Natural slopes usually display complicated exposed rock surfaces that are characterized by complex and substantial terrain undulation and ubiquitous undesirable phenomena such as vegetation cover and rockfalls.This st...Natural slopes usually display complicated exposed rock surfaces that are characterized by complex and substantial terrain undulation and ubiquitous undesirable phenomena such as vegetation cover and rockfalls.This study presents a systematic outcrop research of fracture pattern variations in a complicated rock slope,and the qualitative and quantitative study of the complex phenomena impact on threedimensional(3D)discrete fracture network(DFN)modeling.As the studies of the outcrop fracture pattern have been so far focused on local variations,thus,we put forward a statistical analysis of global variations.The entire outcrop is partitioned into several subzones,and the subzone-scale variability of fracture geometric properties is analyzed(including the orientation,the density,and the trace length).The results reveal significant variations in fracture characteristics(such as the concentrative degree,the average orientation,the density,and the trace length)among different subzones.Moreover,the density of fracture sets,which is approximately parallel to the slope surface,exhibits a notably higher value compared to other fracture sets across all subzones.To improve the accuracy of the DFN modeling,the effects of three common phenomena resulting from vegetation and rockfalls are qualitatively analyzed and the corresponding quantitative data processing solutions are proposed.Subsequently,the 3D fracture geometric parameters are determined for different areas of the high-steep rock slope in terms of the subzone dimensions.The results show significant variations in the same set of 3D fracture parameters across different regions with density differing by up to tenfold and mean trace length exhibiting differences of 3e4 times.The study results present precise geological structural information,improve modeling accuracy,and provide practical solutions for addressing complex outcrop issues.展开更多
Orthorhombic Nb_(2)O_(5)(T-Nb_(2)O_(5))is attractive for fast-charging Li-ion batteries,but it is still hard to realize rapid charge transfer kinetics for Li-ion storage.Herein,F-doped T-Nb_(2)O_(5) microflowers(F-Nb_(...Orthorhombic Nb_(2)O_(5)(T-Nb_(2)O_(5))is attractive for fast-charging Li-ion batteries,but it is still hard to realize rapid charge transfer kinetics for Li-ion storage.Herein,F-doped T-Nb_(2)O_(5) microflowers(F-Nb_(2)O_(5))are rationally synthesized through topotactic conversion.Specifically,F-Nb_(2)O_(5) are assembled by single-crystal nanoflakes with nearly 97%exposed(100)facet,which maximizes the exposure of the feasible Li^(+)transport pathways along loosely packed 4g atomic layers to the electrolytes,thus effectively enhancing the Li^(+)-intercalation performance.Besides,the band gap of F-Nb_(2)O_(5) is reduced to 2.87 eV due to the doping of F atoms,leading to enhanced electrical conductivity.The synergetic effects between tailored exposed crystal facets,F-doping,and ultrathin building blocks,speed up the Li^(+)/electron transfer kinetics and improve the pseudocapacitive properties of F-Nb_(2)O_(5).Therefore,F-Nb_(2)O_(5) exhibit superior rate capability(210.8 and 164.9 mAh g^(-1) at 1 and 10 C,respectively)and good long-term 10 C cycling performance(132.7 mAh g^(-1) after 1500 cycles).展开更多
BACKGROUND Gastric stromal tumors,originating from mesenchymal tissues,are one of the most common tumors of the digestive tract.For stromal tumors originating from the muscularis propria,compared with conventional end...BACKGROUND Gastric stromal tumors,originating from mesenchymal tissues,are one of the most common tumors of the digestive tract.For stromal tumors originating from the muscularis propria,compared with conventional endoscopic submucosal dissection(ESD),endoscopic full-thickness resection(EFTR)can remove deep lesions and digestive tract wall tumors completely.However,this technique has major limitations such as perforation,postoperative bleeding,and post-polypectomy syndrome.Herein,we report a case of postoperative serous surface bleeding which formed an encapsulated hemoperitoneum in a patient with gastric stromal tumor that was treated with exposed EFTR.Feasible treatment options to address this complication are described.CASE SUMMARY A 47-year-old male patient had a hemispherical protrusion found during gastric endoscopic ultrasonography,located at the upper gastric curvature adjacent to the stomach fundus,with a smooth surface mucosa and poor mobility.The lesion was 19.3 mm×16.1 mm in size and originated from the fourth ultrasound layer.Computed tomography(CT)revealed no significant evidence of lymph node enlargement or distant metastasis.Using conventional ESD technology for mucosal pre-resection,exposed EFTR was performed to resect the intact tumor in order to achieve a definitive histopathological diagnosis.Based on its morphology and immunohistochemical expression of CD117 and DOG-1,the lesion was proven to be consistent with a gastric stromal tumor.Six days after exposed EFTR,CT showed a large amount of encapsulated fluid and gas accumulation around the stomach.In addition,gastroscopy suggested intracavitary bleeding and abdominal puncture drainage indicated serosal bleeding.Based on these findings,the patient was diagnosed with serosal bleeding resulting in encapsulated abdominal hemorrhage after exposed EFTR for a gastric stromal tumor.The patient received combined treatments,such as hemostasis under gastroscopy,gastrointestinal decompression,and abdominal drainage.All examinations were normal within six months of follow-up.CONCLUSION This patient developed serous surface bleeding in the gastric cavity following exposed EFTR.Serosal bleeding resulting in an encapsulated hemoperitoneum is rare in clinical practice.The combined treatment may replace certain surgical techniques.展开更多
Polycrystalline SnO2 fine powder consisting of nano-particles (SnO2-NP), SnO2 nano-sheets (SnO2-NS), and SnO2 containing both nano-rods and nano-particles (SnO2-NR+NP) were prepared and used for CO oxidation. S...Polycrystalline SnO2 fine powder consisting of nano-particles (SnO2-NP), SnO2 nano-sheets (SnO2-NS), and SnO2 containing both nano-rods and nano-particles (SnO2-NR+NP) were prepared and used for CO oxidation. SnO2-NS possesses a mesoporous structure and has a higher surface area, larger pore volume, and more active species than SnO2-NP, and shows improved activity. In contrast, although SnO2-NR+NP has only a slightly higher surface area and pore volume, and slightly more active surface oxygen species than SnO2-NP, it has more exposed active (110) facets, which is the reason for its improved oxidation activity. Water vapor has only a reversible and weak influence on SnO2-NS, therefore it is a potential catalyst for emission control processes.展开更多
上期的第二个话题“跳槽”是目前普遍存在的现象,对此人们看法不一。有些人认为这在国外并非什么新鲜事,中国人也开始这样做说明人们的思想解放了.打破了过去那种在一个单位干一辈子的传统观念.这是社会的进步。也有人把“跳槽”看做是...上期的第二个话题“跳槽”是目前普遍存在的现象,对此人们看法不一。有些人认为这在国外并非什么新鲜事,中国人也开始这样做说明人们的思想解放了.打破了过去那种在一个单位干一辈子的传统观念.这是社会的进步。也有人把“跳槽”看做是人的私欲膨胀,是对金钱和物质利益的过分追求,不利于一个企业或部门的发展,不应提倡。考生如同意后一种观点就可以说:“I don’t think it is reasonable for aperson to change his(her)job frequently.A展开更多
In current underground mining, the stability of the exposed backfill face is a basic issue associated with mining design and has been the subject of considerable research in mining safety and efficiency. In this study...In current underground mining, the stability of the exposed backfill face is a basic issue associated with mining design and has been the subject of considerable research in mining safety and efficiency. In this study, an improved analytical solution for evaluating the safety of vertically exposed faces in backfilling was proposed. Based on a differential slice method, the proposed solution emphasizes the arching effect as having the advantages of more rigor and wider scalability. Feasibility of the proposed solution was validated with classic centrifuge results. Good agreement between compared results indicated that the proposed solution skillfully predicts the behavior of the paste centrifuge model. Additionally, calculation of exposed face safety in sequential filling was presented. The proposed solution has practical significance in mine backfill design.展开更多
The ultimately exposed roof area(UERA)of goaf is crucial to the safety and economics of underground mining.The prediction models do not consider the mechanical weakness of rock mass and ignore the influence of the joi...The ultimately exposed roof area(UERA)of goaf is crucial to the safety and economics of underground mining.The prediction models do not consider the mechanical weakness of rock mass and ignore the influence of the joint damage factor,causing a large predicted exposure area with a high roof falling risk.This work adopted joint damage factor to derive a new UERA prediction model.The relationships between the UERA(S)and the span ratio(m),the density(k)and the diameter of fracture(d)were analysed by the new prediction model.The results showed that the exposed area S and the span ratio m have a U-shaped curve relationship.The S decreases with the increase of m and then increases when m is beyond 2.The exposed roof area S is in an inversely proportional power-law relationship with the fracture surface density k,and the curvature of the S-k relationship curve decreases when d=0.5 and k>7,and S is close to 0.There is a negative correlation between S and the fracture surface diameter d,the curvature of the S-d curve decreases with the increase of d and k,and the variation rate increases first and then decreases with the increase of d;when k=0.5 and d>9,S is close to 0.The predicted values of the UERA prediction model are 119.3,112.8,and 114.6 m2 with different joint damage parameters,which are slightly smaller than the actual critical exposure area of a roof(S=120 m2).The case study shows that the alternative prediction model is reasonable and acceptable and provides new theoretical support for the underground mining safety of sedimentary bauxite ore.展开更多
The present report evaluates the effects of formaldehyde (FA) exposure on peripheral lymphocytes by using heth genetic and immunological parameters. Twenty-three non-smoking students in the study had inhalation exposu...The present report evaluates the effects of formaldehyde (FA) exposure on peripheral lymphocytes by using heth genetic and immunological parameters. Twenty-three non-smoking students in the study had inhalation exposure to 0.508 ±0. 299 mg/m3 of FA for a Period of 8 weeks (3h × 3 times each week) during anatomy classes. As for composition of lymphocyte subsets after FA exposare,significant increase was found in the percentage of CD19(B cells), while sighficant decrease was observed in CD3(total T cells), CD4(T helper-inducer cells), and CD8(T cytotoxic-suppressior cells) with a P<0 .01. Increase in the ratio of T-helper-inducer cells to T-cytotoxic-suppressor cells (T4 / T8) was also observed with statistical sighcance after exposure (P < 0.001). In the meanwhile,no significant difference (P > 0 .05) was reported between lymphocyte prolifendion rate and sisterchromatid exchange (SCE) at the exposure level and duration. It is suggested that the lymphocyte subsets may be most susceptible to the effects of FA, though a single immunological endpoint is rarely related with pathophysiological interpretation.展开更多
The Lower Triassic Feixianguan Formation in the Daxian-Xuanhan region, northeastern Sicbuan is interpreted to be a carbonate platform intermediate between the West Hubei-East Cbongqing marine basin and Guangyuan-Wangc...The Lower Triassic Feixianguan Formation in the Daxian-Xuanhan region, northeastern Sicbuan is interpreted to be a carbonate platform intermediate between the West Hubei-East Cbongqing marine basin and Guangyuan-Wangcang marine basin. Outcrops, well logs and seismic data have disclosed that three sedimentary facies can be identified for the formation: open platform, platform exposed shoal and restricted platform facies. During the early stage of deposition of the Feixianguan Formation, there existed a sedimentary framework all the same as the Late Permian one: open platform in the west, and platform exposed shoal, restricted platform and open platform eastwards. The gradual increase of the shoal area permitted eastward migration of the shoal facies. During the deposition of the third member of the Feixianguan Formation, the study area was invaded by temporary transgressions. Till the deposition of the fourth member of the formation, the study area was prevailed over the unified restricted platform deposits, as indicated by the sedimentary model for the typical carbonate platform shoal deposits. The reservoir rocks in the Feixianguan Formation consist mostly of solution opening dolostone, and the rock types are assembled by oolitic dolostone, residual oolitic dolostone and sucrosic residual oolitic medium- to coarse-grained dolostone. The deep and shallow dual laterologs show relatively high resistivity, clear amplitude differences and time difference saltation of acoustic waves in some intervals. The seismic responses are indicated by low-frequency and highly variable amplitudes and chaotic reflection configurations. The reservoir rocks are characterized by high porosity-high permeability and medium porosity-medium permeability, showing a marked correlation between porosity and permeability. Solution openings are extremely developed in the reservoir rocks, including cast pores, intergranular solution openings, intercrystal pores, intercrystal solution openings, solution openings (caves) and minute fissures. Macropores and coarse pore throats are common. The reservoir rocks are apparently controlled by sedimentary facies in distribution patterns. Vertically, they occur dominantly in the second and first members of the Feixianguan Formation, and laterally in the platform exposed shoals and restricted platforms, where good natural gas potential is expected.展开更多
High efficiency, environmental protection and sustainability have become the main theme of the development of the protection engineering, requiring that the components not only meet the basic functions, but also have ...High efficiency, environmental protection and sustainability have become the main theme of the development of the protection engineering, requiring that the components not only meet the basic functions, but also have chemical properties such as acid and alkali corrosion resistance and aging resistance. Polyisocyanate-oxazodone(POZD) polymer has the above characteristics, it also has the advantages of strong toughness, high strength and high elongation. The concrete slab sprayed with POZD material has excellent anti-blast performance. In order to explore the damage characteristics of POZD sprayed concrete slabs under the action of contact explosion thoroughly, the contact explosion test of POZD concrete slabs with different charges were carried out. On the basis of experimental verification,numerical simulation were used to study the influence of the thickness of the POZD on the blast resistance of the concrete slab. According to the test and numerical simulation results that as the thickness of the coating increases, the anti-blast performance of the concrete slab gradually increases,and the TNT equivalent required for critical failure is larger. Based on the above analysis, empirical expressions on normalized crater diameter, the normalized spall diameter and normalized spall diameter are obtained.展开更多
BACKGROUND Aplasia cutis congenita (ACC) in newborns is a condition in which congenital defects or hypoplasia is present in part of the epidermis,dermis and even subcutaneous tissue (including muscle and bones).First ...BACKGROUND Aplasia cutis congenita (ACC) in newborns is a condition in which congenital defects or hypoplasia is present in part of the epidermis,dermis and even subcutaneous tissue (including muscle and bones).First reported by Cordon in 1767,ACC is a rare disease with a low incidence of 1/100000 to 3/10000.Currently,there are 500 cases reported worldwide.ACC can be accompanied by other malformations.The onset mechanism of the disease remains unknown but is thought to be correlated to factors such as genetics,narrow uterus,foetal skin and amniotic membrane adhesion,use of teratogenic drugs in early pregnancy and viral infection.CASE SUMMARY In August 2018,we treated a newborn with ACC on the left lower limbs using a combination of ionic silver dressing and moist exposed burn ointment (MEBO) and achieved a satisfactory treatment outcome.The skin defects were observed on the external genitals and on areas from the left foot to 3/4 of the upper left side.Subcutaneous tissue and blood vessels were observed in the regions with skin defects.The following treatments were provided.First,the wound was rinsed with 0.9% sodium chloride solution followed by disinfection with povidone-iodine twice.And then MEBO was applied to the wound at a thickness of approximately 1 mm.After applying ionic silver dressing,the wound was covered with sterile gauze.The wound dressing was replaced every 2-3 d.At the 4-mo follow-up,the treatment outcome was satisfactory.There was minimal scar tissue formation,and limb function was not impaired.CONCLUSION The combination of ionic silver dressing and MEBO to ACC is helpful.展开更多
Photocatalytic degradation of gaseous pollutants on Bi-based semiconductors under solar lightirradiation has attracted significant attention.However,their application in gaseous straight-chainalkane purification is st...Photocatalytic degradation of gaseous pollutants on Bi-based semiconductors under solar lightirradiation has attracted significant attention.However,their application in gaseous straight-chainalkane purification is still rare.Here,a series of Bi/BiOBr composites were solvothermally synthe-sized and applied in solar-light-driven photocatalytic degradation of gaseous n-hexane.The charac-terization results revealed that both increasing number of functional groups of alcohol solvent(from methanol and ethylene glycol to glycerol)and solvothermal temperature(from 160 and 180to 200℃)facilitated the in-situ formation of metallic Bi nanospheres on BiOBr nanoplates withexposed(110)facets.Meanwhile,chemical bonding between Bi and BiOBr was observed on theseexposed facets that resulted in the formation of surface oxygen vacancy.Furthermore,the synergis-tic effect of optimum surface oxygen vacancy on exposed(110)facets led to a high visible light re-sponse,narrow band gap,great photocurrent,low recombination rate of the charge carriers,andstrong·O2-and h*formation,all of which resulted in the highest removal efficiency of 97.4%within120 min of 15 ppmv of n-hexane on Bi/BiOBr.Our findings efficiently broaden the application ofBi-based photocatalysis technology in the purification of gaseous straight-chain pollutants emittedby the petrochemical industry.展开更多
The frequency of micronuclei (MN) in cells of the nasal mucosa, oral mucosa and in lym-phocytes was evaluated for 25 students in anatomy classes exposed to formaldehyde (FA) overan 8-week period. Each student served a...The frequency of micronuclei (MN) in cells of the nasal mucosa, oral mucosa and in lym-phocytes was evaluated for 25 students in anatomy classes exposed to formaldehyde (FA) overan 8-week period. Each student served as his or her own control. The time-weighted averageconcentration (TWA) of fOrmaldehyde in anatomical laboratories and in students' dormitorieswas 0. 508 ± 0. 299 mg/m3 and 0. 012 ± 0. 0025mg/m3, respectively. A higher frequency ofmicronuclei was observed in nasal and oral exfoliative cells after formaldehyde exposure (3. 85± 1. 48 vs 1 .20± 0. 676 and 0. 857 ± 0. 558 vs 0. 568 ± 0. 317, paired-t test: P< 0. 001and P < 0. 01, respectively). No significant increase in the frequency of lymphocyte micronu-clei was found after formaldehyde exposure (P >0. 05 ). The present study shows that nasalmucosa cel1s exposed through respiration are the chief target of FA-induced genotoxic effects展开更多
In the later stage of Late Pleistocene, global climate entered into the climax period of Wurm when temperature decreased remarkably and glaciers developed. Information from the East China Sea also confirm that the sea...In the later stage of Late Pleistocene, global climate entered into the climax period of Wurm when temperature decreased remarkably and glaciers developed. Information from the East China Sea also confirm that the sea level fell by at least 130 m at that time (Emery, 1968). The Bohai Sea and Yellow Sea at the climax period were totally exposed, while the East China Sea and South China Sea shelf regions were exposed partly. The exposed shelf area exceeded 1 million km2 and became a salty desert where land plants could not survive. Such were the conditions which led to the desertization of the shelf region.Eolation was the major exogenetic force not only on land but also on the shelf region in the ice age. At the climax period of Wiirm, the northern part of China developed thick layers of loess deposits. The shelf region at that time had similar climatic conditions and sediments. Because the shelf region was not protected by vegetation in the ice age, intensive wind storms remoulded the primarily展开更多
Oxygen vacancy plays vital roles in regulating the electronic and charge distribution of the oxygen deficient materials.Herein,abundant oxygen vacancies are created during assembling the two-dimensional(2D)ultra-thin ...Oxygen vacancy plays vital roles in regulating the electronic and charge distribution of the oxygen deficient materials.Herein,abundant oxygen vacancies are created during assembling the two-dimensional(2D)ultra-thin Bi_(2)MoO_(6) nanoflakes into three dimensional(3D)Bi_(2)MoO_(6) nanospheres,resulting in significantly improved performance for photocatalytical conversion of CO_(2) into liquid hydrocarbons.The increased performance is contributed by two primary sites,namely the abundant oxygen vacancy and the exposed molybdenum(Mo)atom induced by oxygen-migration,as revealed by the theoretical calculation.The oxygen vacancy(Ov)and uncovered Mo atom serving as dual binding sites for trapping CO_(2) molecules render the synchronous fixation-reduction process,resulting in the decline of activation energy for CO_(2) reduction from 2.15 eV on bulk Bi_(2)MoO_(6) to 1.42 eV on Ov-rich Bi_(2)MoO_(6).Such a striking decrease in the activation energy induces the efficient selective generation of liquid hydrocarbons,especially the methanol(C_(2)H_(5) OH)and ethanol(CH_(3) OH).The yields of CH_(3) OH and C_(2)H_(5) OH over the optimal Ov-Bi_(2)MoO_(6) is high up to 106.5 and 10.3μmol g^(-1) respectively,greatly outperforming that on the Bulk-Bi_(2)MoO_(6).展开更多
Cytokinesis-blocked micronucleus assay was applied as a biological dosimeter to detect abnormalities in human peripheral lymphocytes of thirteen students exposed to formaldehyde (FA) during a 12-week (10 h per week) a...Cytokinesis-blocked micronucleus assay was applied as a biological dosimeter to detect abnormalities in human peripheral lymphocytes of thirteen students exposed to formaldehyde (FA) during a 12-week (10 h per week) anatomy class. Breathing-zone air samples colleeted during dissection procedures showed a mean concentration of 2. 37 ppm (3. 17mg/m3 ). Ten students from the same school but without FA exposure served as controls. Chromosome aberrations (CA) and sister chromatid exchanges (SCE) were detected in both groups. The micronuclei (MN) rate (6. 38 ± 2. 50‰ ) and CA rate (5. 92 ±2. 40‰ ) in the FA-exposed group showed a significant increase (P< 0. 01 ) when compared with those of the controls (3. 15 ±1. 46‰and 3. 40 ± 1. 57 % respectively). A correlation between MN and CA in individuals was observed. SCE in the exmpd group were also increased (P< 0. 05), but not so greatly as MN or CA. The results indicated that FA might damage the chromosomes of human lymphocytes.展开更多
BACKGROUND Body parts such as the face and hands are highly exposed during daily life and burns may accumulate in these areas.In addition,residual wounds,scar hyperplasia and contracture often exist in the late stage ...BACKGROUND Body parts such as the face and hands are highly exposed during daily life and burns may accumulate in these areas.In addition,residual wounds,scar hyperplasia and contracture often exist in the late stage of a deep burn in these areas,which may affect patients’appearance,movements,and mental health.However,inadequate attention has been paid to this issue which can result in problems,such as difficulty in healing,possibility of carcinoma,chronic pain and a heavy mental burden.AIM To investigate the long-term medical treatment of patients with severe burns at exposed sites following a mass burn casualty event.METHODS A retrospective analysis of 13 patients with severe burns at exposed sites was performed to determine their respective long-term medical treatment.A combined wound dressing scheme consisting of traditional Chinese and Western medicine was introduced to repair residual wounds.Active and passive functional exercises with massage,Chinese herbal baths and compression fixation were proposed to ameliorate the condition of the hands.A combination of physical,chemical and photoelectrical measures was adopted for anti-scar treatment.A psychological intervention and recovery guide was provided which corresponded to the patients’psychological status.RESULTS Compared to patients who did not simultaneously receive the same treatment,patients who underwent systematic treatment recovered with a lower woundinfection rate(P<0.05),a shorter healing time(13.6±3.2 d)compared with(19.1±3.5 d)and more bearable pain during wound dressing at three days,one week and two weeks after a Chinese herbal bath(P<0.05).Satisfactory results were achieved with regard to restored function of patients’joints and blood supply to nerve endings,closure of the eyelids and the size of mouth opening tended to be normal,and only 7.1%of patients were diagnosed with severe scar hyperplasia and contracture deformity compared with 30.7%in the control group.In addition,the color,thickness,vascular distribution and softness score of the scars improved(P<0.01),and the effects of the psychological intervention was remarkable as shown by the Self-Rating Anxiety Scale and Self-Rating Depression Scale.CONCLUSION A better prognosis can be achieved in patients in the late stage of a burn with active residual wound repair,limb functional exercise,anti-scar and psychological rehabilitation.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2022YFC3080200)the National Natural Science Foundation of China(Grant No.42022053)the China Postdoctoral Science Foundation(Grant No.2023M731264).
文摘Natural slopes usually display complicated exposed rock surfaces that are characterized by complex and substantial terrain undulation and ubiquitous undesirable phenomena such as vegetation cover and rockfalls.This study presents a systematic outcrop research of fracture pattern variations in a complicated rock slope,and the qualitative and quantitative study of the complex phenomena impact on threedimensional(3D)discrete fracture network(DFN)modeling.As the studies of the outcrop fracture pattern have been so far focused on local variations,thus,we put forward a statistical analysis of global variations.The entire outcrop is partitioned into several subzones,and the subzone-scale variability of fracture geometric properties is analyzed(including the orientation,the density,and the trace length).The results reveal significant variations in fracture characteristics(such as the concentrative degree,the average orientation,the density,and the trace length)among different subzones.Moreover,the density of fracture sets,which is approximately parallel to the slope surface,exhibits a notably higher value compared to other fracture sets across all subzones.To improve the accuracy of the DFN modeling,the effects of three common phenomena resulting from vegetation and rockfalls are qualitatively analyzed and the corresponding quantitative data processing solutions are proposed.Subsequently,the 3D fracture geometric parameters are determined for different areas of the high-steep rock slope in terms of the subzone dimensions.The results show significant variations in the same set of 3D fracture parameters across different regions with density differing by up to tenfold and mean trace length exhibiting differences of 3e4 times.The study results present precise geological structural information,improve modeling accuracy,and provide practical solutions for addressing complex outcrop issues.
基金supported by the National Natural Science Foundation of China(No.51802163)the Natural Science Foundation of Henan Province of China(No.222300420252)the Natural Science Foundation of Henan Department of Education(No.20A480004).
文摘Orthorhombic Nb_(2)O_(5)(T-Nb_(2)O_(5))is attractive for fast-charging Li-ion batteries,but it is still hard to realize rapid charge transfer kinetics for Li-ion storage.Herein,F-doped T-Nb_(2)O_(5) microflowers(F-Nb_(2)O_(5))are rationally synthesized through topotactic conversion.Specifically,F-Nb_(2)O_(5) are assembled by single-crystal nanoflakes with nearly 97%exposed(100)facet,which maximizes the exposure of the feasible Li^(+)transport pathways along loosely packed 4g atomic layers to the electrolytes,thus effectively enhancing the Li^(+)-intercalation performance.Besides,the band gap of F-Nb_(2)O_(5) is reduced to 2.87 eV due to the doping of F atoms,leading to enhanced electrical conductivity.The synergetic effects between tailored exposed crystal facets,F-doping,and ultrathin building blocks,speed up the Li^(+)/electron transfer kinetics and improve the pseudocapacitive properties of F-Nb_(2)O_(5).Therefore,F-Nb_(2)O_(5) exhibit superior rate capability(210.8 and 164.9 mAh g^(-1) at 1 and 10 C,respectively)and good long-term 10 C cycling performance(132.7 mAh g^(-1) after 1500 cycles).
文摘BACKGROUND Gastric stromal tumors,originating from mesenchymal tissues,are one of the most common tumors of the digestive tract.For stromal tumors originating from the muscularis propria,compared with conventional endoscopic submucosal dissection(ESD),endoscopic full-thickness resection(EFTR)can remove deep lesions and digestive tract wall tumors completely.However,this technique has major limitations such as perforation,postoperative bleeding,and post-polypectomy syndrome.Herein,we report a case of postoperative serous surface bleeding which formed an encapsulated hemoperitoneum in a patient with gastric stromal tumor that was treated with exposed EFTR.Feasible treatment options to address this complication are described.CASE SUMMARY A 47-year-old male patient had a hemispherical protrusion found during gastric endoscopic ultrasonography,located at the upper gastric curvature adjacent to the stomach fundus,with a smooth surface mucosa and poor mobility.The lesion was 19.3 mm×16.1 mm in size and originated from the fourth ultrasound layer.Computed tomography(CT)revealed no significant evidence of lymph node enlargement or distant metastasis.Using conventional ESD technology for mucosal pre-resection,exposed EFTR was performed to resect the intact tumor in order to achieve a definitive histopathological diagnosis.Based on its morphology and immunohistochemical expression of CD117 and DOG-1,the lesion was proven to be consistent with a gastric stromal tumor.Six days after exposed EFTR,CT showed a large amount of encapsulated fluid and gas accumulation around the stomach.In addition,gastroscopy suggested intracavitary bleeding and abdominal puncture drainage indicated serosal bleeding.Based on these findings,the patient was diagnosed with serosal bleeding resulting in encapsulated abdominal hemorrhage after exposed EFTR for a gastric stromal tumor.The patient received combined treatments,such as hemostasis under gastroscopy,gastrointestinal decompression,and abdominal drainage.All examinations were normal within six months of follow-up.CONCLUSION This patient developed serous surface bleeding in the gastric cavity following exposed EFTR.Serosal bleeding resulting in an encapsulated hemoperitoneum is rare in clinical practice.The combined treatment may replace certain surgical techniques.
基金supported by the National Natural Science Foundation of China (21263015)the Education Department of Jiangxi Province (KJLD14005)the Natural Science Foundation of Jiangxi Province(20151BBE50006,20122BAB203009)~~
文摘Polycrystalline SnO2 fine powder consisting of nano-particles (SnO2-NP), SnO2 nano-sheets (SnO2-NS), and SnO2 containing both nano-rods and nano-particles (SnO2-NR+NP) were prepared and used for CO oxidation. SnO2-NS possesses a mesoporous structure and has a higher surface area, larger pore volume, and more active species than SnO2-NP, and shows improved activity. In contrast, although SnO2-NR+NP has only a slightly higher surface area and pore volume, and slightly more active surface oxygen species than SnO2-NP, it has more exposed active (110) facets, which is the reason for its improved oxidation activity. Water vapor has only a reversible and weak influence on SnO2-NS, therefore it is a potential catalyst for emission control processes.
文摘上期的第二个话题“跳槽”是目前普遍存在的现象,对此人们看法不一。有些人认为这在国外并非什么新鲜事,中国人也开始这样做说明人们的思想解放了.打破了过去那种在一个单位干一辈子的传统观念.这是社会的进步。也有人把“跳槽”看做是人的私欲膨胀,是对金钱和物质利益的过分追求,不利于一个企业或部门的发展,不应提倡。考生如同意后一种观点就可以说:“I don’t think it is reasonable for aperson to change his(her)job frequently.A
基金financially supported by the China Scholarship Council (No. 201506420049)
文摘In current underground mining, the stability of the exposed backfill face is a basic issue associated with mining design and has been the subject of considerable research in mining safety and efficiency. In this study, an improved analytical solution for evaluating the safety of vertically exposed faces in backfilling was proposed. Based on a differential slice method, the proposed solution emphasizes the arching effect as having the advantages of more rigor and wider scalability. Feasibility of the proposed solution was validated with classic centrifuge results. Good agreement between compared results indicated that the proposed solution skillfully predicts the behavior of the paste centrifuge model. Additionally, calculation of exposed face safety in sequential filling was presented. The proposed solution has practical significance in mine backfill design.
基金This work is supported by the National Natural Science Foundation of China(51974135,51704094)the National Key Research and Development Program of China(2016YFC0600802).
文摘The ultimately exposed roof area(UERA)of goaf is crucial to the safety and economics of underground mining.The prediction models do not consider the mechanical weakness of rock mass and ignore the influence of the joint damage factor,causing a large predicted exposure area with a high roof falling risk.This work adopted joint damage factor to derive a new UERA prediction model.The relationships between the UERA(S)and the span ratio(m),the density(k)and the diameter of fracture(d)were analysed by the new prediction model.The results showed that the exposed area S and the span ratio m have a U-shaped curve relationship.The S decreases with the increase of m and then increases when m is beyond 2.The exposed roof area S is in an inversely proportional power-law relationship with the fracture surface density k,and the curvature of the S-k relationship curve decreases when d=0.5 and k>7,and S is close to 0.There is a negative correlation between S and the fracture surface diameter d,the curvature of the S-d curve decreases with the increase of d and k,and the variation rate increases first and then decreases with the increase of d;when k=0.5 and d>9,S is close to 0.The predicted values of the UERA prediction model are 119.3,112.8,and 114.6 m2 with different joint damage parameters,which are slightly smaller than the actual critical exposure area of a roof(S=120 m2).The case study shows that the alternative prediction model is reasonable and acceptable and provides new theoretical support for the underground mining safety of sedimentary bauxite ore.
文摘The present report evaluates the effects of formaldehyde (FA) exposure on peripheral lymphocytes by using heth genetic and immunological parameters. Twenty-three non-smoking students in the study had inhalation exposure to 0.508 ±0. 299 mg/m3 of FA for a Period of 8 weeks (3h × 3 times each week) during anatomy classes. As for composition of lymphocyte subsets after FA exposare,significant increase was found in the percentage of CD19(B cells), while sighficant decrease was observed in CD3(total T cells), CD4(T helper-inducer cells), and CD8(T cytotoxic-suppressior cells) with a P<0 .01. Increase in the ratio of T-helper-inducer cells to T-cytotoxic-suppressor cells (T4 / T8) was also observed with statistical sighcance after exposure (P < 0.001). In the meanwhile,no significant difference (P > 0 .05) was reported between lymphocyte prolifendion rate and sisterchromatid exchange (SCE) at the exposure level and duration. It is suggested that the lymphocyte subsets may be most susceptible to the effects of FA, though a single immunological endpoint is rarely related with pathophysiological interpretation.
文摘The Lower Triassic Feixianguan Formation in the Daxian-Xuanhan region, northeastern Sicbuan is interpreted to be a carbonate platform intermediate between the West Hubei-East Cbongqing marine basin and Guangyuan-Wangcang marine basin. Outcrops, well logs and seismic data have disclosed that three sedimentary facies can be identified for the formation: open platform, platform exposed shoal and restricted platform facies. During the early stage of deposition of the Feixianguan Formation, there existed a sedimentary framework all the same as the Late Permian one: open platform in the west, and platform exposed shoal, restricted platform and open platform eastwards. The gradual increase of the shoal area permitted eastward migration of the shoal facies. During the deposition of the third member of the Feixianguan Formation, the study area was invaded by temporary transgressions. Till the deposition of the fourth member of the formation, the study area was prevailed over the unified restricted platform deposits, as indicated by the sedimentary model for the typical carbonate platform shoal deposits. The reservoir rocks in the Feixianguan Formation consist mostly of solution opening dolostone, and the rock types are assembled by oolitic dolostone, residual oolitic dolostone and sucrosic residual oolitic medium- to coarse-grained dolostone. The deep and shallow dual laterologs show relatively high resistivity, clear amplitude differences and time difference saltation of acoustic waves in some intervals. The seismic responses are indicated by low-frequency and highly variable amplitudes and chaotic reflection configurations. The reservoir rocks are characterized by high porosity-high permeability and medium porosity-medium permeability, showing a marked correlation between porosity and permeability. Solution openings are extremely developed in the reservoir rocks, including cast pores, intergranular solution openings, intercrystal pores, intercrystal solution openings, solution openings (caves) and minute fissures. Macropores and coarse pore throats are common. The reservoir rocks are apparently controlled by sedimentary facies in distribution patterns. Vertically, they occur dominantly in the second and first members of the Feixianguan Formation, and laterally in the platform exposed shoals and restricted platforms, where good natural gas potential is expected.
基金the financial support from National Natural Science Foundation of China (Grant Nos. 11302261 and 11972201)supported by the project of Key Laboratory of Impact and Safety Engineering (Ningbo University),Ministry of Education. The project number is CJ202011。
文摘High efficiency, environmental protection and sustainability have become the main theme of the development of the protection engineering, requiring that the components not only meet the basic functions, but also have chemical properties such as acid and alkali corrosion resistance and aging resistance. Polyisocyanate-oxazodone(POZD) polymer has the above characteristics, it also has the advantages of strong toughness, high strength and high elongation. The concrete slab sprayed with POZD material has excellent anti-blast performance. In order to explore the damage characteristics of POZD sprayed concrete slabs under the action of contact explosion thoroughly, the contact explosion test of POZD concrete slabs with different charges were carried out. On the basis of experimental verification,numerical simulation were used to study the influence of the thickness of the POZD on the blast resistance of the concrete slab. According to the test and numerical simulation results that as the thickness of the coating increases, the anti-blast performance of the concrete slab gradually increases,and the TNT equivalent required for critical failure is larger. Based on the above analysis, empirical expressions on normalized crater diameter, the normalized spall diameter and normalized spall diameter are obtained.
文摘BACKGROUND Aplasia cutis congenita (ACC) in newborns is a condition in which congenital defects or hypoplasia is present in part of the epidermis,dermis and even subcutaneous tissue (including muscle and bones).First reported by Cordon in 1767,ACC is a rare disease with a low incidence of 1/100000 to 3/10000.Currently,there are 500 cases reported worldwide.ACC can be accompanied by other malformations.The onset mechanism of the disease remains unknown but is thought to be correlated to factors such as genetics,narrow uterus,foetal skin and amniotic membrane adhesion,use of teratogenic drugs in early pregnancy and viral infection.CASE SUMMARY In August 2018,we treated a newborn with ACC on the left lower limbs using a combination of ionic silver dressing and moist exposed burn ointment (MEBO) and achieved a satisfactory treatment outcome.The skin defects were observed on the external genitals and on areas from the left foot to 3/4 of the upper left side.Subcutaneous tissue and blood vessels were observed in the regions with skin defects.The following treatments were provided.First,the wound was rinsed with 0.9% sodium chloride solution followed by disinfection with povidone-iodine twice.And then MEBO was applied to the wound at a thickness of approximately 1 mm.After applying ionic silver dressing,the wound was covered with sterile gauze.The wound dressing was replaced every 2-3 d.At the 4-mo follow-up,the treatment outcome was satisfactory.There was minimal scar tissue formation,and limb function was not impaired.CONCLUSION The combination of ionic silver dressing and MEBO to ACC is helpful.
文摘Photocatalytic degradation of gaseous pollutants on Bi-based semiconductors under solar lightirradiation has attracted significant attention.However,their application in gaseous straight-chainalkane purification is still rare.Here,a series of Bi/BiOBr composites were solvothermally synthe-sized and applied in solar-light-driven photocatalytic degradation of gaseous n-hexane.The charac-terization results revealed that both increasing number of functional groups of alcohol solvent(from methanol and ethylene glycol to glycerol)and solvothermal temperature(from 160 and 180to 200℃)facilitated the in-situ formation of metallic Bi nanospheres on BiOBr nanoplates withexposed(110)facets.Meanwhile,chemical bonding between Bi and BiOBr was observed on theseexposed facets that resulted in the formation of surface oxygen vacancy.Furthermore,the synergis-tic effect of optimum surface oxygen vacancy on exposed(110)facets led to a high visible light re-sponse,narrow band gap,great photocurrent,low recombination rate of the charge carriers,andstrong·O2-and h*formation,all of which resulted in the highest removal efficiency of 97.4%within120 min of 15 ppmv of n-hexane on Bi/BiOBr.Our findings efficiently broaden the application ofBi-based photocatalysis technology in the purification of gaseous straight-chain pollutants emittedby the petrochemical industry.
文摘The frequency of micronuclei (MN) in cells of the nasal mucosa, oral mucosa and in lym-phocytes was evaluated for 25 students in anatomy classes exposed to formaldehyde (FA) overan 8-week period. Each student served as his or her own control. The time-weighted averageconcentration (TWA) of fOrmaldehyde in anatomical laboratories and in students' dormitorieswas 0. 508 ± 0. 299 mg/m3 and 0. 012 ± 0. 0025mg/m3, respectively. A higher frequency ofmicronuclei was observed in nasal and oral exfoliative cells after formaldehyde exposure (3. 85± 1. 48 vs 1 .20± 0. 676 and 0. 857 ± 0. 558 vs 0. 568 ± 0. 317, paired-t test: P< 0. 001and P < 0. 01, respectively). No significant increase in the frequency of lymphocyte micronu-clei was found after formaldehyde exposure (P >0. 05 ). The present study shows that nasalmucosa cel1s exposed through respiration are the chief target of FA-induced genotoxic effects
基金Project sponsored by the National Natural Science Foundation of China
文摘In the later stage of Late Pleistocene, global climate entered into the climax period of Wurm when temperature decreased remarkably and glaciers developed. Information from the East China Sea also confirm that the sea level fell by at least 130 m at that time (Emery, 1968). The Bohai Sea and Yellow Sea at the climax period were totally exposed, while the East China Sea and South China Sea shelf regions were exposed partly. The exposed shelf area exceeded 1 million km2 and became a salty desert where land plants could not survive. Such were the conditions which led to the desertization of the shelf region.Eolation was the major exogenetic force not only on land but also on the shelf region in the ice age. At the climax period of Wiirm, the northern part of China developed thick layers of loess deposits. The shelf region at that time had similar climatic conditions and sediments. Because the shelf region was not protected by vegetation in the ice age, intensive wind storms remoulded the primarily
基金financially supported by the National Natural Science Foundation of China(Grants 52072165,52070092,51662031)。
文摘Oxygen vacancy plays vital roles in regulating the electronic and charge distribution of the oxygen deficient materials.Herein,abundant oxygen vacancies are created during assembling the two-dimensional(2D)ultra-thin Bi_(2)MoO_(6) nanoflakes into three dimensional(3D)Bi_(2)MoO_(6) nanospheres,resulting in significantly improved performance for photocatalytical conversion of CO_(2) into liquid hydrocarbons.The increased performance is contributed by two primary sites,namely the abundant oxygen vacancy and the exposed molybdenum(Mo)atom induced by oxygen-migration,as revealed by the theoretical calculation.The oxygen vacancy(Ov)and uncovered Mo atom serving as dual binding sites for trapping CO_(2) molecules render the synchronous fixation-reduction process,resulting in the decline of activation energy for CO_(2) reduction from 2.15 eV on bulk Bi_(2)MoO_(6) to 1.42 eV on Ov-rich Bi_(2)MoO_(6).Such a striking decrease in the activation energy induces the efficient selective generation of liquid hydrocarbons,especially the methanol(C_(2)H_(5) OH)and ethanol(CH_(3) OH).The yields of CH_(3) OH and C_(2)H_(5) OH over the optimal Ov-Bi_(2)MoO_(6) is high up to 106.5 and 10.3μmol g^(-1) respectively,greatly outperforming that on the Bulk-Bi_(2)MoO_(6).
文摘Cytokinesis-blocked micronucleus assay was applied as a biological dosimeter to detect abnormalities in human peripheral lymphocytes of thirteen students exposed to formaldehyde (FA) during a 12-week (10 h per week) anatomy class. Breathing-zone air samples colleeted during dissection procedures showed a mean concentration of 2. 37 ppm (3. 17mg/m3 ). Ten students from the same school but without FA exposure served as controls. Chromosome aberrations (CA) and sister chromatid exchanges (SCE) were detected in both groups. The micronuclei (MN) rate (6. 38 ± 2. 50‰ ) and CA rate (5. 92 ±2. 40‰ ) in the FA-exposed group showed a significant increase (P< 0. 01 ) when compared with those of the controls (3. 15 ±1. 46‰and 3. 40 ± 1. 57 % respectively). A correlation between MN and CA in individuals was observed. SCE in the exmpd group were also increased (P< 0. 05), but not so greatly as MN or CA. The results indicated that FA might damage the chromosomes of human lymphocytes.
基金Supported by Key Research and Development Project of Jiangsu Province,No.BE2018626。
文摘BACKGROUND Body parts such as the face and hands are highly exposed during daily life and burns may accumulate in these areas.In addition,residual wounds,scar hyperplasia and contracture often exist in the late stage of a deep burn in these areas,which may affect patients’appearance,movements,and mental health.However,inadequate attention has been paid to this issue which can result in problems,such as difficulty in healing,possibility of carcinoma,chronic pain and a heavy mental burden.AIM To investigate the long-term medical treatment of patients with severe burns at exposed sites following a mass burn casualty event.METHODS A retrospective analysis of 13 patients with severe burns at exposed sites was performed to determine their respective long-term medical treatment.A combined wound dressing scheme consisting of traditional Chinese and Western medicine was introduced to repair residual wounds.Active and passive functional exercises with massage,Chinese herbal baths and compression fixation were proposed to ameliorate the condition of the hands.A combination of physical,chemical and photoelectrical measures was adopted for anti-scar treatment.A psychological intervention and recovery guide was provided which corresponded to the patients’psychological status.RESULTS Compared to patients who did not simultaneously receive the same treatment,patients who underwent systematic treatment recovered with a lower woundinfection rate(P<0.05),a shorter healing time(13.6±3.2 d)compared with(19.1±3.5 d)and more bearable pain during wound dressing at three days,one week and two weeks after a Chinese herbal bath(P<0.05).Satisfactory results were achieved with regard to restored function of patients’joints and blood supply to nerve endings,closure of the eyelids and the size of mouth opening tended to be normal,and only 7.1%of patients were diagnosed with severe scar hyperplasia and contracture deformity compared with 30.7%in the control group.In addition,the color,thickness,vascular distribution and softness score of the scars improved(P<0.01),and the effects of the psychological intervention was remarkable as shown by the Self-Rating Anxiety Scale and Self-Rating Depression Scale.CONCLUSION A better prognosis can be achieved in patients in the late stage of a burn with active residual wound repair,limb functional exercise,anti-scar and psychological rehabilitation.