Self-healing in epoxy thermoset polymer films triggered by UV light

Self-healing of damaged structures can occur in three processes: capsule-based healing, vascular healing and intrinsic healing of polymers. The latest concept has a tremendous potential to repair damaged polymers and composite structures. Until now self-healing of composite materials has been addressed using capsule based resin with an initiator that polymerises in the damaged region. In this study, self-healing behaviour of cured epoxy thermoset resins modified with an epoxy-functionalised photoresponsive azobenzene molecule has been addressed by UV light without the use of any resin capsules or other component that is not chemically joined with the composites. The study was executed by nanoindentation and atomic force microscopy (AFM). Artificially damaged thermoset films exhibited good self-healing behaviour under UV irradiation only. This effect is attributed to the intrinsic healing mechanism triggered by UV-induced trans→cis isomerization of the azobenzene chromophore which enables the damaged polymeric matrix to recover.Funded by Defence Science and Technology Laboratory (DSTL

Histological studies on the mechanisms for the regulation of glucagon-like peptides(GLPs) in the chicken small intestine （ニワトリ小腸におけるグルカゴン様ペプチド（GLPs）の分泌制御機構に関する組織学的研究）

信州大学(Shinshu university)博士（農学）ThesisMohammad Moniruzzaman Monir . Histological studies on the mechanisms for the regulation of glucagon-like peptides(GLPs) in the chicken small intestine （ニワトリ小腸におけるグルカゴン様ペプチド（GLPs）の分泌制御機構に関する組織学的研究）. 信州大学, 2014, 博士論文. 博士（農学）, 甲第48号, 平成26年3月20日授与.doctoral thesi

Mechanophore-linked hydroxyl-terminated polybutadiene for the remote detection and quantification of mechanical stress

Polymers containing chromophores often exhibit mechanoresponsive behaviour, allowing the remote detection of stress in components such as rocket motors without taking the rockets out of service. Here we describe a polymer comprising a difunctional spiropyran chromophore and methyl methacrylate cross-linked with hydroxyl-terminated polybutadiene (HTPB). This polymer was developed as a sensor for the non-destructive monitoring of mechanical stress by using the force-induced colour changes as a quantitative readout. After about 40 N of load was applied there was a gradual colour changes proportional to the compressive forces on the sample, as revealed by in-situ monitoring using a video camera and UV–Vis spectrometry. The tests highlighted a gradual decrease in the transmitted light intensity at 675 nm with increasing load, due to the opening of the spiropyran rings and their conversion to the coloured merocyanine forms. A reversible change to the initial colour occurred 72 h after the load was removed, but only under artificial fluorescent lighting, confirming that visible light is required for the ring-closing reaction. This new polymer is an ideal candidate for the remote detection of stress-induced damage in inaccessible structures or essential equipment that cannot be withdrawn from service for testing

The use of arthroscopy in diagnosing and treating sports-related cartilage lesions

Background: Sports-related cartilage lesions pose challenges for athletes. Cartilage, vital for smooth joint movement, can be damaged. Arthroscopy, a minimally invasive procedure, allows precise diagnosis and treatment of joint issues, offering quicker recovery and minimal scarring, enhancing orthopedic interventions. This study aimed to assess the use of arthroscopy in diagnosing and treating sports-related cartilage lesions. Methods: This prospective observational study was conducted at the department of orthopaedics and traumatology, Life Line Hospital Moulovibazar, Mount Adora Hospital Sylhet, MAG Osmani Medical College Hospital Sylhet, Bangladesh from January 2022 to December 2023. As the study subjects, a total of 58 patients with non-surgically treated acute or chronic sports-related cartilage lesions were enrolled by using a purposive sampling technique. After 6 months, a follow-up report was recorded. Data were analyzed by using Microsoft Office tools. Results: In this study, 72% of participants underwent cuff repair, with the remaining 28% opting for loop repair. The arthroscopic assessment revealed anterior medial cartilage lesions in 34% and anterior lateral lesions in 28%. Posterior medial, posterior lateral, and mid-talus dome cartilage lesions were observed in 17%, 5%, and 16%, respectively. Capsule repair was employed in 86% of cases. Significant improvement in hip range of motion, as well as radiological parameters like lateral center-edge angle, alpha angle (anteroposterior), and alpha angle (Dunn), was observed 6 months postoperatively (p<0.001). Conclusions: In detecting and treating sports-related cartilage lesions, arthroscopy is an effective method. This minimally invasive less painful treatment approach contributes to faster rehabilitation and a quicker return to normal activities

Healthcare Facilities as Potential Reservoirs of Antimicrobial Resistant Klebsiella pneumoniae:An Emerging Concern to Public Health in Bangladesh

The emergence of virulent extended spectrum β-lactamase producing Klebsiella pneumoniae (ESBL-KP) including carbapenem-resistant Klebsiella pneumoniae (CRKP) in hospital-acquired infections has resulted in significant morbidity and mortality worldwide. We investigated the antibiotic resistance and virulence factors associated with ESBL-KP and CRKP in tertiary care hospitals in Bangladesh and explored their ability to form biofilm. A total of 67 ESBL-KP were isolated from 285 Klebsiella pneumoniae isolates from environmental and patient samples from January 2019 to April 2019. For ESBL-KP isolates, molecular typing was carried out using enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR), antibiotic susceptibility testing, PCR for virulence and drug-resistant genes, and biofilm assays were also performed. All 67 isolates were multidrug-resistant (MDR) to different antibiotics at high levels and 42 isolates were also carbapenem-resistant. The most common β-lactam resistance gene was bla(CTX-M-1) (91%), followed by bla(TEM) (76.1%), bla(SHV) (68.7%), bla(OXA-1) (29.9%), bla(GES) (14.9%), bla(CTX-M-9) (11.9%), and bla(CTX-M-2) (4.5%). The carbapenemase genes bla(KPC) (55.2%), bla(IMP) (28.4%), bla(VIM) (14.9%), bla(NDM-1) (13.4%), and bla(OXA-48) (10.4%) and virulence-associated genes such as fimH (71.6%), ugeF (58.2%), wabG (56.7%), ureA (47.8%) and kfuBC (28.4%) were also detected. About 96.2% of the environmental and 100% of the patient isolates were able to form biofilms. ERIC-PCR-based genotyping and hierarchical clustering of K. pneumoniae isolates revealed an association between environmental and patient samples, indicating clonal association with possible transmission of antimicrobial resistance genes. Our findings can help in improving patient care and infection control, and the development of public health policies related to hospital-acquired infections

Distance Fieldwork in Anthropology

In order to conduct my ethnographic research successfully, I applied a novel but effective means what I prefer to call the distance fieldwork approach. This paper discusses the methods and techniques that I employed to collect data for my research. The use of these methods ensured that I upheld the methodological and ethical principles of ethnographic fieldwork directed from afar. The aim of this paper is not only to outline my research methodology and ethical principles but also to introduce the distance fieldwork approach to anthropological research. I argue that despite distance fieldwork approach has some limitations it can be effective to many extents

Analyzing post-2000 groundwater level and rainfall changes in Rajasthan, India, using well observations and GRACE data

Research on groundwater and water resources is essential for preserving viable environments. Although the arid area has been identified as a significant hotspot for groundwater depletion, the Indian desert region was not included in the initial analysis. This study intends to evaluate Rajasthan's groundwater level (GWL) and rainfall trends from 2000 to 2021 and how variations in GWLs are related to long-term rainfall. Annual GWL and rainfall data time series were collected from 921 monitoring stations for 33 districts of Rajasthan. The GWL trends and rainfall were identified using non-parametric modified Mann-Kendall test and Spearman rho techniques. Pearson's, Kendall's (tau b), and Spearman's analyses were used to determine the correlation between GWL and rainfall. The results from the modified Mann-Kendall and Spearman rho methods reveal that GWL has a significant declining trend in 38 % of districts, where 13 % have no trend, and the rest of 49 % have a rising trend. The yearly rainfall trend at 70 % and 30 % of the districts are rising and stable, respectively. A negative correlation between GWL depth and rainfall was discovered in each district, where 15 % are firm, 58 % are moderate, and 27 % are weak negative correlations. Also, the regression analysis estimates the effect of rainfall on GWL, which was observed: rainfall negatively influenced the depth of GWL at 58 % of the districts, had a positive impact at 33 %, and others had no effect. GRACE TWS anomaly shows a decreasing trend of −1.22 cm/yr, and GRACE and GWL anomalies have a positive relationship (r = 0.471). Results conclude that rainfall is the primary influencer on GWL in this semi-arid region vulnerable to drought