CRITICAL NOREPINEPHRINE DOSE TO PREDICT EARLY MORTALITY DURING CIRCULATORY SHOCK IN INTENSIVE CARE: A RETROSPECTIVE STUDY IN 3423 ICU PATIENTS OVER 4-YEAR PERIOD.

Introduction: The maximal norepinephrine (NE) dose >1 μg/kg/min during circulatory shock apparently is associated with higher mortality, but this threshold needs confirmation. This study aimed at investigating whether NE infusion at a dose >1 μg/kg/min could predict early intensive care unit (ICU) mortality (first 5 days). The secondary objective was to assess the day-by-day relationship between NE dose during the first 4 days of ICU stay and subsequent mortality.

Highly Active Immobilized Catalyst for Ethylene Polymerization: Neutral Single Site Y(III) Complex Bearing Bulky Silylallyl Ligand.

Exploring the surface organometallic chemistry on silica of highly electrophilic yttrium complexes is a relatively uncommon endeavor, particularly when focusing on tris-alkyl complexes characterized by Y-C σ-alkyl bonds. A drawback with this class of complexes once grafted on silica, is the frequent occurrence of alkyl transfer by ring opening of siloxane groups, resulting in a mixture of species. Herein, we employed a more stable homoleptic yttrium allyl complex bearing bulky η-1,3-bis(trimethylsilyl)allyl ligand to limit this transfer reaction.

Rare-Earth Metallocenes for Polymerization of Olefins and Conjugated Dienes: From Fundamental Studies to Olefin Block Copolymers.

The various steps in the mechanism of olefin polymerizations mediated by neutral rare-earth metallocene complexes are discussed. The complexes are either trivalent hydride and alkyl rare-earth compounds or divalent metallocenes that are activated by the monomer via an oxidation step. The stereospecific polymerizations of conjugated dienes based on the association of a cationic metallocene complex and an alkylaluminum and the polymerization mechanism based on monomer insertion into an aluminum-carbon bond are also discussed.

Nitriles as Functionalization and Coupling Agents for Polyolefins Obtained by Coordinative Chain Transfer Polymerization.

Coordinative chain transfer polymerization (CCTP) of ethylene and its copolymerization with 1,3-butadiene is conducted in toluene at 80 °C using a combination of {(MeSi(CH))Nd(μ-BH)[(μ-BH)Li(THF)]} (1) metal complex and various organomagnesium compounds used as chain transfer agents including n-butyl-n-octyl-magnesium (BOMAG), n-butyl-mesityl-magnesium (n-BuMgMes), n-butyl-magnesium chloride (n-BuMgCl), n-pentyl-magnesium bromide (n-CHMgBr), pentanediyl-1,5-di(magnesium bromide) (PDMB) and isobutyl-magnesium chloride (i-BuMgCl). Kinetics and performance in terms of control of the (co)polymerization are comparatively discussed particularly considering the presence of ether and the nature of the organomagnesium compounds employed. Taking advantage of the well-known reactivity between nitrile and molecular organomagnesium compounds, the functionalization of the chains is further carried out by deactivation of the polymerization medium with benzonitrile or methoxybenzonitrile compounds leading to ketone ω-functionalized chains.

Multiblock Copolymers Based on Highly Crystalline Polyethylene and Soft Poly(ethylene-co-butadiene) Segments: Towards Polyolefin Thermoplastic Elastomers.

Block copolymers based on polyethylene (PE) and ethylene butadiene rubber (EBR) were obtained by successive controlled coordinative chain transfer polymerization (CCTP) of a mixture of ethylene and butadiene (80/20) and pure ethylene. EBR-b-PE diblock copolymers were synthesized using the {Me Si(C H ) Nd(BH ) Li(THF)} complex in combination with n-butyl,n-octyl magnesium (BOMAG) used as both the alkylating and chain transfer agent (CTA). Triblock and multiblock copolymers featuring highly semi-crystalline PE hard segments and soft EBR segments were further obtained by the development of a bimetallic CTA, the pentanediyl-1,5-di(magnesium bromide) (PDMB).

Deciphering Siloxane Bond Exchanges: From a Molecular Study to Vitrimerization and Recycling of Silicone Elastomers.

The activity of various additives promoting siloxane equilibration reactions is examined and quantified on model compounds. We found in particular that the "superbase" phosphazene derivative P - Bu can promote very fast exchanges (a few seconds at 90 °C) even at low concentration (<0.1 wt %).

How traditional and digital analytics interventions can enhance lung-protective ventilation strategies during general anaesthesia: A two-year quality improvement project analysis.

Purpose: This quality improvement project evaluated interventions implemented to enhance individual adherence to a lung-protective ventilation strategy and its triad: low tidal volume, PEEP ≥ 5, recruitment manoeuvres.

Methods: For two years, nine anaesthesia workstations were connected to an automated cloud-based analytics software tool, which automatically recorded ventilation parameters as soon as a new patient case was opened. Four quality improvement periods were determined over the first year: baseline, intervention, no intervention, intervention + digital.

Telemedicine for Preanesthesia Consultations During the First COVID-19 Lockdown.

In an effort to avoid travel and interpersonal contact, the COVID-19 health crisis was an opportunity to offer preanesthesia teleconsultation (TCs) to patients scheduled for surgery. We studied the technical feasibility and patient experiences of these TCs using a 4-point Likert scale questionnaire. Eighty-six patients out of 139 responded.

Ethylene-Coordinative Chain-Transfer Polymerization-Induced Self-Assembly (CCTPISA).

Block copolymers based on ethylene (E) and butadiene (B) were prepared using the ansa-bis(fluorenyl) complex {Me Si(C H ) Nd(BH ) Li(THF)} in combination with (n-Bu)(n-Oct)Mg (BOMAG) as a chain-transfer agent. The diblock copolymers incorporating a soft poly(ethylene-co-butadiene) segment, called ethylene butadiene rubber (EBR), and a hard polyethylene (PE) one were obtained by simply adjusting the different feeds of monomers during the polymerization. The soluble EBR block was formed first by feeding the catalytic system dissolved in toluene at 70 °C with a mixture of ethylene and butadiene (E/B molar ratio 80 : 20).

Switch from Anionic Polymerization to Coordinative Chain Transfer Polymerization: A Valuable Strategy to Make Olefin Block Copolymers.

Anionic polymerization of butadiene or/and styrene is performed with lithium initiators, functional or not. The polymer chains are subsequently transferred to magnesium. The resulting polymeryl-magnesium compounds were combined with {(Me Si(C H ) )Nd(μ-BH )[(μ-BH )Li(THF)]} metallocene complex to act as macromolecular chain transfer agents (macroCTAs) in coordinative chain transfer polymerization (CCTP) of ethylene (E) or its copolymerization (CCTcoP) with butadiene (B).

Feasibility of remote digital monitoring using wireless Bluetooth monitors, the Smart Angel™ app and an original web platform for patients following outpatient surgery: a prospective observational pilot study.

Background: Remote monitoring of mean arterial blood pressure (MAP), heart rate (HR) or oxygen saturation (SpO) remains a challenge in outpatient surgery. This study evaluates a new digital technology (Smart Angel™) for remotely monitoring hemodynamic data in real time: data transmitted from the patient's home to a central server, using a dedicated web-based software package.

Methods: Adults scheduled for elective outpatient surgery were prospectively enrolled.

Impact of a preoperative pharmaceutical consultation in scheduled orthopedic surgery on admission: a prospective observational study.

Background: Medication errors have a high prevalence in surgery and management of home medication is strongly involved in these errors. In scheduled surgery, the preoperative consultation is a privileged time to inform the patient about the management of her/his home medication before admission. This study assessed the impact of a pre-anesthesia best possible medication history (PA-BPMH) on admission.

Polyethylene Aerogels with Combined Physical and Chemical Crosslinking: Improved Mechanical Resilience and Shape-Memory Properties.

While the introduction of polymers into aerogels strongly enhances their toughness, truly elastic monolithic aerogels which restore their dimensions upon extensive compression are still challenging to synthesize. In this context hydrophobic semi-crystalline polymers with low glass transition temperatures, and combined stiffness and flexibility, have only recently attracted attention. Shown here is that polyethylene aerogels with a low density, and combined chemical crosslinking and high crystallinity, display high moduli and excellent mechanical resilience.

Monofunctional and Telechelic Polyethylenes Carrying Phosphonic Acid End Groups.

Monofunctional or telechelic polyethylenes (PEs) carrying phosphonic acid end groups are obtained from functional PE produced by catalyzed chain growth (CCG) on magnesium. CCG is first used to produce iodo-end-functionalized PE (PE-I) that is efficiently turned into phosphonate end-functionalized PE (PE-P(O)(OEt) ) in the presence of triethylphosphite through the Michaelis-Arbuzov reaction. A simple treatment of the resulting PE-P(O)(OEt) with bromotrimethylsilane leads to the targeted phosphonic acid end-functionalized PE (PE-P(O)(OH) ) for the first time.

Comparison of axillary nerve block duration using mepivacaine in non-insulin diabetic or renal insufficiency patients: a controlled observational matched multicenter trial.

Background: Although studies in diabetic patients demonstrated delayed recovery after long-acting local anesthetic, its effects with short-acting LA remains to be determined. Using mepivacaine, the authors evaluated the duration of axillary nerve blocks in diabetic (DP), renal failure (creatinine clearance <30 mL.min-1) (RP) and healthy patients (HP).

Polyolefins, a Success Story.

This paper reports the principal discoveries which have played a major role in the polyolefin field and have positioned polyolefins as the most produced plastics. The early development of polyolefins covering the production of LDPE (Low density polyethylene) at ICI (Imperial Chemical Industries) and the discovery of Phillips or Ziegler-Natta catalysts are highlighted in the first section. In the second part, the impact of the implementation of molecular catalysts on the research in polyolefins is discussed together with the most recent advances leading to high-performance tailor-made resins.

The design of a bipodal bis(pentafluorophenoxy)aluminate supported on silica as an activator for ethylene polymerization using surface organometallic chemistry.

A new class of well-defined activating supports for olefin polymerization was obtained via the surface organometallic chemistry approach. High activities in slurry polymerization of ethylene along with industrial-grade physical properties of the resulting polyethylene were obtained when these activators were combined with metallocene complexes in the presence of triisobutylaluminium.

Polyboramines for Hydrogen Release: Polymers Containing Lewis Pairs in their Backbone.

The one-step polycondensation of diamines and diboranes triggered by the in situ deprotonation of the diammonium salts and concomitant reduction of bisboronic acids leads to the assembly of polymer chains through multiple Lewis pairing in their backbone. These new polyboramines are dihydrogen reservoirs that can be used for the hydrogenation of imines and carbonyl compounds. They also display a unique dihydrogen thermal release profile that is a direct consequence of the insertion of the amine-borane linkages in the polymeric backbone.

Toward Anisotropic Hybrid Materials: Directional Crystallization of Amphiphilic Polyoxazoline-Based Triblock Terpolymers.

We present the design and synthesis of a linear ABC triblock terpolymer for the bottom-up synthesis of anisotropic organic/inorganic hybrid materials: polyethylene-block-poly(2-(4-(tert-butoxycarbonyl)amino)butyl-2-oxazoline)-block-poly(2-iso-propyl-2-oxazoline) (PE-b-PBocAmOx-b-PiPrOx). The synthesis was realized via the covalent linkage of azide-functionalized polyethylene and alkyne functionalized poly(2-alkyl-2-oxazoline) (POx)-based diblock copolymers exploiting copper-catalyzed azide-alkyne cycloaddition (CuAAC) chemistry. After purification of the resulting triblock terpolymer, the middle block was deprotected, resulting in a primary amine in the side chain.

Divinyl-end-functionalized polyethylenes: ready access to a range of telechelic polyethylenes through thiol-ene reactions.

Telechelic α,ω-iodo-vinyl-polyethylenes (Vin-PE-I) were obtained by catalytic ethylene polymerization in the presence of [(C5 Me5 )2 NdCl2 Li(OEt2 )2 ] in combination with a functionalized chain-transfer agent, namely, di(10-undecenyl)magnesium, followed by treatment of the resulting di(vinylpolyethylenyl)magnesium compounds ((vinyl-PE)2 Mg) with I2 . The iodo-functionalized vinylpolyethylenes (Vin-PE-I) were transformed into unique divinyl-functionalized polyethylenes (Vin-PE-Vin) by simple treatment with tBuOK in toluene at 95 °C. Thiol-ene reactions were then successfully performed on Vin-PE-Vin with functionalized thiols in the presence of AIBN.

Blood wastage reduction: a 10-year observational evaluation in a large teaching institution in France.

Context: Blood transfusion has increased significantly during the last decade and blood wastage reduction is a medical and economic challenge in hospital practice and for institutional quality, particularly in the ICU and operating theatre.

Objective: To evaluate the impact of multiple strategies in one hospital to reduce red blood cell wastage.

Design: Multicentre, prospective, comparative, observational study.

Site count: is a high-pressure quenched-flow reactor suitable for kinetic studies of molecular catalysts in ethylene polymerization?

Understanding the kinetics of olefin polymerization with Ziegler-Natta and related catalysts means identifying the main kinetic parameters such as k(p) and concentration of active sites. The high-pressure quenched-flow technique could be an absolute method for counting active sites and for activation studies of molecular catalysts. A kinetic study of metallocene catalysts and a phenoxy-imine titanium catalyst in the first instants of polymerization is presented in this paper.

Small changes have consequences: lessons from tetrabenzyltitanium and -zirconium surface organometallic chemistry.

Homoleptic benzyl derivatives of titanium and zirconium have been grafted onto silica that was dehydroxylated at 200 and 700 °C, thereby affording bi-grafted and mono-grafted single-site species, respectively, as shown by a combination of experimental techniques (IR, MAS NMR, EXAFS, and elemental analysis) and theoretical calculations. Marked differences between these compounds and their neopentyl analogues are discussed and rationalized by using DFT. These differences were assigned to the selectivity of the grafting process, which, depending on the structure of the molecular precursors, led to different outcomes in terms of the mono- versus bi-grafted species for the same surface concentration of silanol species.