Management of tibialis anterior tendon rupture: Recommendations based on the literature review

Tibialis anterior tendon (TAT) rupture is a rare injury that commonly diagnosed late due to mild clinical signs and symptoms. Management of TAT rupture is a topic without a clear consensus in the literature. This current concept review tries to shed some light on the data and treatment. Our extensive literature review identified 81 case reports and case series from 1905 to 2018. Several reported management techniques with their advantages and disadvantages were analyzed and our treatment recommendations are given based on current available evidences.Levels of evidenceIV.     

Increasing the rate of the hydrogen evolution reaction in neutral water with protic buffer electrolytes

Electrocatalytic generation of H₂ is challenging in neutral pH water, where high catalytic currents for the hydrogen evolution reaction (HER) are particularly sensitive to the proton source and solution characteristics. A tris(hydroxymethyl)aminomethane (TRIS) solution at pH 7 with a [2Fe-2S]-metallopolymer electrocatalyst gave catalytic current densities around two orders of magnitude greater than either a more conventional sodium phosphate solution or a potassium chloride (KCl) electrolyte solution. For a planar polycrystalline Pt disk electrode, a TRIS solution at pH 7 increased the catalytic current densities for H₂ generation by 50 mA/cm² at current densities over 100 mA/cm² compared to a sodium phosphate solution. As a special feature of this study, TRIS is acting not only as the primary source of protons and the buffer of the pH, but the protonated TRIS ([TRIS-H]⁺) is also the sole cation of the electrolyte. A species that is simultaneously the proton source, buffer, and sole electrolyte is termed a protic buffer electrolyte (PBE). The structure–activity relationships of the TRIS PBE that increase the HER rate of the metallopolymer and platinum catalysts are discussed. These results suggest that appropriately designed PBEs can improve HER rates of any homogeneous or heterogeneous electrocatalyst system. General guidelines for selecting a PBE to improve the catalytic current density of HER systems are offered.

Molecular hydrogen (H₂), a clean-burning and energy-dense fuel source, has been widely discussed as an attractive way to store intermittent energy from solar and wind through water electrolysis (1, 2). Current commercial electrolyzers can be separated into two categories based on their operating pH. The first are acidic polymer electrolyte membrane electrolyzers that work best with rare and expensive platinum-based electrocatalysts for the hydrogen evolution reaction (HER) (3). The second are strongly alkaline electrolyzers that suffer from caustic basic reaction conditions (4). Neutral pH conditions with inexpensive catalysts composed of Earth-abundant elements are a target for practical solar-to-hydrogen fuel devices due to lower cost and fewer safety concerns (5), but achieving fast rates with mild overpotentials under neutral conditions remains a challenge (6–12). In the pH range from 5 to 9, the electrocatalytic activity of platinum (Pt) itself does not conform to the expected thermodynamic potential shift with pH dependence of −59 mV/pH (13). This is due to the low concentration of the hydronium ion in this pH range and a transition to water as the primary reactant, which has a higher thermodynamic requirement for hydrogen evolution (13). Studies of electrocatalysts using buffers to maintain the pH in this range and ionic salts such as potassium chloride (KCl) to provide ionic strength to ensure high solution conductivity have shown that the buffer can aid the HER activity, presumably by acting as a proton donor (6, 14–18). To extend the scope of water-soluble electrocatalysts, biopolymers and bioinspired metallopolymer catalysts have also been studied (7, 12, 17–26). Bren and coworkers recently reported particularly enlightening studies of the effects of buffer pK_a and structure on the mechanism of the hydrogen evolution reaction for cobalt minienzymes (17, 18).We recently reported a new metallopolymer catalyst system built around a customized [2Fe-2S] catalyst site with a bridging aryldithiolato ligand which exhibits remarkable catalytic activity, air stability, and chemical stability (21). The electrocatalytic mechanism of the [2Fe-2S] catalysts with aryldithiolato ligands is known from previous studies and these catalysts operate at rates of 10⁵ s⁻¹ and faster (27–30). The readily synthesized and water-soluble metallopolymer composed of tertiary amine side-chain groups, PDMAEMA-g-[2Fe-2S] (Fig. 1), approached the current density of Pt operating in neutral water under the same conditions and matched the Faradaic yield (97 ± 3%) (21). Although the detailed structural and mechanistic causality of these profound improvements for these metallopolymer electrocatalysts remain subjects of study, the nature of this molecular system is ideal for studying solution effects on the HER reaction at neutral pH for complexes that are normally insoluble in water. In the course of characterizing these electrocatalysts, solutions containing tris(hydroxymethyl)aminomethane (TRIS) at pH 7 were discovered to be exceptionally advantageous to the catalytic rate. In contrast to the few previous studies of TRIS buffer with electrocatalysts (14, 15, 18), we utilized TRIS at a high concentration. At pH 7, TRIS is sufficiently in the cationic protonated form that additional electrolyte such as KCl is not needed for conductance. This important distinction from conventional studies allows TRIS to simultaneously play the roles of pH buffer, proton source, and sole electrolyte. There is precedence in employing buffers in a manner in which they are the sole electrolyte (7, 31–34). Referring to such species simply as a “buffer” or as an “electrolyte” is inadequate in representing the three functions including proton source. For the purposes of this paper we term a species that serves all three functions a protic buffer electrolyte (PBE). In the following discussion, a TRIS PBE solution is one in which [TRIS-H]⁺Cl⁻ is the sole electrolyte and the cation is a proton source, and a sodium phosphate PBE solution is one in which Na⁺[H₂PO₄]⁻ is the sole electrolyte and the anion is a proton source.Open in a separate windowFig. 1.(A) Depiction of the 2e⁻ electrocatalytic HER with POEGMA-g-[2Fe-2S] and/or PDMAEMA-g-[2Fe-2S] metallopolymers using TRIS or sodium phosphate protic buffer electrolytes at pH 7. (B) Image of POEGMA-g-[2Fe-2S] with MW = 14,216 grown in silico. The [2Fe-2S] active site is in the center of the polymer, blue represents the polymer backbone, and the rest are the oligo(ethylene glycol) side chains. See SI Appendix for the details of modeling and a larger image.One of the key unanswered questions for these new catalyst systems is whether the metallopolymer composition (i.e., amine side-chain groups) or the PBEs are more important to afford this outstanding catalytic activity. Herein we study the effects of PBEs by comparing the HER performances of a standard platinum catalyst and a [2Fe-2S] metallopolymer catalyst in TRIS PBE solutions, sodium phosphate PBE solutions, and a KCl electrolyte solution without a PBE. For this study, nonionic water-soluble metallopolymers were used, which were made using oligo(ethylene glycol) side-chain groups on the polymer to avoid the possibility of contributing effects of the protonated amino groups of PDMAEMA-g-[2Fe-2S] referred to earlier. The metallopolymer catalyst used in this work is designated as POEGMA-g-[2Fe-2S] (Fig. 1). We previously reported that this water-soluble metallopolymer was largely inactive for H₂ electrocatalysis at neutral pH in phosphate buffer (22). The current findings suggest that the use of electrolytes composed of inexpensive cationic organic proton donors can be readily applied to any homogeneous or heterogeneous electrocatalyst system as a facile means to enhance HER activity.     

Utilizing transcranial direct current stimulation to enhance laparoscopic technical skills training: A randomized controlled trial

BackgroundTranscranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that delivers constant, low electrical current resulting in changes to cortical excitability. Prior work suggests it may enhance motor learning giving it the potential to augment surgical technical skill acquisition.ObjectivesThe aim of this study was to test the efficacy of tDCS, coupled with motor skill training, to accelerate laparoscopic skill acquisition in a pre-registered (NCT03083483), double-blind and placebo-controlled study. We hypothesized that relative to sham tDCS, active tDCS would accelerate the development of laparoscopic technical skills, as measured by the Fundamentals of Laparoscopic Surgery (FLS) Peg Transfer task quantitative metrics.MethodsIn this study, sixty subjects (mean age 22.7 years with 42 females) were randomized into sham or active tDCS in either bilateral primary motor cortex (bM1) or supplementary motor area (SMA) electrode configurations. All subjects practiced the FLS Peg Transfer Task during six 20-min training blocks, which were preceded and followed by a single trial pre-test and post-test. The primary outcome was changes in laparoscopic skill performance over time, quantified by group differences in completion time from pre-test to post-test and learning curves developed from a calculated score accounting for errors.ResultsLearning curves calculated over the six 20-min training blocks showed significantly greater improvement in performance for the bM1 group than the sham group (t = 2.07, p = 0.039), with the bM1 group achieving approximately the same amount of improvement in 4 blocks compared to the 6 blocks required of the sham group. The SMA group also showed greater mean improvement than sham, but exhibited more variable learning performance and differences relative to sham were not significant (t = 0.85, p = 0.400). A significant main effect was present for pre-test versus post-test times (F = 133.2, p < 0.001), with lower completion times at post-test, however these did not significantly differ for the training groups.ConclusionLaparoscopic skill training with active bilateral tDCS exhibited significantly greater learning relative to sham. The potential for tDCS to enhance the training of surgical skills, therefore, merits further investigation to determine if these preliminary results may be replicated and extended.     

Cabozantinib for relapsed neuroblastoma: Single institution case series

Relapsed high‐risk neuroblastoma has few effective therapies currently available or in development. Cabozantinib is an Food and Drug Administration approved multitargeted tyrosine kinase inhibitor for select adult malignancies with preclinical data suggesting efficacy against neuroblastoma. A safe and tolerable dose has been identified for children, but its efficacy remains unknown. We describe four children with relapsed metastatic neuroblastoma treated with cabozantinib. All four patients had extended disease control (two complete responsesfor >12 months, 2 stable disease >6 months) with manageable predictable toxicities requiring dose reduction in two patients. We discuss the potential for the use of cabozantinib in neuroblastoma.     

Comprehensive profiling of α-glucosidase inhibitors from the leaves of Rubus suavissimus using an off-line hyphenation of HSCCC,ultrafiltration HPLC-UV-MS and prep-HPLC

The leaves of Rubus suavissimus (also called “Chinese sweet tea”) is used not only as a beverage tea and food additive but also as a folk herbal medicine for the treatment of diabetes mellitus. To systematically investigate its material foundation of efficacy for treating diabetes, herein, a hyphenated strategy by off-line coupling high-speed countercurrent chromatography, ultrafiltration HPLC-UV-MS and prep-HPLC was developed. And thus, α-glucosidase inhibitors from Rubus suavissimus leaves was comprehensively profiled, purified and characterized. As a result, twenty-six compounds were identified as potential α-glucosidase inhibitors and favorably isolated by prep-HPLC. Their structures were identified via UV, MS, and ¹H-NMR. Notably, fourteen compounds, including protocatechuic acid (1), myketin (3), epicatechin (4), vanillic acid (6), apigenin (11), catechin (12), ferulic acid (15), luteolin (16), 3, 3′-di-O-methylellagic acid (17), chlorogenic acid (19), 3, 3′-di-O-methylellagic acid-4′-O-β-D-glucoside (20), cinnamic acid (21), syringate (24) and ethylbrevifolin-carboxylate (25), were reported in leaves of Rubus suavissimus for the first time. In addition, α-glucosidase inhibitory activities of compounds 1–26 were evaluated, and eighteen compounds exhibited stronger α-glucosidase inhibitory activities than acarbose (IC₅₀ value at 214.24 ± 3.48 μg/mL, positive control). The results indicated that the proposed method is a highly efficient strategy for comprehensive profiling and purification of bioactive target compounds, including both major and minor components, from natural products.     

Lomitapide for the treatment of hypertriglyceridemia

Introduction: Severe genetic forms of hypertriglyceridemia carry a risk of life-threatening pancreatitis and lack available effective treatments. Lomitapide is a microsomal triglyceride transfer protein inhibitor currently approved for treatment of homozygous familial hypercholesterolemia that may be useful in the management of severe hypertriglyceridemia.

Areas covered: Published trials of lomitapide that reported plasma triglyceride response were reviewed, as was a case report of a patient with hypertriglyceridemia who was treated for 13 years with lomitapide. ClinicalTrials.gov was also reviewed for any unpublished results and ongoing trials.

Expert opinion: Lomitapide demonstrates effective triglyceride lowering and may be a useful treatment for patients with genetic hypertriglyceridemia and recurrent acute pancreatitis who are refractory to traditional treatment. However, long term hepatic safety may be a concern and direct clinical trial-level data are lacking for this indication.     

基于图书馆知识资本循环系统支持的隐性知识转移机制研究

概述知识资本理论的主要观点；分析图书馆知识资本构成、循环的特点；构建图书馆知识资本循环系统知识转移模型和隐性知识转移机制模型；对图书馆知识资本内部结构和外部结构及其对应的内循环和外循环机制进行分析；揭示了图书馆隐性知识转移机制是系统综合机制。