Deaths Associated With Community Donation Bins: A Ten-Year Retrospective Review Describing Five Cases in British Columbia and Ontario

Introduction

Community donation bins have become more common in the urban setting over the past several years. Many nonprofit organizations use these sturdy metal enclosures for unobserved collection of various donated items such as clothing, books, and household items. Although the donated items are often of low individual value, donation bins may become a target of individuals in low socioeconomic situations seeking desired items for personal use or resale, or for personal shelter within the bin.

Methods

To identify donation bin-associated deaths, we reviewed cases taken under the jurisdiction of the coroner for investigation in the provinces of British Columbia and Ontario, Canada, over the years 2009 to 2019.

Results

We present the circumstances and postmortem findings of five deaths that occurred in British Columbia and Ontario (Canada) between 2009 and 2019, wherein the decedents were each believed to have been reaching into donation bins and became caught within the door mechanism and died as a consequence of compression asphyxia involving the chest and/or neck.

Discussion

Donation bins have the potential for harm when individuals attempt to access the bin contents through the entry portal. We advocate for greater attention and changes in the placement location and/or design of these potentially dangerous devices.

Strong and thermostable hydrothermal carbon coated 3D needled carbon fiber reinforced silicon-boron carbonitride composites with broadband and tunable high-performance microwave absorption

Excellent electromagnetic wave (EMW) absorbing materials with high-temperature stable and superior mechanical properties are among the most promising candidates for practical application. Here, novel hydrothermal carbon coated three-dimensional (3D) needled carbon fiber reinforced silicon-boron carbonitride (HC-CF/SiBCN) composites with a hierarchical A (CF)/B (HC)/C (SiBCN) structure were constructed and prepared for the first time by combining hydrothermal transformation and precursor infiltration and pyrolysis (PIP) process. The thickness of the HC coating controlled by the glucose concentration played a crucial role in tailoring the EMW capacity of the composite. The incorporation of SiBCN could not only effectively improve the oxidation resistance but also actively enhance the mechanical properties of the HC coated CF structure. Compared to the weak high-temperature oxidation resistance and mechanical properties of pristine 3D needled CF felt, the composites after the introduction of HC and SiBCN were thermostable in air atmosphere beyond 1000 °C to about above 70% weight retention, and the maximum flexural and compression strength of the composites could reach to 23.51 ± 1.37 and 12.22 ± 1.12 MPa, respectively. A substantial enhancement of EMW absorption ability was achieved through incorporation of HC and SiBCN, which could be attributed to the matched characteristic impedance and enhanced loss ability, whose optimization EMW absorption performance was the minimum reflection loss (RL_min) of -52.08 dB and effective absorption bandwidth (EAB) of 7.64 GHz for the composite obtained by two PIP cycles with 24 wt% glucose solution, demonstrating that the HC-CF/SiBCN composites with high-temperature stable, excellent mechanical and superior EMW absorption properties could be considered as a promising candidate for the applications in harsh environments.

Potential of combating transmission of COVID-19 using novel self-cleaning superhydrophobic surfaces: part II-thermal, chemical, and mechanical durability

In part I, we identified encapsulation, contamination suppression, and virus elimination as our three governing strategies for developing surfaces to combat the transmission and spread of COVID-19. We showed that our recent superhydrophobic nanocomposites has the potential of encapsulating and suppressing the virus so as to limit its transmission and spread. In this study, we examine the durability of the newly developed surfaces when subjected to elevated temperature, chemical attack and mechanical damage in the form of abrasion and compressive load. Extensive tests were conducted to reveal the effect of these parameters on the surface performance. Three aspects of the work were accordingly examined. The first was concerned with controlled thermal stability tests in which the surfaces were subjected to elevated temperatures approaching 350 °C for silicone-based nanocomposites and 150 °C for epoxy-based nanocomposites. The second was concerned with subjecting the surfaces to alkaline and acidic solutions with pH concentrations ranging between 1 and 13. Finally, the third involved surface damage by abrasion tests. Our results show clearly that the newly developed superhydrophobic surfaces are capable of resisting the adverse effects of thermal and chemical attacks as well as mechanical abrasion owing to the excellent structural stability and mechanical properties of the constituents of the nanocomposite. Moreover, our superhydrophobic monolith demonstrated exceptional regenerative capabilities even after being subjected to damaging compressive stresses of up to 10 MPa.

Controversies in preoperative bowel preparation in gynecologic and gynecologic oncology surgery: a review of the literature

PURPOSE

The purpose of this review is to assess the impact of mechanical and oral antibiotics bowel preparation on surgical performance and to investigate their role before gynecologic surgical procedures regarding the infection rates. We also aim to study the updated evidence regarding the use of these different types of bowel preparation, as well as the current preoperative practice applied.

METHODS

An extensive search of the literature was conducted with Medline/PubMed, and the Cochrane Library Database of Systematic Reviews being used for our primary search.

RESULTS

To date, due to the conflicting guidelines by the scientific societies, surgeons do not use a specific pattern of bowel preparation regimen. There are no strong evidence supporting mechanical bowel preparation, but instead, in many cases, patients' adverse effects, both physiological and psychological have been noted. On the other hand, the combined use of oral antibiotic and mechanical bowel preparation has been proven beneficial in colorectal surgery in reducing postoperative morbidities.

CONCLUSION

Based on current literature, in gynecologic surgeries with minimal probability of intraluminal entry, a regimen without any bowel preparation should be applied. The combined administration of both mechanical and oral antibiotic bowel preparation, or even the use of the oral antibiotics alone, should be preserved for cases of increased complexity, where bowel involvement is highly anticipated, such as in gynecologic oncology, as stated in the ERAS protocols. Nonetheless, further research specific to gynecologic surgery is required.

Smart diagnostics devices through artificial intelligence and mechanobiological approaches

The present work illustrates the promising intervention of smart diagnostics devices through artificial intelligence (AI) and mechanobiological approaches in health care practices. The artificial intelligence and mechanobiological approaches in diagnostics widen the scope for point of care techniques for the timely revealing of diseases by understanding the biomechanical properties of the tissue of interest. Smart diagnostic device senses the physical parameters due to change in mechanical, biological, and luidic properties of the cells and to control these changes, supply the necessary drugs immediately using AI techniques. The latest techniques like sweat diagnostics to measure the overall health, Photoplethysmography (PPG) for real-time monitoring of pulse waveform by capturing the reflected signal due to blood pulsation), Micro-electromechanical systems (MEMS) and Nano-electromechanical systems (NEMS) smart devices to detect disease at its early stage, lab-on-chip and organ-on-chip technologies, Ambulatory Circadian Monitoring device (ACM), a wrist-worn device for Parkinson's disease have been discussed. The recent and futuristic smart diagnostics tool/techniques like emotion recognition by applying machine learning algorithms, atomic force microscopy that measures the fibrinogen and erythrocytes binding force, smartphone-based retinal image analyser system, image-based computational modeling for various neurological disorders, cardiovascular diseases, tuberculosis, predicting and preventing of Zika virus, optimal drugs and doses for HIV using AI, etc. have been reviewed. The objective of this review is to examine smart diagnostics devices based on artificial intelligence and mechanobiological approaches, with their medical applications in healthcare. This review determines that smart diagnostics devices have potential applications in healthcare, but more research work will be essential for prospective accomplishments of this technology.

Ambulatory Portable Pneumatic Compression Device as Part of a Multimodal Aspirin-Based Approach in Prevention of Venous Thromboembolism in Outpatient Total Knee Arthroplasty

Background

The purpose of this study is to review the incidence of symptomatic venous thromboembolism (VTE) in patients undergoing outpatient primary total knee arthroplasty (TKA) who used a portable pneumatic compression device as part of their VTE prophylaxis protocol.

Methods

A retrospective review of all outpatient primary TKA procedures in which patients used ambulatory pneumatic compression pumps as part of their multimodal VTE prophylaxis was performed from 2016 through 2018. This yielded a cohort of 1131 patients (1453 TKAs). An aspirin (ASA)-based protocol was used in patients with standard VTE risk receiving either 81 mg or 325 mg of ASA twice daily for 6 weeks postoperatively. High-risk patients received a stronger chemoprophylaxis for 2 weeks followed by ASA for 4 weeks. Pneumatic compression pumps were worn for 23 hours/day for 14 days.

Results

VTE prophylaxis medication was 81-mg ASA in 56% of patients, 325-mg ASA in 10% of patients, and stronger chemoprophylaxis in 34% of patients. Patients were considered morbidly obese (body mass index >40 kg/m²) in 267 (18.4%) procedures. Ninety-seven (6.7%) patients had a preoperative history of VTE event. Forty-nine duplex ultrasounds were performed (3.3% of TKAs). Confirmed VTE events were documented in only 5 (0.3%) patients. All VTEs occurred in high-risk patients who were discharged on stronger chemoprophylaxis. The time (days) to VTE was 3, 3, 7, 45, and 88 days.

Conclusion

The use of portable pneumatic compression pumps as part of a multimodal VTE prophylaxis protocol aided in a very low rate of symptomatic VTE events in patients undergoing outpatient primary TKA.

Relationship between the location of ligamentum flavum hypertrophy and its stress in finite element analysis

Objective

To quantitatively describe the stress of the ligamentum flavum (LF) using the finite element method and to compare the stress at different parts of the healthy LF.

Methods

Based on the high resolution computed tomography imaging data of a healthy 22‐year‐old man, three‐dimensional nonlinear L_4–5 lumbar finite element model (FEM) representing intact condition was developed. The LF, as the object of the present research, was incorporated into the spinal model in the form of solid three‐dimensional structure. The model’s validity is verified by comparing its biomechanical indices, such as range of motion and axial compression pressure displacement, with published results under specific loading conditions. To authenticate the accuracy of the solid LF, the lamina attachments, the central cross‐section, and other anatomy indicators were compared with figures in the published literature. After the average and maximum von Mises stress on the surface of LF under various working conditions were measured using ANSYS and AutoCAD software, the surface stress difference in the LF between the ventral and dorsal sides as well as the lateral and lamina parts were determined.

Results

The FEM predicted a similar tendency for biomechanical indices as shown in previous studies. The lamina attachments, the central cross‐section, and the height as well as the width of the LF in the healthy FEM were in accordance with published results. In the healthy model, the average and maximum von Mises stress in the shallow layer of the LF were, respectively, 1.40, 2.28, 1.76, 1.48, 1.38 and 1.79, 2.41, 1.46, 1.42, 1.71 times that in the deep layer under a compressive preload of 500 N incorporated with flexion, extension, and lateral and rotational moments (10 Nm). The most conspicuous difference in surface stress was observed with the flexion motion, with a nearly 241% difference in the maximum stress and a 228% difference in the average stress compared to those in other states. As far as the whole dorsal side of the LF was concerned, the maximum surface stress was almost all concentrated in the dorsal neighboring facet joint portion. In addition, the maximum and average stress were, respectively, 77%, 72%, 15%, 11%, 71% and 153%, 39%, 54%, 200%, 212% higher in the lateral part than in the lamina part.

Conclusion

Based on the predisposition of LF hypertrophy in the human spine and the stress distribution of this study, the positive correlation between LF hypertrophy and its stress was confirmed.

Echocardiography in Pandemic: Front-Line Perspective, Expanding Role of Ultrasound, and Ethics of Resource Allocation

The grave clinical context of the coronavirus disease 2019 (COVID-19) pandemic must be understood. Italy is immersed in the COVID-19 pandemic. Most of the world will soon follow. The United States currently has the most documented cases of COVID-19 of any nation. Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-associated acute cardiomyopathy is common in critical care patients and is associated with a high mortality rate. Patients with COVID-19 frequently require mechanical support for adequate oxygenation. A severe shortfall of ventilators is predicted. Of equal concern is the projected shortage of trained professionals required to care for patients on mechanical ventilation. Ultrasonography is proving to be a valuable tool for identifying the pulmonary manifestations and progression of COVID-19. Lung ultrasound also facilitates successful weaning from mechanical ventilation. Ultrasonography of the lung, pleura, and diaphragm are easily mastered by experienced echocardiographers. Echocardiography has an established role for optimal fluid management and recognition of cardiac disease, including SARS-CoV-2-associated acute cardiomyopathy. Cardiologists, anesthesiologists, sonographers, and all providers should be prepared to commit their full spectrum of skills to mitigate the consequences of the pandemic. We should also be prepared to collaborate and cross-train to expand professional services as necessary. During a declared health care crisis, providers must be familiar with the ethical principles, organizational structure, practical application, and gravity of limited resource allocation.

Bone resection for mechanically aligned total knee arthroplasty creates frequent gap modifications and imbalances

PURPOSE

The objective of this study was to calculate bone resection thicknesses and resulting gap sizes, simulating a measured resection mechanical alignment (MA) technique for total knee arthroplasty (TKA).

METHODS

MA bone resections were simulated on 1000 consecutive lower limb CT scans from patients undergoing TKA. Femoral rotation was aligned with either the surgical trans-epicondylar axis (TEA) or with 3° of external rotation to the posterior condyles (PC). Imbalances in the extension space, flexion space, medial compartment and lateral compartment were calculated.

RESULTS

Extension space imbalances (≥ 3 mm) occurred in 25% of varus and 54% of valgus knees and severe imbalances (≥ 5 mm) were present in up to 8% of varus and 19% of valgus knees. Higher flexion space imbalance rates were created with TEA versus PC (p < 0.001). Using TEA, only 49% of varus and 18% of valgus knees had < 3 mm of imbalance throughout the extension and flexion spaces, and medial and lateral compartments.

CONCLUSION

A systematic use of the simulated measured resection MA technique for TKA leads to many cases with imbalance. Some imbalances may not be correctable surgically and may result in TKA instability. Modified versions of the MA technique or other alignment methods that better reproduce knee anatomies should be explored.

LEVEL OF EVIDENCE

2.

Physical, mechanical, chemical and biological properties data of gellan gum incorporating titanium dioxide nanoparticles biofilm

Gellan gum incorporating titanium dioxide nanoparticles biofilm was synthesized and characterized using UV, FTIR and XRD to study their physical and chemical properties. The mechanical properties were measured using universal mechanical testing. Meanwhile, the biological properties were investigated towards for antibacterial and cell proliferation. This comprehensive data are relevant with the research article entitled "Gellan gum incorporating titanium dioxide nanoparticles biofilm as wound dressing: Physicochemical, mechanical, antibacterial properties and wound healing studies" [1].

Ab-initio prediction of the mechanical, magnetic and thermoelectric behaviour of perovskite oxides XGaO3 (X = Sc, Ti, Ag) using LDA+U functional: For optoelectronic devices

The mechanical, magnetic and thermoelectric properties of spin polarized XGaO₃ (X = Sc, Ti, Ag) perovskite oxides in cubic phase have been investigated using LDA + U functional through ab-initio study based on density functional theory (DFT) in the framework of WIEN2K simulation code. The Full Potential Linearized Augmented Plane Wave (FP-LAPW) technique along with PBE-GGA functional have been used to optimize the systems and determining exchange-correlation potential. However, in order to address on-site self-interactions error and overcome limitations of PBE-GGA functional, LDA + U has been employed because Hubbard parameter 'U' is found an appropriate remedy to consider on-site self-interactions, and to calculate improved electronic energy band gap. All spin polarized band structures reveal indirect band gap with different energies E_g (eV) such as ↑↓ 0.98 eV for ScGaO₃, ↑1.05 eV and ↓1.70 eV for TiGaO₃, ↑1.13 eV and ↓2.19 eV for AgGaO₃. Thus, all compounds are semiconductor in nature. The analysis of spin polarized total and partial density of states unveil that ScGaO₃ is non-magnetic material, whereas, TiGaO₃ and AgGaO₃ are characterized by strong exchange splitting of 3d (Ti) and 4d (Ag) states with significant spin magnetic moments, i.e., 1.0002 μ_B and -2.0002 μ_B, respectively. The elastic constants, i.e., Bulk, Young and Shear moduli, Poisson's coefficient, Anisotropy factor, Pugh's ratio, Cauchy pressure and melting temperature are calculated through Viogt-Reuss-Hill approximation. The thermoelectric response of the considered perovskites has been determined through semi-classical Boltzmann transport theory in the framework of BoltzTraP simulation code. Basic understandings of the mechanical, magnetic and thermoelectric properties of these compounds are studied for the first time in this manuscript.

[Death due to physical restraint in healthcare institutions]

Physical restraint is frequently used in healthcare institutions, usually in situations where the safety of the person (e.g. fall risk) or that of others (e.g. aggressive behaviour) is compromised, or where essential medical treatment is at stake. The implementation has a major impact with possible psychological consequences, physical injury and even fatal outcomes. In this retrospective study, fifteen deaths due to physical restraint are described. These have been investigated by the Forensic Medicine departments of UZ Leuven (1998 - 2018) and UZ Antwerpen (1999 - 2018). Death was caused by mechanical suffocation in all instances, mainly as a result of inadequate use of bedrails or belt restraint. These avoidable deaths are an urgent plea for a cautious and careful policy on physical restraint. Institutional guidelines and (further) training of health care personnel are of utmost importance. Central aspects are multidisciplinarity (deliberate decision-making), treatment (provoking factors), reticence (search for alternatives), proportionality (least intrusive method), due care (technical implementation), safety (increased supervision), temporality (re-evaluation of moment and duration), registration (accountability and liability) and communication (with all involved).

Predictors of vaginal delivery after cervical ripening using a synthetic osmotic dilator

OBJECTIVE

To evaluate the determinants of vaginal delivery and safety in women undergoing cervical ripening with a synthetic osmotic dilator (Dilapan-S) prior to induction of labor.

METHODS

We conducted a secondary analysis of an international multicenter prospective observational study of Dilapan-S for cervical ripening in pregnancies greater than 32 weeks. Data were obtained in a standardized fashion and entered into a centralized electronic data capture system. The association between Bishop score and vaginal delivery was further evaluated with a multivariate receiver-operating characteristic (ROC) curve analysis. A Wilcoxon rank test and multivariable logistic regression were used for statistical analysis (significance: P < .05).

RESULTS

Between May 2015 and July 2016, 444 pregnant women were included. Three hundred ten (70 %) delivered vaginally. Compared to patients who underwent cesarean delivery, those who delivered vaginally were more likely to have a history of prior vaginal delivery. Vaginal delivery rates were significantly correlated with Bishop scores of pre and post Dilapan-S and difference. After adjusting for age, BMI, number of dilators, cervical ripening time, and gestational age, both prior vaginal delivery and post-Dilapan-S Bishop scores were strong predictors of vaginal delivery (estimate coefficient: 0.1275 ± 0.03 P = .0002; 0.049 ± 0.01 P = .0001; respectively). Aggregate ROC accounting for these variables further supported these findings (AUC = 0.734). The lower confidence interval limit of vaginal delivery rates was above 50 % when post-Dilapan-S Bishop scores were ≥ 5. Cox regression analyses demonstrated that the duration of labor was significant shorter in women that had vaginal delivery.

CONCLUSION

Bishop scores after cervical ripening with Dilapan-S are good predictors of vaginal delivery. Bishop scores < 5 post Dilapan-S may warrant further cervical ripening. Further level 1 trials are needed to compare osmotic dilators to other ripening methods.

In situ formation, structural, mechanical and in vitro analysis of ZrO2/ZnFe2O4 composite with assorted composition ratios

The investigation underline the in situ formation of ZrO₂/ZnFe₂O₄ composites and the resultant structural, morphological, mechanical and magnetic properties. The characterization results ensured the crystallization of tetragonal ZrO₂ (t-ZrO₂) and ZnFe₂O₄ phases at 900 °C. Depending on Zn²⁺/Fe³⁺ content, the composite system revealed a gradual increment in the phase yield of ZnFe₂O₄. The significance of monoclinic ZrO₂ (m-ZrO₂) is also evident in all the systems at 900 °C; however, the incremental heat treatment to 1300 °C indicated its corresponding loss, thus indicating the reverse m- → t-ZrO₂ transition. The crystallization of ZnFe₂O₄ as a secondary phase in the t-ZrO₂ matrix is also affirmed from the morphological analysis. Mechanical studies accomplished good uniformity in all the investigated compositions despite the variation in the phase content of ZnFe₂O₄ in composite system. All the t-ZrO₂/ZnFe₂O₄ composites ensured strong ferrimagnetic features and moreover better biocompatibility and non-toxicity characteristics were displayed from in vitro tests.

Induction of Noninflammatory Pain in an Experimental Foot Lameness Model in Horses

The mechanism by which nonsteroidal anti-inflammatory drugs mitigate pain caused by a heart bar shoe (HBS) model of lameness is unknown. The purpose of this study was to determine if this HBS model of lameness induces inflammation in horses. Five healthy adult horses from a university teaching herd were enrolled. A custom HBS was applied to the left front foot of each horse, followed by induction of the American Association of Equine Practitioners Lameness Score of 4. Inflammatory markers including serum amyloid A (SAA) concentration, local venous tumor necrosis factor alpha and prostaglandin E2 (PGE2) concentrations, and foot temperature were measured before lameness induction and 1, 3, and 13 hours after lameness induction. Lameness induction using the HBS model did not significantly increase production of plasma SAA, tumor necrosis factor alpha, or PGE2 concentrations at measured time points. Immediately and 1 hour after lameness induction, dorsal coronary band temperatures were higher in the left front foot compared with the right front foot, but there was no difference at 3 or 13 hours. In conclusion, the HBS model did not induce inflammation as assessed by select inflammatory markers, suggesting that the HBS model induces mechanical rather than inflammatory pain. This should be considered when using the HBS model to assess analgesic drugs in horses.

Peripheral nociceptive mechanisms in an experimental rat model of fibromyalgia induced by repeated cold stress

Fibromyalgia (FM) is a debilitating disease characterized by generalized and persistent musculoskeletal pain. Although central mechanisms are strongly implicated in the pathogenesis of FM, the involvement of peripheral mechanisms is poorly understood. To understand the peripheral nociceptive mechanisms, we examined muscular nociceptors in an FM model, which was made by exposing rats to repeated cold stress (RCS). A single muscle C-fiber nociceptors were identified through the teased fiber technique using ex vivo muscle-nerve preparations. Response properties of C-fibers to noxious stimuli were systematically analyzed. Messenger RNA expression of neurotrophic factors and inflammatory mediators were also studied in the muscle. In the RCS group, the mechanical response threshold of C-fibers, measured using a ramp mechanical stimulus, was significantly decreased, and the response magnitude was significantly increased in the RCS group when compared with the SHAM group, where the environmental temperature was not altered. The general characteristics of C-fibers and the responsiveness to noxious cold and heat stimuli were similar between the two groups. Messenger RNAs of neurotrophic factors and inflammatory mediators were not changed in the muscle during and after RCS. These results suggest that augmentation of the mechanical response of muscle C-fiber nociceptors contributes to hyperalgesia in the RCS model.

Current status and perspectives of zinc-based absorbable alloys for biomedical applications

Absorbable metals have the potential to serve as the next generation of temporary medical implant devices by safely dissolving in the human body upon vascular tissue healing and bone regeneration. Their implementation in the market could greatly reduce the need of costly and risky additional surgeries for either implant replacement or removal, often required in current permanent implants. Despite the extensive research done over the last two decades on magnesium (Mg) and iron (Fe) based alloys, they have not generally shown a satisfactory combination of mechanical properties, biocompatibility and controlled degradation rate in the physiological environment. Consequently, zinc (Zn) based alloys were introduced in the last few years as alternative materials to overcome the limitations of Fe and Mg-based alloys. The blend of different alloying elements and processing conditions have led to a wide variety of Zn-based alloys having tunable mechanical properties and corrosion rates. This review provides the most recent progress in the development of absorbable Zn-based alloys for biomedical implant applications, primarily for cardiovascular and orthopedic devices. Their biocompatibility, processability and metallurgical aspects, as well as their mechanical behavior and corrosion properties are presented and discussed, including their opportunities, limitations and future research directions. STATEMENT OF SIGNIFICANCE: Temporary orthopedic bioimplants have become increasingly popular as they offer an alternative to prevent complications, like infections or secondary surgeries, often related to the implantation of permanent devices. Iron and magnesium alloys were extensively studied as candidates for absorbable medical applications, but they generally failed to provide a desirable mechanical performance and corrosion characteristics in the physiological environment. Zinc was introduced in the last decade as a potential implant material after showing outstanding biocompatibility and biodegradability. This review summarizes the research advances to date and provides a thorough discussion of the future challenges of absorbable zinc alloys to satisfy the demanding clinical benchmarks for absorbable medical applications. Their biocompatibility, mechanical, and corrosion aspects, both in vitro and in vivo, are comprehensively reviewed and assessed accordingly.

Admission to the surgical intensive care unit during intensivist coverage is associated with lower incidence of postoperative acute kidney injury and shorter ventilator time

PURPOSE

This study aimed to assess the impact of intensivist coverage on the incidence of acute kidney injury (AKI) and ventilator time among patients postoperatively admitted to the intensive care unit (ICU).

METHODS

Adult patients postoperatively admitted to the ICU between January 2012 and December 2017 were retrospectively enrolled. The incidence of AKI within 72 h of surgery and the postoperative ventilator time were compared between the groups covered by intensivists and non-intensivists.

RESULTS

After propensity score (PS) matching, 5650 patients were included in the final analysis (2825 patients in each group). The incidence rate of AKI was significantly higher in the non-intensivist coverage group than in the intensivist coverage group (22.7% vs. 20.2%; P = 0.023). Moreover, logistic regression analysis in the PS-matched cohort showed that the incidence of postoperative AKI in the non-intensivist coverage group increased by 16% compared to that in the intensivist coverage group (odds ratio 1.16, 95% confidence interval 1.02-1.32; P = 0.023). Additionally, the median time of ventilator use in the non-intensivist coverage group was significantly longer than that in the intensivist coverage group [7.8 (interquartile range, IQR 2.6-13.8) h vs. 5.3 (1.8-8.3) h; P < 0.001].

CONCLUSION

High-intensity intensivist coverage is associated with a lower risk of postoperative AKI and shorter postoperative ventilator times. These findings suggested that in addition to medical trainees, initial management of surgical ICU patients by intensivists may lower the risk of AKI and facilitate early weaning from mechanical ventilation.

Coronary artery fixation at iso-arterial pressure: impacts on histologic evaluation and clinical management

Coronary angiography is the standard imaging method for determining the site, extent, and severity of coronary artery disease. Several publications have reported discordance between the degree of coronary artery stenosis determined from post-mortem histologic evaluation and coronary angiography. While the 2-dimensional limitations of coronary angiography are well established, the determination of coronary stenosis based on histologic evaluation of passively fixed samples is also associated with significant biases. In this study, we used patients with chronic coronary artery disease to compare the stenosis severity estimates that were determined using the passive fixation method with those determined using the active fixation method. Our results showed a significant discrepancy between the stenosis in passively fixed coronary arteries when compared with coronary angiography in all major coronary vessels combined (P=.002), and in Cx (P=.045) and CD (P=.026). However, there was no mean difference when compared with perfused (actively fixed) samples when all vessels were combined or examined individually. Iso-physiologic mechanical perfusion (active) fixation yielded significantly reduced coronary artery stenosis means when compared to the passive fixation method in post-mortem evaluations during autopsies. This was evident when all vessels were combined (P=.0001) and assessed individually (Cx (P=.003), LAD (P=.025), LM (P=.056) and RC (P=.007)). Autopsies including cardiac explant patients also showed differences in estimates for all vessels combined (P=.0001) and in Cx (P=.016) and RC (P=.006). In summary, our quantitative histopathology analyses using perfused coronary artery stenosis at physiologic pressure showed significant discrepancies when compared with passive histopathology.

Human decellularized dermal matrix seeded with adipose-derived stem cells enhances wound healing in a murine model: Experimental study

Objective

Full-thickness cutaneous wounds treated with split-thickness skin grafts often result in unaesthetic and hypertrophic scars. Dermal substitutes are currently used together with skin grafts in a single treatment to reconstruct the dermal layer of the skin, resulting in improved quality of scars. Adipose-derived stem cells (ASCs) have been described to enhance wound healing through structural and humoral mechanisms. In this study, we investigate the compatibility of xenogen-free isolated human ASCs seeded on human acellular dermal matrix (Glyaderm®) in a murine immunodeficient wound model.

Methods

Adipose tissue was obtained from abdominal liposuction, and stromal cells were isolated mechanically and cultured xenogen-free in autologous plasma-supplemented medium. Glyaderm® discs were seeded with EGFP-transduced ASCs, and implanted on 8 mm full-thickness dorsal wounds in an immunodeficient murine model, in comparison to standard Glyaderm® discs. Re-epithelialization rate, granulation thickness and vascularity were assessed by histology on days 3, 7 and 12. Statistical analysis was conducted using the Wilcoxon signed-rank test. EGFP-staining allowed for tracking of the ASCs in vivo. Hypoxic culture of the ASCs was performed to evaluate cytokine production.

Results

ASCs were characterized with flowcytometric analysis and differentiation assay. EGFP-tranduction resulted in 95% positive cells after sorting. Re-epithelialization in the ASC-seeded Glyaderm® side was significantly increased, resulting in complete wound healing in 12 days. Granulation thickness and vascularization were significantly increased during early wound healing. EGFP-ASCs could be retrieved by immunohistochemistry in the granulation tissue in early wound healing, and lining vascular structures in later stages.

Conclusion

Glyaderm® is an effective carrier to deliver ASCs in full-thickness wounds. ASC-seeded Glyaderm® significantly enhances wound healing compared to standard Glyaderm®. The results of this study encourage clinical trials for treatment of full-thickness skin defects. Furthermore, xenogen-free isolation and autologous plasma-augmented culture expansion of ASCs, combined with the existing clinical experience with Glyaderm®, aid in simplifying the necessary procedures in a GMP-laboratory setting.

•

ASCs obtained from human liposuction fat were isolated mechanically and cultured xenogen-free in autologous plasma-supplemented medium.

•

Hypoxic culture of the ASCs was performed to evaluate increased cytokine production.

•

Glyaderm® discs were seeded with EGFP-transduced ASCs, and implanted on full-thickness dorsal wounds in an immunodeficient murine model, in comparison to standard Glyaderm® discs.

•

Reëpithelialisation, granulation and vascularization in the ASC-seeded Glyaderm® side were significantly increased, resulting in complete wound healing in 12 days.

•

EGFP-ASCs could be retrieved by IHC in the granulation tissue in early wound healing, and lining vascular structures in later stages.

Structure, luminescence, mechanical and in vitro behavior of zirconia toughened alumina due to terbium substitutions

The significance of Tb³⁺ inclusions at the zirconia toughened alumina (ZTA) structure was explored. The influence of Tb³⁺ content at the crystal structures of ZrO₂ and Al₂O₃ and the resultant optical, mechanical, magnetic and cytotoxicity properties were deliberated. The critical role of Tb³⁺ to attain a structurally stable ZTA until 1500 °C is ensured. Depending on the Tb³⁺ content, either tetragonal zirconia (t-ZrO₂) or cubic zirconia (c-ZrO₂) structures were stabilized while the propensity of Tb³⁺ reaction with Al₂O₃ to yield TbAlO₃ is transpired only after exceeding the occupancy limit in ZrO₂. The green emission and paramagnetic features are imparted by the Tb³⁺ inclusions at the ZTA structure. Dense and pore free microstructures with a direct impact on the improved mechanical features of ZTA is empowered by the presence of Tb³⁺. Further, the results from MTT assay and live/dead cell staining ensured the negligence of Tb³⁺ contained ZTA systems to induce toxicity.

Influence of oxidized starch on physicomechanical, thermal properties, and atomic force micrographs of cassava starch bioplastic film

Oxidized starch was produced and its effect on starch-based bioplastic film has been evaluated. The produced oxidized starch was coarse, brownish with 15.68% carbonyl content, insoluble in cold water and has a positive influence on bioplastic films. The film thickness increased with increase in the amount of added oxidized starch from 0.21% (film_O) to 0.23% (film_6O). The film moisture content dropped from 7.93% (film_O) to 5.36% (film_6O), likewise the film water solubility decreased from 13.48% (film_O) to 5.75% (film_6O). Addition of oxidized starch led to longer biodegradability and enduring water absorption kinetics. The mechanical property was improved by the addition of oxidized starch. The derivative thermogravimetry analysis indicates five degradation stages for all the bioplastic films, while films surface roughness was shown by AFM. The research has revealed that oxidized starch can be used to improve the physicomechanical properties of starch based bioplastic film.

Why a zero CTE mismatch may be better for veneered Y-TZP structures

OBJECTIVE

Compare residual stress distribution of bilayered structures with a mismatch between the coefficient of thermal expansion (CTE) of framework and veneering ceramic. A positive mismatch, which is recommended for metal-ceramic dental crowns, was hypothesized to contribute to a greater chipping frequency in veneered Y-TZP structures. In addition, the multidirectional nature of residual stresses in bars and crowns is presented to explore some apparent contradictions among different studies.

METHODS

Planar bar and crown-shaped bilayered specimens with 0.7 mm framework thickness and 1.5 mm porcelain veneer thickness were investigated using finite element elastic analysis. Eight CTE mismatch conditions were simulated, representing two framework materials (zirconia and metal) and six veneering porcelains (distinguished by CTE values). Besides metal-ceramic and zirconia-ceramic combinations indicated by the manufacturer, models presenting similar mismatch values (1 ppm/°C) with different framework materials (metal or zirconia) and zirconia-based models with metal-compatible porcelain veneers were also tested. A slow cooling protocol from 600 °C to room temperature was simulated. The distributions of residual maximum and minimum principal stresses, as well as stress components parallel to the long axis of the specimens, were analysed.

RESULTS

Planar and crown specimens generated different residual stress distributions. When manufacturer recommended combinations were analysed, residual stresses obtained for zirconia models were significantly higher than those for metal-based models. When zirconia frameworks were combined with metal-compatible porcelains, the residual stress values were even higher. Residual stresses were not different between metal-based and zirconia-based models if the CTE mismatch was similar.

SIGNIFICANCE

Some conclusions obtained with planar specimens cannot be extrapolated to clinical situations because specimen shape strongly influences residual stress patterns. Since positive mismatch generates compressive hoop stresses and tensile radial stresses and since zirconia-based crowns tend to be more vulnerable to chipping, a tensile stress-free state generated with a zero CTE mismatch could be advantageous.

Machine preservation of donor kidneys in transplantation

With increasing demands for 'less than ideal' kidneys for transplantation, machine perfusion of kidneys has been utilized to improve the preservation of kidneys during storage. Hypothermic machine perfusion (HMP) of renal allografts has been shown to reduce delayed graft function rates in both expanded criteria and donation after cardiac death renal allografts. However, the beneficial impact upon long-term graft function is unclear. There has been emerging evidence that both subnormothermic (room temperature) and normothermic machine perfusion (NMP) of allografts have beneficial effects with regards to early graft function, survival and injury in pre-clinical and early clinical studies. Additionally, machine perfusion allows functional assessment of the organ prior to transplantation. Ultimately, the greatest benefit of machine perfusion may be the ability to treat the organ with agents to protect the graft against ischemia reperfusion injury, while awaiting transplantation.