A Raman spectral marker for the iso-octyl chain structure of cholesterol.

Raman spectroscopy provides label-free, specific analysis of biomolecular structure and interactions. It could have a greater impact with improved characterization of complex fingerprint vibrations. Many Raman peaks have been assigned to cholesterol, for example, but the molecular vibrations associated with those peaks are not known. In this report, time-dependent density functional theory calculations of the Raman spectrum of cholesterol are compared to measurements on microcrystalline powder to identify 23 peaks in the Raman spectrum. Among them, a band of six peaks is found to be sensitive to the conformational structure of cholesterol's iso-octyl chain. Calculations on 10 conformers in this spectral band are fit to experimental spectra to probe the cholesterol chain structure in purified powder and in phospholipid vesicles. In vesicles, the chain is found to bend perpendicular to the steroid rings, supporting the case that the chain is a dynamic structure that contributes to lipid condensation and other effects of cholesterol in biomembranes. Statement of Significance: Here we use density functional theory to identify a band of six peaks in cholesterol's Raman spectrum that is sensitive to the conformational structure of cholesterol's chain. Raman spectra were analyzed to show that in fluid-phase lipid membranes, about half of the cholesterol chains point perpendicular to the steroid rings. This new method of label-free structural analysis could make significant contributions to our understanding of cholesterol's critical role in biomembrane structure and function. More broadly, the results show that computational quantum chemistry Raman spectroscopy can make significant new contributions to molecular structure when spectra are interpreted with computational quantum chemistry.

Nine years of surgical activity in the deployed French military role 2 medical treatment facility in Mali.

INTRODUCTION: In January 2013, France launched a military operation in Mali, which ended in August 2022. This study aimed to analyse the global activity performed by a surgical team within the role 2 medical treatment facility (MTF) deployed in Gao during this period, in order to adapt medical battlefield support and combat casualty care teaching. METHODS: A retrospective study was conducted using the French surgical database OpEX (French Military Health Service) from January 2013 to August 2022. All patients operated on were included. RESULTS: During this period, 1298 patients with a median age of 29 (range: 23-38) years were included. Among them, 229 (17.6%) underwent a combat-related trauma surgery (CRTS), 234 (18.0%) underwent a non-CRTS, 167 (12.9%) underwent a non-trauma-related surgery and 668 (51.5%) underwent a scheduled surgery in the context of medical supply to the population.Among the CRTS group, 195 (85.2%) patients underwent an orthopaedic procedure, 73 (31.8%) required a general surgery. Finally, 15 (6.6%) wounded required a specialised surgery. CONCLUSIONS: In line with the activity described in the role 2 MTF deployed in other contemporary asymmetric conflicts, this activity is moderate, especially if only combat-related injuries are considered; medical support to the population occupied most of the surgical activity. For CRTS, most of the traumas are limb traumas. Other traumas are composed of various lesions, which are often life-threatening. This fact imposes the presence of an orthopaedic surgeon with the appropriate equipment, as well as a general surgeon with a wide range of skills, in asymmetric conflicts.

Electron-Poor Butenolides: The Missing Link between Acrylates and Maleic Anhydride in Radical Polymerization.

Butenolides are a class of 5-membered lactones that hold great potential as bio-based monomers to replace oil-derived acrylates, of which they are cyclic analogues. Despite this structural resemblance, the reactivity of the unsaturated ester moiety of electron-poor butenolides leans toward that of maleic anhydride, another essential monomer that does not homopolymerize but copolymerizes in a highly alternating fashion with polarized electron-rich comonomers. By studying the reactivity of 5-methoxy and 5-acyloxy butenolides through a combination of kinetics and density functional theory (DFT) experiments, we explain why electron-poor butenolides constitute a missing link between acrylates and maleic anhydride in radical polymerization.

Humanity's diverse predatory niche and its ecological consequences.

Although humans have long been predators with enduring nutritive and cultural relationships with their prey, seldom have conservation ecologists considered the divergent predatory behavior of contemporary, industrialized humans. Recognizing that the number, strength and diversity of predator-prey relationships can profoundly influence biodiversity, here we analyze humanity's modern day predatory interactions with vertebrates and estimate their ecological consequences. Analysing IUCN 'use and trade' data for ~47,000 species, we show that fishers, hunters and other animal collectors prey on more than a third (~15,000 species) of Earth's vertebrates. Assessed over equivalent ranges, humans exploit up to 300 times more species than comparable non-human predators. Exploitation for the pet trade, medicine, and other uses now affects almost as many species as those targeted for food consumption, and almost 40% of exploited species are threatened by human use. Trait space analyses show that birds and mammals threatened by exploitation occupy a disproportionally large and unique region of ecological trait space, now at risk of loss. These patterns suggest far more species are subject to human-imposed ecological (e.g., landscapes of fear) and evolutionary (e.g., harvest selection) processes than previously considered. Moreover, continued overexploitation will likely bear profound consequences for biodiversity and ecosystem function.

The Raman Active Vibrations of Flavone and Quercetin: The Impact of Conformers and Hydrogen Bonding on Fingerprint Modes.

The detection and analysis of flavonoids by Raman spectroscopy are of interest in many fields, including medicinal chemistry, food science, and astrobiology. Spectral interpretation would benefit from better identification of the fingerprint vibrational peaks of different flavonoids and how they are affected by intermolecular interactions. The Raman spectra of two flavonoids, flavone and quercetin, were investigated through comparisons between spectra recorded from pure powders and spectra calculated with time dependent density functional theory (TDDFT). For both flavone and quercetin, 17 peaks were assigned to specific molecular vibrations. Both flavonoids were found to have a split peak between 1250-1350 cm-1 that is not predicted by TDDFT calculations on isolated molecules. In each case, it is shown that the addition of hydrogen bonded molecules arranged based on crystal structures reproduces the split peaks. These peaks were due to a stretching vibration of the bond between benzopyrone and phenyl rings and represent a characteristic spectral feature of flavonoids. Spectra of pollen grains from Quercus virginiana were also recorded and exhibit several peaks that correspond to the quercetin spectrum.

Treating osteoarticular infections in a Role 2 in Chad: a bacterial epidemiological study.

INTRODUCTION: The treatment of osteoarticular infections in Africa is a medical and surgical challenge due to the difficulties in managing antibiotic therapy after the surgical procedure. The objectives of this study were to identify the types of bacteria in osteoarticular lesions in patients treated in Chad and to determine the spectrum of resistance encountered and the efficacy of available antibiotics. MATERIAL AND METHODS: This is a retrospective study of all intraoperative osteoarticular and soft tissue samples taken in a French Role 2 Medical Treatment Facility of N'Djamena during surgery for chronic osteoarticular infections, in Chad, for 1 year. RESULTS: A total of 160 bacterial strains were identified, with a predominance of Gram-negative bacillus (GNB) and staphylococcus infections. Among staphylococci, 80% were methicillin-sensitive streptococci which were generally multidrug-sensitive. Enterococci were resistant to third-generation cephalosporins, first-generation fluoroquinolones and gentamycin. Among GNB, there was a predominance of enterobacteria compared with non-fermenting GNB, of which 52% were multidrug-resistant and produced extended spectrum beta-lactamases (ESBL). CONCLUSION: Staphylococcus aureus infections are most often sensitive to available antibiotics and therefore have better prognoses than infections caused by other bacteria. In contrast, in half of the cases of GNB, infections were caused by bacteria producing ESBL, thus posing the problem of multidrug-resistance, the risks of which are increased in precarious situations. Therefore, the type of bacteria appears to be a major prognostic factor in the treatment of osteoarticular infections in a Role 2 in Chad. This criterion will need to be considered before any treatment decisions are made.

Elective brachial plexus decompression in neurogenic thoracic outlet syndrome.

We aimed to evaluate functional outcome following elective brachial plexus decompression by compressive fibrous band resection and limited on-demand bone abnormality resection in patients with neurogenic thoracic outlet syndrome (N-TOS). A retrospective continuous observational study was conducted in 17 patients (15 women and 2 men), with a mean age of 42 years, operated on between 2013 and 2021. Twenty brachial plexus decompressions were performed, for 13 objective and 7 subjective N-TOSs, including 3 recurrent N-TOSs. At last follow-up, outcomes were evaluated in terms of residual pain, paresthesia and hand motor deficit, plus patient-reported assessment and Quick-DASH functional scoring. No postoperative complications occurred. At a median follow-up of 12 months (range 6-48 months), complete pain relief and paresthesia resolution were found in 11/15 and 9/14 cases, respectively. All patients reported that their symptoms had improved. In contrast, hand muscle atrophy persisted in all cases (n = 11). Sensorimotor recovery seemed to be poorer and mean Quick-DASH score better in objective than subjective N-TOS patients. Elective brachial plexus decompression seemed to be a safe procedure, providing constant improvement in subjective symptoms related to lower trunk irritation. However, nerve release did not provide hand muscle recovery in patients with objective N-TOS. LEVEL OF EVIDENCE: IV.

Development of a modular photoreactor for the upscaling of continuous flow photochemistry.

The upscaling of biphasic photochemical reactions is challenging because of the inherent constraints of liquid-gas mixing and light penetration. Using semi-permeable coaxial flow chemistry within a modular photoreactor, the photooxidation of the platform chemical furfural was scaled up to produce routinely 29 gram per day of biobased building block hydroxybutenolide, a precursor to acrylate alternatives.

The Raman Active Vibrational Modes of Anthraquinones.

Anthraquinones are a family of natural products with useful bioactivity and optical properties. An anthraquinone called parietin is produced by extremophiles to protect against solar ultraviolet B radiation, so it is a potential biosignature in astrobiology. Raman spectroscopy, which is now used in space environments, can detect molecules such as parietin based on molecular vibrations. In this study, we show that time-dependent density functional theory (TDDFT) can accurately calculate the Raman spectra of three dihydroxyanthraquinones: parietin, emodin, and chrysophanol. By comparing calculated spectra to measured Raman spectra from purified powders, 10 vibrational modes are identified. The detailed molecular motions of these fused ring vibrations are described, and vibrations modes that are common to all three molecules are highlighted. In addition to powder spectra, Raman measurements from the thallus of Xanthoria parietina, a lichen that produces parietin, are reported, with excellent agreement to both the parietin powder and calculated Raman spectra. These results show that TDDFT calculations could make significant contributions to spectral analysis in the search for biotic organic materials beyond Earth.

BoNT/A1 Secondary Failure for the Treatment of Neurogenic Detrusor Overactivity: An Ex Vivo Functional Study.

Management of neurogenic detrusor overactivity (NDO) remains a clinical priority to improve patients' quality of life and prevent dramatic urological complications. Intradetrusor injection of onabotulinumtoxinA (BoNT/A1, botulinum neurotoxin A1) is approved as second therapeutic line in these patients, demonstrating a good efficacy. However, a loss of its efficacy over time has been described, with no clear understanding of the underlying mechanisms. This paper aims at shedding new light on BoNT/A1 secondary failure in NDO through functional and structural analysis. Three groups of patients (either non-NDO, NDO with no toxin history or toxin secondary failure) were investigated using an ex vivo bladder strip assay. Detrusor strips were tensed in organ baths and submitted to electrical field stimulation to generate contractions. Recombinant BoNT/A1 was then added at various concentrations and contractions recorded for 4 h. Histology exploring BoNT/A1 targets, fibrosis and neuronal markers was also used. Detrusor strips from patients with BoNT/A1 secondary failure displayed a smaller sensitivity to toxin ex vivo at 3 nM compared to the other groups. Histological evaluation demonstrated the presence of cleaved Synaptosomal-Associated Protein, 25 kDa (c-SNAP25) in the detrusor from the toxin-secondary failure population, indicating some remaining in vivo sensitivity to BoNT/A1 despite the therapeutic escape. Moreover, residual c-SNAP25 did not affect parasympathetic-driven contractions observed ex vivo. This study confirms the slightly lower efficacy of BoNT/A1 in the BoNT/A1 secondary failure NDO group, suggesting that the escape from BoNT/A1 efficacy in NDO occurs at least at the parasympathetic level and could imply compensatory mechanisms for detrusor contraction.

Riverscape approaches in practice: perspectives and applications.

Landscape perspectives in riverine ecology have been undertaken increasingly in the last 30 years, leading aquatic ecologists to develop a diverse set of approaches for conceptualizing, mapping and understanding 'riverscapes'. Spatiotemporally explicit perspectives of rivers and their biota nested within the socio-ecological landscape now provide guiding principles and approaches in inland fisheries and watershed management. During the last two decades, scientific literature on riverscapes has increased rapidly, indicating that the term and associated approaches are serving an important purpose in freshwater science and management. We trace the origins and theoretical foundations of riverscape perspectives and approaches and examine trends in the published literature to assess the state of the science and demonstrate how they are being applied to address recent challenges in the management of riverine ecosystems. We focus on approaches for studying and visualizing rivers and streams with remote sensing, modelling and sampling designs that enable pattern detection as seen from above (e.g. river channel, floodplain, and riparian areas) but also into the water itself (e.g. aquatic organisms and the aqueous environment). Key concepts from landscape ecology that are central to riverscape approaches are heterogeneity, scale (resolution, extent and scope) and connectivity (structural and functional), which underpin spatial and temporal aspects of study design, data collection and analysis. Mapping of physical and biological characteristics of rivers and floodplains with high-resolution, spatially intensive techniques improves understanding of the causes and ecological consequences of spatial patterns at multiple scales. This information is crucial for managing river ecosystems, especially for the successful implementation of conservation, restoration and monitoring programs. Recent advances in remote sensing, field-sampling approaches and geospatial technology are making it increasingly feasible to collect high-resolution data over larger scales in space and time. We highlight challenges and opportunities and discuss future avenues of research with emerging tools that can potentially help to overcome obstacles to collecting, analysing and displaying these data. This synthesis is intended to help researchers and resource managers understand and apply these concepts and approaches to address real-world problems in freshwater management.

Wartime upper-extremity injuries in the Sahelian strip: Experience from a French Forward Surgical Team deployed in Mali.

This study aimed to analyze upper-extremity combat-related injuries (CRIs) and non-combat-related injuries (NCRIs) treated in the French Forward Surgical Team currently deployed in Gao, Mali. A retrospective study was conducted using the French Military Health Service OpEX surgical database from February 2013 to March 2020. All patients operated on for upper-extremity injury were included: 224 patients, with a mean age of 28.15 years, for 249 upper-extremity injuries. Seventy-six (33.9%) sustained CRIs and 148 (66.1%) NCRIs. Multiple upper-extremity injuries and associated injuries were significantly more common in the CRI group. The majority of NCRIs involved the hand. Debridement and wound care was the most common procedure in both groups. External fixation and fasciotomy were significantly more frequent in the CRI group, and internal fracture fixation in the NCRI group. The overall number of procedures was significantly higher in the CRI group. Due to the high frequency of upper-extremity injury in current theaters of operations, deployed orthopedic surgeons should be trained in basic hand surgery so as to optimally manage both CRIs and NCRIs.

Flexible polyfluorinated bis-diazirines as molecular adhesives.

Motivated by a desire to develop flexible covalent adhesives that afford some of the same malleability in the adhesive layer as traditional polymer-based adhesives, we designed and synthesized two flexible, highly fluorinated bis-diazirines. Both molecules are shown to function as effective crosslinkers for polymer materials, and to act as strong adhesives when painted between two polymer objects of low surface energy, prior to thermal activation. Data obtained from lap-shear experiments suggests that greater molecular flexibility is correlated with improved mechanical compliance in the adhesive layer.

Effects of Conformational Variation on Structural Insights from Solution-Phase Surface-Enhanced Raman Spectroscopy.

Surface-enhanced Raman scattering (SERS) spectra contain information on the chemical structure on nanoparticle surfaces through the position and alignment of molecules with the electromagnetic near field. Time-dependent density functional theory (TDDFT) can provide the Raman tensors needed for a detailed interpretation of SERS spectra. Here, the impact of molecular conformations on SERS spectra is considered. TDDFT calculations of the surfactant cetyltrimethylammonium bromide with five conformers produced more accurate unenhanced Raman spectra than a simple all-trans structure. The calculations and measurements also demonstrated a loss of structural information in the CH2/CH3 scissor vibration band at 1450 cm-1 in the SERS spectra. To study lipid bilayers, TDDFT calculations on conformers of methyl phosphorylcholine and cis-5-decene served as models for the symmetric choline stretch in the lipid headgroup and the C═C stretch in the acyl chains of 1,2-oleoyl-glycero-3-phosphocholine. Conformer considerations enabled a measurement of the distribution of double-bond orientations with an order parameter of SC═C = 0.53.

Blast injury of the hand related to warfare explosive devices: experience from the French Military Health Service.

INTRODUCTION: The objective was to report on the experience of the French Army Health Service in the management of blast injury of the hands related to warfare explosive devices. METHODS: A retrospective study was conducted in the Percy Military Hospital (role 4 medical treatment facility) among French soldiers who presented with a combat-related blast injury of the hand between 2002 and 2018. The functional result was assessed by the disabilities of the arm, shoulder and hand (DASH) and the Orthotics and Prosthetics User Survey (OPUS, upper extremity functional status) scores. Proximal amputations (PAs) and distal amputations (DAs) were distinguished for the analysis. RESULTS: Fifteen patients with a mean age of 31±8 years were included. They totalised 20 blasted hands. There were 16 traumatic amputations: 8 in each of the PA and DA groups. Twelve patients had additional injuries, four of which were polytraumatic. Skin closure time and flap use were higher in the DA group. Only one thumb reconstruction was performed. At a mean follow-up of 6.5±4 years, the number of amputees wearing a prosthesis was higher in the PA group. The mean DASH and OPUS scores were 35.5%±24.0% and 64.0%±19.0%, respectively, with no difference between the two groups. CONCLUSION: The severity of hand blasts related to warfare explosive devices requires the systematic application of damage control surgery. PAs are frequent and secondary reconstruction options are limited. The functional result is poor and similar between proximal and distal amputees.

Evaluation of a fellowship abroad as part of the initial training of the French military surgeon.

INTRODUCTION: Military surgery requires skills that in general cannot be easily learnt in civilian training. Participation in a fellowship abroad adapted to the particular operating conditions of the foreign deployment is one route that might secure the necessary supplementary training. We therefore assessed the relevance of such a fellowship in the preparedness of young military surgeons in their first deployment. METHODS: This study included all active military surgeons who had completed a fellowship abroad during their initial training from 2004 to 2017 in Tchad or Senegal or Djibouti. The collection of data was performed using a questionnaire. The main judgement criterion was the rate of positive answers awarded to the relevance of this fellowship in the preparedness of respondents' first foreign deployment. RESULTS: Sixty-nine of 73 surgeons answered. Sixty-one estimated the fellowship had allowed them to feel more operational during their first mission, with 83.61% rating this feeling as important. Also, 61 recommended the use of a fellowship for war surgery training. The grade assigned to the surgical benefit was 8.48/10. CONCLUSION: A fellowship abroad permits one to become familiar with surgical practice under austere circumstances and the particularities of the surgical structures at the front. Current trainees' feedback confirms its relevance.

Number, type and cost of microbiological tests during HIV Pre-Exposure Prophylaxis: The experience of a French hospital.

BACKGROUND: Microbiological tests are required for individuals on HIV Pre-Exposure Prophylaxis (PrEP), but their real-life numbers, types and cost are poorly described. METHODS: Number, type, and results of microbiological tests performed in a Besançon Hospital-associated laboratory, France, from 2016 to 2019, in the setting of PrEP consultations were retrospectively collected. Costs were estimated by the current reimbursement rate set by the French national protection system. RESULTS: 756 consultations for PrEP initiation or follow-up of 135 persons were performed over 4 years. Among 3434 tests performed in the institution-associated laboratory, 1083 and 2351 were virological and bacteriological tests, respectively. Serology was predominant in virology (98% of virological tests), with HIV, HCV, and HBV screening as the 3 more frequent assays, whereas molecular biology was predominant in bacteriology (63.1% of bacteriological tests) with N. gonorrhoeae and C. trachomatis screening as leader assays. Agar-based culture accounted for 1% of bacterial tests. The global cost of microbiological tests was 45,983.20 euros, corresponding to a mean cost of 60.80 euros per consultation. Virological and bacteriological tests accounted for 37.7% and 62.3% of this budget, respectively. No seroconversion was observed for HIV or HCV. N. gonorrhoeae and C. trachomatis were detected at least once in 39.3% and 22.4% of individuals, respectively, with 15% of symptomatic episodes in both cases. Active syphilis infection was detected in 15.4% of individuals. CONCLUSIONS: Since numerous microbiological tests are required during PrEP, the availability of specific technical platforms should not be neglected by centers wishing to set up PrEP consultations.