Stable Anion Exchange Membrane Bearing Quinuclidinium for High-performance Water Electrolysis.

Anion exchange membranes (AEMs) are core components in anion exchange membrane water electrolyzers (AEM-WEs). However, the stability of functional quaternary ammonium cations, especially under high temperatures and harsh alkaline conditions, seriously affects their performance and durability. Herein, we synthesized a 1-methyl-3,3-diphenylquinuclidinium molecular building unit. Density functional theory (DFT) calculations and accelerated aging analysis indicated that the quinine ring structure was exceedingly stable, and the SN2 degradation mechanism dominated. Through acid-catalyzed Friedel-Crafts polymerization, a series of branched poly(aryl-quinuclidinium) (PAQ-x) AEMs with controllable molecular weight and adjustable ion exchange capacity (IEC) were prepared. The stable quinine structure in PAQ-x was verified and retained in the ex situ alkaline stability. Furthermore, the branched polymer structure reduces the swelling rate and water uptake to achieve a tradeoff between dimensional stability and ionic conductivity, significantly improving the membrane's overall performance. Importantly, PAQ-5 was used in non-noble metal-based AEM-WE, achieving a high current density of 8 A cm-2 at 2 V and excellent stability over 2446 h in a gradient constant current test. Based on the excellent alkaline stability of this diaryl-quinuclidinium group, it can be further considered as a multifunctional building unit to create multi-topological polymers for energy conversion devices used in alkaline environments.

Selective Synthesis of Pyrano[3,2-b]indoles or Cyclopenta[b]indoles Tethered with Medium-Sized Rings via Cascade C-C σ-Bond Cleavage and C-H Functionalization.

Highly atom-economical tandem reactions have been developed for the synthesis of pyrano[3,2-b]indoles or cyclopenta[b]indoles tethered with 7-, 8-, or 9-membered rings. These reactions first undergo a carbon-carbon σ-bond cleavage reaction of cyclic ß-ketoesters. Next, in the presence of CuCl2 and Ag2CO3, intramolecular O-H/C-H coupling occurs to give pyrano[3,2-b]indoles. This is the first example for capture of the enoloxyl radical of the intramolecular C-O bond formation reaction, whereas C3 nucleophilic addition afforded cyclopenta[b]indoles using TsOH·H2O.

Straightforward Stereoselective Synthesis of Seven-Membered Oxa-Bridged Rings through In Situ Generated Cycloheptenol Derivatives.

An iodine-mediated stereoselective synthesis of seven-membered oxa-bridged rings via in situ generated cycloheptenols was reported. This process was realized through the combination of C-C σ-bond cleavage and C-O bond-forming reactions in a one-pot fashion from simple and easily accessible raw materials. The formation of carbon radicals initiated by I2 was the key to the reaction.

Atom-Economic Synthesis of Highly Functionalized Bridged Ring Systems Initiated by Ring Expansion of Indene-1,3-dione.

An atom economic procedure for the regioselective synthesis of bridged seven-membered-ring compounds from simple reactants such as ynones and indene-1,3-dione has been developed. This process was realized through the one-pot reactions of ring-expansion of indene-1,3-dione with alkynyl ketones and successive formal [4+2] cycloaddition. The Michael addition reaction is the key for the regioselectivity of the formal [4+2] cycloaddition.

Regioselective Synthesis of Tetrasubstituted Benzenes via Co-Catalyzed Cycloaddition of Alkynyl Ketones and 2-Acetylpyridines.

A Co(II)-catalyzed cycloaddition reaction of alkynyl ketones and 2-acetylpyridines using 2,2'-bipyridine as the ligand has been developed. These reactions have been realized through Co-catalyzed reductive coupling of two molecules of 2-acetylpyridine followed by regioselective insertion of the alkynone. It is the first example of regioselective cyclotrimerization of one molecule of alkyne and two molecules of monoketone to polysubstituted benzene derivatives in good to excellent yields. A mechanism involving the formation of a cobaltacyclopentane via homocoupling of 2-acetylpyridines is proposed, and it is supported by the DFT calculations.

Active bone material containing modified recombinant human bone morphogenetic protein 2 induces bone regeneration in the alveolar process cleft in rabbits.

The clinical application of most materials used to fill severe bone defects is limited owing to the insufficient ability of such materials to induce bone regeneration over a long repair period. The purpose of this study was to establish a model for the alveolar process cleft in rabbits to evaluate the effect of active bone material in bone defect repair. The active bone material used in this study is a new bone repair material composed of a heterogeneous collagen membrane implanted with modified recombinant human bone morphogenetic protein 2. This proposed active bone material can specifically bind to collagen. Twenty-four young Japanese white rabbits (JWRs) were selected and randomly divided into four groups (normal, control, material, and bone morphogenetic protein groups). The alveolar process cleft model was established by removing an equal volume bone at the left maxillary position. Blood samples were collected from the JWRs 3 and 6 months after the surgery to evaluate the biocompatibility of the active bone materials. Subsequently, the skull model was established, and the appearance was observed. Imaging methods (including X-ray examination and micro-computerized tomography scanning), tissue staining, and immunohistochemistry were employed for the evaluation. The bone collagen material and active bone material exhibited high biocompatibility. In addition, the ability of the active bone material to induce bone repair and regeneration was higher than that of the bone collagen material. The active bone material exhibited satisfactory bone regeneration performance in rabbits, indicating its potential as an active material for repairing congenital alveolar process clefts in humans.

First Report of Sea buckthorn Stem Wilt Caused by Fusarium sporotrichioides in Gansu, China.

Sea buckthorn (Hippophae rhamnoides) is an important deciduous shrub for fruit and ecological restoration in arid and semi-arid regions of China. Twelve Chinese and Russian cultivars (cv. Shenqiuhong, eshi01, ... eshi11) were planted about 1.6 acre area in a seedling nursery, located in Qingyang City of Gansu province in northwest China, where high mortality (more than 70%) of sea buckthorn was observed in late July 2019. Symptoms consisted of massive chlorosis, drooping leaves and dried-up stems on 5-year-old trees. Pieces of tree roots and stems with irregular light-brown discoloration in the xylem vessels were selected. Small pieces of discolored tissue were surface disinfested (1 min in 1% sodium hypochlorite, followed by three rinses with sterile distilled water), air-dried, and placed on potato dextrose agar (PDA) medium for 5 days at 25°C in the dark. A fungus was consistently isolated from both diseased roots and stems tissues. Colonies on PDA grew rapidly. Dense mycelia were pinky-white initially, and became carmine red color with age on the undersurface of the plate. Macroconidia were moderately curved, 3 to 5 marked septa, hyaline, thick walled, and measuring 27.8± 3.6 µm × 4.8 ± 0.5 µm (n = 30). Microconidia were abundant, pear-shaped, ellipsoid to fusoid, often with a papilla at the base, and 8.4 ± 2.2 µm ×3.1 ± 0.3 µm (n = 30). Genomic DNA was extracted for amplification and sequencing of the internal transcribed spacer region (ITS1 and ITS4 primers) (White et al. 1990) of the ribosomal DNA (Accession Nos. MN160235 to MN160238) and translation elongation factor-1 alpha (EF1 and EF2 primers, accession Nos. MN429075 to MN429078) (O'Donnell et al. 1998). The sequences revealed 99% similarity to the sequences of the ITS (AY188917), and 100% identity with EF1-α (JF740808) regions of Fusarium sporotrichioides. Based on morphological and molecular characteristics, the fungus was identified as F. sporotrichioides (Leslie and Summerell 2006). Koch's postulates were fulfilled on healthy, potted 1-year-old sea buckthorn seedings using two isolates in a greenhouse at 25 °C, 90% relative humidity, and 12-hour light/dark photoperiod. Ten potted seedings were inoculated on the stems by placing a 5-mm-diameter mycelial plug (5-day-old PDA cultures for each isolate) into the surface of a wound created with a needle, and the inoculation sites were covered with Parafilm to maintain moisture. Ten seedings were inoculated with PDA plugs as controls. Seven to ten days after inoculation, typical symptoms of dark-brown necrotic lesions on chlorotic leaf margins were observed. About 2 weeks after inoculation, the inoculated stems were gradually dry up, accompanied by withering and fallen leaves. Control plants remained asymptomatic. Pathogens were successfully isolated from the inoculated stems again, exhibiting morphological characteristics identical to those of F. sporotrichioides. Previous papers reported F. sporotrichioides as a common pathogen caused lavender wilt (Cosic et al. 2012), foliar spots on forage corn (Moya-Elizondo et al. 2013) and maize ear rot (Wang et al. 2019). To our knowledge, this is the first report of sea buckthorn stem wilt caused by F. sporotrichioides on several Chinese and Russian cultivars in Gansu province of China. In Heilongjiang province, the same disease was reported in 2010 (Song et al. 2010), nearly 30 longitudes away from Gansu province. Therefore, this disease appears to be a serious risk for future sea buckthorn production.

Repair of alveolar cleft bone defects by bone collagen particles combined with human umbilical cord mesenchymal stem cells in rabbit.

BACKGROUND: Alveolar cleft is a type of cleft lip and palate that seriously affects the physical and mental health of patients. In this study, a model of the alveolar cleft phenotype was established in rabbits to evaluate the effect of bone collagen particles combined with human umbilical cord mesenchymal stem cells (HUC-MSCs) on the repair of alveolar cleft bone defects. METHODS: A model of alveolar clefts in rabbits was established by removing the incisors on the left side of the upper jaw bone collagen particles combined with HUC-MSCs that were then implanted in the defect area. Blood biochemical analysis was performed 3 months after surgery. Skull tissues were harvested for gross observation, and micro-focus computerised tomography (micro-CT) analysis. Tissues were harvested for histological and immunohistochemical staining. The experiments were repeated 6 months after surgery. RESULTS: Bone collagen particles and HUC-MSCs showed good biocompatibility. Bone collagen particles combined with HUC-MSCs were markedly better at inducing bone repair and regeneration than bone collagen particles alone. CONCLUSIONS: Combining HUC-MSCs with bone collagen particles provides a simple, rapid and suitable method to fill a bone defect site and treat of alveolar cleft bone defects.

Application of Magnetic Resonance Diffusion Tensor Imaging in Diagnosis of Lumbosacral Nerve Root Compression

OBJECTIVE: The aim of this study was to assess the value of 3.0T magnetic resonance (MR) Diffusion tensor imaging (DTI) in the diagnosis of lumbosacral nerve root compression. METHODS: The radiology reports, and clinical records of 34 patients with nerve root compression caused by lumbar disc herniation or bulging and 21 healthy volunteers who had undergone magnetic resonance imaging (MRI) and DTI scan were retrospectively reviewed. The differences in fractional anisotropy (FA) and apparent diffusion coefficient (ADC) between compressed and non-compressed nerve roots from patients and the normal nerve roots from healthy volunteers were compared. Meanwhile, the nerve root fiber bundles were observed and analyzed. RESULTS: The average FA and ADC values of the compressed nerve roots were 0.254 ± 0.307 and 1.892 ± 0.346 10^-3mm2/s, respectively. The average FA and ADC values of the non-compressed nerve roots were 0.377 ± 0.659 and 1.353 ± 0.344 10^-3mm2/s, respectively. The FA value of compressed nerve roots was significantly lower than that of non-compressed nerve roots (P < 0.01). The ADC value of compressed nerve roots was significantly higher than that of non-compressed nerve roots. There were no significant differences between the left and right nerve roots of normal volunteers in FA and ADC values (P > 0.05). The nerve roots at different levels of L3-S1 had significantly different FA and ADC values (P < 0.01). Incomplete fiber bundles with extrusion deformation, displacement or partial defect were observed in the compressed nerve root fiber bundles. The real diagnosis of the clinical situation of the nerve can provide neuroscientists with an important computer tool to help them infer and understand the possible working mechanism from the experimental data of behavior and electrophysiology. CONCLUSION: The compressed lumbosacral nerve roots can be accurately localized through 3.0T magnetic resonance DTI, which is instructive for accurate clinical diagnosis and preoperative localization.

Combining Bone Collagen Matrix with hUC-MSCs for Application to Alveolar Process Cleft in a Rabbit Model.

BACKGROUND: Most materials used clinically for filling severe bone defects either cannot induce bone re-generation or exhibit low bone conversion, therefore, their therapeutic effects are limited. Human umbilical cord mesenchymal stem cells (hUC-MSCs) exhibit good osteoinduction. However, the mechanism by which combining a heterogeneous bone collagen matrix with hUC-MSCs to repair the bone defects of alveolar process clefts remains unclear. METHODS: A rabbit alveolar process cleft model was established by removing the bone tissue from the left maxillary bone. Forty-eight young Japanese white rabbits (JWRs) were divided into normal, control, material and MSCs groups. An equal volume of a bone collagen matrix alone or combined with hUC-MSCs was implanted in the defect. X-ray, micro-focus computerized tomography (micro-CT), blood analysis, histochemical staining and TUNEL were used to detect the newly formed bone in the defect area at 3 and 6 months after the surgery. RESULTS: The bone formation rate obtained from the skull tissue in MSCs group was significantly higher than that in control group at 3 months (P < 0.01) and 6 months (P < 0.05) after the surgery. The apoptosis rate in the MSCs group was significantly higher at 3 months after the surgery (P < 0.05) and lower at 6 months after the surgery (P < 0.01) than those in the normal group. CONCLUSIONS: Combining bone collagen matrix with hUC-MSCs promoted the new bone regeneration in the rabbit alveolar process cleft model through promoting osteoblasts formations and chondrocyte growth, and inducing type I collagen formation and BMP-2 generation.

Combining Bone Collagen Material with hUC-MSCs for Applicationto Spina Bifida in a Rabbit Model.

Spina bifida is one of the neural tube defects, with a high incidence in human birth defects, which seriously affects the health and quality of life of patients. In the treatment of bone defects, the source of autologous bone is limited and will cause secondary damage to the patient. At the same time, since the bone tissue in animals needs to play a variety of biological functions, its complex structure cannot be replaced by a single material. The combination of mechanical materials and biological materials has become a common choice. Human umbilical cord mesenchymal stem cells (hUC-MSCs) have the advantages of easy access, rapid proliferation, low immunogenicity, and no ethical issues. It is often used in the clinical research of tissue regeneration and repair. Therefore, in this study, we established a spina bifida model using Japanese white rabbits. This model was used to screen the best regenerative repair products for congenital spina bifida, and to evaluate the safety of regenerative repair products. The results showed that the combination of hUC-MSCs with collagen material had better regeneration effect than collagen material alone, and had no negative impact on the health of animals. This study provides a new idea for the clinical treatment of spina bifida, and also helps to speed up the research progress of regenerative repair products.

Brønsted-Acid-Promoted Selective C2-N1 Ring-Expansion Reaction of Indoles toward Cyclopenta[b]quinolines.

A novel Brønsted-acid-promoted selective C2-N1 ring-expansion reaction of indoles has been developed that provides a rapid and efficient protocol for the preparation of fused quinolines. A variety of corresponding quinolines were obtained in high yields. Controlled experiments revealed that C2-spiroindolenines might be intermediates of this C2-N1 ring-expansion reaction. The notable advantages of this process include excellent yields, good functional group tolerance, and operational simplicity.

Selective C-O Bond Forming Reactions at Indole-C2-Position toward Polycyclic Indolone or Indolinone Derivatives Tethered with Medium-Sized Rings.

A methodology involving the chemoselective synthesis of tetracyclic [1,3]oxazino[3,2-a]indol-4-one or tetracyclic [1,3]oxazino[3,2-a]indoline-4-one tethered with a medium-sized ring by cross dehydrogenative coupling (CDC) or nucleophilic addition (NA) reaction has been developed. [1,3]Oxazino[3,2-a]indol-4-one compounds fused with a medium-sized ring were constructed through a CDC reaction in the presence of I2 and K2CO3. Whereas, [1,3]oxazino[3,2-a]indoline-4-ones tethered with a medium-sized ring were obtained with a TfOH system by NA reaction.

Comparison of percutaneous transforaminal endoscopic discectomy and open lumbar discectomy for lumbar disc herniations: A systematic review and meta-analysis.

Purpose: In order to compare the outcomes of percutaneous transforaminal endoscopic discectomy (PTED) and open lumbar discectomy (OLD) for lumbar disc herniation (LDH). Methods: The Pubmed, Cochrane Library, Web of Sience, Embase, Clinicaltrials.gov, CBM, CNKI, VIP, Wangfang databases were searched from inception to April 30, 2022 to collect the published studies about PTED vs. OLD for treatment of LDH. The Revman 5.2 was used for data analysis. The primary outcomes were excellent rates, complication rates and reoperation rates. The secondary outcomes were length of incision, length of operation, length of hospital stay, and the amount of intraoperative blood loss. Results: A total of nine studies were included, of which, eight randomized controlled trials and one retrospective study involving 1,679 patients with LDH (755 patients for PTED, and 924 patients for OLD) were included. According to meta-analysis, there were no significant difference in excellent rates (odds ratio [OR] = 1.47, 95% confidence intervals [CI]: 0.94-2.28, P = 0.09), reoperation rates (OR = 0.96, 95% CI: 0.50-1.84, P = 0.90), length of operation [standardized mean differences (SMD) = -17.97, 95%CI: -54.83-18.89, P = 0.34], and the amount of intraoperative blood loss (SMD = -128.05, 95%CI: -258.67-2.57, P = 0.05), respectively. There were significant differences in complication rates (OR = 0.22, 95% CI: 0.14-0.33, P < 0.001), length of incision (SMD = -2.76, 95%CI: -2.88--2.65, P < 0.001), and length of hospital stay (SMD = -5.19, 95%CI: -5.36--5.01, P < 0.001), respectively. Conclusions: PTED can achieve better outcomes with respect to the complication rates, length of incision, and length of hospital stay compared with OLD.

Active bone material containing modified recombinant human bone morphogenetic protein-2 induces bone regeneration in rabbit spina bifida.

This study focuses on spina bifida, which is a high incidence among the current clinical manifestations of human birth defects. Because in the treatment of bone defects, the source of autologous bone is limited and it is easy to cause secondary injury to the patient. At the same time, since the bone tissue in animals needs to perform a variety of biological functions, its complex structure cannot be replaced by a single material. Therefore, in this study, we used Japanese white rabbits to establish an animal model similar to human congenital spina bifida. The established animal model is used to screen the best regenerative repair products for the treatment of congenital spondylolisthesis defects, and to evaluate the safety of regenerative repair products. The results show that bone morphogenetic protein (BMP)-2 combined with collagen material has a better regeneration effect than collagen material alone, and it did not negatively affect the health of animals. This study is not only suitable for the screening of large-scale biomaterials, accelerating the research progress of regenerative repair products, but also conducive to the research on the mechanism of regeneration and repair of various materials.

Difunctionalization of Alkynones by Base-Mediated Reaction with α,α-Dithioketones.

A novel 1,2-difunctionalization of alkynones via an umpolung strategy for the synthesis of tetrasubstituted olefins has been developed. This procedure is realized by a formal C-C σ-bond cleavage reaction of cyclic α,α-dithioketones and subsequent deprotection. Notable features of this approach include excellent yields, mild reaction conditions, a broad substrate scope, and operational simplicity.

Repair of alveolar cleft bone defects in rabbits by active bone particles containing modified rhBMP-2.

Objective: A model of alveolar cleft phenotype was established in rabbits to evaluate the effect of active bone particles containing modified rhecombinant human BMP-2 on the repair of the alveolar cleft. Methods: 2-month-old Japanese white rabbits were selected and randomly divided into four groups: normal, control, material and BMP groups. Blood biochemical analysis, skull tomography (microfocus computerized tomography), and histological and immunohistochemical staining analysis of paraffin sections were performed 3  and 6 months after operation. Results: Both types of collagen particles showed good biocompatibility and promoted bone regeneration. The effect of active bone particles on bone repair and regeneration was better than that of bone collagen particles. Conclusions: Active bone particles containing modified rhecombinant human BMP-2 can be used for incisors regeneration.

Increased signal intensity of spinal cord on T2W magnetic resonance imaging for cervical spondylotic myelopathy patients: Risk factors and prognosis (a STROBE-compliant article).

To investigate the risk factors for progression of increased signal intensity (ISI) on T2W magnetic resonance imaging (MRI) and its prognostic value in patients with cervical spondylotic myelopathy (CSM).A total of 109 patients with CSM were included in this study. All the patients were treated with anterior cervical discectomy and fusion. MRI was performed for all 109 patients preoperatively and at the final follow-up. Radiological evaluation included ISI, anterior compression (AC) of dural and spinal cord, hyperintensity region (HR) at the involved level. Clinical data including Japanese Orthopedic Association (JOA) score, Neck Disability Index (NDI) score, and Visual Analogue Scale were collected and evaluated. Patients were divided into 2 groups according to ISI grades (Group A: no hyper-intensity; Group B: presence of ISI). Then all patients presented with ISI were divided into 2 subgroups based on the range of HR (Group B1: hyper-intensity diameter accounts for less than half of the spinal cord diameter at the involved level; Group B2, hyper-intensity diameter accounts for more than half of the spinal cord diameter at the involved level). AC, disease duration, age, and gender were analyzed as potential risk factors.Significantly better JOA and NDI scores were observed in Group A preoperatively and at the final follow-up, compared to Group B (P < .05). Disease duration was found significantly longer in patients with ISI (P < .05). Notably better JOA and NDI scores were noticed in Group B1 rather than Group B2 (P < .05). Logistical regression showed that disease duration was the only factor that significantly correlated with the progress of ISI (P < .001).CSM patients with ISI on T2W MR images had poorer surgical outcomes compared to others, while the increased range of HR may deteriorate preoperative neurological function. Moreover, patients with longer disease duration had greater risk of ISI in spinal cord.

Selective Insertion of Alkynes into C-C σ Bonds of Indolin-2-ones: Transition-Metal-Free Ring Expansion Reactions to Seven-Membered-Ring Benzolactams or Chromone Derivatives.

An unprecedented ring expansion reaction of indolin-2-ones with alkynyl ketones under transition-metal-free conditions has been developed. Base-promoted selective cleavage of a C-C σ bond of the amide is the key in this process, which provides a straightforward and efficient way to synthesize seven-membered-ring benzolactams or chromone derivatives. The significant advantages of this method include readily accessible starting materials, wide scope and functional group tolerance, and high atom economy.

Influence of Ethanol on Pitting Corrosion Behavior of Stainless Steel for Bioethanol Fermentation Tanks.

The role of ethanol (C2H5OH) in pitting corrosion behavior of AISI 316L austenitic stainless steel was investigated in aqueous ethanolic solution with chloride. The pitting susceptibility and surface morphology of 316L in a series of ethanol-containing solutions were examined using X-ray photoelectron spectroscopy (XPS), optical microscopy with 3D stitching, immersion tests, and potentiodynamic polarization measurements. Results demonstrated that the ethanol concentration impacted little on the passive film stability while it dramatically influenced the pitting corrosion susceptibility. Corrosion rate of 316L after immersion tests first increased and then decreased as the concentration of ethanol increased from 0 to 10 M in ferric chloride solution. This, however, did not correspond to the breakdown potential which directly decreased from 489 to 249 mV as the water concentration decreased in ethanolic NaCl solutions. The pits density after both immersion and electrochemical tests showed that the initiation of pitting in ethanolic solution tended to occur at multiple points at the same time. The synergy effect on pitting behavior of hydrolysis enhancement and solubility reduction of metal cations due to the introduction of ethanol has also been discussed.