Comparative analysis of methods for determining the flammability of municipal solid waste as railway transport cargo

A statistical analysis of information about fires that occurred on the railroads shows that it is necessary to enhance the fire protection measures while transporting the fire-hazardous materials (FHM). A comparative analysis of the use of the exergetic index and the flammability potential for forecasting the fire risks connected to the railroad FHM transportation has been performed. The studies considered municipal solid waste (MSW) as promising railway cargo. The values of the MSW chemical exergy and the heat of combustion have been calculated. The conditions and behavior of their variations have been investigated. A system of the substances and materials classification that is based on the exergetic coefficient was introduced. The proposed approach allows us to resolve methodological problems caused by the requirement to account for the technical, economical criteria, and the fire risk indexes into a unified classification system. The conception of the exergetic index improves the objectivity of the procedure for the estimation of the MSW flammability properties.

Single-cell transcriptomic analysis unveils spinal motor neuron subtype diversity underpinning the water-to-land transition in vertebrates

Spinal motor neurons (MNs) integrate sensory stimuli and brain commands to generate motor movements in vertebrates. Distinct MN populations and their diversity has long been hypothesized to co-evolve with motor circuit to provide the neural basis from undulatory to ambulatory locomotion during aquatic-to-terrestrial transition of vertebrates. However, how these subtypes are evolved remains largely enigmatic. Using single-cell transcriptomics, we investigate heterogeneity in mouse MNs and discover novel segment-specific subtypes. Among limb-innervating MNs, we reveal a diverse neuropeptide code for delineating putative motor pool identities. We further uncovered that axial MNs are subdivided by three conserved and molecularly distinct subpopulations, defined by Satb2, Nr2f2 or Bcl11b expression. Although axial MNs are conserved from cephalochordates to humans, subtype diversity becomes prominent in land animals and appears to continue evolving in humans. Overall, our study provides a unified classification system for spinal MNs and paves the way towards deciphering how neuronal subtypes are evolved.

Reliability and validity of the Unified Classification System for postoperative periprosthetic femoral fractures around cemented polished taper-slip stems

Aims This aim of this study was to assess the reliability and validity of the Unified Classification System (UCS) for postoperative periprosthetic femoral fractures (PFFs) around cemented polished taper-slip (PTS) stems. Methods Radiographs of 71 patients with a PFF admitted consecutively at two centres between 25 February 2012 and 19 May 2020 were collated by an independent investigator. Six observers (three hip consultants and three trainees) were familiarized with the UCS. Each PFF was classified on two separate occasions, with a mean time between assessments of 22.7 days (16 to 29). Interobserver reliability for more than two observers was assessed using percentage agreement and Fleiss’ kappa statistic. Intraobserver reliability between two observers was calculated with Cohen kappa statistic. Validity was tested on surgically managed UCS type B PFFs where stem stability was documented in operation notes (n = 50). Validity was assessed using percentage agreement and Cohen kappa statistic between radiological assessment and intraoperative findings. Kappa statistics were interpreted using Landis and Koch criteria. All six observers were blinded to operation notes and postoperative radiographs. Results Interobserver reliability percentage agreement was 58.5% and the overall kappa value was 0.442 (moderate agreement). Lowest kappa values were seen for type B fractures (0.095 to 0.360). The mean intraobserver reliability kappa value was 0.672 (0.447 to 0.867), indicating substantial agreement. Validity percentage agreement was 65.7% and the mean kappa value was 0.300 (0.160 to 0.4400) indicating only fair agreement. Conclusion This study demonstrates that the UCS is unsatisfactory for the classification of PFFs around PTS stems, and that it has considerably lower reliability and validity than previously described for other stem types. Radiological PTS stem loosening in the presence of PFF is poorly defined and formal intraoperative testing of stem stability is recommended. Cite this article: Bone Joint J 2021;103-B(8):1339–1344.

Do standards of care and early outcomes of periprosthetic fractures change during the COVID-19 pandemic? A multicentre study

Background Periprosthetic fractures (PPFs) are a growing matter for orthopaedic surgeons, and patients with PPFs may represent a frail target in the case of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The purpose of this study is to investigate whether hospital reorganisations during the most severe phase of the SARS-CoV-2 pandemic affected standards of care and early outcomes of patients treated for PPFs in Northern Italy. Materials and methods Data were retrieved from a multicentre retrospective orthopaedics and traumatology database, including 14 hospitals. The following parameters were studied: demographics, results of nasopharyngeal swabs, prevalence of coronavirus disease 2019 (COVID-19), comorbidities, general health status (EQ-5D-5L Score), frailty (Clinical Frailty Scale, CFS), pain (visual analogue scale, VAS), anaesthesiologic risk (American Society of Anaesthesiology Score, ASA Score), classification (unified classification system, UCS), type of operation and anaesthesia, in-hospital and early complications (Clavien–Dindo Classification, CDC), and length of stay (LOS). Data were analysed by means of descriptive statistics. Out of 1390 patients treated for any reason, 38 PPFs were included. Results Median age was 81 years (range 70–96 years). Twenty-three patients (60.5%) were swabbed on admission, and two of them (5.3%) tested positive; in three patients (7.9%), the diagnosis of COVID-19 was established on a clinical and radiological basis. Two more patients tested positive post-operatively, and one of them died due to COVID-19. Thirty-three patients (86.8%) presented a proximal femoral PPF. Median ASA Score was 3 (range, 1–4), median VAS score on admission was 3 (range, 0–6), median CFS was 4 (range, 1–8), median EQ-5D-5L Score was 3 in each one of the categories (range, 1–5). Twenty-three patients (60.5%) developed post-operative complications, and median CDC grade was 3 (range, 1–5). The median LOS was 12.8 days (range 2–36 days), and 21 patients (55.3%) were discharged home. Conclusions The incidence of PPFs did not seem to change during the lockdown. Patients were mainly elderly with comorbidities, and complications were frequently recorded post-operatively. Despite the difficult period for the healthcare system, hospitals were able to provide effective conventional surgical treatments for PPFs, which were not negatively influenced by the reorganisation. Continued efforts are required to optimise the treatment of these frail patients in the period of the pandemic, minimising the risk of contamination, and to limit the incidence of PPFs in the future. Level of evidence IV.

Impact of Igneous Rock Admixtures on Geotechnical Properties of Lime Stabilized Clay

This paper investigates the probable influence of powder from two igneous rocks, namely granite and rhyolite, on the geotechnical properties of lime stabilized clay soil. A clay soil sample was collected from Jhelum, city of the province Punjab in Pakistan, and its major geotechnical properties including particle size distribution, Atterberg limits, Activity, compaction parameters, California Bearing Ratio (CBR) and unconfined compressive strength (UCS) were determined by using standard ASTM procedures. Owing to the presence of clay minerals, the Jhelum soil is classified as CH soil (Fat clays) following the Unified classification system. Lime was added to the soil in the range of 0 – 12 % and the most influential lime percentage, i.e. the one causing the highest possible positive impact on geotechnical properties, was chosen for further stabilization. Following a gradual increase by 8 %, up to 32 % of granite and rhyolite powders were separately mixed with the soil sample showing maximum stabilization with lime, i.e. the sample containing 6 % lime. Each of the resulting samples was tested for all the parameters mentioned above. The results demonstrate that addition of granite and rhyolite powders produces significant improvement in workability and performance of the clay soil previously stabilized with 6 % lime. The improvement is obvious from reduction in Plasticity index, Activity and optimum moisture content, and rapid increase in UCS, maximum dry density and CBR. The principal reason for the observed positive changes is the presence of abundant non-active and denser minerals in granite and rhyolite powders as compared to lime and clay soil. Furthermore, the positive impact of rhyolite on the geotechnical behaviour of soil is relatively higher than granite obviously because of its better petrographic features, physical properties and strength.