Ring-Opening Metathesis Polymerization of Cyclic Olefins by (Arylimido)vanadium(V)-Alkylidenes: Highly Active, Thermally Robust <i>Cis</i> Specific Polymerization

Ring-opening metathesis polymerization (ROMP) of various cyclic olefins especially using three (arylimido)­vanadium­(V)-alkylidene catalysts, V­(CHSiMe₃)­(N-2,6-Cl₂C₆H₃) (OC₆F₅) (PMe₃)₂ (<b>3</b>), V­(CHSiMe₃) (NR)­[OC­(CF₃)₃]­(PMe₃)₂ [R = Ph (<b>6</b>), 2,6-Cl₂C₆H₃ (<b>7</b>)] have been explored. Complex <b>3</b> exhibited the highest catalytic activity (ex. TOF = 603 000 h^–1, 168 s^–1) for ROMP of norbornene (NBE) among a series of (imido)­vanadium­(V)-alkylidenes, and the <i>cis</i>-specific living ROMPs of NBE proceeded with remarkable activities (TOF = 125 000–157 000 h^–1 at 25 °C) by the fluorinated alkoxo analogues (<b>6</b>, <b>7</b>). The activities by <b>6</b>, <b>7</b> increased at high temperature (50 and 80 °C) and/or upon addition of PMe₃ without decrease in the <i>cis</i> selectivity (98%). The ROMPs in the presence of 1-hexene by <b>3</b>, <b>7</b> proceeded without significant decrease in the activities, and the <i>M</i>_n values could be controlled by degree of chain transfer (cross metathesis). These dichlorophenylimido analogues (<b>3</b>, <b>7</b>) were effective for ROMPs of various norbornene derivatives; ROMP of cyclooctene took place by <b>3</b>, and the activity increased at high temperature (50, 80 °C)

(Arylimido)vanadium(V)–Alkylidene Complexes Containing Fluorinated Aryloxo and Alkoxo Ligands for Fast Living Ring-Opening Metathesis Polymerization (ROMP) and Highly <i>Cis</i>-Specific ROMP

(Arylimido)­vanadium­(V)–alkylidene complexes, V­(CHSiMe₃)­(<i>N</i>-2,6-X₂C₆H₃)­(OC₆F₅)­(PMe₃)₂ [X = Me (<b>2</b>), Cl (<b>4</b>)], exhibited remarkable catalytic activities for ring-opening metathesis polymerization (ROMP) of norbornene, and the ROMP by <b>2</b> proceeded in a living manner, affording ultrahigh molecular weight polymers. <i>Cis</i>-specific ROMP was achieved with the alkoxo analogues, V­(CHSiMe₃)­(<i>N</i>-2,6-X₂C₆H₃)­[OC­(CH₃)­(CF₃)₂]-(PMe₃)₂ [X = Me (<b>5</b>), Cl (<b>6</b>)]. Both the activity and the selectivity increased upon addition of PMe₃, even at 50 °C

Understanding of Constipation Symptoms and the Diagnosis and Management of Constipation in Chinese Physicians - Fig 3

A. 56% of the doctors thought that psychological factors were the most common risk factors of severe constipation; B. There were inconsistent opinions on the treatment of severe constipation.</p

Understanding on symptoms of constipation.

<p>Understanding on symptoms of constipation.</p

Understanding of Constipation Symptoms and the Diagnosis and Management of Constipation in Chinese Physicians - Fig 2

<p>A.59% of the doctors thought that poor defecation habits were the most common risk factors of constipation; B.67% of the doctors thought that forming good bowel habits was the major method to solve the problem of constipation</p

Additional file 1 of Incidence of suicide among adolescent and young adult cancer patients: a population-based study

Additional file 1: Figure 1. Comparison of suicide risk between AYA and older patients by cancer site. The distribution of suicide risk by tumor type was different between AYA patients and older patients. For AYA patients, SMRs of suicide were higher in those with cancers of colorectal, gonad, breast, cervix and uterus, and soft tissue. For older patients, higher SMRs of suicide were observed in those with cancers of lung and bronchus, stomach, oral cavity and pharynx, hodgkin lymphoma, kidney, thyroid, nervous system, non-hodgkin lymphoma, leukemias, and bladder

Efficacy of rifaximin in treating with small intestine bacterial overgrowth: a systematic review and meta-analysis

Over the past decades, rifaximin has been used to treat with small intestinal bacterial overgrowth (SIBO), however, the true efficacy remains unknown. This systematic review and meta-analysis was performed to assess the safety and efficacy of rifaximin in treating with patients with SIBO. Embase, Pubmed, Cochrane Central Register of Controlled Trials, and Web of Science were searched from inception to April, 2021 for published randomized controlled trials (RCTs) and observational studies with or without comparable arms. A total of 21 observational studies and 5 RCTs involving 874 patients were included. The overall eradication rate according to intention-to-treat analysis (ITT) was 59% (95% CI: 50 to 69%; I2 = 90.69%) and to per protocol analysis (PP) 63% (95% CI: 53 to 72%; I2 = 90.32%). For 5 RCTs included comparing the efficacy between rifaximin and placebo or active controls, there was no significant difference (n = 203, risk ratio = 1.14, 95%CI: 0.59 to 2.19, P = 0.15, I2 = 38%). Subgroup analysis and meta-regression indicated a dose-dependent eradication rate of rifaximin for SIBO. Rifaximin is effective and safe in eradicating SIBO, with a dose-dependent efficacy and commonly associated with the improvement of the gastrointestinal symptoms and underlying diseases.</p

Additional file 2 of Incidence of suicide among adolescent and young adult cancer patients: a population-based study

Additional file 2: Table S1. Suicide Rate in Persons With Cancer by Age at Diagnosis

Additional file 4 of Incidence of suicide among adolescent and young adult cancer patients: a population-based study

Additional file 4: Table S3. Suicide Rates by Anatomic Site of Cancer in patients ≥ 40 years

Additional file 3 of Incidence of suicide among adolescent and young adult cancer patients: a population-based study

Additional file 3: Table S2. Incidence of Suicide Among Cancer Patients ≥ 40 years old by Demographic and Tumor Characteristics