Experimental Approaches for the Synthesis of Low-Valent Metal-Organic Frameworks from Multitopic Phosphine Linkers.

Metal-organic frameworks (MOFs) are the subject of intense research focus due to their potential applications in gas storage and separation, biomedicine, energy, and catalysis. Recently, low-valent MOFs (LVMOFs) have been explored for their potential use as heterogeneous catalysts, and multitopic phosphine linkers have been shown to be a useful building block for the formation of LVMOFs. However, the synthesis of LVMOFs using phosphine linkers requires conditions that are distinct from those in the majority of the MOF synthetic literature, including the exclusion of air and water and the use of unconventional modulators and solvents, making it somewhat more challenging to access these materials. This work serves as a general tutorial for the synthesis of LVMOFs with phosphine linkers, including information on the following: 1) the judicious choice of the metal precursor, modulator, and solvent; 2) the experimental procedures, air-free techniques, and required equipment; 3) the proper storage and handling of the resultant LVMOFs; and 4) useful characterization methods for these materials. The intention of this report is to lower the barrier to this new subfield of MOF research and facilitate advancements toward novel catalytic materials.

A Coordination Polymer of Vaska's Complex as a Heterogeneous Catalyst for the Reductive Formation of Enamines from Amides.

Low-valent metal-organic frameworks (LVMOFs) and related materials have gained interest due to their potential applications in heterogeneous catalysis. However, of the few LVMOFs that have been reported, none have shown catalytic activity. Herein, a low-valent metal-organic material constructed from phosphine linkers and IrI nodes is reported. This material is effectively a crystalline, insoluble analogue of Vaska's complex. As such, the material reversibly binds O2 and catalyzes the reductive formation of enamines from amides.

Sinusitis complicated by intracranial abscess in 3 patients with coronavirus disease 2019: illustrative cases.

BACKGROUND: The novel coronavirus disease 2019 (COVID-19) can be associated with various neurological manifestations, including cerebrovascular disease, seizures, peripheral nerve disease, and encephalitis. Intracranial abscess related to COVID-19 is rare but illustrates a serious complication in the studied cases. OBSERVATIONS: The authors report 3 cases of patients presenting with COVID-19 complicated by sinusitis with associated intracranial abscesses. Each patient underwent craniotomy with washout and sinus debridement during their hospital stay. All 3 patients improved to their baseline following treatment. Similar outcomes have been observed in other cases of intracranial abscess associated with COVID-19 infections. LESSONS: Patients achieved significant improvement following evacuation of the abscess and intravenous antibiotics. Further investigation is needed to determine treatment in relation to COVID-19, and the authors recommend following the standard treatment of intracranial abscess at this time.

Vanadium pyridonates: dimerization, redox behaviour, and metal-ligand cooperativity.

The synthesis, structure, and reactivity of vanadium pyridonate complexes are described. Vanadium(III) pyridonate complexes were accessed through protonolysis and reduction of a tetrakis(amido)vanadium(IV) starting material. Bis(pyridonate) vanadium(IV) precursors could be isolated depending on the amount of proteoligand added. The targeted vanadium(III) species tend to form dimers, but monomeric complexes can be achieved in the presence of neutral donors such as amines or pyridine derivatives or through the use of sterically demanding proligands. The reduction process is proposed to involve dimeric intermediates and be mediated by the amine released from protonolysis, thereby forming the corresponding imine as a byproduct. Isolated amine complexes of vanadium(III) are presented. In contrast, bis(amidate)vanadium(IV) complexes were not found to undergo a similar reduction. This work informs on design principles for the synthesis and application of new vanadium pyridonate catalysts for transformations involving dimerization and PCET for changes in oxidation state.

Misinterpretations of Null Hypothesis Significance Testing Results Near the P-Value Threshold in the Neurosurgical Literature.

BACKGROUND: Although statistical errors have been shown to be prevalent in the medical literature, there has been a paucity of studies focusing on the prevalence of statistical errors in neurosurgery. We examined the contemporary neurosurgical literature for a common statistical mistake, namely, misinterpretations of null hypothesis significance testing results near the P-value threshold by conveying the idea of a trend. METHODS: PubMed/Medline was used to identify all articles published in 6 major neurosurgical journals between 2000 and 2020. The abstracts of these articles were extracted and scrutinized to determine when the word "trend" was used to express near statistical significance. RESULTS: This study included a total of 45,244 articles. Of those, 461 (1.02% [95% confidence interval, 0.86%-1.18%]) employed the word "trend" to indicate near statistical significance, for a total of 3.8 (95% confidence interval, 2.93-4.75) errors per issue per year. The error under study occurred more frequently in Journal of Neurosurgery: Spine and less frequently in Acta Neurochirurgica (P = 0.007). On an annual basis, there was no linear correlation between the total number of articles published per journal and the number of such errors in that journal (r = 0.34, P = 0.01). CONCLUSIONS: Misinterpretations of null hypothesis significance testing results near the P-value threshold are present in at least 1% of the neurosurgical literature. While we believe that most statistical errors in medicine in general and neurosurgery in particular may be unintentional in nature, additional measures should be put in place to prevent the subsequent adoption of such undesirable methodological practices among future researchers.

Surgical Site Infection After Autologous Cranioplasty for Decompressive Craniectomy in Traumatic Brain Injury: A Retrospective Review of Two Level 1 Trauma Centers.

OBJECT: Surgical site infection (SSI) after cranioplasty can result in unnecessary morbidity. This analysis was designed to determine the risk factors of SSI after cranioplasty in patients who received a decompressive craniectomy with the autologous bone for traumatic brain injury (TBI). METHODS: A retrospective review was performed at two level 1 academic trauma centers for adult patients who underwent autologous cranioplasty after prior decompressive craniectomy for TBI. Demographic and procedural variables were collected and analyzed for associations with an increased incidence of surgical site infection with two-sample independent t tests and Mann Whitney U tests, and with a Bonferroni correction applied in cases of multiple comparisons. Statistical significance was reported with a P value of < 0.05. RESULTS: A total of 71 patients were identified. The mean interval from craniectomy to cranioplasty was 99 days (7-283), and 3 patients developed SSIs after cranioplasty (4.2%). Postoperative drain placement (P > 0.08) and administration of intrawound vancomycin powder (P = 0.99) were not predictive of infection risk. However, a trend was observed suggesting that administration of prophylactic preoperative IV vancomycin is associated with a reduced infection rate. CONCLUSIONS: The SSI rate after autologous cranioplasty in TBI patients is lower than previously reported for heterogeneous groups and indications, and the infection risk is comparable to other elective neurosurgical procedures. As such, the authors recommend attempting to preserve native skull and perform autologous cranioplasty in this population whenever possible.

Intracranial metastasis from a malignant peripheral nerve sheath tumor in a patient with neurofibromatosis type 1: A case study and literature review.

INTRODUCTION: Malignant Peripheral Nerve Sheath Tumors (MPNSTs) are a rare type of soft tissue sarcoma. While these tumors often metastasize, intracranial metastases of MPNSTs have only been rarely noted. METHODS: Using Pubmed, Google Scholar, and Science Direct we conducted a systematic review of the literature to identify all reported cases of MPNSTs with metastases to the brain since the inception of these databases through January 2020. Data were extracted and data analysis was completed using python statistical packages. RESULTS: Only 26 cases (including present study) of MPNSTs resulting in intracranial metastases have been reported in the literature. Eight of these 26 cases occurred in patients who were previously diagnosed with Neurofibromatosis Type 1 (NF1). Additionally, one patient had been previously diagnosed with Neurofibromatosis Type 2 (NF2). The average reported time from diagnosis of a MPNST to the time of diagnosis with intracranial metastasis was 36 months, with a median time of 14 months. The average reported survival time for patients after being diagnosed with intracranial metastasis was 5.9 months. The cases that utilized a combination of therapeutic intervention including surgical resection, radiotherapy and chemotherapy saw the greatest improvement of survival times. CONCLUSION: MPNSTs with brain metastases are extremely rare and have a poor prognosis with a 6 months median survival after metastasis. While combination therapy is indicated, further studies on treatment are needed to determine survival benefits. Early and effective initial diagnosis of MPNST before brain metastases occurs is likely to give the best chance of increased overall survival.

Zirconium-Catalyzed Hydroaminoalkylation of Alkynes for the Synthesis of Allylic Amines.

A zirconium-catalyzed hydroaminoalkylation of alkynes to access α,ß,γ-substituted allylic amines in an atom-economic fashion is reported. The reaction is compatible with N-(trimethylsilyl)benzylamine and a variety of N-benzylaniline substrates, with the latter giving the allylic amine as the sole organic product. Various internal alkynes with electron-withdrawing and electron-donating substituents were tolerated. Model intermediates of the reaction were synthesized and structurally characterized. Stoichiometric studies on key intermediates revealed that the open coordination sphere at zirconium, imparted by the tethered bis(ureate) ligand, is crucial for the coordination of neutral donors. These complexes may serve as models for the inner-sphere protonolysis reactions required for catalytic turnover.

The Effect of Teaching Family Medicine Clerkship Students on Preceptor Productivity.

INTRODUCTION: High-quality, experiential learning in outpatient settings is indispensable for medical student education; however these settings are difficult to recruit and retain. The majority of primary care physicians are employed by organizations and are under pressure to increase their relative value unit (RVU) production. Although the common perception that teaching medical students decreases productivity is unproven, it is likely a barrier for primary care physicians pursuing clinical teaching. We sought to investigate whether medical student teaching affects clinical productivity. METHODS: We recruited 15 family medicine (FM) clerkship sites to participate in our study via email and at an in-person meeting. For each preceptor, we collected billing data in the form of current procedural terminology (CPT) codes for all patient encounters and the number of patients seen per half-day for when the preceptor had a student and when they did not. We converted CPT codes to RVU data. We compared differences in productivity for each individual preceptor, and we used a paired t test to examine collective data with and without a student. RESULTS: Ten preceptors at six FM clerkship sites provided reliable data. The average RVU per half-day without a student was 10.84, and it was slightly higher at 11.25 when a student was present (P=.74). The average number of patients seen per half-day without a student was 8.32 and it was slightly lower at 7.87 when a student was present (P=.58). CONCLUSION: This study shows promising data that teaching students in the outpatient setting does not decrease preceptor productivity. This pilot study can lead to a larger-scale exploration of family medicine preceptor productivity in different settings and institutions.

Vanadium Pyridonate Catalysts: Isolation of Intermediates in the Reductive Coupling of Alcohols.

The reductive coupling of alcohols using vanadium pyridonate catalysts is reported. This attractive approach for C(sp3)-C(sp3) bond formation uses an oxophilic, earth-abundant metal for a catalytic deoxygenation reaction. Several pyridonate complexes of vanadium were synthesized, giving insight into the coordination chemistry of this understudied class of compounds. Isolated intermediates provide experimental mechanistic evidence that complements reported computational mechanistic proposals for the reductive coupling of alcohols. In contrast to previous mononuclear vanadium(V)/vanadium(III)/vanadium(IV) cycles, this pyridonate catalyst system is proposed to proceed by a vanadium(III)/vanadium(IV) cycle involving bimetallic intermediates.

Adverse outcomes associated with inappropriate drug use in nursing homes.

BACKGROUND: Little empirical evidence exists regarding the influence and outcomes of inappropriate medication use among elderly nursing home residents. OBJECTIVE: To identify the prevalence of inappropriate medication use among elderly patients in Georgia nursing homes using the Beers criteria and identify the relationship between inappropriate drug use and the likelihood of an adverse health outcome. METHODS: A cohort design was used to review 1117 patient medical records in 15 Georgia nursing homes with a high risk of polypharmacy. Prevalence of inappropriate medication use among elderly patients, as defined by the Beers criteria, was estimated. The adverse health outcomes of hospitalizations, emergency department visits, or deaths were identified from Medicaid claims data. RESULTS: A total of 519 (46.5%) patients received at least one inappropriate medication and 143 (12.8%) patients experienced at least one adverse health outcome. Logistic regression revealed that the total number of medications taken (OR 1.139, 95% CI 1.105 to 1.173) significantly increased the likelihood of receiving an inappropriate drug, while having a diagnosis of "dementia" (OR 0.748, 95% CI 0.565 to 0.991) decreased the likelihood. Inappropriate medication use increased the likelihood of experiencing at least one adverse health outcome more than twofold (OR 2.34, 95% CI 1.61 to 3.40). Propoxyphene use alone was significantly associated with the occurrence of an adverse health outcome (OR 2.39, 95% CI 1.54 to 3.71). CONCLUSIONS: Inappropriate drug use was common in our study cohort. Inappropriate use of medication in the elderly, particularly propoxyphene, is associated with a higher risk of adverse health outcomes.