Cryopreservation of bovine semen using extract of Cinnamomum zeylanicum.

BACKGROUND: Antioxidants minimise oxidative stress and enhance sperm quality in the process of cryopreservation. OBJECTIVE: To assess the impact of Cinnamomum zeylanicum extract as an additive during the post-dilution and post-thaw stages of Murrah buffalo semen cryopreservation. MATERIALS AND METHODS: The semen sample was diluted using Tris-Egg-Yolk-Citric-Acid-Fructose-Glycerol extender and subsequently divided into three groups: Group 1, TEYCAFG without any additives or controls (C); Group 2, TEYCAFG fortified with a 50 ug/mL aqueous extract of cinnamon (T1); and Group 3, TEYCAFG fortified with a 50 ug/mL ethanolic extract of cinnamon (T2). The evaluation included an assessment of progressive motility, live spermatozoa, sperm abnormalities, HOST, CMPT, and enzyme leakage (GOT and GPT) at both the post-dilution and post-thaw stages. RESULTS: The groups that received cinnamon supplementation demonstrated statistically significant improvements (p<0.05) in various parameters, including an increase in the progressive motility, live spermatozoa, and HOS-positive spermatozoa, as well as greater distance traveled by vanguard spermatozoa compared to the control group. Furthermore, the cinnamon-added groups exhibited a significant decrease (p<0.05) in the percentage of sperm abnormalities and lower enzyme leakage (GOT and GPT) in post-thawed semen. CONCLUSION: Aqueous extract of C. zeylanicum at a concentration of 50 µg/mL provides superior protection of sperm structures and functions as compared to both the ethanolic extract of C. zeylanicum at the same concentration and the control group. Doi.org/10.54680/fr24310110712.

Benign and Malignant Oral Lesion Image Classification Using Fine-Tuned Transfer Learning Techniques.

Oral lesions are a prevalent manifestation of oral disease, and the timely identification of oral lesions is imperative for effective intervention. Fortunately, deep learning algorithms have shown great potential for automated lesion detection. The primary aim of this study was to employ deep learning-based image classification algorithms to identify oral lesions. We used three deep learning models, namely VGG19, DeIT, and MobileNet, to assess the efficacy of various categorization methods. To evaluate the accuracy and reliability of the models, we employed a dataset consisting of oral pictures encompassing two distinct categories: benign and malignant lesions. The experimental findings indicate that VGG19 and MobileNet attained an almost perfect accuracy rate of 100%, while DeIT achieved a slightly lower accuracy rate of 98.73%. The results of this study indicate that deep learning algorithms for picture classification demonstrate a high level of effectiveness in detecting oral lesions by achieving 100% for VGG19 and MobileNet and 98.73% for DeIT. Specifically, the VGG19 and MobileNet models exhibit notable suitability for this particular task.

Emergence of a novel sublineage, MYMBD21 under SA-2018 lineage of Foot-and-Mouth Disease Virus serotype O in Bangladesh.

Foot-and-Mouth Disease (FMD) hinders the growth of the livestock industry in endemic countries like Bangladesh. The management and prevention of FMD are severely impacted by the high mutation rate and subsequent frequent generation of newer genotypes of the causative agent, Foot-and-Mouth Disease Virus (FMDV). The current study was conducted in nine districts of Bangladesh during 2019-21 to characterize the circulating FMDV strains based on the VP1 sequence analysis, the major antigenic recognition site providing serotype specificity and high variability of FMDV. This study detected the first emergence of the SA-2018 lineage in Bangladesh along with the predominance of Ind-2001e (or Ind-2001BD1) sublineage of ME-SA topotype under serotype O during 2019-21. The mutational spectrum, evolutionary divergence analysis and multidimensional plotting confirmed the isolates collected from Mymensingh districts, designated as MYMBD21 as a novel sublineage under the SA-2018 lineage. Analysis of the amino acid sequence revealed several changes in the G-H loop, B-C loop and C-terminal region of VP1, revealing a 12-13% divergence from the existing vaccine strains and a 95% VP1 protein homology, with most of the mutations potentially considerable as vaccine escape mutations, evidenced by three-dimensional structural analysis. This is the first report on the emergence of the SA-2018 lineage of ME-SA topotype of FMDV serotype O in Bangladesh, as well as a possible mutational trend towards the emergence of a distinct sublineage under SA-2018 lineage, which calls for in-depth genome-wide analysis and monitoring of the FMD situation in the country to implement a strategic vaccination and effective FMD control program.

Factors associated with low childhood immunization coverage among Rohingya refugee parents in Cox's Bazar, Bangladesh.

INTRODUCTION: Immunization campaigns and Expanded Program on Immunization (EPI) were launched by Government of Bangladesh (GoB) in collaboration with WHO and other Non-governmental Organizations (NGOs) to tackle the increased risk of vaccine preventable disease outbreak in the Rohingya refugee camps. Immunization coverage was found to be lower than expected. However, a few studies explored the factors behind low vaccine uptake among Refugee children. Therefore, this study was aimed. METHODS: A cross sectional study was carried out among Rohingya parents living in registered camps and makeshift settlements located in Teknaf and Ukhiya upazilla of Cox's Bazar, Bangladesh. A total of 224 Rohingya parents were conveniently selected (122 parents from each type of camps). Data was collected using a pretested interviewer-administered semi-structured questionnaire with the help of bilingual volunteers who understand Rohingya dialect. All statistical analyses were carried out in IBM SPSS Version 26 (New York, USA). RESULTS: Total 63.1% of Rohingya parents had good practice regarding childhood immunization (completed EPI vaccination) as per schedule. Of all, 74.6% had good knowledge and 94.7% had positive attitude towards EPI vaccination. Good practice regarding vaccination was significantly more common among parents living in registered camps (77%) than those living in makeshift settlements (49.2%, p<0.001). Multivariable logistic regression analysis revealed that living in registered camps (Adjusted Odds Ratio [aOR]: 2.99; 95% Confidence Interval [CI]: 1.41-6.32) and good knowledge level (aOR: 2.88; 95%CI: 1.32-15.82) were independent determinants of good practice. A separate analysis in both type of camps revealed that in registered camps, good knowledge level (aOR: 3.62; 95%CI: 1.45-9.04) and having >2 children (aOR: 3.71; 95%CI: 1.34-10.27), and in makeshift settlements, father's employment (aOR: 2.33; 95%CI: 1.34-6.72), father's education (aOR: 3.00; 95%CI: 1.34-6.72) and presence of any electronic device (e.g., radio, television, mobile phone) (aOR: 4.01; 95%CI: 0.96-16.84) were significant determinants of good childhood immunization practice. CONCLUSION: Health education and promotion strategies should be implemented to increase knowledge and awareness about EPI immunization benefits among Rohingya parents to ensure greater coverage.

Nigelladine A among Selected Compounds from Nigella sativa Exhibits Propitious Interaction with Omicron Variant of SARS-CoV-2: An In Silico Study.

COVID-19 has been a threat to the entire world for more than two years since its outbreak in December 2019 in Wuhan city of China. SARS-CoV-2, the causative agent, had been reported to mutate over time exposing new variants. To date, no impeccable cure for the disease has been unveiled. This study outlines an extensive in silico approach to scrutinize certain phytochemical compounds of Nigella sativa (mainly the black cumin seeds) targeting the spike protein and the main protease (Mpro) enzyme of the Omicron variant of SARS-CoV-2. The objective of this study is to investigate the extracted compounds with a view to developing a potential inhibitor against the concerned SARS-CoV-2 variant. The investigation contemplates drug-likeness analysis, molecular docking study, ADME and toxicity prediction, and molecular dynamics simulation which have been executed to elucidate different phytochemical and pharmacological properties of the tested compounds. Based on drug-likeness parameters, a total of 96 phytochemical compounds from N. sativa have been screened in the study. Interestingly, Nigelladine A among the compounds exhibited the highest docking score with both the targets with the same binding affinity which is -7.8 kcal/mol. However, dithymoquinone, kaempferol, Nigelladine B, Nigellidine, and Nigellidine sulphate showed mentionable docking scores. Molecular dynamics up to 100 nanoseconds were simulated under GROMOS96 43a1 force field for the protein-ligand complexes exhibiting the top-docking score. The root mean square deviations (RMSD), root mean square fluctuations (RMSF), radius of gyration (Rg), solvent accessible surface area (SASA), and the number of hydrogen bonds have been evaluated during the simulation. From the findings, the present study suggests that Nigelladine A showed the most promising results among the selected molecules. This framework, however, interprets only a group of computational analyses on selected phytochemicals. Further investigations are required to validate the compound as a promising drug against the selected variant of SARS-CoV-2.

A Global Survey of Hypervirulent Aeromonas hydrophila (vAh) Identified vAh Strains in the Lower Mekong River Basin and Diverse Opportunistic Pathogens from Farmed Fish and Other Environmental Sources.

Hypervirulent Aeromonas hydrophila (vAh) has emerged as the etiologic agent of epidemic outbreaks of motile Aeromonas septicemia (MAS) in high-density aquaculture of farmed carp in China and catfish in the United States, which has caused millions of tons of lost fish. We conducted a global survey to better understand the evolution, geographical distribution, and phylogeny of vAh. Aeromonas isolates were isolated from fish that showed clinical symptoms of MAS, and pure cultures were screened for the ability to utilize myo-inositol as the sole carbon source. A total of 113 myo-inositol-utilizing bacterial strains were included in this study, including additional strains obtained from previously published culture collections. Based on a gyrB phylogeny, this collection included 66 A. hydrophila isolates, 48 of which were vAh. This collection also included five new vAh isolates from diseased Pangas catfish (Pangasius pangasius) and striped catfish (Pangasianodon hypophthalmus) obtained in Cambodia and Vietnam, respectively. Genome sequences were generated from representative vAh and non-vAh isolates to evaluate the potential for lateral genetic transfer of the myo-inositol catabolism pathway. Phylogenetic analyses of each of the nine genes required for myo-inositol utilization revealed the close affiliation of vAh strains regardless of geographic origin and suggested lateral genetic transfer of this catabolic pathway from an Enterobacter species. Prediction of virulence factors was conducted to determine differences between vAh and non-vAh strains in terms of virulence and secretion systems. Core genome phylogenetic analyses on vAh isolates and Aeromonas spp. disease isolates (55 in total) were conducted to evaluate the evolutionary relationships among vAh and other Aeromonas sp. isolates, which supported the clonal nature of vAh isolates. IMPORTANCE This global survey of vAh brought together scientists that study fish disease to evaluate the evolution, geographical distribution, phylogeny, and hosts of vAh and other Aeromonas sp. isolates. In addition to vAh isolates from China and the United States, four new vAh isolates were isolated from the lower Mekong River basin in Cambodia and Vietnam, indicating the significant threat of vAh to modern aquaculture and the need for improved biosecurity to prevent vAh spread.

Successful Multi-vessel Percutaneous Coronary Intervention for Recent Myocardial Infarction in a Patient with Dextrocardia and Situs Inversus.

Dextrocardia with situs inversus is a state which is characterized by abnormal positioning of the heart and other internal organs. It is a rare congenital anomaly and the exact cause is not known. More than 60 recognized genes are significant for the proper positioning and patterning of the organs in the body. However, a specific genetic cause of dextrocardia with situs inversus has not been identified and inheritance prototypes have not been established in the majority cases. There are partial available case reports of successful percutaneous coronary intervention (PCI) in these patients who have atherosclerotic coronary artery disease, especially when presenting with myocardial infarction. PCI is technically difficult because of dextrocardia. We hereby describe a 51-year-old male, who had a recent inferior wall myocardial infarction and underwent successful coronary angiography and PCI at a tertiary level hospital in Dhaka, Bangladesh.

Frequency and Risk Factors of Erectile Dysfunction among Bangladeshi Adult Men with Type 2 Diabetes Mellitus.

Various forms of sexual dysfunction occur in men with diabetes mellitus (DM) including disorders of libido, ejaculatory problems, and erectile dysfunction (ED). This cross sectional study was conducted in a tertiary hospital of Bangladesh from December 2017 to May 2018 to find out the frequency and risk factors of ED in subjects with type 2 DM (T2DM). One hundred fifty (150) consecutive male patients with T2DM attending the Endocrinology outpatient department (OPD) of the hospital during the study period were evaluated for the presence of ED by using the International Index of Erectile Function-5 (IIEF-5) questionnaire; their socio-demographic, anthropometric, and clinical data were also recorded. Glycemic status was assessed by measurement of fasting plasma glucose (FPG) and HbA1c. Morning serum testosterone was measured in all. Among 150 subjects 68(45.3%) had ED; ED was mild in 14.7%, mild to moderate in 18.0%, moderate in 6.0% whereas severe ED was present in 6.7% of the subjects. The subjects with ED had higher mean age, longer duration of DM, higher body mass index (BMI), higher HbA1c, higher FPG, higher serum creatinine, and lower serum testosterone level than those without ED. Study subjects in the higher age group and higher duration of DM had higher frequencies of ED. IIEF-5 score showed significant negative correlation with age, duration of DM, HbA1c, fasting plasma glucose, serum creatinine and significant positive correlation with serum testosterone. In logistic regression analysis, duration of DM and serum testosterone were found be independent predictors of ED. Frequency of ED among Bangladeshi type 2 diabetic males is high; duration of DM and serum testosterone are independent predictors of ED in them.

Performance evaluation of novel wet vibrational precipitator.

This study reports the development, construction, and initial testing of a novel vibrational precipitator (VP), patented at Ohio University in 2016, that uses vibrating metal cables with water running over them to capture particulate matter in an exhaust stream. Unlike traditional electrostatic precipitators relying on electric energy to capture particles, this new system uses the concept of vortex shedding to produce vibrations in vertical cables running perpendicular to an exhaust stream. Collisions between particles in the exhaust stream and these vibrating cables cause the particles to land onto a thin film of flowing water around the cables, which carries the particles downward for collection and removal. Initial tests with air containing particulates of 3 micron average particle size show capture efficiencies up to 54% using U.S. Environmental Protection Agency (EPA) Method 5 to measure the particulate concentrations at the upstream and downstream of a VP comprising 8 cells. These results show that this system, without consuming any electric energy, has a significant potential to be a simple and cost-effective way to treat particle-laden exhaust gases. Implications: In this work, for the first time, a novel precipitator is investigated that captures particles without using any particle charging and (hence) any electricity. The capture mechanism is governed by vibrations of collection electrodes, which are vertical steel cables wetted through continuous flow of water. Without any discharge electrodes, electrode suspension mechanism, and ability of the system to be installed in existing ducts, the novel precipitator becomes a simple chamber housing containing multiple collection electrode cells. The preliminary results show that this new technology can achieve net particulate matter capture efficiency of 54%. This paves a pathway forward for reducing capital and operating cost of air pollution control systems.

Integration of novel hybrid composite discharge electrode with semi-pilot novel cross-flow electrostatic precipitator.

Wet electrostatic precipitators (WESPs) are modern-era pollution control systems specifically designed to capture ultrafine particles as well as acid mist, highly resistive and sticky particles; however, this requires the use of expensive corrosion-resistant metal alloys. The work presented here is part of a continuing study at Ohio University aimed at reducing the cost of WESPs by using a novel combination of a polymer collector surfaces with a hybrid composite discharge electrode. In this study, a hybrid composite discharge electrode was tested, for the first time, inside a semi-pilot-scale experimental setup, with collection surfaces consists of a vertical array of strands. Particle laden gases were passed through this array of polymer ropes, which were kept wet by a small flow of water. The discharge electrodes were composite laminates of carbon fibers in a polymer matrix enclosing a metal mesh. The preliminary results showed that this new integrated system of composite discharge electrode and polymer collector surfaces can match or exceed the performance of a conventional metal alloy electrostatic precipitator (ESP) with metal discharge electrodes. There are additional advantages due to the system being compact, lightweight, and highly corrosion resistant. Implications: This study focused on integrating and assessing performance of a novel hybrid composite electrode (HCE) inside semi-pilot novel cross-flow electrostatic precipitator at conditions typically observed in coal-fired power plant exhausts. The results were collected for particulate collection efficiencies and were compared with a rigid metal electrode. The HCE outperformed metal electrode by showing higher particulate collection efficiency. This result showcases substantial potential for these two new technologies (HCE and cross-flow system) as a substitute for conventional metal based wet ESPs.

Plasma Neutrophil Gelatinase Associated Lipocalin (pNGAL) Level to Identify AKI Early in Patients Undergoing Cardiac Valve Surgery.

Cardiac valve surgery is considered one of the most frequent surgical procedures in which AKI is a common & serious complication. Although serum creatinine is routinely used as a marker of renal function, it poorly reflects the immediate post operative period renal function. Within minutes to few hours after a renal insult, plasma neutrophil gelatinase associated lipocalin (pNGAL) is released. The aim of this study was to assess the superiority of pNGAL over serum creatinine in detecting AKI in early post operative period. This prospective observational study was carried out in the Department of Nephrology of National Institute of Kidney Diseases & Urology in collaboration with National Institute of Cardiovascular Diseases (NICVD) & Dhaka Shisu Hospital (DSH) from January 2015 to December 2016. Total 120 patients were selected from inpatient ward of cardiovascular surgery department. According to inclusion & exclusion criteria total 80 patients were included who was undergone cardiac valve surgery. Serum samples for pNGAL were collected from study population 6 hours after completion of surgery & stored at -80°C, serum samples were also collected for serum creatinine day before surgery, in 1st post operative day (POD1) & 2nd post operative day (POD2). Total 79 patients undergoing cardiac surgery, who met the inclusion & exclusion criteria, were consecutively included. There were 44 male (55.69%) and 35 female (40.31%) ranged from 15-60 years, with mean age of 36 years. pNGAL level in the blood of AKI patients (244.19±59.61ng/ml) 6 hours after completion of surgery was significantly higher from the non AKI patients (171.73±68.63ng/ml). A positive significant correlation was found between pNGAL 6 hours after completion of surgery & serum creatinine at POD1, POD2. This study demonstrated that level of pNGAL concentration 6 hours after completion of cardiac valve surgery increased before the rise of serum creatinine level & can thus AKI can be detected earlier by pNGAL.

Study on Hemoglobin Concentration in Patient with Chronic Kidney Disease.

In the present study hemoglobin concentration were estimated in chronic kidney diseased patient to observe the frequency of low hemoglobin level in chronic kidney diseased (CKD) patient and to assess the incidence of anaemia. This cross sectional study was carried out in the department of Physiology of Mymensingh Medical College, Mymensingh, Bangladesh from July 2014 to June 2015. For this purpose, total 200 subjects with age ranged from 25 to 60 years were selected and divided into100 healthy persons as control group and 100 CKD patients as study group. Both control and study group were further divided into 50 male and 50 female. Hemoglobin concentration was evaluated by the Cyanmethemoglobin (CMG) method. Statistical analysis of data was done by unpaired student's 't' test. The results showed that hemoglobin levels decreased significantly in chronic kidney diseased patients than the normal healthy persons. The decreasing frequency of hemoglobin level in CKD may predispose the patients to anemia and increasing the other complications.

Interaction between Hypertension and Asthma in Adult.

Asthma has been defined as a chronic inflammatory disorder of the airways that is associated with recruitment of inflammatory cells and the clinical development of wheezing, shortness of breath, chest tightness, and cough. The prevalence of asthma increased steadily over the latter part of the last century, first in the developed and then in the developing world. Current estimates suggest that asthma affects 300 million people worldwide, with a predicted additional 100 million people affected by 2025. This cross sectional study was conducted from January 1999 to August 1999 on 5642 Bangladeshi people and another same study carried out from November 2009 to April 2010 on 8088 subjects. In 1999 the prevalence of asthma was 6.9% whereas in 2010 it is 6.96%. Both asthma and hypertension are spastic disorders of smooth muscle, there is the similarities between these two diseases may predispose the individuals with one disease to the other. This descriptive type of cross-sectional study was done to find the Interaction between hypertension and asthma in adult and carried out in the Department of Physiology, Mymensingh Medical College, Mymensingh, Bangladesh from July 2014 to January 2016. Fifty (50) male and fifty (50) female adult asthmatic patients aged 18-60 years were included in the study group. They are enrolled from the Department of Medicine, Mymensingh Medical College, Mymensingh and also from locality. For comparison age matched 50 male and 50 female apparently healthy persons were also studied as control. Blood pressure was estimated by auscultatory method by sphygmomanometer. For statistical analysis unpaired student's 't' test was used. Mean blood pressure were significantly increased in study group in comparison to control group and the result was statistically significant (p<0.001). The study findings showed a high prevalence of hypertension among asthmatic patients than non asthmatic healthy persons. From this study, it may be concluded that hypertension and asthma are closely connected.

Novel hybrid composite discharge electrode for electrostatic precipitator.

Over the last few decades, electrostatic precipitators (ESPs) have emerged as effective air pollution control devices for treating coal-fired power plant exhausts. Among the components of the ESP, the discharge electrodes are extremely important in determining the collection efficiency of the ESP. Typically, in wet ESPs, the discharge electrodes used must be made of corrosion-resistant alloys, which makes them extremely expensive and heavy. Hybrid composite discharge electrodes have the potential to be lightweight and corrosion-resistant substitute for traditional metal alloy electrodes used in wet ESPs. In this experimental study, a novel hybrid composite electrode (recently patented at Ohio University) is presented as a substitute for traditional metal electrodes in wet ESPs. The samples of hybrid electrodes were fabricated by using carbon fiber composites, combined with metal mesh, in the shape of a long and thin tape. The electrode's electrical response was evaluated in open atmospheric conditions, while connected to a transformer-rectifier unit to generate a corona current at voltages exceeding 50 kV. Results of these hybrid electrodes were compared with traditional metal electrodes. The hybrid composite discharge electrode produced a uniform corona at comparable power levels to that of metal electrodes, with additional advantages of being compact, lightweight, and highly corrosion resistant. In addition, hybrid composite electrodes exhibited lower corona onset voltage as compared with metal electrodes. The preliminary experimental data are encouraging and show significant potential for this new inexpensive hybrid electrode to replace metal electrodes in wet ESPs, providing comparable (and in some cases exceeding) collection efficiencies with lower ozone generation. IMPLICATIONS: The newly invented hybrid composite electrode (HCE) performance was evaluated through experimentation with conventional metal electrodes. The HCE performance was comparable to the metal electrodes. The HCE also exhibited uniform corona fields and steady power while maintaining similar and in some cases superior electrical performance as compared with metal electrodes and thus shows a significant potential to substitute metal electrodes in wet ESP systems.

Experimental study of cross-flow wet electrostatic precipitator.

This paper reports development and testing of a novel cross-flow wet electrostatic precipitator (WESP), recently patented at Ohio University, that utilizes vertical columns of permeable material in the form of polypropylene ropes placed in a cross-flow configuration within a flue gas stream. The cross-flow design has large surface area, which provides scrubbing action; therefore, it has the potential for removing multiple pollutants, including particulates, gases, vapors, and mists. In this new method, the ropes are kept wet by the liquid (water) introduced from the top of the cells running downward on the ropes by capillary action, making the permeable materials act as the ground electrode for capturing particles from the flue gas. Preliminary testing has shown an efficiency of well above 80% using two cells and three sets of discharge electrodes. Since the material of construction is primarily corrosion-resistant polymeric material, both weight and cost reductions are expected from this new design. IMPLICATIONS: The newly invented cross-flow WESP exhibit particulate collection efficiency of well above 80% when introduced in particulate-laden exhaust flow. This value was obtained using a two cells and three discharge electrodes configuration. The electric field strength has a substantial effect on the collection efficiency. Also, the pressure drop test results indicate that there is a potential to increase the collection area, which, in turn, will increase the collection efficiency further.

In-vitro analysis of forces in conventional and ultrasonically assisted drilling of bone.

BACKGROUND: Drilling of bone is widely performed in orthopaedics for repair and reconstruction of bone. Current paper is focused on the efforts to minimize force generation during the drilling process. Ultrasonically Assisted Drilling (UAD) is a possible option to replace Conventional Drilling (CD) in bone surgical procedures. OBJECTIVE: The purpose of this study was to investigate and analyze the effect of drilling parameters and ultrasonic parameters on the level of drilling thrust force in the presence of water irrigation. METHODS: Drilling tests were performed on young bovine femoral bone using different parameters such as spindle speeds, feed rates, coolant flow rates, frequency and amplitudes of vibrations. RESULTS: The drilling force was significantly dropped with increase in drill rotation speed in both types of drilling. Increase in feed rate was more influential in raising the drilling force in CD compared to UAD. The force was significantly dropped when ultrasonic vibrations up to 10 kHz were imposed on the drill. The drill force was found to be unaffected by the range of amplitudes and the amount of water supplied to the drilling region in UAD. CONCLUSIONS: Low frequency vibrations with irrigation can be successfully used for safe and efficient drilling in bone.

Experimental and numerical investigation of cracking behavior of cortical bone in cutting.

BACKGROUND: Bone cutting is a well-known surgical procedure in orthopaedics and dentistry for fracture treatment and reconstruction. Common complications associated with the process are mechanical damage linked with excessive levels of penetration force. Larger forces may produce minor cracks in bone which may seriously affect strength of fixation and may delay the healing process. OBJECTIVE: This paper investigates cracking behavior in the microstructure of cortical bone in cutting using experimental and numerical techniques. METHODS: Experiments were performed on cortical bone to study the mechanics of crack propagation and evaluate the extent of crack with the drilling force and amount of penetration. Finite element (FE) simulations were performed to visualize the extension and arrest of the cracks in bone microstructure. RESULTS: The length of crack was found to be strongly influenced by the drilling force and amount of drill penetration. Osteon were seen to deflect the cracks at their boundaries. Crack propagation in bone microstructure was observed to depend on anatomical direction. Numerical simulations predicted the direction of crack propagation and found osteon boundaries to act as barrier to the cracks. CONCLUSIONS: Lower drilling force may be used in cutting the bone to avoid cracks in the bone tissue. A detailed FE model based on fracture data of cortical bone is to be produced to simulate cracking of bone microstructure.

Comparative study of conventional and ultrasonically-assisted bone drilling.

BACKGROUND: Bone drilling is a well-known surgical procedure in orthopaedics and dentistry for fracture treatment and reconstruction. Advanced understanding of the mechanics of the drill-bone interaction is necessary to overcome challenges associated with the process and related postoperative complications. OBJECTIVE: The aim of this study was to explore the benefits of a novel drilling technique, ultrasonically-assisted drilling (UAD), and its possible utilization in orthopaedic surgeries. METHODS: The study was performed by conducting experiments to understand the basic mechanics of the drilling process using high speed filming of the drilling zone followed by measurements to quantify thrust force, surface roughness and cracking of the bone near the immediate vicinity of the hole with and without ultrasonic assistance. RESULTS: Compared to the spiral chips produced during conventional drilling (CD), UAD was found to break the chips in small pieces which facilitated their fast evacuation from the cutting region. In UAD, lower drilling force and better surface roughness was measured in drilling in the radial and longitudinal axis of the bone. UAD produced crack-free holes which will enhance postoperative performance of fixative devices anchoring the bone. CONCLUSIONS: UAD may be used as a possible substitute for CD in orthopaedic clinics.

Analysis of temperature in conventional and ultrasonically-assisted drilling of cortical bone with infrared thermography.

BACKGROUND: Bone drilling is widely used in orthopaedics, dental and neurosurgeries for repair and fixation purposes. One of the major concerns in drilling of bone is thermal necrosis that may seriously affect healing at interfaces with fixtures and implants. Ultrasonically-assisted drilling (UAD) is recently introduced as alternative to conventional drilling (CD) to minimize invasiveness of the procedure. OBJECTIVE: This paper studies temperature rise in bovine cortical bone drilled with CD and UAD techniques and their comparison using infrared thermography. METHODS: A parametric investigation was carried out to evaluate effects of drilling conditions (drilling speed and feed rate) and parameters of ultrasonic vibration (frequency and amplitude) on the temperature elevation in bone. RESULTS: Higher levels of the drilling speed and feed rate were found responsible for generating temperatures above a thermal threshold level in both types of drilling. UAD with frequency below 20 kHz resulted in lower temperature compared to CD with the same drilling parameters. The temperatures generated in cases with vibration frequency exceeding 20 kHz were significantly higher than those in CD for the range of drilling speeds and feed rates. The amplitude of vibration was found to have no significant effect on bone temperature. CONCLUSIONS: UAD may be investigated further to explore its benefits over the existing CD techniques.

Pleural effusion: An unusual cause and association.

Filaria has a wide spectrum of presentation. We hereby present a case of Filarial pleural effusion that is a rarity in itself. Filarial lung involvement is usually in the form of tropical pulmonary eosinophilia with pulmonary infiltrates and peripheral eosinophilia, unlike our case where isolated pleural effusion of Filarial etiology was detected. Microfilaria has been isolated from Pleural fluid in very few cases, and ours was one such. Of late, there have been many incidental detections of Filarial parasites from varied anatomical sites in association with malignancy. Even in our case, we had one such unusual association.