Abnormal characterization of dynamic functional connectivity in Alzheimer’s disease

Numerous studies have shown abnormal brain functional connectivity in individuals with Alzheimer’s disease(AD)or amnestic mild cognitive impairment(aMCI).However,most studies examined traditional resting state functional connections,ignoring the instantaneous connection mode of the whole brain.In this case-control study,we used a new method called dynamic functional connectivity(DFC)to look for abnormalities in patients with AD and aMCI.We calculated dynamic functional connectivity strength from functional magnetic resonance imaging data for each participant,and then used a support vector machine to classify AD patients and normal controls.Finally,we highlighted brain regions and brain networks that made the largest contributions to the classification.We found differences in dynamic function connectivity strength in the left precuneus,default mode network,and dorsal attention network among normal controls,aMCI patients,and AD patients.These abnormalities are potential imaging markers for the early diagnosis of AD.

Simulation of jet-flow solid fraction during spray forming

A numerical model was developed to simulate the jet-flow solid fraction of W18Cr4 V high-speed steel during spray forming. The whole model comprises two submodels: one is an individual droplet model, which describes the motion and thermal behaviors of individual droplets on the basis of Newton's laws of motion and the convection heat transfer mechanism; the other is a droplet distribution model, which is used to calculate the droplet size distribution. After being verified, the model was used to analyze the effects of parameters, including the initial gas velocity, deposition distance, superheat degree, and the ratio of gas-to-metal mass flow rates, on the jet-flow solid fraction. Finally, an equation to predict the jet-flow solid fraction directly and conveniently according to the parameters was presented. The values predicted by the equation show good agreement with those calculated by the numerical model.

Anodized metal oxide nanostructures for photoelectrochemical water splitting

Photoelectrochemical(PEC) water splitting offers the capability of harvesting, storing, and converting solar energy into clean and sustainable hydrogen energy. Metal oxides are appealing photoelectrode materials because of their easy manufacturing and relatively high stability. In particular, metal oxides prepared by electrochemical anodization are typical of ordered nanostructures, which are beneficial for light harvesting, charge transfer and transport, and the adsorption and desorption of reactive species due to their high specific surface area and rich channels. However, bare anodic oxides still suffer from low charge separation and sunlight absorption efficiencies. Accordingly, many strategies of modifying anodic oxides have been explored and investigated. In this review, we attempt to summarize the recent advances in the rational design and modifications of these oxides from processes before, during, and after anodization. Rational design strategies are thoroughly addressed for each part with an aim to boost overall PEC performance. The ongoing efforts and challenges for future development of practical PEC electrodes are also presented.

Microstructure and mechanical properties of spark plasma sintered Ti–Mo alloys for dental applications

Ti-Mo alloys with various Mo contents from 6wt% to 14wt% were processed by spark plasma sintering based on elemental pow- ders. The influence of sintering temperature and Mo content on the microstructure and mechanical properties of the resulting alloys were investigated. For each Mo concentration, the optimum sintering temperature was determined, resulting in a fully dense and uniform microstructure of the alloy. The optimized sintering temperature gradually increases in the range of 1100-1300℃ with the increase in Mo content. The microstructure of the Ti-（6-12）Mo ahoy consists of acicular α phase surrounded by equiaxed grains of 13 phase, while the Ti-14Mo al- loy only contains single 13 phase. A small amount of fine α lath precipitated from 13 phase contributes to the improvement in strength and hardness of the alloys. Under the sintering condition at 1250℃, the Ti-12Mo alloy is found to possess superior mechanical properties with the Vickers hardness of Hv 472, the compressive yield strength of 2182 MPa, the compression rate of 32.7%, and the elastic modulus of 72.1 GPa. These results demonstrate that Ti-Mo alloys fabricated via spark plasma sintering are indeed a perspective candidate alloy for dental applications.

300 MPa grade biodegradable high-strength ductile low-alloy(BHSDLA)Zn-Mn-Mg alloys:An in vitro study

300 MPa grade biodegradable Zn-(0.6,0.8)Mn-(<0.1)Mg alloys with yield strengths>300 MPa and elongations>15%have been developed,which are designated as Zn06Mn006Mg(HE)and Zn08Mn005Mg(HE)in as-extruded state.They are the newest members of a small group of biodegradable Zn alloys with mechanical properties beyond the generally accepted benchmark for orthopedic implants.Immersed in simulated body fluid for 30 days,Zn06Mn006Mg(HE)and Zn08Mn005Mg(HE)exhibit corrosion rates of 38 and 53μm y^(-1),respectively.They show high antibacterial rates of 93%-97%against E.coli.In 25%-75%extracts of both the alloys,MC3T3-E1 cell viabilities for 1 day and 3 days are all over 100%,indicating complete cytocompatibility.In 100%extracts for 3 days,both alloys show non-toxicity.After a longtime room temperature storage of 72 weeks,natural embrittling alike Zn-Mg alloys does not happen.The Zn-Mn-Mg alloys still have mechanical properties exceeding the benchmark by a large margin.The in vitro study shows the newly developed BHSDLA Zn-Mn-Mg alloys are promising candidates for orthopedic implants.

Biodegradable Zn-0.5Li alloy rib plate:Processing procedure development and in vitro performance evaluation

Trauma kills more than four million people worldwide each year,with chest trauma accounting for 25%of these deaths.Rib fractures are the main manifestation of chest trauma.Biodegradable Zn alloys offer a new option to overcome clinical problems caused by permanent rib fracture internal fixation mate-rials,e.g.,long-term stress masking and secondary surgery.In this study,the fabrication procedure of biodegradable Zn-0.5Li alloy rib plates is successfully developed,which consists of casting,hot-warm rolling,cutting,and pressing sequentially.Biomechanical three-point bending performance of the Zn al-loy rib plates is comparable to that of commercial pure Ti rib plates,much higher than that of pure Zn rib plates.In addition,the Zn alloy exhibits the best antibacterial ability against E.coli and S.aureus among the three materials.Although the Zn alloy exhibits a weaker MC3T3 cytocompatibility than pure Ti,it is better than pure Zn.This study provides a foundation for the future development of various biodegrad-able Zn alloy rib plates.

Zn-0.8Mn alloy for degradable structural applications:Hot compression behaviors,four dynamic recrystallization mechanisms,and better elevated-temperature strength

Environmentally degradable Zn-0.8Mn alloy is highly ductile,which lays the foundation for developing high-performance Zn-Mn-based alloys.However,not only constitutive equation of this alloy is unknown,but also its dynamic recrystallization(DRX)behavior is unclear,which makes optimization of hot pro-cessing parameters of this alloy almost dependent on trial-and-error.This work aims to tackle these prob-lems.The constitutive equation was deduced to be˙ε=1.38×10^(12)×[sinh(0.009σ)]^(8)exp(-135150/RT).A processing map of the alloy was obtained for the first time,which shows that it has excellent hot formability with narrow instability zones.At a final true strain of 0.8,the volume fraction of DRX grains increased from 37%to 79%with temperature increasing from 150℃to 350℃and strain rate decreas-ing from 10 s^(−1)to 10^(-3)s^(−1).Discontinuous DRX(DDRX),continuous DRX(CDRX),twinning-induced DRX(TDRX),and particle stimulated nucleation(PSN)were activated during hot compressions.DDRX was al-ways the main mechanism.TDRX was completely suppressed at 300℃and above.PSN arose from dis-persed MnZn 13 particles.Furthermore,Zn-0.8Mn alloy exhibited elevated-temperature strengths better than pure Zn and Zn-Al-based alloys.At 300℃and 0.1 s^(−1),its peak stress was 1.8 times of pure Zn,owing to MnZn 13 particles of 277±79 nm impeding the motion of grain boundaries and dislocations.

300 MPa grade highly ductile biodegradable Zn-2Cu-(0.2-0.8)Li alloys with novel ternary phases

Although a few high-strength biodegradable Zn alloys with yield strengths(YSs)over 300 MPa in rolled state have been developed,their elongations(ELs)are generally less than 30%.This study developed rolled Zn-2Cu-x Li(x=0.2 wt.%,0.5 wt.%,0.8 wt.%)alloys with YSs of 316-335 MPa and ELs of 44%-61%.Three-dimensional atom probe(3DAP)and time of flight secondary ion mass spectrometry(TOF-SIMS)were employed to characterize Li distribution.Three kinds of Zn-Cu-Li ternary phases are identified,which are blockyε′-(Cu_(0.5),Li_(0.5))Zn 4,blockyβ′-(Li_(0.9),Cu_(0.1))Zn 4,and small roundγparticles with high Li content in the annealed state.Other identified phases are Zn,β-LiZn 4,andε-CuZn 4 phases.With the increase of Li content in the alloys,ε′phase with 6.50 at.%Cu transforms intoβ′phase with 2.12 at.%Cu,i.e.,the average level in the alloys.Withinε′phase,there exist nano-scale Li clusters andεphase,resulting inε′/εstructure.Dense Zn laths precipitate fromβ′phase,resulting inβ′/Zn lamellar structure.The lamel-lar structure is the matrix of Zn-2Cu-0.8Li and leads to near-isotropic plasticity.Electrochemistry tests show that degradation rates fall in the range of 153-196μm/year,which decrease with Li content.All the alloys exert positive effects on the growth of MC3T3-E1 cells with 10%extract.This research reveals how microstructure evolves in Zn-2Cu-x Li alloys,which lays the foundation for their future applications.

Facile synthesis of bimodal macroporous g-C_3N_4/SnO_2 nanohybrids with enhanced photocatalytic activity

It is of vital importance to construct highly interconnected,macroporous photocatalyst to improve its efficiency and applicability in solar energy conversion and environment remediation.Graphitic-like C_3N_4(g-C_3N_4),as an analogy to two-dimensional(2D)graphene,is highly identified as a visible-lightresponsive polymeric semiconductor.Moreover,the feasibility of g-C_3N_4 in making porous structures has been well established.However,the preparation of macroporous g-C_3N_4 with abundant porous networks and exposure surface,still constitutes a difficulty.To solve it,we report a first facile preparation of bimodal macroporous g-C_3N_4 hybrids with abundant in-plane holes,which is simply enabled by in-situ modification through thermally treating the mixture of thiourea and SnCl_4(pore modifier)after rotary evaporation.For one hand,the formed in-plane macropores endow the g-C_3N_4 system with plentiful active sites and short,cross-plane diffusion channels that can greatly speed up mass transport and transfer.For another,the heterojunctions founded between g-C_3N_4 and SnO_2 consolidate the electron transfer reaction to greatly reduce the recombination probability.As a consequence,the resulted macroporous gC_3N_4/SnO_2 nanohybrid had a high specific surface area(SSA)of 44.3 m^2/g that was quite comparable to most nano/mesoporous g-C_3N_4 reported.The interconnected porous network also rendered a highly intensified light absorption by strengthening the light penetration.Together with the improved mass transport and electron transfer,the macroporous g-C_3N_4/SnO_2 hybrid exhibited about 2.4-fold increment in the photoactivity compared with pure g-C_3N_4.Additionally,the recyclability of such hybrid could be guaranteed after eight successive uses.

Bacterial anti-adhesion surface design:Surface patterning,roughness and wettability:A review

Bacterial adhesion and biofilm formation impose a heavy burden on the medical system. Bacterial adhesion on implant materials would induce inflammation and result in implant failure. The adhesion of bacteria on food-processing and handling equipment may lead to food-borne illness. To reduce and even prevent bacterial adhesion, some bacterial anti-adhesion surface designs have been developed. However,the effect of some surface properties(including surface patterning, roughness and wettability) on bacterial adhesion has not been systematically summarized. In this review, a comprehensive overview of bacterial anti-adhesion surface design is presented. Modifying the surface pattern and roughness could reduce the contact area between bacteria and surfaces to weaken the initial adhesion force. Fabricating superhydrophobic surface or modifying hydrophilic functional groups could hinder the bacterial adhesion. The analysis and discussion about influencing factors of bacterial anti-adhesion surfaces provide basic guidelines on antibacterial surface design for future researches.

High-performance hot-warm rolled Zn-0.8Li alloy with nano-sized metastable precipitates and sub-micron grains for biodegradable stents

Fabricated through a newly developed hot-warm rolling process,Zn-0.8 Li(wt%)alloy has ideal strength and ductility far beyond the mechanical benchmark of materials for biodegradable stents.Precipitation of needle-like Zn in primary p-LiZn4 phase is observed in Zn-Li alloy for the first time.Orientation relationship between them can be described as[1-213]β//[2-1-10](Zn),(10-10)βabout 4.5°from(0002)(Zn).Zn grains with an average size of 640 nm exhibit strong basal texture,detected by transmission electron back-scatter diffraction.Li distribution is determined by three-dimensional atom probe,which reveals the formation of nano-sized metastableα-Li2Zn3 precipitates with a number density of 7.16×10^22 m^-3.The fine lamellar Zn+β-LiZn4 structure,sub-micron grains and the nano-sized precipitates contribute to the superior mechanical properties.

Awareness Status of Chronic Disabling Neurological Diseases among Elderly Veterans

Background：The awareness,treatment and prevention of chronic diseases are generally poor among the elderly population of China,whereas the prevention and control of chronic diseases in elderly veteran communities have been ongoing for more than 30 years.Therefore,investigating the awareness status of chronic disabling neurological diseases （CDND） and common chronic diseases （CCD） among elderly veterans may provide references for related programs among the elderly in the general population.Methods：A cross-sectional survey was conducted among veterans ≥60 years old in veteran communities in Beijing.The awareness of preventive strategies against dementia,Alzheimer＆#39;s disease （AD）,Parkinson＆#39;s disease （PD）,sleep disorders,cerebrovascular disease （CVD） and CCD such as hypertension,and the approaches used to access this information,including media,word of mouth （verbal communication among the elderly） and health care professionals,were investigated via face-to-face interviews.Results：The awareness rates for CCD and CVD were approximately 100%,but that forAD was the lowest at 〈10%.The awareness rates for sleep disorders,PD and dementia,were 51.0-89.4%.Media was the most commonly selected mode of communication by which veterans acquired knowledge about CCD and CVD.Media was used by approximately 80% of veterans.Both health care professionals and word of mouth were used by approximately 50% of veterans.With respect to the source of information about CDND excluding AD,the rates of the use of health care professionals,word of mouth and media were 10.6-28.2%,56.5-76.5%,and approximately 50%,respectively.Conclusions：The awareness of CDND among elderly veterans was significantly lower than that of CCD.More information about CDND should be disseminated by health care professionals.Appropriate guidance will promote the rapid and extensive dissemination of information about the prevention of CDND by media and word-of-mouth peer education.

Design biodegradable Zn alloys: Second phases and their significant influences on alloy properties

Alloying combined with plastic deformation processing is widely used to improve mechanical properties of pure Zn.As-cast Zn and its alloys are brittle.Beside plastic deformation processing,no effective method has yet been found to eliminate the brittleness and even endow room temperature super-ductility.Second phase,induced by alloying,not only largely determines the ability of plastic deformation,but also influences strength,corrosion rate and cytotoxicity.Controlling second phase is important for designing biodegradable Zn alloys.In this review,knowledge related to second phases in biodegradable Zn alloys has been analyzed and summarized,including characteristics of binary phase diagrams,volume fraction of second phase in function of atomic percentage of an alloying element,and so on.Controversies about second phases in Zn-Li,Zn-Cu and Zn-Fe systems have been settled down,which benefits future studies.The effects of alloying elements and second phases on microstructure,strength,ductility,corrosion rate and cytotoxicity have been neatly summarized.Mg,Mn,Li,Cu and Ag are recommended as the major alloying elements,owing to their prominent beneficial effects on at least one of the above properties.In future,synergistic effects of these elements should be more thoroughly investigated.For other nutritional elements,such as Fe and Ca,refining second phase is a matter of vital concern.

Initial formation of corrosion products on pure zinc in simulated body fluid

Zinc was recently suggested to be a potential candidate material for degradable coronary artery stent.The corrosion behavior of pure zinc exposed to r-SBF up to 336 h was investigated by electrochemical measurements and immersion tests. The morphology and chemical composites of the corrosion products were investigated by scanning electron microscope, grazing-incidence X-ray diffraction, X-ray photoelectron spectroscopy and Fourier transform infrared spectrometer. The results demonstrate that the initial corrosion products on the pure zinc mainly consist of zinc oxide/hydroxide and zinc/calcium phosphate compounds. The pure Zn encounters uniform corrosion with an estimated corrosion rate of 0.02-0.07 mmy;during the immersion, which suggests the suitability of pure Zn for biomedical applications.

Initial formation of corrosion products on pure zinc in saline solution

Corrosion product formed on zinc sample during 2 weeks immersion in saline solution has been investigated.The corrosion layer morphology as well as its chemical composition,was analyzed using scanning electron microscopy(SEM),x-ray diffraction(XRD),x-ray photoelectron spectroscopy(XPS)and Fourier transform infrared spectroscopy(FTIR).Electrochemical measurement was used to analyze the corrosion behavior.Zinc oxide,zinc hydroxide and zinc hydroxide chloride were formed on zinc surface in saline solution.The thickness of corrosion layer increased with the time increased.The pure Zn has an estimated corrosion rate of 0.063mmy^−1 after immersion for 336 h.Probable mechanisms of zinc corrosion products formation are presented.

Fabrication and characterization of novel biodegradable Zn-Mn-Cu alloys

Zn-Mn-Cu alloys with micro-alloying of Mn and Cu in Zn are developed as potential biodegradable met- als. Although the as-cast alloys are very brittle, their ductilities are significantly improved through hot rolling. Among the as-cast and the as-hot-rolled alloys, as-hot-rolled Zn-0.35Mn-0.41 Cu alloy has the best comprehensive property. It has yield strength of 198.4 ± 6.7 MPa, tensile strength of 292.4 ± 3.4 MPa, elongation of 29.6 ±3.8% and corrosion rate of 0.050-0.062 mm a^-1. A new ternary phase is characterized and determined to be MnCuZn18, which is embedded in MnZn13, resulting in a coarse cellular/dendritic MnZna3-MnCuZn18 compound structure in Zn-0.75 Mn-0.40Cu alloy. Such a coarse compound structure is detrimental for wrought alloy properties, which guides future design of Zn-Mn-Cu based alloys. The preliminary research indicates that Zn-Mn-Cu alloy system is a promising candidate for potential cardiovascular stent applications.

Facile fabrication of three-dimensional interconnected nanoporous N-TiO_2 for efficient photoelectrochemical water splitting

Three-dimensional （3D） interconnected porous architectures are expected to perform well in photoelectrochemical （PEC） water splitting due to their high specific surface area as well as favourable porous properties and interconnections. In this work, we demonstrated the facile fabrication of 3D interconnected nanoporous N-doped TiO2 （N-TiO2 network） by annealing the anodized 3D interconnected nanoporous TiO2 （TiO2 network） in ammonia atmosphere. The obtained N-TiO2 network exhibited broadened light absorption, and abundant, interconnected pores for improving charge separation, which was supported by the reduced charge transfer resistance. With these merits, a remarkably high photocurrent density at 1.23 V vs. reversible hydrogen electrode （RHE） was realized for the N-TiO2 network without any co-catalysts or sacrificial reagents, and the photostability can be assured after long term illumination. In view of its simplicity and efficiency, this structure promises for perspective PEC applications.

Hierarchical microstructure and two-stage corrosion behavior of a high-performance near-eutectic Zn-Li alloy

In order to improve mechanical and corrosion properties of biodegradable pure Zn,a knowledge-based microstructure design is performed on Zn-Li alloy system composed of hard β-LiZn_(4) and soft Zn phases.Precipitation and multi-modal grain structure are designed to toughen β-LiZn_(4) while strengthen Zn,resulting in high strength and high ductility for both the phases.Needle-like secondary Zn precipitates form in β-LiZn4,while fine-scale networks of string-like β-LiZn4 precipitates form in Zn with a tri-modal grain structure.As a result,near-eutectic Zn-0.48 Li alloy with an outstanding combination of high strength and high ductility has been fabricated through hot-warm rolling,a novel fabrication process to realize the microstructure design.The as-rolled alloy has yield strength(YS) of 246 MPa,the ultimate tensile strength(UTS) of 395 MPa and elongation to failure(EL) of 47 %.Immersion test in simulated body fluid(SBF) for 30 days reveals that Li-rich products form preferentially at initial stage,followed by Zn-rich products with prolonged time.Aqueous insoluble Li_(2) CO_(3) forms a protective passivation film on the alloy surface,which suppresses the average corrosion rate from 81.2 μm/year at day one down dramatically to 18.2 μm/year at day five.Afterwards,the average corrosion rate increases slightly with decrease of Li2 CO_(3) content,which undulates around the clinical requirements on corrosion resistance(i.e.,20 μm/year) claimed for biodegradable metal stents.

Effects of γ-Ray Irradiation on the Fatigue Strength, Thermal Conductivities and Thermal Stabilities of the Glass Fibres/Epoxy Resins Composites

Glass fibres/epoxy resins composites have been performed as ideal materials to make support instruments for high-energy and nuclear physics experiments. The effects of the 3,-ray irradiation on the fatigue strength, thermal conductivities and thermal stabilities of the glass fibres/epoxy resins composites were investigated. And a two-parameter fatigue life model was established to predict the fatigue life of the composites. Results revealed that the y-ray irradiation could probably result in the degradation of epoxy resins, but hardly damage to the glass fibres. And the γ-ray irradiation treatment could significantly affect the fatigue strength of the composites at a low-cycle fatigue stage, but seldom influence at a high-cycle fatigue stage. Furthermore, the fabricated glass fibres/epoxy resins composites after the γ-ray irradiation still presented excellent fatigue strength, ideal thermal conductivities, remarkable dimensional and thermal stabilities, which can meet the actual requirements of normal operation for supporting instruments under high-energy and nuclear physics experiments.

Regulation of RAW 264.7 macrophages behavior on anodic TiO2 nanotubular arrays

Titanium （Ti） implants with TiO2 nanotubular arrays on the surface could regulate cells adhesion, proliferation and differentiation to determine the bone integra- tion. Additionally, the regulation of immune cells could improve osteogenesis or lead in appropriate immune reaction. Thus, we evaluate the behavior of RAW 264.7 macrophages on TiO2 nanotubular arrays with a wide range diameter （from 20 to 120 nm） fabricated by an electrochemical anodization process. In this work, the proliferation, cell viability and cytokine/chemokine secretion were evaluated by CCK-8, live/dead staining and ELISA, respectively. SEM and confocal microscopy were used to observe the adhesion morphology. Results showed that the small size nanotube surface was benefit for the macrophages adhesion and proliferation, while larger size surface could reduce the inflammatory response. These findings contribute to the design of immune-regulating Ti implants surface that supports successful implantation.