Thin-Film Piezoelectric Micromachined Ultrasound Transducers in Biomedical Applications: A Review.

Thin-film piezoelectric micromachined ultrasound transducers (PMUTs) are an increasingly relevant and well-researched field, and their biomedical importance has been growing as the technology continues to mature. This review article briefly discusses their history in biomedical use, provides a simple explanation of their principles for newer readers, and sheds light on the materials selection for these devices. Primarily, it discusses the significant applications of PMUTs in the biomedical industry and showcases recent progress that has been made in each application. The biomedical applications covered include common historical uses of ultrasound such as ultrasound imaging, ultrasound therapy, and fluid sensing, but additionally new and upcoming applications such as drug delivery, photoacoustic imaging, thermoacoustic imaging, biometrics, and intrabody communication. By including a device comparison chart for different applications, this review aims to assist microelectromechanical systems (MEMS) designers that work with PMUTs by providing a benchmark for recent research works. Furthermore, it puts forth a discussion on the current challenges being faced by PMUTs in the biomedical field, current and likely future research trends, and opportunities for PMUT development areas, as well as sharing the opinions and predictions of the authors on the state of this technology as a whole. The review aims to be a comprehensive introduction to these topics without diving excessively deep into existing literature.

Quality of life in Malaysian children with inflammatory bowel disease: An understudied population.

AIM: Quality of life (QoL) in children with inflammatory bowel disease (IBD) is often impaired by underlying disease. We evaluated factors affecting health-related QoL (HRQoL) in Malaysian children with IBD. METHODS: A cross-sectional study using IMPACT-III questionnaires evaluating HRQoL in children aged 8-17 years with duration of IBD of ≥6 months was conducted. IMPACT-III, a validated instrument designed to measure HRQoL in children with IBD, was used. Higher IMPACT-III (maximum = 100) score indicates better HRQoL. Impact of socio-demographic and clinical factors of IBD on the HRQoL was evaluated. Paediatric Crohn's disease (CD) and ulcerative colitis (UC) activity indices were used to classify disease severity. RESULTS: A total of 75 children (UC = 44, CD = 41; mean (SD) age at diagnosis 8.2 (3.5) years) were interviewed at mean age of 12.8 (2.7) years. Mean IMPACT-III score was significantly lower in children with more severe disease (mild: 71.8 (13.6) vs. moderate: 65.5 (10.9) vs. severe: 46.3 (14.5); P < 0.001), history of hospitalisation (yes: 64.0 (14.0) vs. none: 74.1 (12.2), P = 0.034) and a higher number of admissions (r = -0.352, P = 0.041) in preceding 6 months. Diagnosis at a younger age (r = -0.31, P = 0.007) and a longer duration of disease (r = 0.286, P = 0.013) was associated with higher score. A higher weight-for-age (r = 0.261, P = 0.023) or body mass index-for-age z-score (r = 0.235, P = 0.042) was correlated with a better body image domain score, respectively. CONCLUSIONS: In Malaysian children with IBD, HRQoL was adversely affected by a more severe disease. Better control of disease activity and maintaining long-term remission are important to improve the HRQoL in childhood IBD.

Presence of tumour capsule on contrast-enhanced CT is associated with improved outcomes of stereotactic body radiation therapy in hepatocellular carcinoma patients.

PURPOSE: Stereotactic body radiation therapy (SBRT) is a novel local therapy for the treatment of hepatocellular carcinoma (HCC). While effective, there is currently no reliable radiological marker to guide patient selection. In this study, we investigated the prognostic value of capsule appearance on contrast-enhanced computed tomography (CT) for patients undergoing SBRT. MATERIALS AND METHODS: Between 2006 and 2017, 156 consecutive patients with Child-Pugh score class A/B and HCC ≥ 5 cm who underwent SBRT were retrospectively analysed. Baseline triple-phase CTs of the abdomen were reviewed for the presence of capsule appearances and correlated with objective response rate (ORR), overall survival (OS) and pattern of treatment failure. RESULTS: Capsule appearance on CT was present in 83 (53.2%) patients. It was associated with improved ORR by Response Evaluation Criteria in Solid Tumours (RECIST) (60.2 vs. 24.7%, p < 0.001) and Modified Response Evaluation Criteria in Solid Tumours (mRECIST) (78.3 vs. 34.2%, p < 0.001). The presence of a capsule was also associated with superior 2­year local control (89.1 vs. 51.4%, p < 0.001) and 2­year OS (34.1 vs. 14.8%, p < 0.01). Hepatic out-field failure was the dominant mode of progression, which was less common in patients with intact capsule (54.2 vs. 60.3%, p = 0.01). CONCLUSION: Capsule appearance on CT could potentially be a non-invasive prognostic marker for selecting HCC patients to undergo SBRT. A larger cohort is warranted to validate our findings.

Environmental risk factors for inflammatory bowel disease: A case control study in Southeast Asian children.

AIM: Early-life environmental exposure, which has important implications in the pathogenesis of inflammatory bowel disease (IBD), is not well understood in Asian children. We examined environmental factors prior to the development of childhood IBD in a Southeast Asian population. METHODS: We conducted a case control study in IBD diagnosed before 18 years of age and controls matched by gender, age and ethnicity. A questionnaire recording medical, family, dietary and social histories, home environment, childhood diseases and immunisation status was used. RESULTS: In a multivariate analysis involving 70 children with IBD (Crohn's disease (CD) = 38; ulcerative colitis (UC) = 32) and 140 controls, childhood acute gastroenteritis (odds ratio (OR): IBD 6.9; CD 7.8; UC 5.8) and excessive antibiotic usage in early childhood (OR: IBD 5.3; CD 4.2; UC 4.8) were significantly associated with IBD, CD and UC. Having a fish or turtle aquarium (OR 6.0), major stressful life events (OR 5.6) and attending the same school concurrently with a sibling (OR 2.9) were significant risk factors for IBD. Duration of breastfeeding >6 months (OR: IBD 0.4; UC 0.2) and safe water consumption (OR: IBD 0.2; UC 0.2) reduced the odds of having IBD and UC, respectively. Being vaccinated for rotavirus reduced the odds of developing IBD (OR 0.1). CONCLUSIONS: Several risk and protective factors were identified in this environmental risk study in Southeast Asian children with IBD. This knowledge has important implications in understanding disease aetiology and future prevention strategies to reduce the development of IBD in Southeast Asian children.

Hospital outcomes of children admitted to intensive care in British Columbia via interfacility transfer versus direct admission from 2015 to 2017: a descriptive analysis.

BACKGROUND: Pediatric intensive care relies on having experienced and effective transport systems to transfer critically ill children to the appropriate centre for care. Our aim was to compare hospital outcomes among children admitted directly to a pediatric intensive care unit (PICU) with those of children transferred from another facility. METHODS: We conducted a descriptive study using electronic medical records and the PICU database from the BC Children's Hospital. Patients admitted to the PICU from January 2015 to December 2017 were included. We excluded patients who were admitted electively, were admitted for recovery postoperatively, or had inconsistent or out-of-range addresses. We compared hospital mortality rates, use of mechanical ventilation within 24 hours of admission and length of PICU stay between children admitted directly from the BC Children's Hospital emergency department and those transferred from a referring institution. RESULTS: During the study period, there were 870 unique admissions comprising 386 direct admissions and 484 transferred patients. Transported patients were younger, were more critically ill on presentation and required longer stays. The proportions of children who died and of children who required mechanical ventilation within 24 hours of admission were higher in the transported group than in the group admitted directly from the emergency department (8.3% v. 3.9%, p = 0.008, and 75.8% v. 58.0%, p < 0.001, respectively). INTERPRETATION: Mortality rate and use of intensive care resources were higher among children who were transported. Further research is needed to examine the key factors driving the differences in outcomes, including the severity of illness on first presentation, transport team composition, and transport distance and duration.

Anti-instinctive Learning Behavior Revealed by Locomotion-Triggered Mild Heat Stress in Drosophila.

Anti-instinctive learning, an ability to modify an animal's innate behaviors in ways that go against one's innate tendency, can confer great evolutionary advantages to animals and enable them to better adapt to the changing environment. Yet, our understanding of anti-instinctive learning and its underlying mechanisms is still limited. In this work, we describe a new anti-instinctive learning behavior of fruit flies. This learning paradigm requires the fruit fly to respond to a recurring, aversive, mild heat stress by modifying its innate locomotion behavior. We found that experiencing movement-triggered mild heat stress repeatedly significantly reduced walking activity in wild type fruit flies, indicating that fruit flies are capable of anti-instinctive learning. We also report that such learning ability is reduced in dopamine 1-like receptor 1 (Dop1R1) null mutant and dopamine 2-like receptor (Dop2R) null mutant flies, suggesting that these two dopamine receptors are involved in mediating anti-instinctive learning in flies.

Pharmacological inhibition of Bax-induced cell death: Bax-inhibiting peptides and small compounds inhibiting Bax.

IMPACT STATEMENT: Bax induces mitochondria-dependent programed cell death. While cytotoxic drugs activating Bax have been developed for cancer treatment, clinically effective therapeutics suppressing Bax-induced cell death rescuing essential cells have not been developed. This mini-review will summarize previously reported Bax inhibitors including peptides, small compounds, and antibodies. We will discuss potential applications and the future direction of these Bax inhibitors.

Pulmonary hypertension and isolated right heart failure complicating amiodarone induced hyperthyroidism.

Hyperthyroidism is a common side effect encountered in patients prescribed long-term amiodarone therapy for cardiac arrhythmias. We previously studied 354 patients prescribed amiodarone in whom the occurrence of hyperthyroidism was associated with major adverse cardiovascular events including heart failure, myocardial infarction, ventricular arrhythmias, stroke and even death [1]. We now present a case of amiodarone-induced hyperthyroidism complicated by isolated right heart failure and pulmonary hypertension that resolved with treatment of hyperthyroidism. Detailed quantitative echocardiography enables improved understanding of the haemodynamic mechanisms underlying the condition.

Beta-galactosidase (Escherichia coli) has a second catalytically important Mg2+ site.

It is shown here that Escherichia coli beta-galactosidase has a second Mg2+ binding site that is important for activity. Binding of Mg2+ to the second site caused the k(cat) (with oNPG as the substrate) to increase about 100 s(-1); the Km was not affected. The Kd for binding the second Mg2+ is about 10(-4)M. Since the concentration of free Mg2+ in E. coli is about 1-2 mM, the second site is physiologically significant. Non-polar substitutions (Ala or Leu) for Glu-797, a residue in an active site loop, eliminated the k(cat) increase. This indicates that the second Mg2+ site is near to Glu-797. The Ki values of transition state analogs were decreased by small but statistically significant amounts when the second Mg2+ site was occupied and Arrhenius plots showed that less entropic activation energy is required when the second site is occupied. These inhibitor and temperature results suggest that binding of the second Mg2+ helps to order the active site for stabilization of the transition state.

Colloidal crystal films: advances in universality and perfection.

For three-dimensional photonic crystals, made either by top-down microfabrication or by bottom-up self-assembly approaches, to comply with the stringent requirements of optical telecommunication applications, their degree of structural perfection and optical quality must meet an exceptionally high standard. Only with such superior quality photonic crystals can their unique optical properties be harnessed in optical devices and circuits constructed from micrometer-sized optical components. In this paper, we present a new strategy for making silica colloidal crystal films with a sufficiently high level of structural perfection and optical quality to make it competitive as a practical route to photonic crystal optical components. The attainment of this goal takes due cognizance of three key synergistic factors in the film formation process. The first recognizes the necessity to prepare high-quality silica spheres, which are highly monodisperse, with a polydispersity index significantly better than 2%, and the second recognizes that the population of spheres must be devoid of even the smallest fraction of substantially smaller or larger spheres or sphere doublets. The latter turns out to have a minimal effect on the polydispersity index, and yet a major detrimental effect on the overall structural order of the film. The third concerns the film-forming method itself, which necessitated the development of a novel process founded upon isothermal heating evaporation-induced self-assembly (IHEISA) of spheres on a planar substrate. This new method has several advantages over previously reported ones. It is able to deposit very high-quality silica colloidal crystal film rapidly over large areas, with a controlled thickness and without any restrictions on sphere sizes.