A Thermally Stable SO-Releasing Mechanophore: Facile Activation, Single-Event Spectroscopy, and Molecular Dynamic Simulations.

Polymers that release small molecules in response to mechanical force are promising candidates as next-generation on-demand delivery systems. Despite advancements in the development of mechanophores for releasing diverse payloads through careful molecular design, the availability of scaffolds capable of discharging biomedically significant cargos in substantial quantities remains scarce. In this report, we detail a nonscissile mechanophore built from an 8-thiabicyclo[3.

Selective Ring-Opening Allene Metathesis: Polymerization or Ruthenium Vinylidene Formation.

Selective ring-opening allene metathesis polymerization (ROAlMP) and ruthenium vinylidene formation from 1,2-cyclononadiene () by simple catalyst selection are discussed. Grubbs second-generation catalyst (G2) favors the formation of an alkylidene leading to the ROAlMP of (). Grubbs first-generation catalyst (G1) favors vinylidene formation and prevents the homopolymerization of () even at elevated temperatures.

Mechanically Triggered Carbon Monoxide Release with Turn-On Aggregation-Induced Emission.

Polymers that release functional small molecules under mechanical stress potentially serve as next-generation materials for catalysis, sensing, and mechanochemical dynamic therapy. To further expand the function of mechanoresponsive materials, the discovery of chemistries capable of small molecule release are highly desirable. In this report, we detail a nonscissile bifunctional mechanophore (i.

Depolymerization of Bottlebrush Polypentenamers and Their Macromolecular Metamorphosis.

The depolymerization of bottlebrush (BB) polymers with varying lengths of polycyclopentene (PCP) backbone and polystyrene (PS) grafts is investigated. In all cases, ring closing metathesis (RCM) depolymerization of the PCP BB backbone appears to occur through an end-to-end depolymerization mechanism as evidenced by size exclusion chromatography. Investigation on the RCM depolymerization of linear PCP reveals a more random chain degradation process.

Polypentenamer Renaissance: Challenges and Opportunities.

This Viewpoint highlights the viability and increasing variety of functionalized polypentenamers as unique and valuable materials created through enthalpy-driven ring-opening metathesis polymerization (ROMP) of low ring strain cyclopentene monomers. The terms "low ring strain" and "enthalpy-driven" are typically conflicting ideologies for successful ROMP; however, these monomers possess a heightened sensitivity to reaction conditions, which may be leveraged in a number of ways to provide performance elastomers with good yield and precise functional topologies. Over the last several years, a rekindled interest in these systems has led to a renaissance of research aimed at improving their synthesis and exploring their potential.

Well-Defined and Precision-Grafted Bottlebrush Polypentenamers from Variable Temperature ROMP and ATRP.

Polypentenamer macroinitiators are synthesized through variable temperature ring opening metathesis polymerization of 3-cyclopentenyl α-bromoisobutyrate, which has sufficient ring strain (Δ = -22.6 kJ mol) to produce targeted molar mass (<5% from theoretical), low dispersity (1.17 ≤ ≤ 1.

Precision Polyelectrolytes with Phenylsulfonic Acid Branches at Every Five Carbons.

A precision polyethylene containing phenyl branches at every fifth carbon (p5Ph) is nearly quantitatively functionalized (≈95%) with sulfonic acid groups on the para-position of each phenyl branch (p5PhS-H). Unlike polystyrene sulfonate (PSS), p5PhS-H has a glass transition temperature (T = 109 °C) well below its thermal decomposition temperature (T ≈ 200 °C), making this new material capable of thermal processing into molds and films at temperatures between these thermal limits. Neutralization of the sulfonic acid groups with varying counter cations (Li , Na , Cs ) produces a new class of precision polyelectrolytes.

A Precision Ethylene-Styrene Copolymer with High Styrene Content from Ring-Opening Metathesis Polymerization of 4-Phenylcyclopentene.

Ring-opening metathesis polymerization of 4-phenylcyclopentene is investigated for the first time under various conditions. Thermodynamic analysis reveals a polymerization enthalpy and entropy sufficient for high molar mass and conversions at lower temperatures. In one example, neat polymerization using Hoveyda-Grubbs second generation catalyst at -15 °C yields 81% conversion to poly(4-phenylcyclopentene) (P4PCP) with a number average molar mass of 151 kg mol(-1) and dispersity of 1.

The relationship between patients' perception of the effects of neurofibromatosis type 2 and the domains of the Short Form-36.

Objectives: To investigate the relationship between those issues concerning quality of life in patients with neurofibromatosis type 2 (NF2) as identified by the closed set NF2 questionnaire and the eight norm-based measures and the physical component summary (PCS) and mental component summary (MCS) scores of the Short Form-36 (SF-36) Questionnaire.

Design: Postal questionnaire study.

Setting: Questionnaires sent to subjects' home addresses.

Use of a closed set questionnaire to measure primary and secondary effects of neurofibromatosis type 2.

Objectives: To identify the greatest difficulties reported by people affected by neurofibromatosis type 2, and to determine the relationship between the primary and secondary effects of the disease.

Design: Postal questionnaire study.

Setting: Questionnaire sent to subjects' home addresses.

Radiocephalic and brachiocephalic arteriovenous fistula outcomes in the elderly.

Background: A recent meta-analysis has suggested that patients aged >65 have worse outcomes with radiocephalic arteriovenous fistulas (RCAVFs) compared with brachiocephalic arteriovenous fistulas (BCAVFs). We hypothesized that outcomes in patients aged > or = 80--a rapidly expanding cohort within this elderly group--might be skewing the results, and that age >65 may not be a contraindication to RCAVF formation. This study examined the effect of age group (<65, 65 to 79, >or =80) on functional outcomes (use; primary and secondary functional patency) in RCVAFs and BCAVFs.

A comparison between transposed brachiobasilic arteriovenous fistulas and prosthetic brachioaxillary access grafts for vascular access for hemodialysis.

Objective: Patients requiring access for hemodialysis in whom radiocephalic or brachiocephalic arteriovenous fistulas cannot be formed or have failed present a significant clinical challenge. We compare outcomes in patients undergoing transposed brachiobasilic arteriovenous fistulas (BBAVF) with expanded polytetrafluoroethylene brachioaxillary access grafts in a single European center.

Methods: We identified all patients undergoing a first upper limb tertiary-access procedure-that is, either BBAVF or brachioaxillary access graft for hemodialysis-between January 1, 2000, and December 31, 2005.

Comparison of different methods of risk stratification in urgent and emergency surgery.

Background: The aim was to compare a number of risk scoring systems prospectively in a cohort of patients who underwent non-elective surgery.

Methods: This was a cohort study of 2349 consecutive patients who had urgent or emergency surgery in a district general hospital in the UK. All patients were scored prospectively using the Revised Goldman Cardiac Risk Index (RGCRI), Portsmouth modification of the Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (P-POSSUM), Surgical Risk Score (SRS) and Biochemistry and Haematology Outcome Models (BHOM).

Lessons learned from a randomised controlled study of perioperative beta blockade in high risk patients undergoing emergency surgery.

Background: Perioperative beta blockade has been shown to reduce mortality after major elective surgery. The aim of this study was to determine whether it could reduce the rate of death and morbidity from cardiac complications in high risk patients undergoing emergency surgery.

Methods: Over a one-year interval all patients undergoing major non-elective orthopaedic or general surgery were screened to identify those at high risk of cardiac complications.

Identifying high-risk patients undergoing urgent and emergency surgery.

Introduction: The aim was to identify high-risk patients undergoing non-elective orthopaedic and general surgery.

Patients And Methods: This was a retrospective cohort study of all non-elective general and orthopaedic surgical procedures performed in a 1-year interval in a district general hospital. A total of 1869 patients underwent urgent or emergency surgery in the calendar year 2000.

School hearing screening programme in the UK: practice and performance.

Background: Paediatric audiology services and screening programmes are currently under review.

Aims And Methods: To investigate current practice and performance of the school hearing screening programme (SHSP) by means of a questionnaire.

Results: SHSP was found to detect previously unrecognised hearing loss at low cost.

Comparison of POSSUM scoring and the Hardman Index in selection of patients for repair of ruptured abdominal aortic aneurysm.

Background: The aim was to assess to what extent the POSSUM (Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity) and Hardman scoring systems were predictive of outcome after surgery for ruptured abdominal aortic aneurysm (RAAA).

Methods: From January 1990 to December 2001, 232 patients presented with RAAA. Forty-one were treated conservatively and all died; the remainder had emergency surgery.

The Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM).

Background And Methods: The development of the Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) is described and its methods of analysis and value in a modern surgical practice are reviewed. A computerized search of all published data in Medline, the Cochrane Library and Embase was made for the last 12 years. Relevant articles were then searched manually for further papers on risk analysis, case-mix comparison and POSSUM methodology.

Molecular genetic analysis of the NF2 gene in young patients with unilateral vestibular schwannomas.

Neurofibromatosis type 2 (NF2) must be suspected in patients presenting with a unilateral vestibular schwannoma at a young age who are therefore at theoretical risk of developing bilateral disease. We identified 45 patients aged 30 years or less at the onset of symptoms of a unilateral vestibular schwannoma. Molecular genetic analysis of the NF2 gene was completed on peripheral blood samples in all 45 and on 28 tumour samples.

Short-term results of femoropopliteal subintimal angioplasty.

Background: Subintimal angioplasty may be more successful than conventional (intraluminal) angioplasty for treatment of long femoropopliteal occlusions. This study assessed the clinical and haemodynamic outcome of subintimal angioplasty.

Methods: All patients with femoropopliteal occlusions treated by subintimal angioplasty over a 3-year period at two centres were reviewed.

Probability of bilateral disease in people presenting with a unilateral vestibular schwannoma.

Background: Some 4%-5% of those who develop vestibular schwannomas have neurofibromatosis type 2 (NF2). Although about 10% of these patients present initially with a unilateral vestibular schwannoma, the risk for a patient with a truly sporadic vestibular schwannoma developing contralateral disease is unknown.

Methods: A United Kingdom survey of 296 patients with NF2 was reviewed for laterality of vestibular schwannoma at presentation and the presence of other NF2 related features.

Differential diagnosis of type 2 neurofibromatosis: molecular discrimination of NF2 and sporadic vestibular schwannomas.

Patients who present with unilateral vestibular schwannomas either at a young age or with additional features of type 2 neurofibromatosis (NF2) are at risk of developing bilateral disease and transmitting a risk of neurogenic tumours to their offspring. We have identified 15 patients from a series of 537 with unilateral vestibular schwannomas who also had one or more of the following: other tumours (10/15), features of NF2 (3/15), or a family history of neurogenic tumours (5/15). No germline NF2 mutations were detected and in 7/9 cases where tumour material was available for analysis a germline mutation in the NF2 gene has been excluded.