Geochemistry and detrital zircon records of the Ruyang-Luoyu groups,southern North China Craton:Provenance,crustal evolution and Paleo-Mesoproterozoic tectonic implications

Paleo-to Mesoproterozoic sedimentary rocks in the southern margin of the North China Craton(NCC)are represented by the Ruyang and Luoyu groups.We studied the sedimentary rocks from the Yunmengshan and Beidajian formations of the Ruyang Group and the Cuizhuang and Sanjiaotang formations of the Luoyu Group.Detrital zircon grains from these formations have U–Pb age populations of 3.64–3.31 Ga,2.96–2.86 Ga,2.72–2.59 Ga,2.56–2.47 Ga,2.45–2.0 Ga,1.99–1.85 Ga and 1.84–1.65 Ga.The geochemical features of the sedimentary rocks suggest that some of the sediments were sourced from intermediate to felsic magmatic rocks.The age groups of the detrital zircon are roughly consistent with the tectono-thermal events in the southern margin of the NCC.The Hf isotopic compositions of detrital zircon from the sedimentary rocks in Ruyang and Luoyu groups suggest that significant crustal growth and reworking of the NCC took place during the Neoarchean and early-to mid-Paleoproterozoic,while crustal reworking at the Paleoarchean and late-Paleoproterozoic,and crustal growth at the Mesoarchean.We suggest the depositional times of the Ruyang Group and Luoyu Group are constrained to no older than 1.75–1.7 Ga and 1.7–1.65 Ga,respectively.Formation of late-Paleoproterozoic basins related to the strike slip and extrusion tectonics that cross-cut the NCC during the late Paleoproterozoic(<1.75 Ga),and the late Paleoproterozoic sedimentation once isochronous developed in the southern margin of the NCC through the Taihang region of the interior NCC and linked the Yanshan–Liaoxi regions of the northern NCC.

Preparation of Al2O3–SiO2 composite aerogels and their Cu2+absorption properties

In order to remediate heavy metal ions from waste water,Al2O3–SiO2 composite aerogels are prepared via a sol–gel and an organic solvent sublimation drying method.Various characterisation techniques have been employed including X-ray diffraction(XRD),Fourier transform infrared spectrometry(FTIR),scanning electron microscope(SEM),Energy-dispersion X-ray spectroscopy(EDX),Brunauer–Emmett–Teller(BET)N2 adsoprtion isotherm,and atomic absorption spectrometer(AAS).XRD and FTIR suggest that the aerogels are composed of mainly Al2O3 and minor SiO2.They have a high specific surface area(827.544 m^2/g)and high porosity(86.0%)with a pore diameter of~20 nm.Their microstructures show that the distribution of Al,Si,and O is homogeneous.The aerogels can remove~99%Cu^2+within~40 min and then reach the equilibrium uptake(~69 mg/g).Preliminary calculations show that the Cu2+uptake by the aerogels follows pseudo second-order kinetics where chemical sorption may take effect owing largely to the high surface area,high porosity,and abundant functional groups,such as Al–OH and Si–OH,in the aerogel network.The prepared aerogels may serve as efficient absorbents for Cu^2+removal.

Human umbilical cord blood stem cells and brainderived neurotrophic factor for optic nerve injury: a biomechanical evaluation

Treatment for optic nerve injury by brain-derived neurotrophic factor or the transplantation of human umbilical cord blood stem cells has gained progress, but analysis by biomechanical indicators is rare. Rabbit models of optic nerve injury were established by a clamp. At 7 days after injury, the vitreous body received a one-time injection of 50 μg brain-derived neurotrophic factor or 1 × 10^6 human umbilical cord blood stem cells. After 30 days, the maximum load, maximum stress, maximum strain, elastic limit load, elastic limit stress, and elastic limit strain had clearly improved in rabbit models of optical nerve injury after treatment with brain-derived neurotrophic factor or human umbilical cord blood stem cells. The damage to the ultrastructure of the optic nerve had also been reduced. These findings suggest that human umbilical cord blood stem cells and brain-derived neurotrophic factor effectively repair the injured optical nerve, improve biomechanical properties, and contribute to the recovery after injury.

Shear-thickening behavior of Fe-ZSM5 zeolite slurry and its removal with alumina/boehmites

A cryogenic scanning electron microscopy（cryo-SEM） technique was used to explore the shear-thickening behavior of Fe-ZSM5 zeolite pastes and to discover its underlying mechanism. Bare Fe-ZSM5 zeolite samples were found to contain agglomerations, which may break the flow of the pastes and cause shear-thickening behaviors. However, the shear-thickening behaviors can be eliminated by the addition of halloysite and various boehmites because of improved particle packing. Furthermore, compared with pure Fe-ZSM5 zeolite samples and its composite samples with halloysite, the samples with boehmite（Pural SB or Disperal） additions exhibited network structures in their cryo-SEM images; these structures could facilitate the storage and release of flow water, smooth paste flow, and avoid shear-thickening. By contrast, another boehmite（Versal 250） formed agglomerations rather than network structures after being added to the Fe-ZSM5 zeolite paste and resulted in shear-thickening behavior. Consequently, the results suggest that these network structures play key roles in eliminating the shear-thickening behavior.

Delayed massive cerebral infarction after perioperative period of anterior cervical discectomy and fusion:A case report

BACKGROUND Cerebral infarction is an extremely rare postoperative complication of anterior cervical discectomy and fusion(ACDF),particularly in the delayed setting.We present a case who had a sudden stroke on day 18 after surgery.By sharing our experience with this case,we hope to provide new information about stroke after anterior cervical surgery.CASE SUMMARY We present the case of a 61-year-old man with more than 20 years of hypertension and 14 years of coronary heart disease who had suffered a stroke 11 years ago.The patient was admitted for a multiple ACDF due to symptoms of cervical spondylotic myelopathy and had a sudden stroke on day 18 after surgery.Imaging findings showed a large-area infarct of his left cerebral hemisphere and thrombosis in his left common carotid artery.With the consent of his family,the thrombus was removed and a vascular stent was implanted through an interventional operation.Forty days later,the patient was transferred to a rehabilitation hospital for further treatment.He had normal consciousness but slurred speech at the 1-year follow-up evaluation.The motor and sensory functions of his hemiplegic limbs partially recovered.CONCLUSION This case illustrated that a postoperative stroke related to anterior cervical surgery may be attributed to prolonged carotid retraction and might have a long silent period.Preventive measures include careful preoperative and postoperative examination for high-risk patients as well as gentle and intermittent retraction of carotid artery sheath during operation.

PdPbBi nanoalloys anchored reduced graphene-wrapped metal-organic framework-derived catalyst for enhancing ethylene glycol electrooxidation

For future clean energy demand,it is essential to develop highly efficient and durable materials for use in renewable energy conversion devices.Herein,we report an electrocatalyst loaded with Pd-Pb-Bi nanoalloys on reduced graphene(rGO)-wrapped In_(2)O_(3)(PdPbBi@rGO/In_(2)O_(3))prepared by a hydrothermal method.PdPbBi@rGO/In_(2)O_(3)exhibits higher forward current density(229.12 mA·cm^(-2)),larger electrochemical active surface area(ECSA)(85.87 m^(2)·g^(-1)Pd),smaller impedance(12.68Ω)and lower E_(onset)(-0.56 V)than commercial Pd/C.Specifically,the current density and ECS A are 8.46 and3.38 times higher than those of commercial Pd/C(27.07 mA·cm^(-2),25.41 m^(2)·g^(-1)Pd),respectively.Furthermore,the oxidation mechanism of ethylene glycol and the removal of carbon monoxide[CO]_(ads)from the surface of Pd are also discussed in detail.The columnar support structure wrapped by rGO provides a huge active surface area for catalysis.Moreover,the electronic effect of Pd-PbBi nanoalloys can accelerate the removal of CO intermediate species,obtain more Pd active sites and improve the electrocatalytic performance.Our first synthesis of this highly electrocatalyst offers promising value for commercial application in direct fuel cells.

Schroth exercises improve health-related quality of life and radiographic parameters in adolescent idiopathic scoliosis patients

Background:Finding an optimal treatment strategy for adolescent idiopathic scoliosis(AIS)patients remains challenging because of its intrinsic complexity.For mild to moderate scoliosis patients with lower skeletal growth potential(Risser 3-5),most clinicians agree with observation treatment;however,the curve progression that occurs during puberty,the adolescent period,and even in adulthood,remains a challenging issue for clinicians.The aim of the study is to investigate the efficacy of Schroth exercise in AIS patients with lower skeletal growth potential(Risser 3-5)and moderate scoliosis(Cobb angle 20°-40°).Methods:From 2015 to 2017,data of 64 patients diagnosed with AIS in Peking University Third Hospital were reviewed.Forty-three patients underwent Schroth exercise were classified as Schroth group,and 21 patients underwent observation were classified as observation group.Outcomes were measured by health-related quality of life(HRQOL)and radiographic parameters.HRQOL was assessed using the visual analog scale(VAS)scores for back,Scoliosis Research Society-22(SRS-22)patient questionnaire.Radiographic spinopelvic parameters were obtained from anteroposterior and lateral X-rays.The pre-treatment and post-treatment HRQOL and radiographic parameters were tested to validate Schroth exercise efficacy.The inter-rater reliability of the radiographic parameters was tested using the interclass correlation coefficient(ICC).The pairedt test was used to examine HRQOL and radiographic parameters.Clinical relevance between C2-C7 sagittal vertical axis(SVA)and thoracic kyphosis was analyzed using Spearman correlation.Results:In Schroth group,VAS back score,SRS-22 pain,and SRS-22 self-image domain were significantly improved from pre-treatment 3.0±0.8,3.6±0.5,and 3.5±0.7 to post-treatment 1.6±0.6(t=5.578,P=0.013),4.0±0.3(t=-3.918,P=0.001),and 3.7±0.4(t=-6.468,P<0.001),respectively.No significant improvements of SRS-22 function domain(t=-2.825,P=0.088)and mental health domain(t=-3.174,P=0.061)were observed.The mean Cobb angle decreased from 28.9±5.5°to 26.3±5.2°at the final follow-up,despite no statistical significance was observed(t=1.853,P=0.102).The mean C2-C7 SVA value decreased from 21.7±8.4 mm to 17.0±8.0 mm(t=-1.224P=0.049)and mean T1 tilt decreased from 4.9±4.2°to 3.5±3.1°(t=2.913,P=0.011).No significant improvement of radiographic parameters and HRQOL were observed in observation group.Conclusions:For AIS patients with a Risser 3-5 and a Cobb angle 20°-40°,Schroth exercises improved HRQOL and halted curve progression during the follow-up period.Both cervical spine alignment and shoulder balance were also significantly improved after Schroth exercises.We recommend Schroth exercises for patients with AIS.

Cerebrospinal Fluid Leakage after Thoracic Decompression

Objective： The objective of this study is regular and special features. to review cerebrospinal fluid leakage （CSFL） after thoracic decompression and describe its Data Sources： Literature cited in this review was retrieved from PubMed and Medline and was primarily published during the last 10 years. ＂Cerebrospinal fluid＂, ＂leakage＂, ＂dural tears＂, and ＂thoracic decompression＂ were the indexed terms. Relevant citations in the retrieved articles were also screened to include more data. Study Selection： All retrieved literature was scrutinized, and tbur categories were recorded： incidence and risk factors, complications, treatment modalities, and prognosis. Results： CSFL is much more frequent after thoracic decompression than after cervical and lumbar spinal surgeries. Its occurrence is related to many clinical factors, especially the presence of ossified ligaments and the adhesion of the dural sac. While its impact on the late neurological recovery is currently controversial, CSFL increases the risk of other perioperative complications, such as low intracranial pressure symptoms, infection, and vascular events. The combined use of primary repairs during the operation and conservative treatment postoperatively is generally effective for most CSFL cases, whereas lumbar drains and reoperations should be implemented as rescue options for refractory cases only. Conclusions： CSFL after thoracic decompression has not been specifically investigated, so the present study provides a systematic and comprehensive review of the issue. CSFL is a multi-factor-related complication, and pathological fators play a decisive role. The importance of CSFL is in its impact on the increased risk of other complications during the postoperative period. Methods to prevent these complications are in need. In addition, though the required treatment resources are not special for CSFL after thoracic decompression, most CSFL cases are conservatively curable, and surgeons should be aware of it.

Recurrence Factors in Giant Cell Tumors of the Spine

Background： Giant cell tumors （GCTs） are benign, locally aggressive tumors. We exalnined the rate of local rectirrence of spinal GCTs and sought to identify recurrence factors in patients who underwent surgery. Methods： Between 1995 and 2014, 94 mobile spine GCT patients were treated at our hospital, comprising 43 male and 51 female patients with an average age of 33.4 years. Piecemeal intralesional spondylectomy and total en bloc spondylectomy （TES） were performed. Radiotherapy was suggested for recurrent or residual GCT cases. Since denosumab was not available before 2014 in our country, only interferon and/or zoledronic acid was suggested. Results： Of the 94 patients, four underwent conservative treatment and 90 underwent operations. Seventy-five patients （79.8%） were followed tip for a minimum of 24 months or until death. The median follow-up duration was 75.3 months. The overall recurrence rate was 37.3%. Ten patients （13.3%） died before the last follow-up （rnedian： 18.5 months）. Two patients （2.6%） developed osteogenic sarcoma. The local recurrence rate was 80.0% （24/30） in patients who underwent intralesional curettage, 8.8% （3/34） in patients who underwent extracapsular piecemeal spondylectomy,and 0 （0/9） in patients who underwent TES. The risk factors for local recurrence were lesions located in the cervical spine （P = 0.049）, intralesional curettage （P 〈 0.001 ）, repeated surgeries （P 0.014）, and malignancy （P 〈 0.001 ）. Malignant transformation was a significant risk factor for death （P 〈 0.001 ）. Conclusions： Cervical spinal tumors, curettage, and nonintact tumors were risk l;actors for local recurrence. Intralesional curettage and malignancy were the most important significant factors for local rectirrence and death, respectively.