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Purpose: Complex enteric fistulas (CEF) represent general surgeons’ nightmare. This paper aims to explore the impact on failure-to-rescue (FTR) rate of a standardised and integrated surgical and critical care step-up approach. Methods: This was a retrospective observational cohort study. Patients treated for CEF from 2009 to 2019 at Niguarda Hospital were included. Each patient was approached following a three-step approach: study phase, sepsis control and strategy definition phase, and surgical rescue phase. Results: Sixteen patients were treated for CEF. Seven fistulas were classified as complex entero-cutaneous (ECF) and nine as entero-atmospheric fistula (EAF). Median number of surgical procedures for fistula control before definitive surgical attempt was 11 (IQR 2–33.5). The median time from culprit surgery and the first access at Niguarda Hospital to definitive surgical attempt were 279 days (IQR 231–409) and 120 days (IQR 34–231), respectively. Median ICU LOS was 71 days (IQR 28–101), and effective hospital LOS was 117 days, (IQR 69.5–188.8). Three patients (18.75%) experienced spontaneous fistula closure after conversion to simple ECF, whereas 13 (81.25%) underwent definitive surgery for fistula takedown. Surgical rescue was possible in nine patients. Nine patients underwent multiple postoperative revision for surgical complications. Four patients failed to be rescued. Conclusion: An integrated step-up rescue strategy is crucial to standardise the approach to CEF and go beyond the basic surgical rescue procedure. The definition of FTR is dependent from the examined population. CEF patients are a unique cluster of emergency general surgery patients who may need a tailored definition of FTR considering the burden of postoperative events influencing their outcome.

Background/objectives: Reports about the implementation of recommendations from acute pancreatitis guidelines are scant. This study aimed to evaluate, on a patient-data basis, the contemporary practice patterns of management of biliary acute pancreatitis and to compare these practices with the recommendations by the most updated guidelines. Methods: All consecutive patients admitted to any of the 150 participating general surgery (GS), hepatopancreatobiliary surgery (HPB), internal medicine (IM) and gastroenterology (GA) departments with a diagnosis of biliary acute pancreatitis between 01/01/2019 and 31/12/2020 were included in the study. Categorical data were reported as percentages representing the proportion of all study patients or different and well-defined cohorts for each variable. Continuous data were expressed as mean and standard deviation. Differences between the compliance obtained in the four different subgroups were compared using the Mann-Whitney U, Student's t, ANOVA or Kruskal-Wallis tests for continuous data, and the Chi-square test or the Fisher's exact test for categorical data. Results: Complete data were available for 5275 patients. The most commonly discordant gaps between daily clinical practice and recommendations included the optimal timing for the index CT scan (6.1%, χ2 6.71, P = 0.081), use of prophylactic antibiotics (44.2%, χ2 221.05, P < 0.00001), early enteral feeding (33.2%, χ2 11.51, P = 0.009), and the implementation of early cholecystectomy strategies (29%, χ2 354.64, P < 0.00001), with wide variability based on the admitting speciality. Conclusions: The results of this study showed an overall poor compliance with evidence-based guidelines in the management of ABP, with wide variability based on the admitting speciality. Study protocol registered in ClinicalTrials.Gov (ID Number NCT04747990).

Carbon nanothreads are the most exciting carbon based nanomaterials recently discovered. Obtained by compressing aromatics around 20 GPa, they are characterized by potentially exceptional mechanical properties. The reaction mechanisms have been partly elucidated through computational studies and x-ray diffraction experiments. However, in all these studies, the electronic modifications to which the molecule is subjected with increasing pressure are neglected as also if, and to which extent, the electronic excited states are involved in the high-pressure reactivity. In fact, the pressure increase induces remarkable changes in the electronic properties of molecular crystals, which are often directly related to the reaction’s onset and path. We report the pressure evolution of the two-photon induced emission spectrum of crystalline stilbene, the archetype of a class of molecules from which double-core nanothreads are obtained, with the twofold purpose of gaining insight into the reaction mechanism and monitoring if the structural changes observed in x-ray diffraction studies have a detectable counterpart in the electronic properties of the system. The freezing of the spectral diffusion observed on rising pressure is ascribed to a hampered conformational rearrangement because of the larger stiffness of the local environment. The transition to the high pressure phase where the nanothreads form is revealed by the slope change of the pressure shift of all spectral components, while the progressive intensification with pressure of the 0-0 transition suggests a strengthening of the ethylenic bond favoring the charge delocalization on the benzene moieties, which is likely the trigger of the chemical instability.

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.

STUDY DESIGN: Retrospective study. OBJECTIVE: Following SARS-CoV-2 pandemic break-out a lockdown period for the population and a reorganization of the Health System were needed. Hub-function Centers for time-dependent diseases were identified and Niguarda Hospital (Milan) was selected as main Regional Trauma Center. The purpose of our study is to report the experience of Niguarda Maxillofacial Trauma Team during this period, pointing out epidemiological changes in the presentation of trauma in comparison to the previous 3 years. METHODS: Two hundred and sixteen patients were admitted to the Emergency Department from 8th March 2020 to 8th May 2020. One hundred and eighty-one had a diagnosis of Major Trauma and 36 had also facial fractures; 35 patients had isolated facial fractures. Data were compared to the activity during the same period in 2017-2019 and statistical analysis was carried out concerning demographic and clinical characteristics, trauma dynamics and positivity to COVID-19. RESULTS: Cumulative curves of patients admitted because of Major Trauma describe a superimposable linear trend in years 2017-2019, while 2020 shows an increase from April 16th. Average age and number of more severe patients were higher than previous years. Epidemiological changes concerned road accidents, accidents involving pedestrians and cyclists, interpersonal violence, suicide attempts and domestic accidents. The incidence of facial fractures was confirmed through years and, according to its measured severity, 75% of patients required management. COVID-19 positivity without systemic symptoms didn’t influence the type of treatment. CONCLUSION: The COVID-19 lockdown offers a unique opportunity to study the reversal epidemiological effects on trauma.

Chemical reactivity between As and N2 , leading to the synthesis of crystalline arsenic nitride, is here reported under high pressure and high temperature conditions generated by laser heating in a Diamond Anvil Cell. Single crystal synchrotron X-ray diffraction at different pressures between 30 and 40 GPa provides evidence for the synthesis of a covalent compound of AsN stoichiometry, crystallizing in a cubic P213 space group, in which each of the two elements is single-bonded to three atoms of the other and hosts an electron lone pair, in a tetrahedral anisotropic coordination. The identification of characteristic structural motifs highlights the key role played by the directional repulsive interactions between non-bonding electron lone pairs in the formation of the AsN structure. Additional data indicate the existence of AsN at room temperature from 9.8 up to 50 GPa. Implications concern fundamental aspects of pnictogens chemistry and the synthesis of innovative advanced materials.

Enteroatmospheric fistula (EAF) is defined as an enteric leak into an open abdomen. Its occurrence is one of the most feared complications for the acute care surgeon. The incidence of EAF is currently increasing due to a more liberal use of damage control surgery. Daily management is burdened by high complication and mortality rates and relevant costs for the national health system. Early identification and referral to specialized centers are critical aspects for better outcomes. The approach should be based on a step-up process in which surgery is the light at the end of the tunnel. The first steps should focus on clinical assessment and optimization of metabolic, septic and anatomical aspects. The intermediate step before definitive surgery is demanding in terms of time and resources and relies on different surgical techniques for fistula management. Definitive surgery can be planned only when timing and clinical condition are respected. Acute care surgeons must be aware that the clinical pathway of EAF patients is not always straightforward. This chapter aims to overview the critical aspects of classification and management of EAF and is designed to be a daily practice guide, with clinical and surgical insights relevant not only to experienced acute care surgeons.

Bile duct injury (BDI) is a dangerous complication of cholecystectomy, with significant postoperative sequelae for the patient in terms of morbidity, mortality, and long-term quality of life. BDIs have an estimated incidence of 0.4–1.5%, but considering the number of cholecystectomies performed worldwide, mostly by laparoscopy, surgeons must be prepared to manage this surgical challenge. Most BDIs are recognized either during the procedure or in the immediate postoperative period. However, some BDIs may be discovered later during the postoperative period, and this may translate to delayed or inappropriate treatments. Providing a specific diagnosis and a precise description of the BDI will expedite the decision-making process and increase the chance of treatment success. Subsequently, the choice and timing of the appropriate reconstructive strategy have a critical role in long-term prognosis. Currently, a wide spectrum of multidisciplinary interventions with different degrees of invasiveness is indicated for BDI management. These World Society of Emergency Surgery (WSES) guidelines have been produced following an exhaustive review of the current literature and an international expert panel discussion with the aim of providing evidence-based recommendations to facilitate and standardize the detection and management of BDIs during cholecystectomy. In particular, the 2020 WSES guidelines cover the following key aspects: (1) strategies to minimize the risk of BDI during cholecystectomy; (2) BDI rates in general surgery units and review of surgical practice; (3) how to classify, stage, and report BDI once detected; (4) how to manage an intraoperatively detected BDI; (5) indications for antibiotic treatment; (6) indications for clinical, biochemical, and imaging investigations for suspected BDI; and (7) how to manage a postoperatively detected BDI. Supplementary Information The online version contains supplementary material available at 10.1186/s13017-021-00369-w.

Poly(ionic liquid)s are an interesting class of compounds because of their unique chemical and physical properties gathering the characteristics of ionic liquids and polymers. Pressure and temperature have been demonstrated to be alternative parameters to obtain polymers from monomeric species using only physical tools. In this work, we investigate the reaction under high pressure and room temperature of the ionic liquid 1-allyl-3-methylimidazolium iodide by using the diamond anvil cell technique in combination with synchrotron X-ray diffraction and electronic and vibrational spectroscopies. The results indicate a chemical reaction happening through the terminal double bond of the allyl group both in crystalline and glassy phases with the onset of the reaction around ∼7 GPa. Vibrational spectra present evidence for an oligomerization reaction in both the phases. The reaction occurring both in glassy and crystal phases indicates a mechanism not driven by collective motions and likely related to local topological arrangements. The results presented herein extend our understanding of ionic liquid instability boundaries under high pressure and contribute to the development of alternative synthetic routes to achieve poly(ionic liquids).

The pressure-induced reactivity of aromatic molecules in the crystal phase has been recently demonstrated to be a practicable route for the synthesis of crystalline nanothreads. The formation of th...

The insertion of oxygen and nitrogen molecules in the one-dimensional (1D) pore system of the zeolite TON was studied at high pressure by vibrational spectroscopy, X-ray diffraction, and Monte Carlo (MC) molecular modeling. Rietveld refinements and MC modeling indicate that, on average, six diatomic molecules per unit cell enter the pores of the zeolite. This induces changes in compressibility and distortion related to the Cmc21-to-Pbn21 phase transition compared to the empty-pore material. The filling behavior with N2 and O2 under pressure is similar to that of argon, suggesting that the kinetic diameter, which is very close in these three systems, plays a major role. The orientation of the diatomic molecules appears to have a rather minor effect on filling occurring at a slightly higher pressure for N2, which has a larger kinetic diameter. Both inserted molecules, initially not showing any marked orientation, begin to exhibit a degree of orientational order above 2 GPa.

The presence of ions induces perturbations in the water network, these structural and dynamic modifications can extent over space scales overcoming the local solvation shell: aqueous solutions of sodium perchlorate (NaClO4) are characterized by extended phenomena of structure breaking of the solvent network. The aim of the present work is the experimental investigation of the interplay between the local structural modifications induced by the perchlorate ions and the collective dynamical properties of the solvent. Ultrafast Optical Kerr Effect (OKE) and time resolved infrared absorption are the experimental techniques adopted: OKE is mostly sensitive to the collective properties of the sample, while transient IR provides access to local properties of the solvent. Classical Molecular Dynamics (MD) simulations support the analysis of the experimental results. All experiments and simulations are performed at room temperature, varying the concentrations (0–6 M) and varying the applied pressure (10−4–1.3 GPa). Experiments and computer simulations confirm that pressure and concentration have convergent effects on the water dynamics, due to the analogous modification of the short-range liquid structure that cancel some dynamical anomalies typical of pure water. Both local and collective dynamic observables point to structural properties as responsible for their peculiar pressure and concentration dependence.

Noncompressible torso injuries (NCTIs) represent a trauma-related condition with high lethality. This study&rsquo, s aim was to identify potential prediction factors of mortality in this group of trauma patients at a Level 1 trauma center in Italy. Materials and Methods: A total of 777 patients who had sustained a noncompressible torso injury (NCTI) and were admitted to the Niguarda Trauma Center in Milan from 2010 to 2019 were included. Of these, 166 patients with a systolic blood pressure (SBP) &lt, 90 mmHg were considered to have a noncompressible torso hemorrhage (NCTH). Demographic data, mechanism of trauma, pre-hospital and in-hospital clinical conditions, diagnostic/therapeutic procedures, and survival outcome were retrospectively recorded. Results: Among the 777 patients, 69% were male and 90.2% sustained a blunt trauma with a median age of 43 years. The comparison between survivors and non-survivors pointed out a significantly lower pre-hospital Glasgow coma scale (GCS) and SBP (p &lt, 0.001) in the latter group. The multivariate backward regression model identified age, pre-hospital GCS and injury severity score (ISS) (p &lt, 0.001), pre-hospital SBP (p = 0.03), emergency department SBP (p = 0.039), performance of torso contrast enhanced computed tomography (CeCT) (p = 0.029), and base excess (BE) (p = 0.008) as independent predictors of mortality. Conclusions: Torso trauma patients who were hemodynamically unstable in both pre- and in-hospital phases with impaired GCS and BE had a greater risk of death. The detection of independent predictors of mortality allows for the timely identification of a subgroup of patients whose chances of survival are reduced.

High-pressure behavior of hexamethylenetetramine (urotropine) was studied in situ using angle-dispersive single-crystal synchrotron X-ray diffraction (XRD) and Fourier-transform infrared absorption (FTIR) spectroscopy. Experiments were conducted in various pressure-transmitting media to study the effect of deviatoric stress on phase transformations. Up to 4 GPa significant damping of molecular librations and atomic thermal motion was observed. A first-order phase transition to a tetragonal structure was observed with an onset at approximately 12.5 GPa and characterized by sluggish kinetics and considerable hysteresis upon decompression. However, it occurs only in non-hydrostatic conditions, induced by deviatoric or uniaxial stress in the sample. This behavior finds analogies in similar cubic crystals built of highly symmetric cage-like molecules and may be considered a common feature of such systems. DFT computations were performed to model urotropine equation of state and pressure dependence of vibrational modes. The first successful Hirshfeld atom refinements carried out for high-pressure diffraction data are reported. The refinements yielded more realistic C-H bond lengths than the independent atom model even though the high-pressure diffraction data are incomplete.

We present a study on the phase stability of dense carbon dioxide (${\mathrm{CO}}_{2}$) at extreme pressure-temperature conditions, up to 6200 K within the pressure range $37\ifmmode\pm\else\textpm\fi{}9$ to $106\ifmmode\pm\else\textpm\fi{}17\text{ }\text{ }\mathrm{GPa}$. The investigations of high-pressure high-temperature in situ x-ray diffraction patterns recorded from laser-heated ${\mathrm{CO}}_{2}$, as densified in diamond-anvil cells, consistently reproduced the exclusive formation of polymeric tetragonal ${\mathrm{CO}}_{2}$-V at any condition achieved in repetitive laser-heating cycles. Using well-considered experimental arrangements, which prevent reactions with metal components of the pressure cells, annealing through laser heating was extended individually up to approximately 40 min per cycle in order to keep track of upcoming instabilities and changes with time. The results clearly exclude any decomposition of ${\mathrm{CO}}_{2}$-V into the elements as previously suggested. Alterations of the Bragg peak distribution on Debye-Scherrer rings indicate grain coarsening at temperatures $g4000\text{ }\text{ }\mathrm{K}$, giving a glimpse of the possible extension of the stability of the polymeric solid phase.

High-pressure behavior of hexamthyleneteramine (urotropine) was studied in situ using angle-dispersive single-crystal synchrotron X-ray diffraction (XRD) and Fourier transform infrared absorption (FTIR) spectroscopy. Experiments were conducted in various pressure transmitting media (helium and neon for XRD, nitrogen and KBr for FTIR experiments) to study the effect of deviatoric stress on phase transformations. Contrary to As4O6 arsenolite, a material of similar cage-like molecular structure, no pressure-induced helium penetration into the crystal structure was observed. Instead, two pressure-induced structural changes are observed. The first one is suggested by the following occurrences: (i) gradual quenching of the magnitudes of atomic displacement parameters, (ii) diminishing libration contribution to the experimental C−N bond length, (iii) discontinuity in calculated IR-active vibrational modes and (iv) asymptotically vanishing discrepancy between the experimental and DFT‑calculated unit cell volume. All these features reach a plateau at ~4 GPa and can be attributed to a damping of molecular librations and atomic thermal motion, pointing to the existence of a second-order isostructural phase transition. The second transformation, with an onset at ~12.5 GPa is a first-order phase transition to a tetragonal structure, characterized by sluggish kinetics and considerable hysteresis upon decompression. However, it occurs only in non-hydrostatic conditions, induced by a deviatoric stress in the sample. This behavior finds analogies in similar cubic crystals built of highly symmetric cage-like molecules and may be considered a common feature of such systems. Last but not least, it is worth noting successful Hirshfeld atom refinements, carried out for the incomplete high-pressure diffraction data up to 14 GPa, yielded more realistic C−H bond lengths than the independent atom model.

High-pressure behavior of hexamthyleneteramine (urotropine) was studied in situ using angle-dispersive single-crystal synchrotron X-ray diffraction (XRD) and Fourier transform infrared absorption (FTIR) spectroscopy. Experiments were conducted in various pressure transmitting media (helium and neon for XRD, nitrogen and KBr for FTIR experiments) to study the effect of deviatoric stress on phase transformations. Contrary to As4O6 arsenolite, a material of similar cage-like molecular structure, no pressure-induced helium penetration into the crystal structure was observed. Instead, two pressure-induced structural changes are observed. The first one is suggested by the following occurrences: (i) gradual quenching of the magnitudes of atomic displacement parameters, (ii) diminishing libration contribution to the experimental C−N bond length, (iii) discontinuity in calculated IR-active vibrational modes and (iv) asymptotically vanishing discrepancy between the experimental and DFT‑calculated unit cell volume. All these features reach a plateau at ~4 GPa and can be attributed to a damping of molecular librations and atomic thermal motion, pointing to the existence of a second-order isostructural phase transition. The second transformation, with an onset at ~12.5 GPa is a first-order phase transition to a tetragonal structure, characterized by sluggish kinetics and considerable hysteresis upon decompression. However, it occurs only in non-hydrostatic conditions, induced by a deviatoric stress in the sample. This behavior finds analogies in similar cubic crystals built of highly symmetric cage-like molecules and may be considered a common feature of such systems. Last but not least, it is worth noting successful Hirshfeld atom refinements, carried out for the incomplete high-pressure diffraction data up to 14 GPa, yielded more realistic C−H bond lengths than the independent atom model.

Background Emergency Department Thoracotomy (EDRT) after traumatic Cardio-pulmonary Arrest (CPR) can be used to salvage select critically injured patients. Indications of this surgical procedure are widely debated and changed during last decades. We provide the available literature about EDRT in the effort to provide a comprehensive synthesis about the procedure, likelihood of success and patient’s outcome in the different clinical setting, accepted indications and technical details adopted during the procedure for different trauma injuries. Methods Literature from 1975 to 2020 was retrieved from multiple databases and reviewed. Indications, contraindications, total number and outcome of patients submitted to EDRT were primary endpoints. Results A total number of 7236 patients received EDRT, but only 7.8% survived. Penetrating trauma and witnessed cardiopulmonary arrest with the presence of vital signs at the trauma center are the most favorable conditions to perform EDRT. Conclusions EDRT should be reserved for acute resuscitation of selected dying trauma patient. Risks of futility, costs, benefits of the surgical procedure should be carefully evaluated before performing the surgical procedure.

High-pressure behavior of hexamthyleneteramine (urotropine) was studied in situ using angle-dispersive single-crystal synchrotron X-ray diffraction (XRD) and Fourier transform infrared absorption (FTIR) spectroscopy. Experiments were conducted in various pressure transmitting media (helium and neon for XRD, nitrogen and KBr for FTIR experiments) to study the effect of deviatoric stress on phase transformations. Contrary to As4O6 arsenolite, a material of similar cage-like molecular structure, no pressure-induced helium penetration into the crystal structure was observed. Instead, two pressure-induced structural changes are observed. The first one is suggested by the following occurrences: (i) gradual quenching of the magnitudes of atomic displacement parameters, (ii) diminishing libration contribution to the experimental C−N bond length, (iii) discontinuity in calculated IR-active vibrational modes and (iv) asymptotically vanishing discrepancy between the experimental and DFT‑calculated unit cell volume. All these features reach a plateau at ~4 GPa and can be attributed to a damping of molecular librations and atomic thermal motion, pointing to the existence of a second-order isostructural phase transition. The second transformation, with an onset at ~12.5 GPa is a first-order phase transition to a tetragonal structure, characterized by sluggish kinetics and considerable hysteresis upon decompression. However, it occurs only in non-hydrostatic conditions, induced by a deviatoric stress in the sample. This behavior finds analogies in similar cubic crystals built of highly symmetric cage-like molecules and may be considered a common feature of such systems. Last but not least, it is worth noting successful Hirshfeld atom refinements, carried out for the incomplete high-pressure diffraction data up to 14 GPa, yielded more realistic C−H bond lengths than the independent atom model.

Significance Some substances are known to exist in several different structurally disordered solid states and transform between them similarly to structural phase transitions between crystalline polymorphs. This interesting and yet not fully understood phenomenon is called polyamorphism, and notable examples include water, SiO 2 , Si, etc. Here we present an example of such behavior in a simple molecular substance, SO 2 . By using experimental high-pressure techniques, we observe a reversible transition between different amorphous states around 26 GPa. Experimental results are well supported by ab initio simulations, which identify the high-pressure amorphous form as a nonmolecular, polymeric one consisting of intertwined chains. Our findings contribute to the fundamental understanding of structure of disordered matter as well as high-pressure behavior of simple archetypal molecules.

Optical materials: X 8, 100065 (2020). doi:10.1016/j.omx.2020.100065, Published by Elsevier, Amsterdam

Despite water being the most common and most widely studied substance in the world, it still presents unknown aspects. In particular, water shows several thermodynamic and dynamical anomalies in the liquid and supercooled metastable phases, and the natures of these phases are still hotly debated. Here, we report measurements of water using the optical Kerr effect as a function of pressure along two isotherms, at 273 K from 0.1 to 750 MPa and at 297 K from 0.1 to 1350 MPa, reaching the supercooled metastable phase. The structural relaxation and the low frequency vibrational dynamics of water show a peculiar pressure dependence similar to that of other dynamical properties. The data analysis suggests the presence in the water phase diagram of a crossover area that divides two regions characterized by different dynamic regimes, which appear to be related to two liquid forms, one dominated by the high density water and the other by the low density water.

Pressure-induced polymerization of aromatic compounds leads to novel materials containing sp3 carbon-bonded networks. The choice of the molecular species and the control of their arrangement in the crystal structures via intermolecular interactions, such as the arene–perfluoroarene interaction, can enable the design of target polymers. We have investigated the crystal structure compression and pressure-induced polymerization reaction kinetics of two polycyclic 1:1 arene–perfluoroarene cocrystals, naphthalene/octafluoronaphthalene (NOFN) and anthracene/octafluoronaphthalene (AOFN), up to 25 and 30 GPa, respectively, using single-crystal synchrotron X-ray diffraction, infrared spectroscopy, and theoretical computations based on density-functional theory. Our study shows the remarkable pressure stability of the parallel arene–perfluoroarene π-stacking arrangement and a reduction of the interplanar π-stacking separations by ca. 19–22% before the critical reaction distance is reached. A further strong, discontinuous, and irreversible reduction along the stacking direction at 20 GPa in NOFN (18.8%) and 25 GPa in AOFN (8.7%) indicates the pressure-induced breakdown of π-stacking by formation of σ-bonded polymers. The association of the structural distortion with the occurrence of a chemical reaction is confirmed by a high-pressure kinetic study using infrared spectroscopy, indicating one-dimensional polymer growth. Structural predictions for the fully polymerized high-pressure phases consisting of highly ordered rods of hydrofluorocarbons are presented based on theoretical computations, which are in excellent agreement with the experimentally determined unit-cell parameters. We show that the polymerization takes place along the arene–perfluoroarene π-stacking direction and that the lateral extension of the columns depends on the extension of the arene and perfluoroarene molecules.

Self-assembly of organic macrocycles has been exploited as a preliminary step in the synthesis of soluble and tailorable carbon-based nanostructures. Functionalized nanotubes have been prepared using, as core building blocks, nearly planar ring structures containing several alkyne units, exploiting the geometry achieved in the spontaneous preassembling step driven by π interaction. Covalent cross-linking between these units was achieved by thermal or photochemical activation with UV light. Here, we apply a moderate pressure in a sapphire anvil cell (1.0 GPa) to facilitate the preassembling and induce the cross-linking under pressure either with visible light, absorbed by two-photon absorption, or thermally. We observe a high yield of enhanced quality cross-linked nanotubes in a sample, showing, at ambient pressure, only side-chain decomposition. These results show that moderate pressures, easily achievable in large volume cells, are able to selectively favor topochemical reactions in such complex organic ...

The high-pressure chemical reactivity of nitromethane, under irradiation with visible and near-UV laser light, was investigated by in situ FTIR spectroscopy in a diamond anvil cell. The reactivity was probed at different pressures (0.2, 1.2, 5.0, 15.3, and 28.0 GPa) with different excitation wavelengths (514, 458, and 350 nm), with all absorbed through a two-photon process. Insight into the reaction mechanism was gained by measuring the near-UV absorption spectrum of nitromethane as a function of pressure to 32 GPa, the threshold pressure above which it reacts spontaneously in the absence of electronic excitation. We were thus able to determine the pressure evolution of the two lowest-energy transitions (σ → π* and a singlet–triplet transition). The information obtained from the absorption spectra together with the reactivity data allowed us to locate the red absorption edge of the higher-energy π → π* transition and its pressure shift. The excitation of the σ → π* transition was not able to induce any ph...

Black phosphorus was studied by state-of-the-art synchrotron X-ray diffraction in a Diamond Anvil Cell during room temperature compression in the presence of He, H2, N2 and Daphne Oil 7474. The data demonstrate that the existence of the pseudo simple-cubic (p-sc) structure above 10.5 GPa is an intrinsic feature of P independent from the pressure transmitting medium. In the case of He, the pressure evolution of the lattice parameters and unit cell volume of P across the A17, A7 and p-sc structures was obtained and the corresponding EOS derived, providing a deeper insight on the recently reported p-sc structure. The results presented in this letter highlight the key role of the s-p orbital mixing in the formation and stabilization of the p-sc structure up to ~30 GPa, solving apparent contradictions emerging from previous literature and finally bringing order to the sequence of the high pressure A7 layered structure in group 15 elements.

1. Though multistage axial turbines are being widely used since many decades for water steam expansion or in gas turbines, their use in ORCs has traditionally found limitations as a consequence of the choice of designing turbines with cantilever arrangements. 2. The choice of the cantilever arrangement is mainly related to the advantages of having simple shaft bearings design, only one rotating seal system in contact with the working fluid, a lighter and more compact turbine casing, only one side of the turbine casing occupied with the bearing and sealing systems (leaving the other side free to host the outlet duct for working fluid expanded vapour which often features very large volumetric flow rates), easiness of access for ordinary and extraordinary maintenance. Hence cantilever arrangement involves definitely lower turbine costs, both in terms of Capex and Opex and is practically the only solution adopted by the industrial suppliers of ORC turbines. 3. By adopting the cantilever arrangement the installation of several turbine discs hosting several expansion stages, traditionally installed one close to the other, would increase the overhang mass of the turbine rotor and decrease the natural frequencies of the system, yielding some mechanical problems and, at the end, limiting the possibility of installing, practically, more than 2-3 stages with this kind of arrangement. 4. On the other hand, however, modern ORC turbines require to increase number of stages to better exploit the expansion enthalpy drop, in order to increase turbine efficiency and/or to allow to adopt a low rotating speed (even 1,500 rpm) for a direct connection with synchronous generator. 5. The paper will describe an innovative solution that has allowed to increase the number of stages from the traditional 2-3 to at least 5 without leaving the effective cantilever arrangement, keeping the concept of ‘rigid’ rotor (i.e. operating below the first flexional natural frequency), with very low measured vibrations. 6. Operating data of a 9 MW 5 stage ORC turbine put in operation in 2016 will also be presented.

Molecular nitrogen is a benchmark system for condensed matter and, in particular, for looking at universal properties of strongly confined dense systems. We conducted Raman and X-ray diffraction measurements on a dense and disordered form of molecular nitrogen subnanoconfined in a noncatalytic pure SiO2 zeolite under pressure, up to 50 GPa. In this form, N-2-N-2 interactions and, consequently, distances are found to be very dose to those of bulk N-2 and intramolecular interactions progressively weaken upon increasing pressure. Surprisingly, the filled zeolite is still crystalline at 50 GPa with silicon in tetrahedral coordination by oxygen, which is a record pressure for this type of coordination among all the known forms of silica. We have thus found a rationale for the polymerization of a number molecules occurring in the microchannels of noncatalytic zeolites under pressure, where the pressure threshold is found to be very similar to that observed in bulk samples.

The n-paraphenylene family comprises chains of phenylene units linked together by C-C bonds that are between single- and double-bonded, and where n corresponds to the number of phenylene units. In this work, we compare the response of the optical properties of different phenylene arrangements. We study linear chains (LPP), cyclic systems (CPPs), and non-conjugated cyclic systems with two hydrogenated phenylenes (H4[n]CPP). Particularly, the systems of interest in this work are [6]LPP, [12]- and [6]CPP and H4[6]CPP. This work combines Raman and infrared spectroscopies with absorption and fluorescence (one- and two-photon excitations) measured as a function of pressure up to maximum of about 25 GPa. Unprecedented crystallographic pressure-dependent results are shown on H4[n]CPP, revealing intramolecular &pi, &pi, interactions upon compression. These intramolecular interactions justify the H4[n]CPP singular optical properties with increasing fluorescence lifetime as a function of pressure.

International audience; Condensed O2 tends to form clusters, even with a long-range order. In particular, in solid oxygen, strong intermolecular charge transfer at high pressures leads to the formation of (O2)4 tetramers above 10 GPa, in the ε-O2 phase, with weak O2–O2 chemical bonds. Indeed, ε-O2 is entirely made of these tetramers. We conducted experimental investigations on strongly densified O2 in a different environment, that is to say in the form of a subnano phase build up within the 1D microchannels of a purely siliceous, inert zeolite, TON, at pressures of 0.5–20 GPa, by means of diamond anvil cells. Our X-ray diffraction and infrared and Raman spectroscopy results consistently show that oxygen forms clusters in this nanophase, above 10 GPa, similar to ε-O2, except that the clusters are rather of the type of weakly bonded (O2)2 dimers in this case. Also, by analogy with bulk oxygen, we show that the O2 spin within the dimers departs from S = 1 toward lower values, upon increasing pressure. Our findings thereby add to the general view on essential properties of highly dense oxygen.

2,4,6-Tricyano-1,3,5-triazine is an attractive precursor for the synthesis of extended layered and nanoporous carbon nitrides. Using high pressure can achieve this via one-step condensation reactions. As a first step towards this goal we have characterized the structural properties and stability P-T range of the monomer (phase I) using synchrotron X-ray diffraction combined with FTIR spectroscopy under combined high pressure and high temperature conditions in a resistively heated diamond anvil cell. A new high pressure structure (phase II) appeared following compression to above 2.4 GPa at ambient temperature. The structure was identified as orthorhombic belonging to space group P2(1)2(1)2(1). The pressure-temperature conditions of the I-II phase boundary, as well as the melting line have been established. The chemical transformation of the phase II crystal was studied between 4 and 10 GPa at temperatures ranging from 550 to 300 K. X-ray and spectroscopic examination of the reaction products revealed a crystalline phase that could be assigned to a layered carbon nitride containing linked s-triazine rings along with amorphous material. Analysis of the kinetics indicates that the structural transformation is driven by defect formation.

Homogeneous melting of crystals is a complex multistep process involving the formation of transient states at temperatures considerably higher than the melting point. The nature and persistence of these metastable structures are intimately connected to the melting process, and a precise definition of the temporal boundaries of these phenomena is not yet available. We set up a specifically designed experiment to probe by transient infrared absorption spectroscopy the entire dynamics, ranging from tens of picoseconds to microseconds, of superheating and melting of an ice crystal. In spite of a large excess of energy provided, only about 30% of the micrometric crystal liquefies in the first 20-25 ns because of the long persistence of the superheated metastable phase that extends for more than 100 ns. This behavior is ascribed to the population of low-energy states that trap a large amount of energy, favoring the formation of a metastable, likely plastic, ice phase.

The crystalline A17 layered structure of Phosphorus, commonly indicated as black Phosphorus, was synthesized for the first time at high pressure by Bridgman back in 1914 [1] and is currently attracting a growing attention from chemists, physicists and materials scientists due to the appealing properties of its monolayer counterpart named Phosphorene [2]. Recently, high pressure studies have reported the observation of a pseudo simple cubic (p-sc) structure in the phase diagram of Phosphorus up to 30 GPa, significantly raising the pressure limit for the layered structures of P and opening new perspectives for their stabilization and functionalization [3-4]. On the other side, the experimental report of superconductivity in compressed PH 3 [5], with no structural characterization so far, has stimulated experimental and theoretical efforts to investigate the high pressure stability of different systems containing Phosphorus and Hydrogen, which can be responsible for such behavior in analogy with H 2 S [6,7]. In this study we investigated the chemical reactivity of black Phosphorus and molecular Hydrogen under high pressure and high temperature conditions, which were generated using a membrane Diamond Anvil Cell (DAC) in combination with laser heating. The sample was probed by means of synchrotron X-ray diffraction at ESRF-ID27 and by FTIR and Raman spectroscopy at LENS. The visual inspection of the sample after laser heating clearly showed the consumption of Phosphorus. Correspondingly, the analysis of the experimental XRD and spectroscopic data indicated the formation of different reaction products containing P-H bonds, particularly PH 3 , H-functionalized Phosphorus fragments and a solid product identified as a van der Waals compound made of PH 3 and H 2 , whose crystal structure was accurately determined from single crystal data. The identification of this compound, representing so far a missing piece, consistently fills a gap in the periodic table for Phosphorus, in agreement with analogous compounds reported in literature formed by the hydrides of Carbon (CH 4 ), Sulphur (H 2 S), Selenium (H 2 Se) and Iodine (HI) in the presence of H 2 [8-11]. Furthermore, the observation of this compound provides new experimental evidence for the formation of unexpected chemical species originating from the high pressure chemistry of Phosphorus and Hydrogen, possibly shedding new light on the high pressure superconductivity of Phosphorus-Hydrogen systems. Acknowledgments: Thanks are expressed to EC through the European Research Council (ERC) for funding the project PHOSFUN "Phosphorene functionalization: a new platform for advanced multifunctional materials" (Grant Agreement No. 670173) through an ERC Advanced Grant. References [1] P. W. Bridgman, J. Am. Chem. Soc. 1914, 36, 1344. [2] M. Peruzzini et al., Eur. J. Inorg. Chem. 2019, 1476. [3] D. Scelta et al., Angew. Chem. Int. Ed. 2017, 56, 14135. [4] D. Scelta et al., Chem. Commun. 2018, 54, 10554. [5] A. P. Drozdov et al., arXiv:1508.06224 (2015). [6] T. Bi et al., Angew. Chem. Int. Ed. 2017, 56, 10192. [7 M. Liu et al. J. Raman Spectrosc. 2018, 49, 721. [8] M. S. Somayazulu et al., Science 1996, 271, 1400. [9] T. A. Strobel et al. Phys. Rev. Lett. 2011, 107, 255503 .[10] E. J. Pace et al., J. Chem. Phys. 2017, 147, 184303. [11] Binns J. et al., Phys. Rev. B 2018, 97, 024111. Keywords: Phosphorus, Hydrogen, high pressure chemistry

Complications in colorectal surgery include a wide range of clinical conditions, which increase mortality, morbidity, hospital stay and costs. In some cases, the placement of a self-expanding metal stent may represent a possible therapeutic strategy, avoiding further surgery. In order to verify the feasibility and safety of the technique, we reviewed the medical literature, between January 1997 and 2015, selecting 32 studies. Inclusion criteria were based on Preferred Reporting Items for Systematic reviews and Meta-Analyses recommendations. The estimated rate of early success was 73.3% (95% CI 66.3–79.3), raising from 25 to 68% in the time frame 1997–2007. The rate of early complications was 31.4% (95% CI 25.3–38.3%), progressively decreasing from 75 to 43% up to 2009. The rate of surgery for acute complication was 9.3% (95% CI 6.0–14.2%), reduced on time course from 25 to 9%. The rate of closure of dehiscence was 74.5% (95% CI 62.8–83.5%), while the rate of long-lasting success was 57.3% (95% CI 50.3–64.0%). Endoscopic stenting in the early postoperative management of anastomotic complications after colorectal surgery should be considered in patients with minimal risk for sepsis, as a safe and often effective alternative to surgery. However, in order to establish the safety and efficacy of this technique, prospective studies involving a larger cohort of patients are required.

// Roberto Bini 1 , Simone Comelli 2 , Renzo Leli 1 , Giacomo Paolo Vaudano 2 , Daniele Savio 2 , Tiziana Viora 1 , Alfredo Addeo 3 1 General Surgery Department, SG Bosco Hospital, Turin, Italy 2 Interventional Radiology- Neuroradiology Department, SG Bosco Hospital, Turin, Italy 3 Oncology Department, Bristol Cancer Center, Bristol, UK Correspondence to: Roberto Bini, email: rebinidoc@gmail.com Keywords: debiri, rectal cancer, chemoembolization, cancer recurrence Received: November 09, 2015 Accepted: May 20, 2016 Published: June 10, 2016 ABSTRACT Purpose: Assess the feasibility, safety and efficacy of TACE with irinotecan loaded micro particles (debiri) for the treatment of locally advanced rectal cancer patients. Results: We assessed the Edmonton Symptom Assessment System (ESAS). The tool is designed to assess nine common symptoms in cancer patients: pain, tiredness, nausea, depression, anxiety, drowsiness, appetite, wellbeing and shortness of breath. The ESAS score was 7 in 10/12 (83%) patients before treatment and 6 in 2/12 (16.5%) patients. After treatment in 6/12 (50%) patients the score dropped to 3; 3/12 (33%) reported 4, 1/12 (8%) reported 2. All patients experienced local control disease with a degree of citoreduction; in 4 cases (33%) we observed outstanding responses with a dramatic reduction in the tumors size which led us to surgical radical resections. Materials and methods: We run a prospective mono-institutional study where we recruited, 12 non- consecutive patients with histology confirmation of rectal cancer, inoperable and not treatable due to severe comorbidities, or pelvic recurrence/progression after curative treatment, chemotherapy, radiotherapy and/or surgery. Their performance status (PS) ECOG was 2-3 . Twelve patients (10 male and 2 female) with a median age 71 (range 56-89) were recruited in the study. Conclusions: The study has met the primary endpoint and showed encouraging activity. Debiri could be a possible option for locally advanced/inoperable or recurred rectal cancer patients. Further trials are warranted to validate this methodic in early stages.

The pressure-induced transformation of molecular crystals can give rise to new materials characterized by intriguing hardness or energetic properties. Mechanisms regulating these reactions at the molecular level result from a complex interplay among crystal structure, lattice dynamics, and electronic properties. Here, we show that the formation of a three-dimensional amorphous carbon nitride by compressing phase II s-triazine is controlled by the competition between two different mechanisms, one entirely structural and the other electronic, representing the first example where such occurrence is demonstrated. Temperature drives the reactivity below 8 GPa by ruling the lattice dynamics, whereas above 8 GPa the electronic modifications, uniquely governed by pressure, trigger the chemical transformation. The amorphous material synthesized has a bonding structure characterized by a bulk typical of a strongly conjugated three-dimensional carbon nitride with hydrogen atoms migrated to saturate C and N terminations.

Background Gastrointestinal (GI) perforations are an acute surgical dilemma, with diagnostic workup often requiring abdominal imaging. Post-operative care for these patients may vary and oftentimes includes ICU care for sepsis, but not always. We evaluated if free fluid and air on computed tomography (CT) could be associated with sepsis, septic shock and mortality in GI perforations. The aim of our study was a correlation between a new CT-scan scoring system and septic complications in GI perforations. Methods We conducted an observational retrospective study about patients who underwent emergency surgery for intestinal perforation between January 2014 and June 2017. Inclusion criteria were a CT-scan positive for free fluid and air, and an intestinal perforation confirmed intraoperatively. A CT-score was created to evaluate location and extent of free fluid and air related to clinical outcome and prognosis. Univariate analysis between the CT score and the various clinical outcomes was conducted with the non-parametric Mann-Whitney test for continuous variables and with the chi-square test for categorical variables. Results One-hundred and fifty-one patients were evaluated. The mortality was 23.18% and the complications were present in 45.95%. The median CT score for patients who developed complications was 3, compared with a value of 2 in the absence of complications (P=0.008). A CT score of 4 or greater had a sensitivity and specificity for predicting pre-operative sepsis of 73.33% and 64.42% respectively, and for pre-operative septic shock of 35.56% and 93.27%. Looking at post-operative sepsis, sensitivity and specificity were 57.45% and 70.19%, and for septic shock 36.17% and 85.85%. Spearman correlation analysis revealed that at higher scores at CT score corresponded higher scores at the P-POSSUM morbidity, P-POSSUM mortality and WSES Sepsis Severity Score. Conclusions Our CT score shows a significant correlation with validated predictive scoring systems with regards to predicting sepsis, septic shock and complications-and seems to be a useful outcome predictor in GI perforation.

Carbon dioxide is a widespread simple molecule in the Universe. In spite of its simplicity it has a very complex phase diagram, forming both amorphous and crystalline extended phases above 40 GPa. The stability range and nature of these phases are still debated, especially in view of their possible role within the deep carbon cycle. Here, we report static synchrotron X-ray diffraction and Raman high-pressure experiments in the megabar range providing evidence for the stability of the polymeric phase V at pressure-temperature conditions relevant to the Earth’s lowermost mantle. The equation of state has been extended to 120 GPa and, contrary to earlier experimental findings, neither dissociation into diamond and ε-oxygen nor ionization was observed. Severe deviatoric stress and lattice deformation along with preferred orientation are removed on progressive annealing, thus suggesting CO2-V as the stable structure also above one megabar., The nature and stability of carbon dioxide under extreme conditions relevant to the Earth’s mantle is still under debate, in view of its possible role within the deep carbon cycle. Here, the authors perform high-pressure experiments providing evidence that polymeric crystalline CO2 is stable under megabaric conditions.

Background Hemorrhagic shock (HS) is a major threat to patients with trauma and spontaneous bleeding. The aim of the study was to investigate early effects of vasopressin on metabolic and hemodynamic parameters and endothelium permeability by measuring capillary leakage compared to those of other resuscitation strategies in a HS model. Methods Forty-five Sprague-Dawley rats were randomized into five groups: S group (n = 5), sham-operated rats without shock or resuscitation; HS group (n = 10), HS and no resuscitation; RL group (n = 10), HS and resuscitation with Ringer’s lactate (RL); RLB group (n = 10), HS and resuscitation with two-third shed blood plus RL; and vasopressin group (n = 10), HS and resuscitation with RL, followed by continuous infusion of 0.04 U/kg/min vasopressin. The effects of resuscitation on hemodynamic parameters [mean arterial pressure (MAP), superior mesenteric artery blood flow (MBF), and mesenteric vascular resistances (MVR)], arterial blood gases, bicarbonate, base deficit, and lactate levels as well as on capillary leakage in the lung, ileum, and kidney were investigated. Capillary leakage was evaluated with Evans blue dye extravasation. Results In the vasopressin group, the MAP was higher than in the RL and RLB groups (p

One-dimensional diamondoid polyaniline-like nanothreads combine the outstanding mechanical properties of carbon nanotubes with the versatility of NH2 groups., Low-dimensional nanomaterials such as highly ordered polyaniline (PANI) have attracted considerable interest due to their expected extraordinary electronic and optoelectronic properties. In spite of several attempts, the attainment of atomically well-ordered PANI is a long-standing challenge. Pressure-induced polymerization of aromatic molecules in the crystal phase has been demonstrated as a practicable route for the synthesis of highly ordered polymers but this approach has never been tested to produce PANI. Here we show the synthesis of diamondoid polyaniline-like nanothreads at 33 GPa and 550 K by compressing aniline in crystal phase-II. Infrared spectroscopy, transmission electron microscopy, X-ray diffraction data, and DFT calculations support the formation of this totally new polyaniline-like nanothread. The NH2-enriched carbon nanothread combines the outstanding mechanical properties of carbon nanotubes with the versatility of NH2 groups decorating the exterior of the nanothreads representing potential active sites for doping and as linkers for molecules with biological interest and inorganic nanostructures. The synergy of all of these properties emphasizes the strong potential of this material to be applied in a broad range of areas, from chemistry to materials engineering.

The recent synthesis of Phosphorene [1,2] and the theoretical predictions of a variety of related 2D allotropes [3] have raised a growing interest from the scientific community about the layered structures of Phosphorus. Indeed, black Phosphorus (bP, A17), formed by the ordered stacking of Phosphorene layers in a similar way as graphene is related to graphite, is actually the starting material for the synthesis of Phosphorene by exfoliation techniques. However, while the synthesis and stabilization of Phosphorene are still challenging tasks, its chemistry and functionalization represent frontier research topics. Within this perspective, pressure has been shown to be a very effective tool. Besides bP, another layered structure of P, rhombohedral A7, made by the stacking of blue Phosphorene layers, is indeed experimentally accessible by pressure. Remarkably, pressure has recently allowed to gain fundamental insight about the mechanism ruling the formation of chemical bonds between P layers, unveiling the existence of an intermediate p-sc structure between the layered rhombohedral A7 and the non-layered simple-cubic phases of P, significantly raising the pressure limit where the layers of P can be observed up to at least 30 GPa [4]. In this study we report the high pressure and high temperature chemistry of Phosphorus in the presence of N2 by means of state-of-the-art synchrotron X-ray diffraction (at ESRF-ID27), FTIR and Raman spectroscopy, using membrane Diamond Anvil Cell for the generation of static high pressure and laser heating for in situ generation of high temperature. Besides the N- functionalization of Phosphorene layers, this study is relevant to the substantially unexplored chemistry of the lowest Z pnictogens and to the synthesis of new PN compounds. Crystalline black Phosphorus was laser heated under different pressure and temperature conditions, corresponding to different crystalline structures of Phosphorus (A17, A7 and sc), above and below the melting line of N2. The results indicate a pressure dependent chemical reactivity, leading to different reaction products, according to the applied pressure. The low pressure data demonstrated the first direct synthesis of gamma-P3N5 from the elements, avoiding any precursor or byproduct [5]. Raman spectra and XRD patterns were acquired at high and ambient pressure, tracing the equation of state of the material, and providing new experimental input about the existence of the predicted delta- P3N5 phase [6-7]. References [1] Liu, H.; Neal, A. T.; Zhu, Z.; Luo, Z.; Xu, X.; Tománek, D.; Ye, P. D. Phosphorene: An Unexplored 2D Semiconductor with a High Hole Mobility, ACS Nano 2014, 8, 4033-4041. [2] Li, L.; Yu, Y.; Ye, G. J.; Ge, Q.; Ou, X.; Wu, H.; Feng, D.; Chen, X. H.; Zhang, Y. Black phosphorus field-effect transistors, Nat. Nanotechnol. 2014, 9, 372-377. [3] Woo Hyun Han, W.H. Sunghyun Kim, S.; Lee, I-H.; Chang, L.J. Prediction of Green Phosphorus with Tunable Direct Band Gap and High Mobility, J. Phys. Chem. Lett. 2017, 8, 4627-4632. [4] Scelta, D.; Baldassarre, A.; Serrano-Ruiz, M.; Dziubek, K.; Cairns, A. B.; Peruzzini, M.; Bini, R.; Ceppatelli, M. Interlayer Bond Formation in Black Phosphorus at High Pres- sure, Angew. Chem. Int. Ed. 2017, 56, 14135-14140. [5] Landskron, K.; Huppertz, H.; Senker, J. and Schnick, W. High-Pressure Synthesis of gamma- P3N5 at 11 GPa and 1500 °C in a Multianvil Assembly: A Binary Phosphorus (V) Nitride with a Three-Dimensional Network Structure from PN4 Tetrahedra and Tetragonal Pyramids Angew. Chem. Int. Ed. 2001, 40, 2643-2645. [6] Dong, J.; Kinkhabwala, A. A.; McMillan, P. F. , High-pressure polymorphism in phosphorus nitrides Physica Status Solidi B, 2004, 210, 2319-2325. [7] Kroll, P.; Schnick, W. A Density Functional Study of Phosphorus Nitride P3N5 : Refined Geometries, Properties, and Relative Stability of alpha-P3N5 and gamma-P3N5 and a Further Possible High-Pressure Phase delta-P3N5 with Kyanite-Type Structure Chem. Eur. J. 2002, 8, 3530- 3537.

Pressure is an extraordinary tool to modify direction and strength of intermolecular interactions with important consequences on the chemical stability of molecular materials. The decrease of the distance among nearest neighbour molecules can give rise to reactive configurations reflecting the crystal arrangement and leading to association processes. In this context, the role of the H-bonds is very peculiar because their usual strengthening with rising pressure does not necessarily configure a decrease of the reaction activation energy but, on the contrary, can give rise to an anomalous stability of the system. In spite of this central role, the mechanisms by which a chemical reaction is favoured or prevented by H-bonding under high pressure conditions is a poorly explored field. Here we review a few studies where the chemical behaviour of simple molecular systems under static compression was related to the H-bonding evolution with pressure. These results are able to clarify a wealth of changes of the chemical and physical properties caused by the strengthening with pressure of the H-bonding network and provide additional tools to understand the mechanisms of high-pressure reactivity, a mandatory step to make these synthetic methods of potential interest for applicative purposes.

A pressure induced lattice expansion of Graphite Oxide (GO) in presence of NH 3 was observed by X-ray diffraction during room temperature compression and decompression up to 7 GPa in a diamond anvil cell (DAC). A remarkable increase ( ∼ 11%) of the interlayer d-spacing of GO was observed between 0.2 and 1.1 GPa in the liquid phase of NH 3 , indicating the occurrence of molecular insertion between the GO layers. The expansion is reversible with the release of pressure, thus leading to a pressure induced breathing of the GO lattice. The presence of high density NH 3 between the GO layers opens new perspectives for N-doping and chemical functionalization of GO and for designing new advanced carbon based nanostructured materials.

One-step synthesis using only physical tools is an appealing “green” method for the realization of technological materials. High-pressure conditions are particularly suitable in the attainment of extended supramolecular networks and in combination with high-temperature are effective in selecting specific reaction pathways to increase product quality. Here we show how pressures below 3 GPa and temperatures on the order of 420 K are effective for the synthesis, from urea crystal phase IV, of 2D graphitic carbon nitride oxide with enhanced crystalline quality. Angle-dispersive X-ray diffraction and Fourier transform IR spectroscopy show that the reaction becomes less selective at higher pressure with the formation of melamine and ammonium carbamate as byproducts. An anomalous positive slope is shown by the P–T instability boundary, likely arising from unfavorable hydrogen bonding with respect to the topochemical path, making urea an interesting case study for gaining insight into the role of hydrogen bonding in solid-state reactivity.

Black phosphorus was compressed at room temperature across the A17, A7 and simple‐cubic phases up to 30 GPa, using a diamond anvil cell and He as pressure transmitting medium. Synchrotron X‐ray diffraction showed the persistence of two previously unreported peaks related to the A7 structure in the pressure range of the simple‐cubic phase. The Rietveld refinement of the data demonstrates the occurrence of a two‐step mechanism for the A7 to simple‐cubic phase transition, indicating the existence of an intermediate pseudo simple‐cubic structure. From a chemical point of view this study represents a deep insight on the mechanism of interlayer bond formation during the transformation from the layered A7 to the non‐layered simple‐cubic phase of phosphorus, opening new perspectives for the design, synthesis and stabilization of phosphorene‐based systems. As superconductivity is concerned, a new experimental evidence to explain the anomalous pressure behavior of Tc in phosphorus below 30 GPa is provided.

Molecular nitrogen is a benchmark system for condensed matter and, in particular, for looking at universal properties of strongly confined dense systems. We conducted Raman and X-ray diffraction measurements on a dense and disordered form of molecular nitrogen subnanoconfined in a noncatalytic pure SiO

Introduction Central venous catheterizations are common intraoperative procedures. Central venous catheter (CVC) placements are usually performed with patients lying in the supine position using real-time ultrasound (US) guidance. Case description A 43-year-old man underwent open right popliteal artery reconstruction in the prone position for a limb-threatening injury. Excessive continuous intraoperative bleeding, increased by a coexisting pelvic fracture, was temporarily stabilized by a T POD device, but with the need of external fixation, required the placement of CVC, which was not feasible whilst in the prone position without US help. A view of the left internal jugular vein (IJV) was obtained with pediatric T probe and a CVC was placed using real-time US guidance, without complications. Conclusions We demonstrated the feasibility and safety of US-guided CVC placements in an emergency setting.

Angle-dispersive X-ray diffraction and Fourier transform infrared spectroscopy have been employed to study the phase diagram of urea crystal beyond 15 GPa and at temperatures in excess of 400 K. Previously reported Bridgman phase II was structurally characterized for the first time, and it is discovered that it coincides with room-temperature phase IV. Large metastability P-T regions were identified for all phases in the sequence I-III-IV-V, ascribed to the difficulty to disrupt the H- bonding network, a prerequisite to accomplish the molecular rearrangement necessary for the structural transformation. High-temperature studies and use of a hydrostatic compression medium allows the thermodynamic boundaries of phase III, and partly of phase IV, to be identified therefore making a considerable step forward in the knowledge of the phase diagram of urea. (Graph Presented).