Review on the Fabrication of Surface Functional Structures for Enhancing Bioactivity of Titanium and Titanium Alloy Implants

Titanium and its alloys have been widely applied in many biomedical fields because of its excellent mechanical properties,corrosion resistance and good biocompatibility.However,problems such as rejection,shedding and infection will occur after titanium alloy implantation due to the low biological activity of titanium alloy surface.The structures with specific functions,which can enhance osseointegration and antibacterial properties,are fabricated on the surface of titanium implants to improve the biological activity between the titanium implants and human tissues.This paper presents a comprehensive review of recent developments and applications of surface functional structure in titanium and titanium alloy implants.The applications of surface functional structure on different titanium and titanium alloy implants are introduced,and their manufacturing technologies are summarized and compared.Furthermore,the fabrication of various surface functional structures used for titanium and titanium alloy implants is reviewed and analyzed in detail.Finally,the challenges affecting the development of surface functional structures applied in titanium and titanium alloy implants are outlined,and recommendations for future research are presented.

Research Progress on Structure and Bioactivity of Longan Polysaccharide

Longan originates from southern China and has high nutritional and health value.Recent phytochemistry and pharmacology studies have shown that polysaccharides are a main bioactive component of longan.Longan polysaccharides possess antioxidant,anti-aging,anti-tumor,immunomodulatory,and other bioactivities.Hot-water extraction,ethanol precipitation,and ultrasonic extraction are generally used to extract water-soluble longan polysaccharides.However,the relationship between the structure and bioactivity of longan polysaccharides remains unclear,requiring further investigation.The aim of this review is to evaluate the current literature focusing on the extraction,purification,structural characterization,and biological activity of longan polysaccharides.We believe that this review would provide a useful bibliography for further innovation and a basis for using longan polysaccharides in functional food.

Molecular characteristics and structure–activity relationships of food-derived bioactive peptides

Peptides are functional active fragments of proteins which can provide nutrients needed for human growth and development,and they also have unique physiological activity characteristics relative to proteins.Bioactive peptides contain a great deal of development potential.More specifically,food-derived bioactive peptides have the advantages of a wide variety of sources,unique structures,high efficiency and safety,so they have broad development prospects.This review provides an overview of the current advances regarding the preparation,functional characteristics,and structure–activity relationships of food-derived bioactive peptides.Moreover,the prospects for the future development and application of food-derived bioactive peptides are discussed.This review may provide a better understanding of foodderived bioactive peptides,and some constructive inspirations for further research and applications in the food industry.

Synthesis, Bioactivity and Crystal Structure Analysis of 2-(Benzo[d]isothiazol-3-yloxy)-N-(3-cyano-1-(4-fluorophenyl)-1H-pyrazol-5-yl) Acetamide

A novel benzisothiazolin-3-one derivative, 2-（benzo[d]isothiazol-3-yloxy）-N-（3- cyano-l-（4-fluorophenyl）-lH-pyrazol-5-yl） acetamide （8）, was synthesized from the initial compound benzo[d]isothiazol-3（2H）-one （BIT） 1 and 4-fluoroaniline 3. The structure of the target compound 8 was determined by elemental analyses, IR and 1H NMR. The single crystals of intermediate compound 6 and the target compound 8 were obtained and determined by X-ray diffraction analysis. The preliminary biological activity was also evaluated and the results showed tile target compound exhibited a good anti-microbial activity.

Structural Features and Biological Activities of Bioactive Compounds from Fortunella margarita(Lour.) Swingle：A Review

Fortunella margarita（Lour.） Swingle, commonly known as kumquat, is the smallest citrus fruit. It thrives in southeastern China and is widely cultivated and consumed in the world due to its multiple health benefits. It has been used as an important herbal medicine in traditional Chinese medicine and also as one of the most popular fruits. There are various kinds of bioactive compounds in F. margarita, such as polysaccharides, limonoids, essential oils, flavonoids, phenolic acids, vitamins, dietary fiber, etc. In addition, many studies have reported that these bioactive compounds can be used as antioxidant, antimicrobial, hypolipidemic, drosophila lure components in functional foods, pharmaceuticals and daily chemical products due to their biological activities. This review focuses on the structural features and biological activities of polysaccharides, limonoids, essential oils and flavonoids and other bioactive substances from F. margarita and their potential applications in food, daily chemical and pharmaceutical industries.

Synthesis,Crystal Structure and Bioactivity of N-Phenethyl-4-hydroxy-4-phenyl Piperidine Hydrochloride

A novel compound N-phenethyl-4-hydroxy-4-phenyl piperidine hydrochloride （C19H24ClNO·H2O） has been synthesized and structurally characterized by elemental analysis, IR, ^1H NMR spectra and single-crystal X-ray diffraction. The crystal belongs to orthorhombic, space group P212121 with a = 8.6306（8）, b = 11.0464（10）, c = 19.3221（18）A^°, V = 1842.1（3）A^°^3, Z = 4, Dc =1.211 g/cm^3,μ = 0.217 mm^-1, Mr= 335.86, F（000） = 720, S = 0.973, R = 0.0420 and wR = 0.1009 for 3627 unique reflections with 3157 observed ones （I 〉 2σ（I））. In the crystal, the dihedral angles made by piperidine ring with two benzene rings are 84.8（6） and 62.5（7）°, respectively. Intermolecular O-H…O and O-H…Cl hydrogen bonds involving water molecules form chains along the b axis, which stabilizes the crystal structure. The preliminary bioactivity tests indicated that the title compound has good effect of cellular growth inhibition to K562 cells and potential bioactivity of anti-leukemia.

What diameter?What height?Influence of measures of average tree size on area-based allometric volume relationships

Volume is an important attribute used in many forest management decisions.Data from 83 fixed-area plots located in central New Brunswick,Canada,are used to examine how different measures of stand-level diameter and height influence volume prediction using a stand-level variant of Honer's(1967)volume equation.When density was included in the models(Volume=f(Diameter,Height,Density))choice of diameter measure was more important than choice of height measure.When density was not included(Volume=f(Diameter,Height)),the opposite was true.For models with density included,moment-based estimators of stand diameter and height performed better than all other measures.For models without density,largest tree estimators of stand diameter and height performed better than other measures.The overall best equation used quadratic mean diameter,Lorey's height,and density(root mean square error=5.26 m^3·ha^(-1);1.9%relative error).The best equation without density used mean diameter of the largest trees needed to calculate a stand density index of 400 and the mean height of the tallest 400 trees per ha(root mean square error=32.08 m^(3)·ha^(-1);11.8%relative error).The results of this study have some important implications for height subsampling and LiDAR-derived forest inventory analyses.

Synthesis, Crystal Structure and Bioactivity of N-(phenethylcarbamothioyl)cyclopent-1-enecarboxamide

The compound N-（phenethylcarbamothioyl）cyclopent-1-enecarboxamide was synthesized by the reaction of cyclopent-1-enecarbonyl isothiocyanate with phenethylamine in acetone, and its structure was characterized by IR, 1H NMR and X-ray crystal structure determination. The crystal of the title compound belongs to triclinic, space group P1 with a = 6.9500（7）, b = 9.4618（9）, c = 11.3256（11）, α = 71.522（9）, β = 81.830（8）, γ = 89.237（8）o, Z = 2, V = 698.80（12）3, Dc = 1.304 g/cm3, μ = 0.225 mm-1, F（000） = 292, R = 0.0413 and wR = 0.1073 for 1996 observed reflections with I 〉 2σ（I）. Intramolecular N（2）–H（2）···O（1） interactions as well as intermolecular N（2）–H（2）···O（1）, N（1）–H（1）···S（1） and C（12）–H（12）···S（1） hydrogen bonds help to stabilize the crystal structure. X-ray diffraction analysis reveals that the structure of the new compound exhibits a one-dimensional infinite chain-like structure. The cytotoxicity of the compound was investigated by MTT assay. The results show that the compound is toxic to A549 tumor cell.

Microstructural analysis of a subhorizontal gold-quartz vein deposit at Donalda,Abitibi greenstone belt,Canada:Implications for hydrodynamic regime and fluid-structural relationship

The Donalda gold deposit in the southern part of the Archean Abitibi greenstone belt consists mainly of a subhonzontal gold-quartz vein perpendicular to subvertical shear zones.The 0.3—0.5 m thick vein is characterized by vein-parallel banding structures indicating multiple episodes of fracture opening and mineral precipitation.Measurement of the c-axis of primary growth quartz indicates that quartz preferentially grew perpendicular to the fracture,suggesting open space filling and/or extensional nature of the fracture.Measurement of the orientations of microfractures,veinlets and fluid—inclusion planes（FIPs） crosscutting primary growth quartz indicates that the vein minerals were subject to a vertical maximum principal stress（σ_1）,which is inconsistent with the subhorizontalσ_1 inferred from the regional stress field with N—S shortening.This apparent discrepancy is explained by invoking episodic fluid pressure fluctuation between supralithostatic and hydrostatic regimes accompanied by episodic opening and closing of the sub-horizontal fracture.When fluid pressure was higher than the lithostatic value,the fracture was opened and primary growth minerals were precipitated,whereas when fluid pressure decreased toward the hydrostatic value,the hanging wall of the fracture collapsed,causing collision of protruding primary growth minerals from both sides of the fracture and resulting in formation of vein-parallel deformation bands.The columns where the two facing sides of the fracture collided were subject to higher-than-lithostatic stress due to the bridging effect and reduced support surface area,explaining the development of verticalσ_1.This hypothesis is consistent the fault-valve model,and explains the flipping ofσ_1 without having to change the regional stress field.

Structural Relationships along a Neoarchean Arc-Continent Collision Zone, North China Craton

The Archean North China Craton is composed of the Western Block,Eastern Block and the intervening Central Orogenic Belt.A 4-10 km wide and 85 km long tectonic mélange belt informally called the Zanhuang tectonic

Preparation by enzymolysis and bioactivity of iron complex of fish protein hydrolysate (Fe-FPH) from low value fish

Preparation of Fe^2＋ chelate of fish protein hydrolysate （Fe-FPH） obtained from low value fish proteins was introduced and its bioactivity was studied by compound enzymolysis. The optimum conditions for hydrolysate chelating Fe^2＋ are DH （degree of hydrolysis） at 5%, pH 7.0, 20℃ and 15 min chelating time for FM （material not being defatted）. Four types of Fe-FPH including CA （deposit after chelating）, CB （deposit in 50% of absolute ethanol solution）, CC （suspended deposit in 80% of absolute ethanol solution）, and CD （bottom deposit in 80% of absolute ethanol solution） were fractionated with absolute ethanol from FM. Structural analysis through infra-red spectrum revealed that Fe^2＋ was combined strongly with amino-group and carboxyl-group in each chelate and each Fe^2＋ could form two five-member ring structures. All of the four chelates were shown more significant antioxidative activity and can be used as natural hydrophobic and hydrophilic antioxidant. Among all the chelates, the CB possesses the most effective antioxidative activity at 92% as high as that of a-tocopherol. Among all Fe-FPHs, only CD showed the most effective antibacterial activity against Escherichia coli, Staphylococcus aureus, Salmonella typhi, and Bacillus subtilis and can be used as natural antibacterial. It provides a more effective way for utilization of low value fish proteins and key information of Fe-FPH as additive in food industry.

Automatic extraction and structuration of soil–environment relationship information from soil survey reports

In addition to soil samples, conventional soil maps, and experienced soil surveyors, text about soils(e.g., soil survey reports) is an important potential data source for extracting soil–environment relationships. Considering that the words describing soil–environment relationships are often mixed with unrelated words, the first step is to extract the needed words and organize them in a structured way. This paper applies natural language processing(NLP) techniques to automatically extract and structure information from soil survey reports regarding soil–environment relationships. The method includes two steps:(1) construction of a knowledge frame and(2) information extraction using either a rule-based method or a statistic-based method for different types of information. For uniformly written text information, the rule-based approach was used to extract information. These types of variables include slope, elevation, accumulated temperature, annual mean temperature, annual precipitation, and frost-free period. For information contained in text written in diverse styles, the statistic-based method was adopted. These types of variables include landform and parent material. The soil species of China soil survey reports were selected as the experimental dataset. Precision(P), recall(R), and F1-measure(F1) were used to evaluate the performances of the method. For the rule-based method, the P values were 1, the R values were above 92%, and the F1 values were above 96% for all the involved variables. For the method based on the conditional random fields(CRFs), the P, R and F1 values for the parent material were, respectively, 84.15, 83.13, and 83.64%; the values for landform were 88.33, 76.81, and 82.17%, respectively. To explore the impact of text types on the performance of the CRFs-based method, CRFs models were trained and validated separately by the descriptive texts of soil types and typical profiles. For parent material, the maximum F1 value for the descriptive text of soil types was 90.7%, while the maximum F1 value for the descriptive text of soil profiles was only 75%. For landform, the maximum F1 value for the descriptive text of soil types was 85.33%, which was similar to that of the descriptive text of soil profiles(i.e., 85.71%). These results suggest that NLP techniques are effective for the extraction and structuration of soil–environment relationship information from a text data source.

Stand structure and height-diameter relationship of a degraded Populus euphratica forest in the lower reaches of the Tarim River, Northwest China

Understanding stand structure and height-diameter relationship of trees provides very useful information to establish appropriate countermeasures for sustainable management of endangered forests. Populus euphratica, a dominant tree species along the Tarim River watershed, plays an irreplaceable role in the sustainable development of regional ecology, economy and society. However, as the result of climate changes and human activities, the natural riparian ecosystems within the whole river basin were degraded enormously, particularly in the lower reaches of the river where about 320 km of the riparian forests were either highly degraded or dead. In this study, we presented one of the main criteria for the assessment of vitality of P. euphrafica forests by estimating the defoliation level, and analyzed forest structure and determined the height-diameter （height means the height of a tree and diameter means the diameter at breast height （DBH） of a tree） relationship of trees in different vitality classes （i.e. healthy, good, medium, senesced, dying, dead and fallen）. Trees classified as healthy and good ac- counted for approximately 40% of all sample trees, while slightly and highly degraded trees took up nearly 60% of total sample trees. The values of TH （tree height） and DBH ranged from 0-19 m and 0-125 cm, respectively. Trees more than 15 m in TH and 60 cm in DBH appeared sporadically. Trees in different vitality classes had different distribution patterns. Healthy trees were mainly composed more of relatively younger trees than of degraded tress. The height-diameter relationships differed greatly among tress in different vitality classes, with the coefficients ranging from 0.1653 to 0.6942. Correlation coefficients of TH and DBH in healthy and good trees were higher than those in trees of other vitality classes. The correlation between TH and DBH decreased with the decline of tree vitality. Our results suggested that it might be able to differentiate degraded P. euphratica trees from healthy trees by determining the height-diameter correlation coefficient, and the coefficient would be a new parameter for detecting degradation and assessing sustainable management of floodplain forests in arid regions. In addition, tree vitality should be taken into account to make an accurate height-diameter model for tree height prediction.

Atomically Dispersed Catalysts:Precise Synthesis,Structural Regulation,and Structure-Activity Relationship

Atomically dispersed catalysts(ADCs)have been diffusely researched for the development of advanced catalytic processes owing to their welldefined structure,high atomic utilization,and outstanding activity.Precisely decoding the intrinsic structures and coordination microenvironments of ADCs still confronts significant challenges.Overcoming these challenges is important for profound understanding of the structure-activity relationships and directing the future design of ADCs.Herein,this minireview summarizes recent progress and advanced characterization techniques for the engineering of ADCs,including single-atom catalysts,dualatom catalysts,and atomic cluster catalysts with regard to precise synthesis,structural regulation,and the structure-performance relationship.The catalytic merits and regulation strategies of recent breakthroughs in energy conversion,enzyme mimicry,and organic synthesis are thoroughly discussed to disclose the catalytic mechanism-guided ADCs design.Finally,a comprehensive summary of the future challenges and potential prospects is presented to stimulate more design and application possibilities for ADCs.We believe that this comprehensive minireview will open up novel pathways for the widespread utilization of ADCs in diverse catalytic processes.

Structural Characterization and Octanol/water Partition Coefficients(LogP) Prediction for Oxygen-containing Organic Compounds

New descriptors were constructed and structures of some oxygen-containing organic compounds were parameterized. The multiple linear regression（MLR） and partial least squares regression（PLS） methods were employed to build two relationship models between the structures and octanol/water partition coefficients（LogP） of the compounds. The modeling correlation coefficients（R） were 0.976 and 0.922, and the ＂leave one out＂ cross validation correlation coefficients（R（CV）） were 0.973 and 0.909, respectively. The results showed that the structural descriptors could well characterize the molecular structures of the compounds; the stability and predictive power of the models were good.

Study on the Quantitative Structure-toxicity Relationships for the Selected Esters by Using Molecular Electronegativity Interaction Vector (MEIV)

The molecular electronegativity interaction vector （MEIV） was used to describe the molecular structure of 30 selected esters. Two excellent QSTR models were built up by using multiple linear regression （MLR） and partial least-squares regression （PLS）. The correlation coefficients （R） of the two models were 0.945 and 0.941, respectively. The models were evaluated by performing the cross validation with the leave-one-out （LOO） procedure. The cross-verification correlation coefficients （RCV） of the two models were 0.921 and 0.919, respectively. The results showed that the models constructed in this work could provide estimation stability and favorable predictive ability.

Synthesis, Crystal Structure and Bioactivities of 1-(4-Chlorophenyl)-3-[5-(pyrid-4-yl)-1,3,4-thiadiazol-2-yl]urea

The title compound 1-（4-chlorophenyl）-3-[5-（pyrid-4-yl）-1,3,4-thiadiazol-2-yl]urea （C14H10CIN5OS, Mr = 331.79） has been synthesized by the reaction of 2-amino-5-（pyrid-4-yl）- 1,3,4-thiadiazole with 4-chlorobenzoyl azide, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to triclinic system, space group PI with a = 5.8550（8）, b = 7.5668（10）, c = 16.416（2）A, α= 78.364（2）, β= 81.204（2）, γ= 84.749（2）°, V= 702.58（16）A^3, Z= 2, Dc = 1.568 g/cm^3, p = 0.429 mm ^-1, F（000） = 340, the final R = 0.0442 and wR = 0.1092 for 2001 observed reflections （1 〉 2σ（I））. X-ray diffraction analysis reveals that the title molecule is nearly planar. In the crystal structure, the molecules are linked by strong intermolecular N-H…N hydrogen bonds together with weak nonclassical intennolccular （C-H…Y, Y = N, O and CI） hydrogen bonds and stacked through π-π interactions. The preliminary bioassay shows that the title compound exhibits good fungicidal activities against Rhizoctonia solani, Botrytis cinerea and Dothiorella gregaria.

Microwave-assisted Syntheses,Structures and Bioactivities of α-Aminophosphonates Containing Pyrazole and 2-Hydroxybenzyl Units

Using 3-amino-4-cyanopyrazole, salicylaldehyde and dialkylphosphite as materials, a series of a-aminophosphonates containing pyrazole and 2-hydroxybenzyl units were synthesized under microwave irradiation without solvents and catalysts. The structures of the compounds were verified by IR, 1H NMR, J3C NMR and elemental analysis. The crystal structure of diisobutyl {a-[3- （4-cyano-lH-pyrazol）amino）]-N-（2-hydroxylbenzyl）}phosphonate （4d, C19H27N404P） was deter- mined by single-crystal X-ray diffraction. Compound 4d crystallizes in the orthorhombic system, space group Pbcn with a = 17.329（4）, b = 20.091（5）, c = 12.433（3）/k, V = 4328.7（17） A3, M,. = 406.42, Dc = 1.247 g/cm3, Z = 8, F（000） = 1728,μ = 0.158 mm-1, MoKa radiation （2 = 0.71073 A）, the final R = 0.064 and wR = 0.0169 for observed reflections with I 〉 2σ（I）. X-ray diffraction analysis reveals that two planes lie in 4d, and the dihedral angle is 85.76°. Intermolecular O（1）-H（1B）-O（2）, N（1）-H（1）-N（4）, N（3）-H（3）.-.N（2） and N（3）-H（3）...O（1） hydrogen bonds are found in the structure. All the compounds were evaluated for their antiviral and antitumor activities respectively. Among them, 4d and 4e showed moderate anti-TMV activities at 500 gg/mL, and 4e possessed excellent antitumor activity against PC3 cells at 10 gmol/L.

Analysis of genetic diversity and structure across a wide range of germplasm reveals genetic relationships among seventeen species of Malus Mill,native to China

China is a center of diversity for Malus Mill,with 27 native species including 21 wild species and six domesticated species.We applied a set of 19 simple sequence repeat markers to genotype 798 accessions of 17 species(12 wild species and five cultivated species)of Malus originating from 14 provinces in China.A total of 500 alleles were detected.Diversity statistics indicated a high level of genetic variation as quantified by the average values of the effective allele number(N_(e)).expected heterozygosity(H_(e)),and Shannon's Information Index(I)(10.309,0.886,and 2.545,respectively).Malus sieversii(MSR;H_(e)=0.814,I=2.041,N_(e)=6.054),M.baccata(MBB;H_(e)=0.848,/=2.350,N_(e)=8.652),M.toringoides(MTH;He=0.663,I=1.355,N_(e)=3.332),and M.hupehensis(MHR;H_(e)=0.539,I=0.912,N_(e)=0.579)showed a higher level of genetic diversity in this study than the previous studies.MSR and MBB contributed to the origin and evolution of some accessions of M.domestica subsp.chinensis(MDC).However,other accessions of MDC showed a closer genetic distance with MBB and cultivated species,especially M.robusta(MRB),M.asiatica(MAN),and M.prunifolia(MPB).Not all accessions of MDC were descended from MSR in Xinjiang Uygur Autonomous Region of China.This research provides novel insights into the genetic relationships of Malus native to China,which will be useful for genetic association studies,germplasm conservation,and breeding programs.

Structural Modification for Antitumor Nitrogenous Steroids

Natural steroids have been showing notable cytotoxic activities, which are quite interesting lead compounds for the development of anticancer drug including estramustine and prednimustine. Considering that these semi-synthetic molecules are nitrogen mustard functionalized steroidal derivatives, the present review is focused on the methodologies of introducing nitrogen atom or nitrogen-containing heterocycles on A^D rings or side chains of steroids, and analysis of the structure-activity relationship（SAR） for these man-made cytotoxic steroids.