Diversity of protonated mixed pyrene-water clusters investigated by collision induced dissociation.

Protonated mixed pyrene-water clusters, (Py)(HO)H, where = [1-3] and = [1-10], are generated using a cryogenic molecular cluster source. Subsequently, the mass-selected mixed clusters undergo controlled collisions with rare gases, and the resulting fragmentation mass spectra are meticulously analyzed to discern distinct fragmentation channels. Notably, protonated water cluster fragments emerge for ≥ 3, whereas they are absent for = 1 and 2.

Threshold collision induced dissociation of protonated water clusters.

We report threshold collision induced dissociation experiments on protonated water clusters thermalized at low temperature for sizes n = 19-23. Fragmentation cross sections are recorded as a function of the collision energy and analyzed with a statistical model. This model allows us to account for dissociation cascades and provides values for the dissociation energies of each cluster.

Water Attachment onto Size-Selected Cationic Pyrene Clusters.

We report measurements of the attachment rates of water molecules onto mass-selected cationic pyrene clusters for size from = 4 to 13 pyrene units and for different collision energies. Comparison of the attachment rates with the collision rates measured in collision-induced dissociation experiments provides access to the values of the sticking coefficient. The strong dependence of the attachment rates on size and collision energy is rationalized through a model in which we use a Langevin-type collision rate and adjust on experimental data the statistical dissociation rate of the water molecule from the cluster after attachment.

Collision-induced dissociation of protonated uracil water clusters probed by molecular dynamics simulations.

Collision-induced dissociation experiments of hydrated molecular species can provide a wealth of important information. However, they often need a theoretical support to extract chemical information. In the present article, in order to provide a detailed description of recent experimental measurements [Braud , , 2019, , 014303], collision simulations between low-energy protonated uracil water clusters (HO)UH and an Ar atom were performed using a quantum mechanics/molecular mechanics formalism based on the self-consistent-charge density-functional based tight-binding method.

Characterisation of pragmatic postoperative PAin Trajectories over seven days and their association with CHronicity after 3 months: a prospective, pilot cohort study (PATCH study).

Background: Reliable outcome measurement providing information both on early and late postoperative pain outcomes are still lacking. The purpose of this study was: 1) to characterise postoperative pain trajectories according to an innovative pragmatic concept: ideal pain trajectory (rapid and sustained pain relief) vs non-ideal pain trajectories (late, transient, or no pain relief); and 2) to assess the incidence of persistent post-surgical pain (PPSP) and the potential association between non-ideal pain trajectories and PPSP.

Methods: This prospective observational pilot cohort study was performed from March until June 2016.

Multimodal oral analgesia strategy after ambulatory arthroscopic shoulder surgery: case series using adaptive therapeutic approaches by sequential analysis.

Background: Pain control and quality of recovery (QoR) at home remains a challenge after ambulatory shoulder arthroscopy. This study aims to assess the QoR and pain relief using a sequential implementation strategy for rescue analgesic drugs.

Methods: After institutional review board approval, patients (>18 years, American Society of Anesthesiology [ASA] score 1-3 stable) scheduled for ambulatory surgery under general anesthesia with a single-shot interscalene nerve block were enrolled.

Post-operative opioid-related adverse events with intravenous oxycodone compared to morphine: A randomized controlled trial.

Background: The value of intravenous oxycodone compared to morphine remains controversial. The purpose of this trial was to compare opioid-related adverse events (ORAES) of intravenous oxycodone and morphine after total hip arthroplasty.

Methods: Patients scheduled for total hip arthroplasty were enrolled in this study of post-operative pain treatment with intravenous oxycodone or intravenous morphine (ratio 1:1).

Threshold collision induced dissociation of pyrene cluster cations.

We report threshold collision induced dissociation experiments on cationic pyrene clusters, for sizes n = 2-6. Fragmentation cross sections are recorded as a function of the collision energy and analyzed with a statistical model. This model can account for the dissociation cascades and provides values for the dissociation energies.

Thermal evaporation of pyrene clusters.

This work presents a study of the thermal evaporation and stability of pyrene (CH) clusters. Thermal evaporation rates of positively charged mass-selected clusters are measured for sizes in the range n = 3-40 pyrene units. The experimental setup consists of a gas aggregation source, a thermalization chamber, and a time of flight mass spectrometer.

Size-dependent proton localization in hydrated uracil clusters: A joint experimental and theoretical study.

A collision-induced dissociation study of hydrated protonated uracil (HO)UH clusters is reported. The mass-selected clusters collide with water molecules and rare gases at a controlled center of mass collision energy. From these measurements, absolute fragmentation cross sections and branching ratios are extracted as a function of the uracil hydration.

Theoretical investigation of the solid-liquid phase transition in protonated water clusters.

Protonated water clusters have received a lot of attention as they offer tools to bridge the gap between molecular and bulk scales of water. However, their properties are still not fully understood and deserve further theoretical and experimental investigations. In this work, we simulate the caloric curves of protonated water clusters (HO)H (n = 20-23).

Tracheal extubation with suction vs. positive pressure during emergence from general anaesthesia in adults: A randomised controlled trial.

Background: After general anaesthesia (GA) in adults, the optimal tracheal extubation technique (positive pressure or suctioning) remains debated. The primary endpoint of this study was to assess the effects of these techniques on onset time of desaturation (SpO<92%).

Methods: Sixty-nine patients with a body mass index<30 scheduled for elective orthopaedic surgery were allocated to positive pressure (PP) or suctioning (SUC) group.

A gas aggregation source for the production of heterogeneous molecular clusters.

We present the design of a versatile gas aggregation source that allows producing molecular beams of charged clusters containing a controlled amount of chosen impurities. Several examples of clusters production using this source characterized by time of flight mass spectrometry are presented here. We demonstrate the source ability to produce homogeneous clusters, such as pure protonated water and alcohol clusters, as well as inhomogeneous ones such as water clusters containing a few units of uracil, glycine, sulfuric acid, or pyrene.

Opioid-sparing effect of nefopam in combination with paracetamol after major abdominal surgery: a randomized double-blind study.

Background: Because nefopam's morphine-sparing is debated when combined with paracetamol, this study aimed to assess pain relief by IV nefopam in combination with paracetamol after major abdominal surgery.

Methods: This was a prospective, double-blinded randomized controlled study including patients (ASA I-III, >18 years) scheduled for elective colectomy surgery by laparotomy. Patients were randomized into the nefopam group (N.

Sore throat following three adult supraglottic airway devices: A randomised controlled trial.

Background: Sore throat is a common complaint after surgery. It affects patient satisfaction and can affect activity after discharge. The supraglottic airway device (SAD) offers an alternative to traditional tracheal intubation with potential benefit in preventing sore throat.

Attachment of Water and Alcohol Molecules onto Water and Alcohol Clusters.

Absolute attachment cross sections of single molecules M (M = water, ethanol, or methanol) onto positively charged mass-selected clusters XnH(+) (X = water, ethanol, or methanol) were measured for cluster sizes ranging from tens to hundreds of molecules and center-of-mass collision energies varying from 0.1 to ∼1 eV. The attachment cross sections, which converge as expected toward geometrical cross sections at large cluster sizes, are systematically and noticeably lower than geometrical cross sections at small sizes.

Experimental nanocalorimetry of protonated and deprotonated water clusters.

An experimental nanocalorimetric study of mass selected protonated (H2O)nH(+) and deprotonated (H2O)n-1OH(-) water clusters is reported in the size range n = 20-118. Water cluster's heat capacities exhibit a change of slope at size dependent temperatures varying from 90 to 140 K, which is ascribed to phase or structural transition. For both anionic and cationic species, these transition temperatures strongly vary at small sizes, with higher amplitude for protonated than for deprotonated clusters, and change more smoothly above roughly n ≈ 35.

Stroke volume optimization after anaesthetic induction: An open randomized controlled trial comparing 0.9% NaCl versus 6% hydroxyethyl starch 130/0.4.

Objective: Postinduction hypotension during general anaesthesia could be corrected by a rapid cardiac preload optimization by fluid infusion. The type of fluid to be used in this context remains debated. The aim of our study was to compare the amount of fluid challenges required to optimize stroke volume after induction of anaesthesia with colloid (HES) or crystalloid (0.

Heat capacities of mass selected deprotonated water clusters.

Heat capacities of mass selected deprotonated water clusters (H(2)O)(n-1)OH(-) have been measured in the size range n = 48-118, as a function of temperature. We have found that they undergo a melting-like transition in the range 110-130 K. The transition temperature is size dependent with a strong correlation with the dissociation energy around the shell closure at n = 55.

Attachment cross-sections of protonated and deprotonated water clusters.

Attachment cross-sections of water molecules onto size selected protonated (H(2)O)(n)H(+) and deprotonated (H(2)O)(n - 1)OH(-) water clusters have been measured in the size range n = 30-140 for 10 eV kinetic energy of the clusters in the laboratory frame. Within our experimental accuracy, the attachment cross-sections are found to have the same magnitude and size dependence for both species. It is shown that electrostatic interactions are likely to play a role even for the largest sizes investigated.

Fragmentation cross sections of protonated water clusters.

We have measured fragmentation cross sections of protonated water cluster cations (H(2)O)(n=30-50)H(+) by collision with water molecules. The clusters have well-defined sizes and internal energies. The collision energy has been varied from 0.

Poor prognostic value of the modified Mallampati score: a meta-analysis involving 177 088 patients.

The modified Mallampati score is used to predict difficult tracheal intubation. We have conducted a meta-analysis of published studies to evaluate the Mallampati score as a prognostic test. A total of 55 studies involving 177 088 patients were included after comprehensive electronic and manual searches.

Two-step melting of Na(41)(+).

The heat capacity of the mass selected Na(41) (+) cluster has been measured using a differential nanocalorimetry method. A two-peak structure appears in the heat capacity curve of Na(41) (+), whereas Schmidt and co-workers [M. Schmidt, J.

Attachment cross sections of protonated water clusters.

The attachment of water molecules onto size selected protonated water clusters has been experimentally investigated. Absolute attachment cross sections are measured as a function of cluster size, collision energy, and initial cluster temperature. Although thermal evaporation is ruled out in our experiment, attachment cross sections become significantly smaller than hard sphere cross sections as the collision energy increases.

[Triple nerve block for ambulatory knee arthroscopy].

Background: The purpose of this study was to evaluate intra- and postoperative conditions of the triple nerve block technique (femoral, obturator, sciatic block) for outpatient knee arthroscopic procedures.

Methods: After written informed consent, ASA I-III patients received a combined triple nerve block with 30-40 ml lidocaine or mepivacaine (1,5%). Blocks were performed using a nerve stimulation technique.