Factors resisting protein adsorption on hydrophilic/hydrophobic self-assembled monolayers terminated with hydrophilic hydroxyl groups

The hydroxyl-terminated self-assembled monolayer(OH-SAM),as a surface resistant to protein adsorption,exhibits substantial potential in applications such as ship navigation and medical implants,and the appropriate strategies for designing anti-fouling surfaces are crucial.Here,we employ molecular dynamics simulations and alchemical free energy calculations to systematically analyze the factors influencing resistance to protein adsorption on the SAMs terminated with single or double OH groups at three packing densities(∑=2.0 nm^(-2),4.5 nm^(-2),and 6.5 nm^(-2)),respectively.For the first time,we observed that the compactness and order of interfacial water enhance its physical barrier effect,subsequently enhancing the resistance of SAM to protein adsorption.Notably,the spatial hindrance effect of SAM leads to the embedding of protein into SAM,resulting in a lack of resistance of SAM towards protein.Furthermore,the number of hydroxyl groups per unit area of double OH-terminated SAM at ∑=6.5 nm^(-2) is approximately 2 to 3 times that of single OH-terminated SAM at ∑=6.5 nm^(-2) and 4.5 nm^(-2),consequently yielding a weaker resistance of double OH-terminated SAM towards protein.Meanwhile,due to the structure of SAM itself,i.e.,the formation of a nearly perfect ice-like hydrogen bond structure,the SAM exhibits the weakest resistance towards protein.This study will complement and improve the mechanism of OH-SAM resistance to protein adsorption,especially the traditional barrier effect of interfacial water.

Upper Bound Solution of the Resisting Moment Bearing Capacity of A Composite Bucket Shallow Foundation of An Offshore Wind Turbine in Sand

Bearing the large moment that is generated by the wind load that acts on the upper structure of offshore wind turbines is an important feature of their foundations that is different from other offshore structures.A composite bucket shallow foundation(CBSF)has been proposed by Tianjin University to address the soft geological conditions in the offshore regions of China for wind turbines.The CBSF is a new type of foundation and is effective against large moments.The soil deformation test of a CBSF and the numerical simulation study under the same working conditions are carried out to determine the failure mechanism of a CBSF under moment loading.The resisting soil compression rateηm is defined as a new empirical parameter that indicates the ability of the soil inside the bucket to resist moment loading.The upper limit of the resisting moment bearing capacity of the bucket foundation is derived through the upper bound theorem of classical plasticity theory based on the failure mechanism.The calculation method is validated by tests of bucket models with different height-diameter ratios in sand under moment loading.

Snow resisting capacity of Caragana microphylla and Achnatherum splendens in a typical steppe region of Inner Mongolia,China

Snow resisting capacity of vegetation is important for secondary distribution of water resources in seasonal snow areas of grassland because it affects the regeneration,growth and nutrient circulation of vegetation in grassland.This study investigated vegetation characteristics(canopy height,canopy length and crown width)of Caragana microphylla Lam.(shrub)and Achnatherum splendens(Trin.)Nevski.(herb),and snow morphologies(snow depth,snow width and snow braid length)in a typical steppe region of Inner Mongolia,China in 2017.And the influence of vegetation characteristic on snow resisting capacity(the indices of bottom area of snow and snow volume reflect snow resisting capacity)was analyzed.The results showed that snow morphology depends on vegetation characteristics of shrub and herb.The canopy height was found to have the greatest influence on snow depth and the crown width had the greatest influence on snow width.The canopy length was found to have little influence on morphological parameters of snow.When the windward areas of C.microphylla and A.splendens were within the ranges of 0.0-0.5 m2 and 0.0-8.0 m2,respectively,the variation of snow cover was large;however,beyond these areas,the variation of snow cover became gradually stable.The potential area of snow retardation for a single plant was 1.5-2.5 m2 and the amount of snow resistance was 0.15-0.20 m3.The bottom area of snow and snow volume(i.e.,snow resisting capacity)of clumped C.microphylla and A.splendens was found to be 4 and 25 times that of individual plant,respectively.The results could provide a theoretical basis both for the estimation of snow cover and the establishment of a plant-based technical system for the control of windblown snow in the typical steppe region of Inner Mongolia.

Effectiveness of two conventional methods for seismic retrofit of steel and RC moment resisting frames based on damage control criteria

This study investigates the efficiency of two types of rehabilitation methods based on economic justification that can lead to logical decision making between the retrofitting schemes. Among various rehabilitation methods, concentric chevron bracing（CCB） and cylindrical friction damper（CFD） were selected. The performance assessment procedure of the frames is divided into two distinct phases. First, the limit state probabilities of the structures before and after rehabilitation are investigated. In the second phase, the seismic risk of structures in terms of life safety and financial losses（decision variables） using the recently published FEMA P58 methodology is evaluated. The results show that the proposed retrofitting methods improve the serviceability and life safety performance levels of steel and RC structures at different rates when subjected to earthquake loads. Moreover, these procedures reveal that financial losses are greatly decreased, and were more tangible by the application of CFD rather than using CCB. Although using both retrofitting methods reduced damage state probabilities, incorporation of a site-specific seismic hazard curve to evaluate mean annual occurrence frequency at the collapse prevention limit state caused unexpected results to be obtained. Contrary to CFD, the collapse probability of the structures retrofitted with CCB increased when compared with the primary structures.

Optimal seismic retrofit model for steel moment resisting frames with brittle connections

Based on performance-based seismic engineering, this paper proposes an optimal seismic retrofit model for steel moment resisting frames（SMRFs） to generate a retrofit scheme at minimal cost. To satisfy the acceptance criteria for the Basic Safety Objective（BSO） specified in FEMA 356, the minimum number of upgraded connections and their locations in an SMRF with brittle connections are determined by evolutionary computation. The performance of the proposed optimal retrofitting model is evaluated on the basis of the energy dissipation capacities, peak roof drift ratios, and maximum interstory drift ratios of structures before and after retrofitting. In addition, a retrofit efficiency index, which is defined as the ratio of the increment in seismic performance to the required retrofitting cost, is proposed to examine the efficiencies of the retrofit schemes derived from the model. The optimal seismic retrofit model is applied to the SAC benchmark examples for threestory and nine-story SMRFs with brittle connections. Using the retrofit efficiency index proposed in this study, the optimal retrofit schemes obtained from the model are found to be efficient for both examples in terms of energy dissipation capacity, roof drift ratio, and maximum inter-story drift ratio.

Resistance to chemical attack of bittern-resisting cement in high-bittern environment

A new kind of bittern-resisting cement （BRC） was introduced. This material is based on the ternary cementitious system of clinker containing C4A3 S phase, high-activity ground granulated blast-furnace slag （GGBFS） and fly ash （FA）. The hydration process and the hydrated products of BRC were studied by means of XRD, TG-DTA and SEM, and the resistance to chemical attack of BRC in high-bittern environment was also examined. The corrosion experiment in seven kinds of brines proved that BRC exhibits an excellent resistance to chemical attack of bittern. The corrosion resistance factors were calculated and all of them were greater than 0.96. It showed that BRC totally controls the cement-based material corrosion in brines from four aspects： （1） making full use of the dominant complementation effect of mineral materials; （2） diminishing the hydrated products easy to be attacked; （3） improving the microstructure of hardened cement mortar; （4） degrading the chemical attack of bittern.

The Analysis of the Line Pattern of Nonlinear Winding Filament on FRP Composite Air Vessel Resisting High Pressure

The FW process is a prefect method of manufacturing FRP composite air vessel resisting high pressure and aerial press vessel.In this paper FW pattern of FRP composite air vessel resisting high pressure was analyzed in a nutshell.The stability of FW patterns on end head is very sensitive to changing of pattern parameter.Consequently,its FW pattern was based on geodesic track.The FW angles and on equators depend on the dimension of end part and the condition of geodesic FW.Generally speaking, the polar holes of rocket engine shell are disproportional.Therefore,the FW angles of the shell column are changeable.The feasi- bility of nongeodesic FW of the shell column was discussed in this paper.Furthermore,it expounded the indispensable condition be- tween the length of shell column and the FW friction coefficient.At the same time,the general mathematic models of the movement control of nongeodesic FW were deduced.

Seismic design factors for RC special moment resisting frames in Dubai,UAE

This study investigates the seismic design factors for three reinforced concrete （RC） framed buildings with 4, 16 and 32-stories in Dubai, UAE utilizing nonlinear analysis. The buildings are designed according to the response spectrum procedure defined in the 2009 International Building Code （IBC＇09）. Two ensembles of ground motion records with 10% and 2% probability of exceedance in 50 years （10/50 and 2/50, respectively） are used. The nonlinear dynamic resPonses to the earthquake records are computed using IDARC-2D. Key seismic design parameters are evaluated; namely, response modification factor （R）, deflection amplification factor （Cd）, system overstrength factor （Ωo）, and response modification factor for ductility （Rd） in addition to inelastic interstory drift. The evaluated seismic design factors are found to significantly depend on the considered ground motion （10/50 versus 2/50）. Consequently, resolution to the controversy of Dubai seismicity is urged. The seismic design factors for the 2/50 records show an increase over their counterparts for the 10/50 records in the range of 200%-400%, except for the D~ factor, which shows a mere 30% increase. Based on the observed trends, perioddependent R and Cd factors are recommended if consistent collapse probability （or collapse prevention performance） in moment frames with varying heights is to be expected.

THE HYDRATES AND MICROSTRUCTURE OF PERMEABLITY RESISTING PORTLAND CEMENT

The hydrating products and microstructure of permeability resisting portland cement have been studied by x-ray diffraction (XRD) and electron microscopy (EM). The hydrates such as calcium silicates hydrate and calcium sulphaluminate hydrate, ettringite crystal of needles can be observed under the EM, most of which were filled into pores of hardened cement paste.

LONG-TERM CREEP AND RUPTURE PROPERTIES OF HEATRESISTING STEELS AND ALLOYS

The present status of NRIM Creep Data Sheet Project and the recent activities of long-term creep and rupture studies on heat resisting steels are described. The project has been continued to produce long-term data such as 100 000h-creep rupture strength for 47 kinds of principal heat resisting steels and alloys, including welded joints. The long-term creep deformation behavior and microstructural evolution during creep have been shown to be complicated.

Acceleration of DNA Replication of Klenow Fragment by Small Resisting Force

DNA polymerases are an essential class of enzymes or molecular motors that catalyze processive DNA syntheses during DNA replications. A critical issue for DNA polymerases is their molecular mechanism of processive DNA replication. We have proposed a model for chemomechanical coupling of DNA polymerases before, based on which the predicted results have been provided about the dependence of DNA replication velocity upon the external force on Klenow fragment of DNA polymerase I. Here, we performed single molecule measurements of the replication velocity of Klenow fragment under the external force by using magnetic tweezers. The single molecule data verified quantitatively the previous theoretical predictions, which is critical to the chemomechanical coupling mechanism of DNA polymerases. A prominent characteristic for the Klenow fragment is that the replication velocity is independent of the assisting force whereas the velocity increases largely with the increase of the resisting force,attains the maximum velocity at about 3.8 pN and then decreases with the further increase of the resisting force.

Agricultural Drought Resisting and Hydrological-Ecological Changes Taking Hebei Province in North China as an Example

Drought is usually supposed to be a rainfall deficiency problem. Most studies and practices to mitigate drought disaster are focusing on water development and irrigation, while neglecting that the agriculture system is a compounded human-natural system. Drought situation and tendency is also driven by human coping strategies. This paper takes Hebei Province in north China as an example, studing the spirally interact process of drought resisting and hydrological ecological feedback. The result shows that large scale water projects construction facilitated irrigation. With improved irrigation, farmers enhanced multiple crop index and land-use intensity greatly and increased the sowing area of water consuming crop, winter wheat. At the same time, both crop yield and gross output are raising steadily. Water demand and depletion in agricultural system increase year by year. This gradually leads to highly dependent on over exploitation of water resources, especially overdraw of groundwater. The process deteriorated the stability of hydrological-ecological system and made the ecological environment drying up. Drying up environment is breeding greater vulnerability and risk of drought in the long term. For sustainable development, integrated drought risk management should be based on the balance between sustainable water supply and water demand. The key is to improve agricultural system＇s adaptive and resilient capacity to drought.

Seismic Evaluation of Steel Moment Resisting Frames (MRFs)—Supported by Loose Granular Soil

Soil underneath a structure might affect the behavior and the overall response of the structure in seismic events. The role of loose soil conditions and the inclusion of soil-structure interaction (SSI) in the analysis are important issues that need to be addressed. Since steel structures are light, two configurations designed as spatial and perimeter are considered to study the effect of soil on the steel structural frames for the same building. The paper provides a parametric analysis on the influence of SSI on the overall performance of MRFs (Moment Resisting Frames) according to the provisions of Saudi Building Code (SBC) [1]. A case study has been developed in which spatial and perimeter moment resisting frames of 12, 6 and 3 stories residential buildings are designed using Saudi Building Code (SBC) prescriptions. A modal response spectrum analysis has been carried out to see the influence of SSI on the fundamental period of vibration, top story displacement and inter-story drift limitations. Moreover, a static non-linear analysis has been performed to investigate the performance of frames, thus allowing to identify the influence of SSI on the structural design of steel MRFs.

DIFFUSION COUPLE BETWEEN HIGHSTRENGTH WEAR-RESISTING ALUMINUM BRONZE AND MACHINING TOOLS MATERIALS

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IMPROVEMENT OF TYPE IV CRACKING RESISTANCE OF 9Cr HEAT RESISTING STEEL WELDMENT BY BORON ADDITION

Creep lives of high Cr ferritic heat resisting steel weldments decrease due to Type Ⅳ fracture, which occurs as a result of formation and growth of creep voids and cracks on grain boundaries in fine-grained heat affected zone (HAZ). Because boron is considered to suppress the coarsening of grain boundary precipitates and growth of creep voids, we have investigated the effect of boron addition on the creep properties of 9Cr steel weldments. Four kinds of 9Cr3WSCoVNb steels with boron content varying from 4.7×10-5 to 1.8×10-4 and with nitrogen as low as 2.0×10-5 were prepared. The steel plates were welded by gas tungsten arc welding and crept at 923K. It was found that the microstructures of HAZ were quite different from those of conventional high Cr steels such as P91 and P92, namely the fine-grained HAZ did not exist in the present steel weldments. Boron addition also has the effect to suppress coarsening of grain boundary carbides in HAZ during creep. As a result of these phenomena, the welded joints of present steels showed no Type Ⅳ fractures and much better creep lives than those of conventional steels.

Effect of Rare Earths on Corrosion Resisting Properties of Carbon-Manganese Clean Steels

Electrochemistry experiments were made on carbon-manganese clean steel with rare earths Ce and La respectively to observe corrosion parameters such as corrosion current i_(corr), and characteristic potential of pitting E_b. The results indicate that the rare earths have effect on corrosion resisting properties of carbon-manganese clean steel, and the optimum contents of La is about 0.011% (mass fraction) and Ce about 0.014% (mass fraction) respectively. The change of corrosion resistance is related to the action of rare earths on microstructure and effect on surface state of samples in the process of polarization.

Study on Seawater Corrosion Resisting Properties ofAl-Mg-RE Alloy Gauze

The corrosion resistance of gauzes made of various materials, including Al-Mg-RE alloy with various RE contents, Al-Mg alloy, low-carbon steel and plastic, was evaluated and compared. The experimental methods used include immersion method, salt spray test, weight loss test, electrode potential analysis and metallographic method, etc. The corrosion resistance of Al-Mg-RE alloy gauzes in mediums such as running water, natural seawater, NaCl solution with various concentrations, 0.05 mol.L-1 Na2SO4 solution, and 10% H2SO4 solution etc., is superior to those of Al-Mg alloy gauzes made in either China or U.S.A., and much superior to those of gauzes made of low-carbon steel and plastic. The electrode potentials of the Al-Mg-RE alloy in both the natural seawater and 0.05 mol.L-1 Na2SO4 solution increase linearly with increasing RE content in the alloy. The microstructure in the Al-Mg-RE alloy has been refined and the shape of compounds has been obviously changed comparing with those in Al-Mg alloy without RE elements. AU these microstructural changes are favorable to the corrosion resistance of the alloy. The Al-Mg-RE alloy gauze may be used as a substitute for those made df Al-Mg alloy, low-carbon steel and plastic in moisture marine or industrial environment for better serviceability.

Improved Corrosion Resisting Property of Magnetism Iron Fiber by SiO₂Coating

To improve the oxidation resistance property of iron fibers, a SiO2 coated iron fiber was prepared by sol-gel method, and its microstructure, element and phase composition, antioxidation property, and crystallization were characterized by scanning electron microscopy, thermal gravimetric analysis, X-ray diffraction and 3% CuSO4 solution dripping. It was found that the surface of the iron fiber can be fully covered with SiO2 by using Sol-Gel method. Our results also indicated that the time of iron begin to be corrupted in 3% CuSO4 solution drip increased from 30 s to 240 s, and the temperature increased from 200?C to 310?C. In addition, the oxidation and antioxidation mechanisms of the SiO2 coated iron fiber have also been discussed in this work.

Resisting method of acupuncture at movement-painful points for treating the refractory cases of frozen shoulder during adhesion period:A randomized controlled study

Objective:To objectively evaluate the clinical effect of resisting method of acupuncture at movementpainful points on treating the refractory cases of frozen shoulder during adhesion period,and to compare with that of the conventional acupuncture method.Methods:According to the random grouping principle,90 patients with frozen shoulder during adhesion period were divided into"resisting method acupuncture group,general acupuncture group,and physiotherapy group",30 patients in each.In the resisting method acupuncture group,the resisting method of needling was applied at the"movement-painful points",and during acupuncture the patient was asked to do shoulder movements.In the general acupuncture group,the conventional needling method of acupuncture was applied at the conventional three shoulder-acupoints.In the physiotherapy group,the patients were treated with shock wave at the affected shoulder.All groups were treated once a day,5 times a week,a total of 2 weeks as a course of treatment.After one course of treatment,the clinical effect of the three groups was evaluated.The shoulder pain and shoulder function scale(Constant-Murley),Rating Scale of the American Shoulder and Elbow Surgeons(ASES),and infrared thermal imaging temperature change score were observed.Results:After treatment,the shoulder pain was relieved and movement improved in all three groups,whilst the cured and remarkably effective rate of the resisting method acupuncture group was 96.7%(29/30),better than those of the general acupuncture group 86.2%(25/29)and the physiotherapy group 73.3%(22/30),with a statistically significant difference(P<0.05);the VAS score of the resisting method acupuncture group was significantly lower than those of the other two groups(P<0.05),the ConstantMurley score and the ASES score were significantly lower than those of the other two groups(all P<0.05),and the infrared thermal imaging temperature change score was significantly improved in comparing with those of the other two groups,with a statistically significant difference(both P<0.05).Conclusion:The resisting method of needling has an obvious analgesic effect and is able to restore the joint movement function in the treatment of refractory frozen shoulder during adhesion period.

Understanding the link between type 2 diabetes mellitus and Parkinson's disease:role of brain insulin resistance

Type 2 diabetes mellitus and Parkinson's disease are chronic diseases linked to a growing pandemic that affects older adults and causes significant socio-economic burden.Epidemiological data supporting a close relationship between these two aging-related diseases have resulted in the investigation of shared pathophysiological molecular mechanisms.Impaired insulin signaling in the brain has gained increasing attention during the last decade and has been suggested to contribute to the development of Parkinson's disease through the dysregulation of several pathological processes.The contribution of type 2 diabetes mellitus and insulin resistance in neurodegeneration in Parkinson's disease,with emphasis on brain insulin resistance,is extensively discussed in this article and new therapeutic strategies targeting this pathological link are presented and reviewed.