Stability, Chemical Bonding, and Electron Lone Pair Localization in AsN at High Pressure by Density Functional Theory Calculations.

The covalent bonding framework of crystalline single-bonded cubic AsN, recently synthesized under high pressure and high temperature conditions in a laser-heated diamond anvil cell, is here studied by means of density functional theory calculations and compared to single crystal X-ray diffraction data. The precise localization of the nonbonding electron lone pairs and the determination of their distances and orientations are related to the presence of characteristic structural motifs and space regions of the unit cell dominated by repulsive electronic interactions, with the relative orientation of the electron lone pairs playing a key role in minimizing the energy of the structure. We find that the vibrational modes associated with the expression of the lone pairs are strongly localized, an observation that may have implications for the thermal conductivity of the compound. The results indicate the thermodynamic stability of the experimentally observed structure of AsN above ∼17 GPa, provide a detailed insight into the nature of the chemical bonding network underlying the formation of this compound, and open new perspectives to the design and high pressure synthesis of new pnictogen-based advanced materials for potential applications of energetic and technological relevance.

Injury Patterns of Electric-Scooter Related Trauma: A Systematic Review With Proportion Meta-Analysis.

Electric scooter (ES)-related injuries are increasing but poorly described. Clinicians need more information to be prepared for these patients. We supposed two prevalent patterns of patients: mildly injured (predominant upper-limb injuries) and severely injured (predominant head trauma). This study aims to understand the frequency of ES-related injuries and patients' characteristics despite the heterogeneity of data currently available. A systematic review with a proportion meta-analysis was conducted on studies with a multidisciplinary description of ES-related injuries in adult patients (PROSPERO-ID: CRD42022341241). Articles from inception to April 2023 were identified in MEDLINE, Embase, and Cochrane's databases. The risk of bias was evaluated using ROBINS-I. Twenty-five observational studies with 5387 patients were included in the meta-analysis, depending on reported data. Upper-limb (31.8%) and head (19.5%) injuries are the most frequent (25/25 studies included). When injured while riding, 19.5% of patients are intoxicated with drugs/alcohol, and only 3.9% use a helmet, increasing the possibility of severe injuries. About 80% of patients are victims of spontaneous falls. Half of the patients self-present to the ED, and 69.4% of cases are discharged directly from the ED. Studies' limitations include an overall moderate risk of bias and high heterogeneity. Electric scooter-related accidents are commonly associated with upper-limb injuries but often involve the head. Spontaneous falls are the most common mechanism of injury, probably related to frequent substance abuse and helmet misuse. This hot topic is not adequately investigated due to a lack of data. A prospective registry could fill this gap.

Exploring High-Pressure Polymorphism in Carbonic Acid through Direct Synthesis from Carbon Dioxide Clathrate Hydrate.

Carbon dioxide (CO2) is widespread in astrochemically relevant environments, often coexisting with water (H2O) ices and thus triggering a great interest regarding the possible formation of their adducts under various thermodynamic conditions. Amongst them, solid carbonic acid (H2CO3) remains elusive, yet being widely studied. Synthetic routes followed for its production have always been characterised by drastic irradiation on solid ice mixtures or complex procedures on fluid samples (such as laser heating at moderate to high pressures). Here we report about a simpler yet effective synthetic route to obtain two diverse carbonic acid crystal structures from the fast, cold compression of pristine clathrate hydrate samples. The two distinct polymorphs we obtained, differing in the water content, have been deeply characterised via spectroscopic and structural techniques to assess their composition and their astonishing pressure stability, checked up to half a megabar, also highlighting the complex correlations between them so to compile a detailed phase diagram of this system. These results may have a profound impact on the prediction and modelisation of the complex chemistry which characterises many icy bodies of our Solar System.

High-pressure and high-temperature synthesis of crystalline Sb3 N5.

A chemical reaction between Sb and N2 was induced under high-pressure (32-35 GPa) and high-temperature (1600-2200 K) conditions, generated by a laser heated diamond anvil cell. The reaction product was identified by single crystal synchrotron X-ray diffraction at 35 GPa and room temperature as crystalline antimony nitride with Sb3 N5 stoichiometry and structure belonging to orthorhombic space group Cmc21 . Only Sb-N bonds are present in the covalent bonding framework, with two types of Sb atoms respectively forming SbN6 distorted octahedra and trigonal prisms and three types of N atoms forming NSb4 distorted tetrahedra and NSb3 trigonal pyramids. Taking into account two longer Sb-N distances, the SbN6 trigonal prisms can be depicted as SbN8 square antiprisms and the NSb3 trigonal pyramids as NSb4 distorted tetrahedra. The Sb3 N5 structure can be described as an ordered stacking in the bc plane of bi- layers of SbN6 octahedra alternated to monolayers of SbN6 trigonal prisms (SbN8 square antiprisms). The discovery of Sb3 N5 finally represents the long sought-after experimental evidence for Sb to form a crystalline nitride, providing new insights about fundamental aspects of pnictogens chemistry and opening new perspectives for the high-pressure chemistry of pnictogen nitrides and the synthesis of an entire class of new materials.

High-pressure structure and reactivity of crystalline bibenzyl: Insights and prospects for the synthesis of functional double-core carbon nanothreads.

The high-pressure synthesis of double-core nanothreads derived from pseudo-stilbene crystals represents a captivating approach to isolate within the thread chromophores or functional groups without altering its mechanical properties. These entities can be effectively utilized to finely tune optical properties or as preferential sites for functionalization. Bibenzyl, being isostructural with other members of this class, represents the ideal system for building co-crystals from which we can synthesize double-core nanothreads wherein bridging chromophores, such as the azo or ethylene moieties, are embedded in the desired concentration within a fully saturated environment. To achieve this, a critical step is the preliminary characterization of the high-pressure behavior of crystalline bibenzyl. We report here an accurate investigation performed through state-of-the-art spectroscopic techniques, Raman and Fourier transform infrared spectroscopy, and x-ray diffraction up to 40 GPa. Our findings reveal a strongly anisotropic compression of the crystal, which determines, at pressures between 1 and 2 GPa, consistent modifications of the vibrational spectrum, possibly related to a torsional distortion of the molecules. A phase transition is detected between 9 and 10 GPa, leading to a high pressure phase where, above 24 GPa, the nanothread formation is observed. However, the observed reaction was limited in extent and required significantly higher pressures in comparison to other members of the pseudo-stilbene family. This comprehensive study is imperative in laying the foundation for future endeavors, aiming to synthesize double-core nanothreads from pseudo-stilbene crystals, and provides crucial insights into the high-pressure behavior and phase transitions of crystalline bibenzyl.

High pressure decomposition of a sandwich compound.

While it is widely recognized that purely organic molecular systems with multiple bonds undergo chemical condensation at sufficiently high pressures (from tenths to tens of GPa), the fate of organometallics at extreme conditions remains largely underexplored. We have investigated the high pressure (up to 41 GPa) chemical transformations in a simple molecular system known as nickelocene, (C5H5)2Ni, which serves as a representative example of a class of organometallics called sandwich compounds. Nickelocene decomposed above 13 GPa, at room temperature, while lower pressure thresholds have been observed at higher temperatures (295-573 K). The products were identified as nanocomposite materials, primarily composed of disordered, nickel-rich nanoparticles segregated within an extended, amorphous matrix of hydrogenated carbon (a-C:H). The investigation was conducted by means of diamond anvil cells in combination with optical spectroscopies and microscopy, synchrotron x-ray absorption spectroscopy and diffraction, as well as transmission electron microscopy. Our findings have the potential to stimulate further research into the high-pressure chemical reactivity of organometallics and open up new synthesis routes for the production of metal-based nanoparticles, which find a wide range of applications.

The burden of the knowledge-to-action gap in acute appendicitis.

BACKGROUND: The burden of emergency general surgery (EGS) is higher compared to elective surgery. Acute appendicitis (AA) is one of the most frequent diseases and its management is dictated by published international clinical practice guidelines (CPG). Adherence to CPG has been reported as heterogeneous. Barriers to clinical implementation were not studied. This study explored barriers to adherence to CPG and the clinico-economic impact of poor compliance. METHODS: Data were extracted from the three-year data lock of the REsiDENT-1 registry, a prospective resident-led multicenter trial. We identified 7 items from CPG published from the European Association of Endoscopic Surgery (EAES) and the World Society of Emergency Surgery (WSES). We applied our classification proposal and used a five-point Likert scale (Ls) to assess laparoscopic appendectomy (LA) difficulty. Descriptive analyses were performed to explore compliance and group comparisons to assess the impact on outcomes and related costs. We ran logistic regressions to identify barriers and facilitators to implementation of CPG. RESULTS: From 2019 to 2022, 653 LA were included from 24 centers. 69 residents performed and coordinated data collection. We identified low compliance with recommendations on peritoneal irrigation (PI) (25.73%), abdominal drains (AD) (34.68%), and antibiotic stewardship (34.17%). Poor compliance on PI and AD was associated to higher infectious complications in uncomplicated AA. Hospitalizations were significantly longer in non-compliance except for PI in uncomplicated AA, and costs significantly higher, exception made for antibiotic stewardship in complicated AA. The strongest barriers to CPG implementation were complicated AA and technically challenging LA for PI and AD. Longer operative times and the use of PI negatively affected antibiotic stewardship in uncomplicated AA. Compliance was higher in teaching hospitals and in emergency surgery units. CONCLUSIONS: We confirmed low compliance with standardized items influenced by environmental factors and non-evidence-based practices in complex LA. Antibiotic stewardship is sub-optimal. Not following CPG may not influence clinical complications but has an impact in terms of logistics, costs and on the non-measurable magnitude of antibiotic resistance. Structured educational interventions and institutional bundles are required.

Contrast-enhanced ultrasound (CEUS) in the follow-up of abdominal solid organ trauma: an international survey prior to the PseAn study.

BACKGROUND: The blunt and penetrating abdominal trauma follow-up relies on contrast CT scan to detect solid organ injuries. CEUS is not widely used worldwide, despite its accuracy and feasibility in identifying parenchymal and vascular lesions. This survey aims to define the current use of CEUS in Trauma Centers and the expectations of Emergency Surgeons regarding its role. METHODS: We sent an online questionnaire composed of 10 questions to trauma physicians worldwide during the period of September 2022 to March 2023. RESULTS: 59 participants from 53 different centers answered the questionnaire. 76.2% of the enrolled participants have CEUS available at their Institution, and 49.2% think that it can replace CT scan. Contrast-CT scan remains the preferred option in the follow-up of blunt liver (69.5%), spleen (72.9%) and kidney (76.3%) injuries, followed by CEUS which is used in 18.6% for liver, 20.3% for spleen and 15.3% for kidney injuries. The results are similar for penetrating abdominal trauma, with contrast CT scan being the first-line imaging technique (91.5% for liver, 91.5% for spleen and 88.1% for kidney injuries), followed by CEUS (5.1% for liver, 5.1% for spleen and 6.8% for kidney injuries). CONCLUSIONS: Our survey shows that CEUS is still underutilized in the follow-up of abdominal trauma, even though many emergency surgeons consider it as a valid alternative to contrast CT scan.

High temperature decomposition of polymeric carbon monoxide at pressures up to 120 GPa.

While polymeric carbon monoxide (pCO) has been experimentally found to remain amorphous and undecomposed at room temperature up to 50 GPa, the question of whether crystalline counterparts of it can be obtained naturally raises. From different computational studies, it can be inferred that either the crystallization of amorphous pCO (a-pCO) or its decomposition into a mixture of CxOy suboxides (x > y) or carbon and CO2 may occur. In this study, we report experimental investigations of the high temperature (700-4000 K) transformation of a-pCO in the 47-120 GPa pressure range, conducted by x-ray diffraction in laser heated diamond anvil cells. Our results show the formation of no crystalline phases other than CO2 phase V, thus indicating the decomposition of the pristine a-pCO into CO2 and, likely, a mixture of amorphous CxOy suboxides and amorphous carbon hardly detectable at extreme conditions. These results support the theoretical picture of the pCO decomposition. We also show that the pressure-temperature kinetic border for this decomposition is very steep, thus indicating a strongly pressure-dependent kinetic barrier.

Complexities in the structural evolution with pressure of water-ammonia mixtures.

The structural evolution with pressure of icy mixtures of simple molecules is a poorly explored field despite the fundamental role they play in setting the properties of the crustal icy layer of the outer planets and of their satellites. Water and ammonia are the two major components of these mixtures, and the crystal properties of the two pure systems and of their compounds have been studied at high pressures in a certain detail. On the contrary, the study of their heterogeneous crystalline mixtures whose properties, due to the strong N-H⋯O and O-H⋯N hydrogen bonds, can be substantially altered with respect to the individual species has so far been overlooked. In this work, we performed a comparative Raman study with a high spatial resolution of the lattice phonon spectrum of both pure ammonia and water-ammonia mixtures in a pressure range of great interest for modeling the properties of icy planets' interiors. Lattice phonon spectra represent the spectroscopic signature of the molecular crystals' structure. The activation of a phonon mode in plastic NH3-III attests to a progressive reduction in the orientational disorder, which corresponds to a site symmetry reduction. This spectroscopic hallmark allowed us to solve the pressure evolution of H2O-NH3-AHH (ammonia hemihydrate) solid mixtures, which present a remarkably different behavior from the pure crystals likely to be ascribed to the role of the strong H-bonds between water and ammonia molecules characterizing the crystallites' surface.

"Stabilize the Unstable": Treatment Pathophysiology in Bleeding Trauma Patients, from the Field to the ICU. State of the Art.

The results of the Global Burden of Disease (GBD) study showed that, in 2019, 8% of deaths worldwide were trauma related [...].

Detection of post-traumatic abdominal pseudoaneurysms by CEUS and CT: A prospective comparative global study (the PseAn study)-study protocol.

The success of non-operative management in trauma increased with the availability of new-generation CT scan machines, endoscopy, and angiography, becoming the standard of care in hemodynamically stable trauma patients with abdominal solid organ injuries, with a success rate of 78% to 98%. Post-traumatic pseudoaneurysms (PAs) can develop at any region of an injured artery and they may cause delayed bleeding in splenic or hepatic trauma, with an incidence in patients treated with NOM of 2%-27% and 1.2%-6.1% respectively. Diagnosis is made by angiography, contrast-enhanced computer tomography (CT), or Doppler Ultrasound (US) while the use of contrast-enhanced ultrasound (CEUS), has increased in recent years although few data are available about CEUS feasibility in the follow-up setting. The PseaAn study has been designed to assess the role of CEUS in the follow-up of abdominal trauma by defining its sensitivity, specificity and predictive values compared with abdominal CT scan. The PseAn study is a multi-centric international diagnostic cross-sectional study initiated by the Level I Trauma Center of the Niguarda Ca' Granda Hospital in Milan, Italy. To study the role of CEUS in detecting post-traumatic splenic, hepatic, and renal PAs compared with the gold standard of CT with intravenous contrast at different follow-up time points, and whether it can replace CT scan in the follow-up of solid organ injuries, patients with OIS III and above will undergo a follow-up with both a CEUS and CT scan to detect post-traumatic parenchymal pseudoaneurysm within two to five days from injury. The use of CEUS in the follow-up of abdominal trauma follow-up (particularly blunt trauma) has increased, to minimise the use of ionizing radiation and contrast media and encouraging results have been published during the last decade showing that CEUS is an accurate technique for evaluating traumatic lesions of solid abdominal organs. Conclusions We think that CEUS, which is underused worldwide, is a useful and safe tool that may replace CT scan in follow-up with the major advantage of reduced radiation. Our current study may give stronger evidence to support this view.

Increasing Trend in Violence-Related Trauma and Suicide Attempts among Pediatric Trauma Patients: A 6-Year Analysis of Trauma Mechanisms and the Effects of the COVID-19 Pandemic.

Background: Trauma is the leading cause of morbidity and mortality in the pediatric population. During the COVID-19 pandemic (COVID-19), different trends for pediatric trauma (PT) were described. This study aims to explore the trend over time of PT in our center, also considering the effects of COVID-19, focusing on trauma mechanisms, violence-related trauma (VRT) and intentionality, especially suicide attempts (SAs). Methods: All PT patients accepted at Niguarda Trauma Center (NTC) in Milan from January 2015 to December 2020 were retrospectively analyzed. We considered demographics and clinical variables and performed descriptive and year comparison analyses. Results: There were 684 cases of PT accepted at NTC: 84 in 2015, 98 in 2016, 125 in 2017, 119 in 2018, 114 in 2019 and 144 in 2020 (p < 0.001), 66.2% male, mean age 9.88 (±5.17). We observed a higher number of traffic-related, fall-related injuries and an increasing trend for VRT and SAs, peaking in 2020. We report an increasing trend over time for head trauma (p = 0.002). The Injury Severity Score did not significantly change. During COVID-19 we recorded a higher number of self-presenting patients with low priority codes. Conclusions: NTC is the adult level I referral trauma center for the Milan urban area with pediatric commitment. During COVID-19, every traumatic emergency was centralized to NCT. In 2020, we observed an increasing trend in SAs and VRT among PT patients. The psychological impact of the COVID-19 restriction could explain this evidence. The long-term effects of COVID-19 on the mental health of the pediatric population should not be underestimated. Focused interventions on psychological support and prevention of SAs and VRT should be implemented, especially during socio-demographic storms such as the last pandemic.

Surgeons' attitudes during laparoscopic appendectomy: do subjective intraoperative assessments affect the choice of peritoneal irrigation? A spin-off analysis from the REsiDENT-1 multicentre prospective observational trial.

AIMS: Laparoscopic appendectomy (LA) for acute appendicitis (AA) is one of the most performed procedures. The effects of peritoneal lavage (PL) and the reasons to perform it have not been cleared and all meta-analyses didn't show a statistical advantage to prevent infectious complications. This study aims to investigate surgeons' perceptions during LA, comparing intraoperative findings with histological results, and exploring how surgeons' subjectivity influences the decision-making process on PL. METHODS: Data were extracted from the two-year data lock from REsiDENT-1 registry, a prospective resident-led multicentre observational trial. This study investigates the relationships between PL and postoperative intraabdominal abscesses (pIAA) introducing a classification for AA to standardize the intraoperative grading. We included pre, intra, and postoperative variables. We applied our classification proposal, used a five-point Likert scale (Ls) to assess subjective LA difficulty and ran a concordance analysis between the assessment of AA and histology. Subsequently, a multivariate logistic regression model was built to find factors influencing PL. RESULTS: 561 patients were enrolled from twenty-one hospitals and 51 residents. 542 procedures were included in the logistic regression analysis and 441 in the concordance analysis, due to missing data. PL was used in 222 LA (39, 6%). We discovered a moderate positive monotonic relationship between surgical evaluation and histology, p < 0.001. Despite this, the reliability of the surgeon's assessment of appendicitis is progressively lower for gangrenous and perforated forms. The increasing grade of contamination, the increasing grade of subjective difficulty and the intraoperative finding of a gangrenous or perforated appendicitis were independent predictors of PL. CONCLUSION: This study shows how surgeons' evaluation of AA severity overestimated more than half of gangrenous or perforated appendices with the perception of a challenging procedure. These perceptions influenced the choice of PL. We proved that the evaluation during LA could be affected by subjectivity with a non-negligible impact on the decision-making process.

Comparison between level 1 and level 2 trauma centers for the management of splenic blunt trauma.

INTRODUCTION: The management of blunt splenic trauma has evolved in the last years, from mainly operative approach to the non-operative management (NOM). The aim of this study is to investigate whether trauma center (TC) designation (level 1 and level 2) affects blunt splenic trauma management. METHODS: A retrospective analysis of blunt trauma patients with splenic injury admitted to 2 Italian TCs, Niguarda (level 1) and San Carlo Borromeo (level 2), was performed, receiving either NOM or emergency surgical treatment, from January 1, 2015 to December 31, 2020. Univariate comparison was performed between the two centers, and multivariate analysis was carried out to find predictive factors associated with NOM and splenectomy. RESULTS: 181 patients were included in the study, 134 from level 1 and 47 from level 2 TCs. The splenectomy/emergency laparotomy ratio was inferior at level 1 TC for high-grade splenic injuries (30.8% for level 1 and 100% for level 2), whose patients presented higher incidence of other injuries. Splenic NOM failure was registered in only one case (3.3%). At multivariate analysis, systolic pressure, spleen organ injury scale (OIS) and injury severity score (ISS) resulted significant predictive factors for NOM, and only spleen OIS was predictive factor for splenectomy (Odds Ratio 0.14, 0.04-0.49 CI 95%, P < .01). CONCLUSION: Both level 1 and 2 trauma centers demonstrated application of NOM with a high rate of success with some management difference in the treatment and outcome of patients with splenic injuries between the two types of TCs.

Factors Influencing the Difficulty and Need for External Help during Laparoscopic Appendectomy: Analysis of 485 Procedures from the Resident-1 Multicentre Trial.

Purpose: To identify preoperative predictive factors for technically challenging laparoscopic appendectomy (LA) and the need for external help to laparoscopically complete the procedure. Methods: We analysed data from a two-year data lock on the Resident-1 multicentre registry. The operator classified each procedure following a five-grade Likert scale to define technical difficulty. We performed univariate analysis comparing Grade 1−3 versus 4−5 procedures and then built a logistic regression model to identify independent predictors of Grade 4−5 procedures defined as needing external help to complete a LA. Results: 561 patients were recruited from 2019 to 2021, and 485 patients were included in the final analysis due to missing data. A BMI > 30 kg/m2, preoperative CT scan, and the AIR score were independent preoperative predictors of complex LA with the need for external help to be completed. Patients undergoing such procedures were more affected by CA, had longer operative times, and had the worst postoperative outcomes. Conclusion: The preoperative identification of technically demanding LA could be helpful in optimising the preoperative planning, maximise surgeons' preparedness, and include expert surgeons in the procedure earlier. Creating a scoring system for the technical difficulty of LA is desirable.

Risk Factors for Retained Hemothorax after Trauma: A 10-Years Monocentric Experience from First Level Trauma Center in Italy.

Thoracic trauma occurs in 20-25% of all trauma patients worldwide and represents the third cause of trauma-related mortality. Retained hemothorax (RH) is defined as a residual hematic pleural effusion larger than 500 mL after 72 h of treatment with a thoracic tube. The aim of this study is to investigate risk factors for the development of RH in thoracic trauma and predictors of surgery. A retrospective, observational, monocentric study was conducted in a Trauma Hub Hospital in Milan, recording thoracic trauma from January 2011 to December 2020. Pre-hospital peripheric oxygen saturation (SpO2) was significantly lower in the RH group (94% vs. 97%, p = 0.018). Multivariable logistic regression analysis identified, as independent predictors of RH, sternum fracture (OR 7.96, 95% CI 1.16-54.79; p = 0.035), pre-admission desaturation (OR 0.96; 95% CI 0.77-0.96; p = 0.009) and the number of thoracic tube maintenance days (OR 1.22; 95% CI 1.09-1.37; p = 0.0005). The number of tubes placed and the 1° rib fracture were both significantly associated with the necessity of surgical treatment of RH (2 vs. 1, p = 0.004; 40% vs. 0%; p = 0.001). The risk of developing an RH in thoracic trauma should not be underestimated. Variables related to RH must be taken into account in order to schedule a proper follow-up after trauma.

Regenerative Medicine to Improve Outcomes of Ventral Hernia Reconstruction (REPAIR Study) Phase 1: Find the Best Decellularization Protocol for the Human Dermis.

Background: Tissue regeneration is a complex process that allows wounds to heal. Many options are currently available to help human skin repair and to reduce the recurrence of hernias. The aim of this study is to analyze the best decellularization protocol for allogenic human dermal tissues. Methods: Dermal flaps from donors were used and compared with a control group. Each flap was subjected to seven different decellularization protocols and washed with a sequence of five solutions. The samples were then subjected to four control tests (such as Nile Red), and long-term contacts were analyzed to assess whether the decellularized dermis samples could support the growth of human fibroblasts. Results: All the samples had an average residual viability of 60%. Except for one sample, the decellularization treatments were able to reduce cell viability significantly. The Nile Red test showed a significant reduction in phospholipid content (mean 90%, p-value < 0.05) in all treatments. The cell growth increased in a linear manner. As described in the literature, sodium-dodecyl-sulfate (SDS) caused an interference between the test and the detergent. Conclusions: This paper shows the first step to finding the best decellularization protocol for allografting human dermal tissues. Further biocompatibility tests and DNA quantification are necessary.

Personalized Medicine in Acute Care Surgery: Are We Ready to Deal with Our Failures?

During the first decade of the 21st century, the American College of Surgeons Committee on Trauma (ACS-COT), the Western Trauma Association (WTA), the Eastern Association for the Surgery of Trauma (EAST), and the American Association for the Surgery of Trauma (AAST) established an ad hoc committee to develop a new specialty that embraces trauma surgery, critical surgical care, and emergency surgery [...].