shares the chemical structure of natural bone as seen in x-ray diffraction. It is known that the DBM alone is osteoinductive. In-vivo osteoinductivity testing of the formulations in an intramuscular, athymic rat model demonstrated that the combination material is also osteoinductive. Two formulations were chosen for in-vivo efficacy testing based on the results of in-vitro and in-vivo characterization. These formulations were studied using rabbit critical-sized femoral core defect model. The formulations were composed of DBM with particle sizes of 250 to 710 μm, carboxymethyl-cellulose (CMC) as the viscosity modifier and weight percent compositions of 50% DBM/ 45% CPC/ 5% CMC and 60% DBM/ 30% CPC/ 10% CMC. Bone integration and healing was graded at 6, 12, and 24 weeks. The two formulations were compared to the gold standard autograft at 12 weeks and to an empty defect as the negative control at 24 weeks. Based on micro-computed topography (μCT), both formulations allowed for continuity of bone throughout the defect region at all time points. No differences in dense area fraction were seen between two formulations at 6 weeks (p = 0.8661). There was no significant statistical difference between the two formulations and autograft at 12 weeks (p = 0.2467). At 24 weeks, both formulations had significantly higher dense area fractions than empty controls (p = 0.0001). Histologically, the biology of the treatment areas appeared to have returned to normal by 24 weeks with CPC appearing to be the principal osteogenic inducer. In conclusion, these combinations of CPC and DBM offers significant advantages (handling, mechanical properties and osteoinductivity) over current DBM products and can be an effective alternative to autograft in healing of bone defects.
Titanium Surface Modification Techniques for Implant Fabrication – From Microscale to the Nanoscale
Authors: Subramani Karthikeyan
Published: March 2010

This manuscript reviews about titanium surface modification techniques for its application in orthopaedic and dental implants. There are a few limitations in the long term prognosis of orthopaedic and dental implants. Poor osseointegration with bone, periimplant infection leading to implant failure and short term longevity demanding revision surgery, are to mention a few. Micro- and nanoscale modification of titanium surface using physicochemical, morphological and biochemical approaches have resulted in higher bone to implant contact ratio and improved osseointegration. With recent advances in micro, nano-fabrication techniques and multidisciplinary research studies focusing on bridging biomaterials for medical applications, TiO2 nanotubes have been extensively studied for implant applications. The need for titanium implant surface that can closely mimic the nanoscale architecture of human bone has become a priority. For such purpose, TiO2 nanotubes of different dimensions and architectural fashions at the nanoscale level are being evaluated. This manuscript discusses in brief about the in-vitro and in-vivo studies on titanium surface modification techniques. This manuscript also addresses the recent studies done on such nanotubular surfaces for the effective delivery of osteoinductive growth factors and anti bacterial/ anti inflammatory drugs to promote osseointegration and prevent peri-implant infection.
Performance of Surfactant Flooding in Heterogeneous Two-Layered Porous Media
Authors: Fathaddin M.T. , Buang P.N. , Elraies K.A.
Published: March 2010

In this paper, simulation study was conducted to investigate the effect of spatial heterogeneity of multiple porosity fields on oil recovery, residual oil and microemulsion saturation. The generated porosity fields were fed into UTCHEM for simulating surfactant flooding in heterogeneous two-layered porous media. From the analysis, surfactant flooding was more sensitive than water flooding to the spatial distribution of multiple porosity fields. Residual oil saturation in upper and lower layers after water flooding was about the same with the reservoir heterogeneity. On the other hand, both residual oil and microemulsion saturation in the two layers after surfactant flooding became more equal as porosity distribution standard increased. Spatial heterogeneity of multiple porosity fields had only a small effect on residual oil saturation and recovery factor. The variation of recovery factor due to the reservoir heterogeneity was under 4.2%.
Markov Chain Analysis of Accident Data: The Case of an Oil and Gas Firm in the Niger Delta Area of Nigeria
Authors: Igboanugo A.C.
Published: March 2010

Concerned that management of job-oriented accidents has remained a daunting challenge for all stakeholders in Nigeria oil-industry, a longitudinal study was made to appraise the patterning of episodic incidence of industrial accidents in a typical oil and gas company operating in the Nigeria flank of the oil-rich Niger Delta Basin. A 10-year historical accident data were characterized and found to have absorbing chain properties. Four open-and-shot transition states namely : fatality, accident, near-miss and unsafe act, that are subject to ergodicity, were identified and used to craft a value digraph which define the stable transition probability matrix. The results, which suggest that on the average, 59% of staff are wasted through fatality or severe accidents, also points to escalating rates of fatalities and disabilities stemming from accidents thus calling for the need to review the existing hazard operations studies (HAZOPS) and hazard identification schemes (HAZIDS) so as to assist in whittling down, as low as reasonably practicable, the perceived unpleasant trend. The author is of the opinion that industrial accident victims, unlike in road traffic accident (RTA), habituate several times before entering the absorbing state.
Stabilizing Effect of Biobased Additives on the Thermal Degradation of PVC
Authors: Egbuchunam T.O. , Okieimen F.E. , Balköse D.B.
Published: March 2010

Novel biobased additives prepared from rubber seed oil were evaluated as thermal stabilizer for PVC. Divalent metal (barium and cadmium) soaps of rubber seed oil were prepared by metathesis in aqueous alcohol and characterized by thermal methods (differential scanning calorimetry and thermogravimetry). The stabilizing effect of the soaps and their admixtures on the thermal degradation of PVC powder and plasticized PVC was examined by dynamic thermogravimetry and dehydrochlorination studies at 160oC using the Thermomat equipment. The metal soaps showed multiple decomposition endotherms but were generally stable (with weight loss less than 5%) within the temperature range (180 – 220oC) frequently used in the processing of PVC. Using the Broido model, values of apparent activation energy of decomposition of between 50 and 200 kJmol-1 were obtained for the soaps. The biobased additives were found to be relatively effective in stabilizing PVC in powder and plasticized forms against thermal degradation. Using inhibition/retardation time, temperature of incipient decomposition, and temperature at which various extents of decomposition was attained as indices of thermal stabilization, the results from this study indicate a potential for the application of the biobased additives as thermal stabilizer for PVC in rigid and flexible formulations.
A Study of Load Capacity of Finite Slider Bearings with Slip Surfaces and Stokesian Couple Stress Fluids
Authors: Oladeinde M.H. , Akpobi John A.
Published: March 2010

A mathematical model for the hydrodynamic lubrication of finite slider bearings with velocity slip and couple stress lubricants is presented. A numerical solution for the mathematical model using finite element scheme is obtained using four node linearly interpolated quadrilateral elements. Stiffness integrals obtained from the weak form of the governing equations were solved using Gauss Quadrature to obtain a finite number of stiffness matrices. The global system of equations was obtained for the bearing and solved using Gauss Seidel iterative scheme. The converged pressure solution was used to obtain the load capacity of the bearing. Numerical experiments reveal the existence of an optimum velocity slip for which maximum benefit is obtained for the slider bearing in terms of bearing load. Increase in the slip parameter beyond this optimum value was shown not to augment the bearing load. Computations put forth also affirm that the bearing load is augmented with increase in couple stress parameter. An optimal film thickness ratio was also obtained for which load capacity is maximized with or without the application of slip to the bearing surfaces.
Optimization of Thermofluid Systems with Second Law
Authors: Adavbiele A.S.
Published: March 2010

This paper presents an overview of the concept of second law applications to all processes of thermofluid systems. The presentation is motivated by the need for engineers to be familiar with the new concept of exergy and entropy generation minimization, EGM which are used to design industrial production plants or individual components to maximize their energetic efficiency, and to minimize their environmental impact. It is essential for understanding to what extent resource and energy scarcities, nature’s capacity to assimilate loss as well as the irreversibility of transformation processes, constrain economic action. With these techniques and computational fluid dynamics, CFD, which is used for the conversion of the differential equations of flow to algebraic equations, designers can use the second law to focus on particular regions where design modifications can be made to improve and optimize thermofluid systems performance. Two case studies of exergy/EGM computations are presented for the design of open cycle simple gas turbine and vapour compression refrigeration.
Sol-Gel Synthesis and Structural Characteristics of Optical Y3Al5O12:Eu3+ Thick Films
Authors: Carrillo Romo Felipe J. , García Murillo A. , Ramírez Meneses Esther , Torres Orozco Claudia , Morales-Ramírez Ángel de Jesús
Published: March 2010

Thick films of Y3Al5O12:Eu3+ were dip-coated on silica substrate from sols. The synthesis was accomplished by using aluminium tri-sec-butoxide, yttrium chloride and europium nitrate as starting materials and isopropanol as solvent. Single-crystalline Y3Al5O12:Eu3+ cubic perovskite thick films were analyzed by X-Ray Diffraction and confirmed by Atomic Force Microscopy observations. The Y3Al5O12:Eu3+ thick film waveguiding properties was studied using an He-Ne laser (632.8 nm) for “m-lines” spectroscopy (MLS), which showed that film thickness and refractive index were 1.3 µm and 1.6385  0.001, respectively, after 1100 °C heat treatment. The increase is associated with film crystallization produced by different heat treatments.
Structural Studies of ZnS Nanoparticles by High Resolution Transmission Electron Microscopy
Authors: Gayou V.L. , Salazar Hernández B. , Delgado Macuil R. , Zavala G. , Santiago P. , Oliva A.I.
Published: March 2010

Zinc sulfide (ZnS), a representative of wide band gap semiconductor nanocrystals, has an excitonic Bohr radius (aBZnS ) of 2.5 nm. It makes ZnS nanoparticles (ZnS NP) having such size very interesting as small biomolecular probes for fluorescence and laser scanning microscopy. To date, ZnS NP of diameters larger than aBZnS has been subject of extensive experimental and theoretical studies. However many questions remain open concerning the synthesis of undoped and uncapped ZnS NP of diameters less than 2.5 nm. To further probe into the physical properties of undoped and uncapped ZnS NP, in this work we report on studies of uncapped ZnS nanoparticles synthesized by a wet chemical process at room temperature. Three colloidal suspensions (named A, B and C, respectively) were obtained from 9:1, 1:1 and 1:9 volume mixtures of 1mM ZnSO4 and 0.85mM Na2S aqueous solutions. Qualitative differences in UV-Vis absorption spectra are discussed in the context of Z-contrast scanning transmission electron microscopy (Z-contrast), low and high resolution transmission electron microscopy (TEM) results. Distribution of particle size is dependent on different volumes of source solutions. For the intermediate mixture, it has been found that about 78% of ZnS nanoparticles have a diameter smaller than the excitonic Bohr Radius of 2.5 nm. HRTEM studies have revealed that nanoparticles grow preferentially with hexagonal structure.
Estimation of Interaction Parameter and Structure Factor of Specific Drug Delivering Fluorocarbon Nanosystems
Authors: Ravi S. , Arockia Jayalatha K.
Published: March 2010

From the theoretical point of view, characterization of nano particle interaction depends much on the particle diameter , packing factor , the parameter of the Lennard-Jonnes (LJ) pair potential function  (r) and static structure factor S (Q). A novel method suggested in this paper has been tested on seven specific drug delivering fluorocarbons by estimating the strength of interaction /k of  (r) and S(Q) in terms of the elementary parameter . The importance of this paper is that, the input parameter viz., packing factor has been obtained from the experimental ultrasonic velocity of those seven systems. Calculations were extended for different temperatures involving four different equations of states to back up the application of the model. Though there is a lack of analytical results to compare, our predictions are encouraging.
Structure Study of ZnO:Eu with the Supercell Method
Authors: Blanca-Romero A. , Flores-Riveros A. , Rivas-Silva J.F.
Published: March 2010

One of the interests on the study of doped materials with rare earths in their bulk or nanoscale size is owing to the enhancement of the intensity of light in their photoluminescence when a lanthanide exists in a receptor material, as ZnO in our case. Until now, one of the most useful theories for calculations of electronic properties in molecular and solid state systems is the Density Functional Theory (DFT), which is not capable to manage well the presence of high localized electrons, as in lanthanide compounds in general and the doped case in particular. We propose to study these materials with super cell model using some correction to the standard calculations. For this goal, we employ the WIEN2k [1] code using the LDA+U approximation to take into account the strong correlation of the f electrons coming from the lanthanide. We emphasise the study of deformation due to the presence of Eu ion in the structure of host material, optimizing the position of neighboring Oxygen atoms. This deformation has been related to Kondo Resonance [2] appearing around the Fermi Energy of the compound, due to hybridization [3] among the f electrons from rare earth and neighboring oxygen levels.
CSVT as a Technique to Obtain Nanostructured Materials: WO3-x
Authors: Goiz O. , Chávez F. , Felipe C. , Peña-Sierra R. , Morales N.
Published: March 2010

The growth of tungsten oxide nanowires on silicon substrates without using any catalyst is demonstrated by means of close-spaced vapor transport (CSVT) technique at atmospheric pressure. The source was formerly prepared from a tungsten foil to produce a tungsten oxide film. CSVT array is completed with silicon substrates located at a distance of ~350 m over the tungsten oxide source at moderate temperatures (~750°C). Two distinct kinds of nanostructures were produced; a uniform distribution of free standing tungsten oxide wires of several micrometers in length with diameters less than 150 nm; and wires assembled to form nanowire bundle. The X-ray diffraction characterizations show that the phases of WO2.7 and WO2.9 are present.
Formation of SiOF Films by APCVD Using TEOS-O3-HF Gas Mixture
Authors: Pacio Mauricio , Juárez H. , Díaz-Becerril T. , Rosendo-Andrés E. , García-Salgado G. , Escalante G. , Ramirez G.
Published: March 2010

Fluorinated silicon oxide (SiOF) films have been prepared in a conventional atmospheric pressure chemical vapor deposition (APCVD) reactor. APCVD technique utilizes tetraethoxysilane, ozone and hydrofluoric anhydride as gas sources. SiOF films are deposited by changing the temperature of deposit. Substrate holder was maintained in the temperature range of 200 to 275°C. Films were characterized based on the deposition temperature. Chemical bonding structure of the films was evaluated by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and ellipsometry techniques. FTIR spectra revealed Si-F bond at about 935 cm-1. Incorporation of fluorine has a minimal contribution in the reduction of refractive index of SiOF films from 1.46 to 1.35.Therefore, the main mechanism responsible for this reduction of refractive index is the porosity generated by incorporation of fluorine atom in the SiOF films. Dielectric constant was reduced from 4.2 corresponding to that of SiO2 films, to the values in the range of 3.18 to 3.6 for SiOF films deposited by APCVD technique.
Microstructure and Mechanical Properties of Nano-Crystalline Al-Mg-Mn System
Authors: Ebnalwaled A.A. , Abou Zied M.
Published: March 2010

Nano - crystalline Al-Mg-Mn was synthesized by ball milling technique. Microstructure of these alloys has been studied from X-ray line broadening. The crystallite size of nano - crystalline Al-Mg-Mn system decreases by increasing the Mg content, While the micro-strain, median diameter,, and geometrical standard deviations,  increases by increasing the Mg content. Micro-hardness of our system has been investigated by Vickers hardness test. The hardness increases by increasing the Mg content.
Preparation by Prato Reaction and UV-Characterization of Several Fulleropyrrolidines
Authors: Jiménez Gómez M.A. , Garza Castañón Mauricio , Kharissova O.V. , Kharisov B.I. , Ortiz Méndez U.
Published: March 2010

1-methyl-2-phenylfulleropyrrolidine (1), 1-methyl-2-(4-(1-piperidyl)-phenyl)-fulleropyrrolidine (2), 1-methyl-2-(4-fluorophenyl)-fulleropyrrolidine (3) and 1-methyl-2-(3-hydroxy-2-naphtyl)-3,4-fulleropyrrolidine (4) were synthesized by Prato reaction and characterized in the reaction mixture by UV-Vis spectroscopy and matrix assisted laser desorption ionization (MALDI). A comparison of theoretical and experimental UV spectra was carried out.
T Cell Ig Domain and Mucin Domain 1 Engagement on Invariant NKT Cells in the Presence of TCR Stimulation Enhances IL-4 Production but Inhibits IFN-γ Production
Authors: Kim Hye Sung , Kim Hyun Soo , Lee Chang Woo , Chung Doo Hyun
Published: March 2010

The T cell Ig domain and mucin domain (TIM)1 protein expressed on the surface of Th2 cells regulates the immune response by modulating cytokine production. However, the functional roles of TIM1 have not been examined in NKT cells. Therefore, we investigated the immunologic effects of TIM1 on NKT cells. We found that mouse NK1.1+TCR-β+, α-galactosyl ceramide/CD1d dimer+ NKT, and NKT hybridoma (DN32.D3) cells constitutively express TIM1 and TIM4 on their surface. Engagement of TIM1 on NKT cells by any of several anti-TIM1 mAbs suppressed the production of IFN-γ in the presence of TCR stimulation in vitro and in vivo, whereas the effects of such engagement on Th2 cytokine production by the NKT cells varied with the particular anti-TIM1 Ab clone. Moreover, in DN32.D3 TIM4-knockdown NKT hybridoma cells, TIM1 engagement by rTIM1 or TIM4 enhanced IL-4 production while inhibiting IFN-γ production in the presence of α-galactosyl ceramide stimulation. TIM1 engagement increased GATA-3 expression but reduced T-bet expression in NKT cells in the presence of TCR engagement. The adoptive transfer of NKT cells preincubated with anti-TIM1 mAbs into Jα18−/− mice aggravated bleomycin-induced pulmonary fibrosis by suppressing IFN-γ production. Taken together, these results suggest that TIM1 costimulation on NKT cells enhances the cellular production of IL-4 while inhibiting the production of IFN-γ. Thus, as a differential regulator of the immune response, TIM1 on NKT cells may be a useful therapeutic target for immune diseases.