Low Temperature Dynamic Polaron Liquid in a Manganite Exhibiting Colossal Magnetoresistance.

Polarons-fermionic charge carriers bearing a strong companion lattice deformation-exhibit a natural tendency for self-localization due to the recursive interaction between electrons and the lattice. While polarons are ubiquitous in insulators, how they evolve in transitions to metallic and superconducting states in quantum materials remains an open question. Here, we use resonant inelastic x-ray scattering to track the electron-lattice coupling in the colossal magneto-resistive bi-layer manganite La_{1.2}Sr_{1.8}Mn_{2}O_{7} across its metal-to-insulator transition. The response in the insulating high-temperature state features harmonic emissions of a dispersionless oxygen phonon at small energy transfer. Upon cooling into the metallic state, we observe a drastic redistribution of spectral weight from the region of these harmonic emissions to a broad high energy continuum. In concert with theoretical calculations, we show that this evolution implies a shift in electron-lattice coupling from static to dynamic lattice distortions that leads to a distinct polaronic ground state in the low temperature metallic phase-a dynamic polaron liquid.

Polarized tip-enhanced Raman spectroscopy at liquid He temperature in ultrahigh vacuum using an off-axis parabolic mirror.

Tip-enhanced Raman spectroscopy (TERS) combines inelastic light scattering well below the diffraction limit down to the nanometer range and scanning probe microscopy and, possibly, spectroscopy. In this way, topographic and spectroscopic as well as single- and two-particle information may simultaneously be collected. While single molecules can now be studied successfully, bulk solids are still not meaningfully accessible. It is the purpose of the work presented here to outline approaches toward this objective. We describe a home-built, liquid helium cooled, ultrahigh vacuum TERS. The setup is based on a scanning tunneling microscope and, as an innovation, an off-axis parabolic mirror having a high numerical aperture of ∼0.85 and a large working distance. The system is equipped with a fast load-lock chamber, a chamber for the in situ preparation of tips, substrates, and samples, and a TERS chamber. Base pressure and temperature in the TERS chamber were ∼3 × 10-11 mbar and 15 K, respectively. Polarization dependent tip-enhanced Raman spectra of the vibration modes of carbon nanotubes were successfully acquired at cryogenic temperature. The new features described here including very low pressure and temperature and the external access to the light polarizations, thus the selection rules, may pave the way toward the investigation of bulk and surface materials.

Evolution of military evacuation activity in French Guiana over 10 years: a retrospective observational study.

BACKGROUND: Three permanent military operations are established in French Guiana. The Cayenne medical unit is a French military search and rescue unit and provides MEDEVAC and CASEVAC for ill and injured soldiers. The main objective of this study was to describe the temporal trends of its evacuation missions over 10 years. The secondary purpose was to document the means used for these missions. METHODS: This retrospective observational study included patients who were evacuated for a medical reason or an injury during military operations in French Guiana. We collected the data from the computerised registers the medical department had stored. RESULTS: From 1 January 2010 to 31 December 2019, 1070 patients were included, representing a median annual incidence of 115 (IQR 91-122) evacuations. Of these, 602 (59%) were evacuated by helicopter, 214 (21%) by airplane, 182 (18%) by ambulance and 19 (2%) by pirogue.Reasons for evacuation were diseases in 664 (62%) patients, non-battle injuries in 389 (36%) patients and battle injuries in 17 (2%) patients. Finally, 286 (29%) evacuations were MEDEVAC and 712 (71%) were CASEVAC.Over the years, the increasing number of evacuations reached a maximum of 183 in 2018. Helicopter evacuations, once the primary mode of evacuation, have declined proportionately in favour of other means of evacuation. CONCLUSION: Evacuation missions by the Cayenne medical unit increased over the 10-year study period, while helicopter use decreased. This evolution is a response to the constraints of adapting military operations to fight against illegal gold mining in the Amazonian Forest. Improvement of the means and procedures allows provision of the best care to patients while ensuring the ongoing conduct of military operations.

Organ donation after out-of-hospital cardiac arrest: a population-based study of data from the Paris Sudden Death Expertise Center.

BACKGROUND: Organ shortage is a major public health issue, and patients who die after out-of-hospital cardiac arrest (OHCA) could be a valuable source of organs. Here, our objective was to identify factors associated with organ donation after brain death complicating OHCA, in unselected patients entered into a comprehensive real-life registry covering a well-defined geographic area. METHODS: We prospectively analyzed consecutive adults with OHCA who were successfully resuscitated, but died in intensive care units in the Paris region in 2011-2018. The primary outcome was organ donation after brain death. Independent risk factors were identified using logistic regression analysis. One-year graft survival was assessed using Cox and log-rank tests. RESULTS: Of the 3061 included patients, 136 (4.4%) became organ donors after brain death, i.e., 28% of the patients with brain death. An interaction between admission pH and post-resuscitation shock was identified. By multivariate analysis, in patients with post-resuscitation shock, factors associated with organ donation were neurological cause of OHCA (odds ratio [OR], 14.5 [7.6-27.4], P < 0.001), higher pH (OR/0.1 increase, 1.3 [1.1-1.6], P < 0.001); older age was negatively associated with donation (OR/10-year increase, 0.7 [0.6-0.8], P < 0.001). In patients without post-resuscitation shock, the factor associated with donation was neurological cause of OHCA (OR, 6.9 [3.0-15.9], P < 0.001); higher pH (OR/0.1 increase, 0.8 [0.7-1.0], P = 0.04) and OHCA at home (OR, 0.4 [0.2-0.7], P = 0.006) were negatively associated with organ donation. One-year graft survival did not differ according to Utstein characteristics of the donor. CONCLUSIONS: 4% of patients who died in ICU after OHCA led to organ donation. Patients with OHCA constitute a valuable source of donated organs, and special attention should be paid to young patients with OHCA of neurological cause.

[Fighting against unexplained sudden death]. / Mort subite, en quête d'une explication.

Sudden cardiac death, mostly related to ventricular arrhythmia, is a major public health issue, with still very poor survival at hospital discharge. Although coronary artery disease remains the leading cause, other etiologies should be systematically investigated. Exhaustive and standardized exploration is required to eventually offer specific therapeutics and management to the patient as well as his/her family members in case of inherited cardiac disease. Identification and establishing direct causality of the detected cardiac anomaly may remain challenging, underlying the need for a multidisciplinary and experimented team.

Raman Study of Cooper Pairing Instabilities in (Li_{1-x}Fe_{x})OHFeSe.

We studied the electronic Raman spectra of (Li_{1-x}Fe_{x})OHFeSe as a function of light polarization and temperature. In the B_{1g} spectra alone we observe the redistribution of spectral weight expected for a superconductor and two well-resolved peaks below T_{c}. The nearly resolution-limited peak at 110 cm^{-1} (13.6 meV) is identified as a collective mode. The peak at 190 cm^{-1} (23.6 meV) is presumably another collective mode since the line is symmetric and its energy is significantly below the gap energy observed by single-particle spectroscopies. Given the experimental band structure of (Li_{1-x}Fe_{x})OHFeSe, the most plausible explanations include conventional spin-fluctuation pairing between the electron bands and the incipient hole band and pairing between the hybridized electron bands. The absence of gap features in A_{1g} and B_{2g} symmetry favors the second case. Thus, in spite of various differences between the pnictides and chalcogenides, this Letter demonstrates the proximity of pairing states and the importance of band structure effects in the Fe-based compounds.

Pediatric victims involved in urban fires in Paris and its suburbs: Epidemiology, prehospital care, and lessons learned.

AIM: The literature includes few reports on the prehospital care of pediatric casualties of urban house fires. Here we aimed to describe the epidemiology of pediatric fire victims, focusing on their injuries, prehospital care, and survival. METHODS: This retrospective study included children under 15 years of age who were victims of urban house fires and who received care from prehospital medical teams. The variables analyzed included epidemiology, specific care provided by prehospital emergency services, the number of cardiac arrests, and survival rates. RESULTS: Over the 15-month study period, 365 house fires required the presence of at least one prehospital medical team. Casualties of these fires included 121 pediatric victims (median age, 4 years [interquartile range: 2-9 years]). All children were initially treated by a prehospital medical team that was not specialized in pediatrics. Six children (4.9%) received secondary treatment from a pediatric support team. Of the 121 children, 114 (94.2%) suffered from smoke inhalation and seven (5.8%) from burns. Two patients who were in cardiac arrest at their initial medical care did not survive. CONCLUSION: Pediatric fire casualties were initially managed by prehospital medical teams that were not specialized in pediatrics. As in adults, the main injuries were secondary to smoke inhalation, but this has increased toxicity in children. Prehospital teams not specialized in pediatrics can optimize their practice via the sharing of experiences, team training, and cognitive aid checklist for pediatric fire victims.

How many patients could benefit from REBOA in prehospital care? A retrospective study of patients rescued by the doctors of the Paris fire brigade.

INTRODUCTION: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a technique to control haemorrhage by placing a retrograde catheter in an artery and inflating a balloon at its tip. This retrospective study aimed to evaluate the proportion of injured people who could potentially have benefited from this technique prior to hospitalisation, including on the scene or during transport. METHODS: A retrospective analysis was conducted of all patients with trauma registered in the Paris Fire Brigade emergency medical system between 1 January and 31 December 2014. Inclusion criteria included all patients over 18 years of age with bleeding of supposedly abdominal and/or pelvic and/or junctional origin, uncontrolled haemorrhagic shock or cardiac arrest with attempted resuscitation. RESULTS: During this study period, a total of 1159 patients with trauma (3.2%) would have been eligible to undergo REBOA. Death on scene rate was 83.8% (n=31) and six patients had a beating heart when they arrived at the hospital. Ten out of the 37 patients had spontaneous circulatory activity. Among them, four people died on the scene or during transport. Thirty-six out of 37 patients were intubated, one benefited from the use of a haemostatic dressing and one benefited from a tourniquet. CONCLUSIONS: REBOA can be seen as an effective non-surgical solution to ensure complete haemostasis during the prehospital setting. When comparing the high mortality rate following haemorrhage with the REBOA's rare side effects, the risk-benefit balance is positive. Given that 3% of all patients with trauma based on this study would have been eligible for REBOA, we believe that this intervention should be available in the prehospital setting. The results of this study will be used: educational models for REBOA balloon placement using training manikins, with an ultimate aim to undertake a prospective feasibility study in the prehospital setting.

Perspectives: using polymer modeling to understand the formation and function of nuclear compartments.

Compartmentalization is a ubiquitous feature of cellular function. In the nucleus, early observations revealed a non-random spatial organization of the genome with a large-scale segregation between transcriptionally active-euchromatin-and silenced-heterochromatin-parts of the genome. Recent advances in genome-wide mapping and imaging techniques have strikingly improved the resolution at which nuclear genome folding can be analyzed and have revealed a multiscale spatial compartmentalization with increasing evidences that such compartment may indeed result from and participate to genome function. Understanding the underlying mechanisms of genome folding and in particular the link to gene regulation requires a cross-disciplinary approach that combines the new high-resolution techniques with computational modeling of chromatin and chromosomes. In this perspective article, we first present how the copolymer theoretical framework can account for the genome compartmentalization. We then suggest, in a second part, that compartments may act as a "nanoreactor," increasing the robustness of either activation or repression by enhancing the local concentration of regulators. We conclude with the need to develop a new framework, namely the "living chromatin" model that will allow to explicitly investigate the coupling between spatial compartmentalization and gene regulation.

[Reasons for proximal femoral fracture surgery delays : Analysis of the structured dialog in Rheinland-Pfalz]. / Verzögerte Versorgung hüftgelenknaher Femurfrakturen : Analyse des Strukturierten Dialogs Rheinland-Pfalz.

BACKGROUND: For the "preoperative stay" quality indicator , which is part of the external quality assurance for proximal femoral fractures (module 17/1), a tolerance range for surgery within 48 h after admission of ≤15 % is given. MATERIALS AND METHODS: The structured dialog (2014) in Rheinland-Pfalz was analyzed with respect to reasons for delaying surgery for more than 48 h after admission. RESULTS: A total of 331 cases were analyzed. In 60.7 % patient-related reasons and in 13.3 % administrative reasons were found. In 9.1 % the statements were not feasible. Due to a lack of software-related specifications in 7.3 % a wrong preoperative length of stay was generated. Wrong coding or a computer-related problem was found in 6.6 %. The most common reason for delay was the intake of an anticoagulant (25.7 %). CONCLUSION: The significance of the quality indicator "Preoperative stay" without division into whether this was administrative or patient-related must be considered critically.

Out-of-hospital cardiac arrest phone detection: those who most need chest compressions are the most difficult to recognize.

UNLABELLED: Dispatcher-assisted cardiopulmonary resuscitation increases the likelihood of survival and thus is highly recommended. However, the detection rate of out-of-hospital cardiac arrest (OHCA) is very different from one system to another, and early recognition of cardiac arrest in the dispatch centre remains challenging. The aim of this study was to assess the provision of dispatcher-assisted cardiopulmonary resuscitation in the main French dispatch centre. METHODS: In the Paris Fire Brigade, each patient over 15 years of age who presented an OHCA from 15 to 31 May 2012 was prospectively included. Field data and tape recordings of emergency calls were studied by three experienced physicians, to assess the rate (and delay) of OHCA recognition and chest compression initiation, and identify the causes of unrecognized OHCA. RESULTS: Among 82 consecutive calls for detectable cardiac arrest, the dispatcher recognized 50/82 (61%). The median times from call to OHCA recognition and from call to chest compression initiation were, respectively, 2 min 23s (1 min 51 s to 3 min 7s) and 3 min 37s (2 min 57 s to 5 min). The main causes of non-recognition of OHCA were the absence or incomplete assessment of breathing and the presence of agonal breathing. No cardiac arrest was missed when the dispatcher followed the local dispatch algorithm; this included the gesture of putting the hand on the abdomen and measuring the breathing frequency. Hospital admission with a beating heart was paradoxically 18% for detected cardiac arrest and 47% for undetected cardiac arrest (p=0.007). This paradox could be explained by the relation between agonal breathing and, on the one hand, good prognosis of OHCA and, on the other hand, difficulties in recognizing OHCA. CONCLUSION: The improvement of cardiac arrest recognition in the dispatch centre seemed mandatory, as the cardiac arrests of better immediate prognosis were not well detected. The measurement of OHCA recognition and CPR initiation by phone should be encouraged in dispatch centres as a key to initiating corrective measures.

[Storing succinylcholine in prehospital settings following the recommendations of the French National Agency for the safety of medicines]. / Conservation de la succinylcholine en préhospitalier après recommandations de l'Agence nationale de santé et du médicament.

OBJECTIVE: The French National Pharmaceuticals Agency (ANSM) has recommanded in July 2012 not to break the cold chain before using succinylcholine (Celocurine®). RESEARCH OBJECTIVE: to understand the pre-clinical evolution of the conservation modes of this curare. RESEARCH TYPE: Descriptive study before (year 2011) and after (year 2012). PATIENTS AND METHOD: Online survey to French Samu/Smur. DATA COLLECTED: SMUR location, conservation method at clinical base, in the mobile unit (UMH) and at the patient. Principal decision criteria: evolution of the conservation modes before and after the recommendation (qualitatives variables compared with a Fisher test). RESULTS: Out of 101 SAMU/SMUR, 62 answered. Conservation modes of succinylcholine vials were significantly different (P<0.001). Proper conservation was observed in 26 % of the cases before and 43 % after. Mobile units (UMH) equipped with a fridge increased from one out of two to 77 %. The lack of conservation modes passive or active on UMH went from 31 % to 3.4 % with isotherms bags with ice when a fridge was not available. The destruction of capsules at current temperature in a 24-hour period increased: 22 % before, 47 % after (P=0.04). CONCLUSION: After recommendations from ANSM, conservation modes and destruction of succinylcholine in a prehospital environment were significantly impacted.

[Traumatic aortic rupture and concomitant type B aortic dissection after skiing accident]. / Traumatische Aortenruptur mit begleitender Typ-B-Aortendissektion nach Skiunfall.

The occurrence of aortic dissections after deceleration trauma is commonplace but aortic injuries after blunt trauma are extremely rare complications. We report a case of an acute aortic rupture accompanied by a type B dissection after a skiing accident with blunt thoracic trauma and renal contusion. The leading symptom was the onset of hematuria 12 h later. The computed tomography (CT) angiography permitted the exact diagnosis and the patient was transferred for acute thoracic endovascular aortic repair. This regimen resulted in the patient achieving a stable condition and potentially harmful complications could be avoided.