Computer simulation-based nanothermal field and tissue damage analysis for cardiac tumor ablation.

Radiofrequency ablation is a nominally invasive technique to eradicate cancerous or non-cancerous cells by heating. However, it is still hampered to acquire a successful cell destruction process due to inappropriate RF intensities that will not entirely obliterate tumorous tissues, causing in treatment failure. In this study, we are acquainted with a nanoassisted RF ablation procedure of cardiac tumor to provide better outcomes for long-term survival rate without any recurrences. A three-dimensional thermo-electric energy model is employed to investigate nanothermal field and ablation efficiency into the left atrium tumor. The cell death model is adopted to quantify the degree of tissue injury while injecting the Fe3O4 nanoparticles concentrations up to 20% into the target tissue. The results reveal that when nanothermal field extents as a function of tissue depth (10 mm) from the electrode tip, the increasing thermal rates were approximately 0.54362%, 3.17039%, and 7.27397% for the particle concentration levels of 7%, 10%, and 15% compared with no-particle case. In the 7% Fe3O4 nanoparticles, 100% fractional damage index is achieved after ablation time of 18 s whereas tissue annihilation approach proceeds longer to complete for no-particle case. The outcomes indicate that injecting nanoparticles may lessen ablation time in surgeries and prevent damage to adjacent healthy tissue.

Dynamic Treatment Regimes Using Bayesian Additive Regression Trees for Censored Outcomes.

To achieve the goal of providing the best possible care to each individual under their care, physicians need to customize treatments for individuals with the same health state, especially when treating diseases that can progress further and require additional treatments, such as cancer. Making decisions at multiple stages as a disease progresses can be formalized as a dynamic treatment regime (DTR). Most of the existing optimization approaches for estimating dynamic treatment regimes including the popular method of Q-learning were developed in a frequentist context. Recently, a general Bayesian machine learning framework that facilitates using Bayesian regression modeling to optimize DTRs has been proposed. In this article, we adapt this approach to censored outcomes using Bayesian additive regression trees (BART) for each stage under the accelerated failure time modeling framework, along with simulation studies and a real data example that compare the proposed approach with Q-learning. We also develop an R wrapper function that utilizes a standard BART survival model to optimize DTRs for censored outcomes. The wrapper function can easily be extended to accommodate any type of Bayesian machine learning model.

Role of Nuclear Morphometry in the Cytologic Evaluation of Benign and Malignant Thyroid Lesions.

Thyroid lesions are very common problem in Bangladesh. To categorize the type of lesion, FNAC is a reliable, minimally invasive and cost-effective diagnostic modality. In routine cytology, precise categorization into benign and malignant is highly subjective. So, additional methods are needed to improve the accuracy of cytological diagnosis. Computerized semi-automatic nuclear morphometry is an objective and reproducible tool for quantitative evaluation of nuclear features which may help to differentiate between benign and malignant thyroid lesions in cytology. Objective of the study was to apply morphometry with regard to nuclear size parameters, shape parameters and nuclear chromasia with derivation of suitable cutoff values to differentiate benign and malignant lesions of thyroid gland. This cross-sectional study was done in total 55 cases at the Department of Pathology, Bangabandhu Sheikh Mujib Medical University, Bangladesh from March 2018 to February 2020. Morphometry was done on images containing diagnostic cells captured from cytological smears with open source ImageJ morphometric software. In this study, all the nuclear size parameters and one nuclear shape parameter was found significant in differentiating benign and malignant lesions. No significant difference was observed in analysis of chromasia parameter. The cut-off values derived between all benign and malignant lesions for mean value of nuclear area, maximum feret diameter, perimeter and aspect ratio were 40.20µm², 8.46µm, 6.68µm, 28.28µm and 1.35 respectively with sensitivity of 86%, 95%, 81%, 90% and specificity of 97%, 93%, 97% and 97% respectively. The Nuclear morphometry may be used as an adjunctive tool to routine thyroid cytology.

Difference in presentation, outcomes, and hospital epidemiologic trend of COVID-19 among first, second, and third waves: a review of hospital records and prospective cohort study.

This study aimed to examine the differences in epidemiologic and disease aspects among patients with coronavirus disease-19 (COVID-19). Methods: The authors reviewed the hospital records between April 2020 and September 2021 and followed up on the patients for post-COVID complications. Findings: Older adult patients were predominantly affected during the third wave, and middle-aged patients were predominantly affected during the first and second waves. Men were predominantly admitted, considering the three waves, although more women were admitted in the second wave. Cough was more common in the second and third waves than in the first wave 522 (59.7%). Respiratory distress was the most common in the third wave, 251(67.1%), and least common in the first wave, 403 (46.1%). Anosmia was more common in the third wave 116 (31.2%). In the third wave, patients presenting in a critical state 23 (6.2%) and with severe disease 152 (40.8%) were more common. The hospital admission median (IQR) was longer in the first wave, 12 (8-20), than in other waves. More patients were admitted in the first wave (52%) than in the other waves, and patients received more oxygen in the third wave (75%) than in the other waves. Death occurred more commonly in the first wave (51%) than in the other waves. The positivity rate was higher in the third wave (22.8%) than in the other waves. In the third wave, the positivity rate was higher in women (24.3%) than in men. Post-COVID cough increased in the second wave, and fatigue was higher in the third wave than in the other waves. Tiredness and memory loss were greater during the second wave than in other waves. Conclusion: The authors found differences in the presentation, outcomes, and hospital epidemiologic trend of COVID-19 among the three waves.

A graphene-like BeS monolayer as a promising gas sensor material with strain and electric field induced tunable response: a first-principles study.

A comprehensive investigation of the gas sensing potential of BeS monolayer has been conducted using DFT calculations. Twelve common pollutant gases: NH3, NO2, NO, CO, CO2, CH4, H2, O2, N2, H2S, H2O and SO2, have been studied. Our analysis reveals defect states in the band structure near the Fermi level and strong hybridization between gas molecule orbitals and the BeS monolayer. We observe higher adsorption energies for NH3 and CO compared to other popular gas sensing materials. The optical properties of CO2 and NO2 adsorbed on the BeS monolayer show increased reflectivity and absorption coefficient in the UV and far infrared region. Tensile strain has minimal impact on adsorption energy, while biaxial compressive strains enhance the gas sensing capability of the BeS monolayer. The application of an electric field offers control over gas adsorption and desorption. We propose the BeS monolayer as a promising candidate for future gas molecule sensing applications due to its high adsorption energy, rapid recovery time, and distinct optical properties.

Extra Biliary Complications of Laparoscopic Cholecystectomy: Experience from a Study of 1420 Cases.

To evaluate the extra biliary complications of laparoscopic cholecystectomy and the outcome of management of those complications. This descriptive observational study was carried out at CMH Dhaka and CMH Jashore, Bangladesh from March 2016 to March 2022. A total of 1420 patients who underwent Laparoscopic cholecystectomy were included in this study. Extra biliary complications of laparoscopic cholecystectomy were divided into i) Access related ii) Intraoperative (procedure related) and iii) Postoperative complications. The incidence of access-related, intra-operative or procedure-related and postoperative complications was 2.88%, 4.91% and 1.82% respectively. Access related complications were extra-peritoneal insufflations 1.34%, port site bleeding 1.26%, small bowel laceration 0.21% and transverse colon injury 0.07%. Intraoperative or procedural extra biliary complications were liver injury 0.56%, duodenal perforation 0.07%, colon injury 0.07%, bleeding through cystic artery 0.49% and bleeding from gall bladder bed 1.12%. Postoperative complications were port site infection (PSI) 1.05%, port site hernia (PSH) 0.56%, major sepsis 0.14% and ischemic stroke 0.07%. Two of colonic injuries were the major complications encountered in this series, diagnosed during the procedure and converted to open procedure. Duodenal perforation encountered in one case during difficult dissection in the Callot's triangle, diagnosed during the procedure and managed laparoscopically by intra-corporeal suturing. No mortality reported in this series. Extra biliary complications are almost equally common as biliary complications in laparoscopic cholecystectomy and can be life-threatening. An early diagnosis and effective management of complications accordingly, are the utmost requirement for favorable outcome in laparoscopic cholecystectomy.

Effect of Ultrasonication Parameters on the Structural, Morphological, and Electrical Properties of Polypyrrole Nanoparticles and Optimization by Response Surface Methodology.

Polypyrrole (PPy) nanoparticles are reliable conducting polymers with many industrial applications. Nevertheless, owing to disadvantages in structure and morphology, producing PPy with high electrical conductivity is challenging. In this study, a chemical oxidative polymerization-assisted ultra-sonication method was used to synthesize PPy with high conductivity. The influence of critical sonication parameters such as time and power on the structure, morphology, and electrical properties was examined using response surface methodology. Various analyses such as SEM, FTIR, DSC, and TGA were performed on the PPy. An R2 value of 0.8699 from the regression analysis suggested a fine correlation between the observed and predicted values of PPy conductivity. Using response surface plots and contour line diagrams, the optimum sonication time and sonication power were found to be 17 min and 24 W, respectively, generating a maximum conductivity of 2.334 S/cm. Meanwhile, the model predicted 2.249 S/cm conductivity, indicating successful alignment with the experimental data and incurring marginal error. SEM results demonstrated that the morphology of the particles was almost spherical, whereas the FTIR spectra indicated the presence of certain functional groups in the PPy. The obtained PPy with high conductivity can be a promising conducting material with various applications, such as in supercapacitors, sensors, and other smart electronic devices.

Role of Nuclear Morphometry in the Cytologic Evaluation of Benign and Malignant Breast Lesions.

Breast cancer is the most common diagnosed cancer in female over the world. It is the most important cause of 'cancer death' among female. For diagnosis of breast masses the Fine needle aspiration cytology (FNAC) is applied as the primary tool. Though it is an easy, rapid and comparatively minimally invasive and inexpensive procedure for quick diagnosis, it is largely a subjective tool. Computer-assisted image morphometry provides a new influential method for high-precision measurement of nuclear features and can help to differentiate between benign and malignant breast aspirates. Therefore, the aim of study was to evaluate computer assisted semi-automatic nuclear morphometry on cytology of breast lesions to differentiate benign and malignant lesions of breast. Total 70 cases were included in this cross sectional study, performed in the department of Pathology, Mymensingh Medical College, Mymensingh, Bangladesh from March 2019 to February 2021. Morphometric analysis was done on images captured from FNAC slides of the selected cases. Image J Morphometric Software was used for image analysis. Statistical analysis was done by using SPSS 26.0 version. On analysis of morphometry, four nuclear size parameters, two nuclear shape parameters and one nuclear chromasia parameter were measured. The cut-off values with sensitivity and specificity between benign and malignant category for mean nuclear area were 61.54µm², 91.0%, 97.0%, for mean maximum feret diameter 10.89µm, 94.0%, 95.0%, for mean minimum feret diameter 7.71µm, 94.0%, 97.0% and for mean nuclear perimeter 33.32µm, 94.0%, 95.0% respectively. So, in this observation, morphometry is adjunctive tools which may overcome the limitations of inter observer agreement, improve diagnostic accuracy and avoid unnecessary repeat Fine Needle Aspiration (FNA) in breast aspirates.

Vascular Endothelial Growth Factor Expression in Colorectal Adenocarcinoma of Resected Samples and its Association with Histological Grade and Pathological Stage.

Colorectal carcinoma (CRC) is one of the major public health problems. Vascular endothelial growth factor (VEGF) is an effective angiogenic factor and plays a pivotal role in the development, progression and metastasis of CRC. It also could further help in selecting patients of high risk of disease progression for adjuvant therapy. Therefore, this study was undertaken to reveal the importance of angiogenic factor (VEGF) as an adjunctive tool with histologic parameters of CRC. Total 45 cases were included in this cross-sectional observational study, performed in the department of Pathology, Mymensingh Medical College, Mymensingh and Immunohistochemistry was done in the department of Pathology, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh from March 2019 to February 2021. All the cases were evaluated for VEGF immunohistochemical expression. Majority of cases were low grade adenocarcinoma (86.9%) and most common stage was stage III (48.9%). Among 45 cases collectively 13 (4-negative + 9-weak positive) cases were low for VEGF expression and 32 (22-moderate positive + 10-strong positive) cases were high for VEGF expression. Statistically significant association was found with VEGF expression and increasing tumor stage as well as with lymph node metastasis (p<0.05). VEGF had positive significant correlation with stage (r=0.322; p=0.031) of tumor. However, no correlation with VEGF expression and grade (r=0.219; p=0.149) and other clinicopathological parameters of tumor was seen.

Prevalence of Hepatitis B Virus Infection among Children with Liver Disease Admitted In Mymensingh Medical College Hospital.

Hepatitis B virus infection is an important cause of liver disease. Hepatitis B Virus may present with varying degree of severity. In older children, 5-10% cases leading to chronic liver disease, cirrhosis and hepatocellular carcinoma. This descriptive cross sectional study was done to assess the prevalence of Hepatitis B Virus infection among hospitalized children with liver disease in pediatric department of Mymensingh Medical College Hospital, Bangladesh from December 2015 to October 2016. All the children of both sexes having age between six months to twelve years admitted in the pediatric ward with acute or chronic liver disease were included in this study by purposive sampling. A written consent was obtained from legal guardian of children before inclusion. Ethical clearance was obtained from competent authority. A detailed history was taken from parents in each case according to pre-designed questionnaire about demography of the patients and the risk factors of the liver disease. A thorough clinical examination and available relevant investigations like serological testing for HBV infection was done in all patients. We had figure out the seropositivity of HBV among patients having liver disease by doing HBsAg and Anti-HBc IgM. Progress of the patient was monitored by daily clinical examinations and by investigating HBsAg and Anti-HBc IgM. Finally data analysis was done by SPSS version 21.0. Among total 100 patients most (44%) patients were in 7-10 years old and most (62%) of the participants were male. Acute liver disease was 58% cases and chronic liver disease was 42% cases. HBsAg was positive in 1 case among acute liver disease and 5 cases among chronic cases. Total 6 (six) patients were found positive for HBsAg. Anti HBc IgM was positive in 4 patients among acute liver disease. Among these Anti HBc IgM positive (4) patients only one had both HBsAg and Anti HBc IgM positive. So, four patients were confirming suffered from acute viral hepatitis because they had anti HBc IgM positive. On the contrary 5 patients suffered from chronic hepatitis by hepatitis B because they were only HBsAg positive. So, in this study 9 patients (9%) were confirming suffered from HBV infection. Possible transmission factors of hepatitis B were history of (H/O) blood transfusion/trauma/parenteral injection, H/O umbilical sepsis, H/O maternal illness/infection during pregnancy. HBV still is a major cause of morbidity. All the children with liver disease should be routinely tested for HBV.

Evaluation of Surgical Correction of Adolescent Idiopathic Scoliosis by Transpedicular Screws and Rods.

Transpedicular screw fixation is a challenging procedure for the correction of deformity of Adolescent Idiopathic Scoliosis (AIS) in the dorso-lumbar spine. The inadvertently misplaced screws have a high risk of complications. The exactness of the pedicle screws is normally distinct as the screws axis being fully enclosed within the cortices of the pedicle. Evaluation of the surgical correction of adolescent idiopathic scoliosis by transpedicular screws and rods was done in single posterior dynamic approach. This prospective observational study was conducted in the National Institute of Traumatology and Orthopedic Rehabilitation, Dhaka and different Hospitals in Dhaka, Bangladesh from July 2015 to March 2017. Ten patients at the age >9 years and <19 years who were admitted with a diagnosis of AIS during the period of study. The pedicle is a power nucleus of the vertebra and offers a secure grip of all 3 columns. Pedicle screw instrumentation has advantages of rigid fixation with improved 3D correction and it has been accepted as a reliable method with a high margin of safety. Accurate placement of the pedicle screws is important to reduce possible irreversible complication. So, all cases were corrected by transpedicular screws and rods in single posterior approach. In every case fusion was done in selected segments. In this study out of 10 patients 7(70.0%) were 10 to 14 years of age and 3(30.0%) were 15 to 18 years. Mean age 9.51±2.13 years. Minimum 10 years and maximum 18 years. Majority 7(70.0%) of the patients were female and the rest 3(30.0%) male. Five (50.0%) presented with level of involvement, 3(30.0%) patients thoracic and 2(20.0%) patients had lumbar. Maximum 7(70.0%) presented right sided involvement and rest 3(30.0%) left sided involvement. Before surgical intervention 100% patients had rib hump and positive Adams forward bending test, 70.0% patients had asymmetry of shoulder and uneven hip and also 50% patients had pain. After surgical treatment with transpedicular screws and rods through posterior approach, 70% of patients improved in terms of deformity. The average major curve deformity as defined by Cobb angle measurements was measured to be 54.9°±9.9° (40°-68°) in pre-surgery. After surgery this deformity corrected to 16.0°±4.9° (10°-24°) on average as measured in erect posture posterior anterior and lateral view. This represents significant improvement average of 71.4±4.3% (64.6-75.09) (p<0.001). This correction was maintained at 24 months after surgery. Functional results assessed by Modified Macnab criteria, significant number of 7(70.0%) patients had excellent outcome, 2(20.0%) patients had good outcome, 1(10.0%) patients had fair outcome and no poor outcome. Ninety percent (90%) patients had satisfactory results. No patient deteriorates neurologically after surgery. It is concluded that satisfactory curve correction and maintenance thereof is possible in adolescent idiopathic scoliosis, with posterior instrumentation by transpedicular screw and rods with effective reduction of cost and associated risks.

E-cadherin Gene (CDH1) Expression in Low Grade Astrocytoma.

Astrocytoma is the commonest primary brain tumor. These are feared due to their invasiveness in brain parenchyma so are less amenable to surgical removal and current chemotherapy regimens with a high mortality rate. Cell adhesion molecule (CAM) E-cadherin (CDH1) downregulation has been associated with tumors of different system and organs featuring invasion and metastasis. Therefore, the aim of the study was to find out the level of E-cadherin gene expression in low grade astrocytoma. In this cross-sectional study, 22 formalin fixed paraffin embedded tissue were taken as cases. Three non tumorous brain tissue and 1fresh post-mortem brain tissue were taken as control. Histological features were studied under light microscope with Haematoxylin and Eosin (H&E stain). Expression of CDH1 gene was analyzed by real time - polymerase chain reaction (RT-PCR) by comparative cyclic threshold (Ct) value method. The change in E-cadherin expression was measured by fold change in comparison with the control brain tissue. The data was tabulated and statistical analysis was performed. Among the 22 study cases 8(36.36%) were World Health Organization (WHO) Grade I and 14(63.63%) were WHO Grade II. All tumors showed downregulation of CDH1 gene in comparison with non-tumorous control tissue. The result is statistically significant (p=0.019). So, the study data revealed that downregulation of E-cadherin gene occurs in low grade astrocytoma and tumors of WHO Grade II showed more downregulation than Grade I tumors.

Comparative Study of Green and Synthetic Polymers for Enhanced Oil Recovery.

Several publications by authors in the field of petrochemical engineering have examined the use of chemically enhanced oil recovery (CEOR) technology, with a specific interest in polymer flooding. Most observations thus far in this field have been based on the application of certain chemicals and/or physical properties within this technique regarding the production of 50-60% trapped (residual) oil in a reservoir. However, there is limited information within the literature about the combined effects of this process on whole properties (physical and chemical). Accordingly, in this work, we present a clear distinction between the use of xanthan gum (XG) and hydrolyzed polyacrylamide (HPAM) as a polymer flood, serving as a background for future studies. XG and HPAM have been chosen for this study because of their wide acceptance in relation to EOR processes. To this degree, the combined effect of a polymer's rheological properties, retention, inaccessible pore volume (PV), permeability reduction, polymer mobility, the effects of salinity and temperature, and costs are all investigated in this study. Further, the generic screening and design criteria for a polymer flood with emphasis on XG and HPAM are explained. Finally, a comparative study on the conditions for laboratory (experimental), pilot-scale, and field-scale application is presented.

Chemotherapeutic resistance of head and neck squamous cell carcinoma is mediated by EpCAM induction driven by IL-6/p62 associated Nrf2-antioxidant pathway activation.

Overexpression of epithelial cell adhesion molecule (EpCAM) has been associated with chemotherapeutic resistance, leads to aggressive tumor behavior, and results in an adverse clinical outcome. The molecular mechanism by which EpCAM enrichment is linked to therapeutic resistance via Nrf2, a key regulator of antioxidant genes is unknown. We have investigated the link between EpCAM and the Nrf2 pathway in light of therapeutic resistance using head and neck squamous cell carcinoma (HNSCC) patient tumor samples and cell lines. We report that EpCAM was highly expressed in Nrf2-positive and HPV-negative HNSCC cells. In addition, cisplatin-resistant tumor cells consisted of a higher proportion of EpCAMhigh cells compared to the cisplatin sensitive counterpart. EpCAMhigh populations exhibited resistance to cisplatin, a higher efficiency in colony formation, sphere growth and invasion capacity, and demonstrated reduced reactive oxygen species (ROS) activity. Furthermore, Nrf2 expression was significantly higher in EpCAMhigh populations. Mechanistically, expression of Nrf2 and its target genes were most prominently observed in EpCAMhigh populations. Silencing of EpCAM expression resulted in the attenuation of expressions of Nrf2 and SOD1 concomitant with a reduction of Sox2 expression. On the other hand, silencing of Nrf2 expression rendered EpCAMhigh populations sensitive to cisplatin treatment accompanied by the inhibition of colony formation, sphere formation, and invasion efficiency and increased ROS activity. The molecular mechanistic link between EpCAM expression and activation of Nrf2 was found to be a concerted interaction of interleukin-6 (IL-6) and p62. Silencing of p62 expression in EpCAMhigh populations resulted in the attenuation of Nrf2 pathway activation suggesting that Nrf2 pathway activation promoted resistance to cisplatin in EpCAMhigh populations. We propose that therapeutic targeting the Nrf2-EpCAM axis might be an excellent approach to modulate stress resistance and thereby survival of HNSCC patients enriched in EpCAMhigh populations.

A Simple and Reliable Cooling Approach for the Cryopreservation of Hematopoietic Stem Cells: the Passive Cooling Rate-controlled Technique.

BACKGROUND: Cryopreservation of hematopoietic stem cells (HSCs) has widely been used in stem cell transplantation and cellular therapy treating various human diseases. However, the current conventional cooling approach for the cryopreservation of HSCs has the following potential problems: (1) requirement of a very expensive computer-programmed liquid nitrogen freezer (LNF) for the cooling rate control, (2) a large consumption of liquid nitrogen, (3) periodic breakdown of the LNF due to the mechanical failure of the liquid nitrogen valves (i.e., magnetic-solenoid valves) inside the LNF, and (4) constant monitoring of the LNF operation during the HSCs cooling process. OBJECTIVE: To test and evaluate a simple and reliable approach for the cryopreservation of HSCs using the passive cooling technique. MATERIALS AND METHODS: A passive cooling-rate-controlled device (PCD) was developed and used to cryopreserve HSCs. The PCD is inexpensive, simple, and user-friendly, which needs only the minimum maintenance and no consumption of liquid nitrogen. The PCD was compared to the LNF for the cryopreservation of HSCs in the present study through experiments. The cell viability and functionality were evaluated after cryopreservation. RESULTS: In comparison with the LNF method, the PCD approach enabled high cell viability/survival, recovery rate, and functionality after cryopreservation processes. CONCLUSION: The PCD offers a cost-effective, simple, and reliable approach for the optimal cryopreservation of HSCs.

Association of Serum Vitamin D (25OHD) Level with Acute Exacerbation of Chronic Obstructive Pulmonary Disease.

Acute exacerbations of COPD is characterized by a change in the patients baseline dyspnoea, cough and/or sputum that is beyond normal day to day differences and guides to a change in standard medications in a patient with COPD. Vitamin D influences the innate & adaptive immune system, and exerts pleiotropic antimicrobial and anti-inflammatory responses. Vitamin D deficiency is frequent among COPD patients but its contributory role in disease exacerbations is widely debated. This study was aimed to assess relationship between reduced serum vitamin D (25-OHD) level with COPD severity and acute exacerbation. This observational cross-sectional study was carried out in the department of Respiratory Medicine, NIDCH, Mohakhali, Dhaka, Bangladesh from October 2016 to September 2017. Consecutive 80 hospital admitted patients with acute exacerbation of chronic obstructive pulmonary disease diagnosed on the basis of clinical history & pulmonary function tests and 78 age & sex matched controls were investigated for serum vitamin D (25-OHD) level. Among the COPD patients, 37% had Vitamin D deficiency (<20ng/ml) and 28.75% had Vitamin D insufficiency (20-29ng/ml). Mean vitamin D (25-OHD) level of COPD patients (25.82±10.62ngm/ml) was found to be significantly lower than healthy controls (32.57±11.32ngm/ml). Vitamin D deficiency was found, by Pearson correlation test, to be significantly associated with severity of COPD. Multivariate analysis showed that age (in years), FEV1 (percent predicted), frequent exacerbators (≥2 in the last year), and smoking (>40 pack year) were significantly associated with Vitamin D deficiency. Acute exacerbation of chronic obstructive pulmonary disease patients was found to have vitamin D deficiency and vitamin D deficiency was significantly associated with severity of COPD. Vitamin D deficiency was also associated with frequent disease exacerbation.

Surface-Acoustic-Wave-Based Lab-on-Chip for Rapid Transport of Cryoprotectants across Cell Membrane for Cryopreservation with Significantly Improved Cell Viability.

Cryopreservation is essential to effectively extend the shelf life of delicate biomaterials while maintaining proper levels of cell functions. Cryopreservation requires a cryoprotective agent (CPA) to suppress intracellular ice formation during freezing, but it must be removed prior to clinical use due to its toxicity. Conventional multistep CPA loading and unloading approaches are time consuming, often creating osmotic shocks and causing mechanical injuries for biological samples. An efficient surface-acoustic-wave- (SAW-) based lab-on-a-chip (LoC) for fast loading and removal of CPAs is presented here. With the SAW-based multistep CPA loading/removal approach, high concentration (3 m) CPA can be successfully loaded and removed in less than 1 min. Results show that the technique causes the least harm to umbilical cord matrix mesenchymal stem cells as compared to conventional method, and an average of 24% higher cell recovery rate is achieved, while preserving the integrity and morphology of the cells. This device is the first of its kind to combine high loading/unloading efficiency, high cell viability, and high throughput into one LoC device, offering not only a more efficient and safer route for CPA loading and removal from cells, but also paving the way for other cryopreservation-dependent applications.

Optimization of prostatic cryosurgery with multi-cryoprobe based on refrigerant flow.

Cryosurgery is a promising novel minimally invasive surgical technique to eradicate carcinoma and non-carcinoma tissues by freezing. In this research, we applied a transient 3D two-phase refrigerant flow model inside the LN2 boiling chamber as well as a bioheat transfer model inside the tissues to evaluate the optimized ablation outcome during prostatic cryosurgery. For the evaluation of the scenarios, a defect function was used that considers non-ablated target tissue (prostate/cancer tissue) as well as ablated healthy tissue, in which the ablated tissue was evaluated using a temperature threshold. Three different configurations using three LN2 cryoprobes were analyzed during the modeling study, and the best configuration with the three LN2 cryoprobes positioned isoscelesly was found. For this configuration, temperature distributions and temperature profiles at specific points within the tissue were investigated numerically. Owing to its low computational cost, the 3D coupled model has an advantage in accurate modeling cryosurgery for curing numerous diseases.

Near-infrared laser mediated modulation of ice crystallization by two-dimensional nanosheets enables high-survival recovery of biological cells from cryogenic temperatures.

Two-dimensional (2D) graphene oxide (GO) and molybdenum disulfide (MoS2) nanosheets (NSs) have been widely used as photothermal agents and as potential carriers of antitumor drugs. Their spatial thermal effects have been extensively explored for use at physiological and hyperthermic temperatures (37 to 46 °C). Furthermore, the modulation of the spatial thermal distributions with these NSs may have even more profound applications in the microstructural control of biomaterials at cryogenic temperatures (-196 to 37 °C). These applications include bioinspired microfabrication via freezing, food and drug freeze-drying, and biomaterial cryopreservation. However, such thermal effects of NSs and their applications at cryogenic temperatures had never been fully explored. Therefore, in this study, we have utilized the near-infrared laser induced photothermal effects of GO and MoS2 NSs to suppress the ice nucleation and ice crystal growth during warming of the biosamples. Using this approach, biological cells subjected to fast cooling to a deeply frozen state (-196 °C) were successfully recovered with high survival rates and full biological functionality. Thus, we provide a NS based effective approach to control the crystallization behaviors of water during warming at cryogenic temperatures, as NSs may have wide applications in both materials science and bioengineering.