Micromechanical testing and property upscaling of planetary rocks:A critical review

Knowledge of the mechanical behavior of planetary rocks is indispensable for space explorations.The scarcity of pristine samples and the irregular shapes of planetary meteorites make it difficult to obtain representative samples for conventional macroscale rock mechanics experiments(macro-RMEs).This critical review discusses recent advances in microscale RMEs(micro-RMEs)techniques and the upscaling methods for extracting mechanical parameters.Methods of mineralogical and microstructural analyses,along with non-destructive mechanical techniques,have provided new opportunities for studying planetary rocks with unprecedented precision and capabilities.First,we summarize several mainstream methods for obtaining the mineralogy and microstructure of planetary rocks.Then,nondestructive micromechanical testing methods,nanoindentation and atomic force microscopy(AFM),are detailed reviewed,illustrating the principles,advantages,influencing factors,and available testing results from literature.Subsequently,several feasible upscaling methods that bridge the micro-measurements of meteorite pieces to the strength of the intact body are introduced.Finally,the potential applications of planetary rock mechanics research to guiding the design and execution of space missions are environed,ranging from sample return missions and planetary defense to extraterrestrial construction.These discussions are expected to broaden the understanding of the microscale mechanical properties of planetary rocks and their significant role in deep space exploration.

Expression and Characterization of a Novelλ-Carrageenase Cgl150A_Wa from Wenyingzhuangia aestuarii

λ-Carrageenan is a highly sulfated polysaccharide alternating of 1,4-O-α-D-galactopyranose-2,6-sulfate(D2S,6S)and 1,3-O-β-D-galactopyranose-2-sulfate(G2S).λ-Carrageenases are desirable tools forλ-carrageenan degradation.Based on the genome mining,a novelλ-carrageenase Cgl150A_Wa was cloned from the bacterium Wenyingzhuangia aestuarii and expressed in Escherichia coli.Cgl150A_Wa was an endo-acting enzyme and exhibited its maximum activity at 30℃and pH 8.0.By employing a glycomics strategy that combined ultra-performance liquid chromatography-mass spectrometry analysis and glycoinformatics,Cgl150A_Wa was proven to degradeλ-carrageenan octaose and hexaose,and the major hydrolysis product of Cgl150A_Wa wasλ-carrageenan tetrose.In addition to the typicalλ-carrageenan motifs,the active center of Cgl150A_Wa might tolerate desulfatedλ-carrageenan motifs.Cgl150A_Wa is a potential biotechnological tool for preparingλ-carrageenan oligosaccharides and structural investigation.

Physiology of medicinal and aromatic plants under drought stress

Drought poses a significant challenge,restricting the productivity of medicinal and aromatic plants.The strain induced by drought can impede vital processes like respiration and photosynthesis,affecting various aspects of plants’growth and metabolism.In response to this adversity,medicinal plants employ mechanisms such as morphological and structural adjustments,modulation of drought-resistant genes,and augmented synthesis of secondary metabolites and osmotic regulatory substances to alleviate the stress.Extreme water scarcity can lead to leaf wilting and may ultimately result in plant death.The cultivation and management of medicinal plants under stress conditions often differ from those of other crops.This is because the main goal with medicinal plants is not only to increase the yield of the above-ground parts but also to enhance the production of active ingredients such as essential oils.To elucidate these mechanisms of drought resistance in medicinal and aromatic plants,the current review provides a summary of recent literature encompassing studies on the morphology,physiology,and biochemistry of medicinal and aromatic plants under drought conditions.

Utilization of pH-driven methods to fortify nanoemulsions with multiple polyphenols

Simple but effective methods are required to incorporate multiple bioactive polyphenols into delivery systems to increase their dispersibility,stability and bioavailability.We developed and tested three p Hdriven protocols for creating nanoemulsions loaded with multiple lipophilic polyphenols.These protocols differed in how the different polyphenols were incorporated into the nanoemulsions.The impact of these three methods on the formation,properties,and gastrointestinal fate of nanoemulsions loaded with curcumin,resveratrol,and quercetin was investigated.The three methods produced nanoemulsions with similar initial particle properties:droplet diameters(0.15,0.16,and 0.15μm)and zeta-potentials(–59,–58,and–58 m V),respectively.However,the average encapsulation efficiencies(82%,88%,and 61%),gastrointestinal stabilities(83%,97%,and 29%)and bioaccessibilities(77%,90%,and 73%)for curcumin,resveratrol,and quercetin were somewhat different.In particular,more quercetin degradation occurred using the approach that held it under alkaline conditions for extended periods.In general,the p H-driven method provides researchers with a versatile approach of incorporating multiple polyphenols with different characteristics into functional food and beverages using a simple and inexpensive method.

GREEN INFRASTRUCTURE PLANNING ON CAMPUS CASE STUDIES FROM UNIVERSITY OF MASSACHUSETTS-AMHERST

College campuses pride themselves in being leaders in promoting innovation in both technical and theoretical aspects of all fields of study, including sustainability. The drive for sustainability in higher education has become institutionalized in many college campuses in the form of offices of sustainability, as well as membership in the American Association for Sustainability in Higher Education (AASHE). In par­allel, but not always in concert, are more grass-roots efforts by students to promote sustainability through recycling programs, urban agriculture, and similar initiatives. Students are often frustrated between the classroom lessons they learn about sustain­ability and the slow adoption of sustainable practices in the “real-world,” including on campus. In order to address this issue, faculty have begun to engage students in the sustainability challenges facing their own campuses. The Journal of Green Building showcases these projects in the New Directions in Teaching and Research section of the journal. As part of this series, this article will highlight a course at the University of Massachusetts-Amherst in which students engage in green infrastructure planning projects for the campus.

Effect of ionic strength and mixing ratio on complex coacervation of soy protein isolate/Flammulina velutipes polysaccharide

Soy protein isolate(SPI)is a commercial protein with balanced amino acids,while the poor solubility impedes its use in traditional foods.To overcome the problem,the complex coacervation of SPI/Flammulina velutipes polysaccharide(FVP)were investigated.Initial results revealed that the suitable amounts of FVP contributed to reducing the turbidity of SPI solution.Under electrostatic interaction,the formation of SPI/FVP coacervates were spontaneous and went through a nucleation and growth process.Low salt concentration(C_(NaCl)=10,50 mmol/L)led to an increase in the critical pH values(pHc,pHφ1)while the critical pH values decreased when C_(NaCl)≥100 mmol/L.The concentration of NaCl ions increased the content ofα-helix.With the increase of FVP,the critical pH values decreased and the content ofβ-sheet increased through electrostatic interaction.At SPI/FVP ratio of 10:1 and 15:1,the complex coacervation of SPI/FVP were saturated,and the coacervates had the same storage modulus value.SPI/FVP coacervates exhibited solid-like properties and presented the strongest storage modulus at C_(NaCl)=50 mmol/L.The optimal pH,SPI/FVP ratio and NaCl concentration of complex coacervation were collected,and the coacervates demonstrated a valuable application potential to protect and deliver bioactives and food ingredients.

The protective effect of carnosic acid on dextran sulfate sodium-induced colitis based on metabolomics and gut microbiota analysis

Accumulating evidence suggests that the gut microbiota plays an important role in the pathogenesis of inflammatory bowel disease(IBD).Carnosic acid(CA)is a major antioxidant component of rosemary and sage.Herein,we investigated the protective effects of dietary CA on dextran sodium sulfate(DSS)-induced colitis mouse model with an emphasis on its impact on the composition and metabolic function of gut microbiota.We found that CA effectively attenuated DSS-stimulated colitis in mice,as evidenced by reduced disease activity index(DAI),and systemic and colonic inflammation.Additionally,CA restored microbial diversity and improved the composition of gut microbiota in DSS-treated mice.Moreover,Spearman’s correlation coefficient showed a significant correlation between the fecal metabolites and the gut microbiota species.Changes in gut microbiota and the correlated metabolites might partially explain CA’s anti-inflammatory effects against colitis.Future clinical trials are needed to determine the therapeutic effects and mechanisms of CA on IBD in humans.

Nanomaterials for Fighting Multidrug-Resistant Biofilm Infections

Multidrug-resistant bacterial infections represent a dire threat to global health.The development of antibiotic resistance in bacteria coupled with the lack of development of new antibiotics is creating infections requiring antibiotics of last resort,and even some infections for which we have no available treatment.Biofilm-based infections present some of the most challenging targets for treatment.The biofilm matrix provides a physical barrier that can impede access of antibiotics and antimicrobials to resident bacteria.The phenotypic diversity found in biofilms further exacerbates the difficulty of eliminating infections,with quiescent“persister”cells evading therapeutics and re-initiating infections after treatment.Nanomaterials provide a tool for combatting these refractory biofilm infections.The distinctive size regime and physical properties of nanomaterials provide them with the capability to penetrate and disrupt biofilms.Nanomaterials can also access antimicrobial pathways inaccessible to conventional antimicrobials,providing a synergistic strategy for treating biofilm infections.This review will summarize key challenges presented by antibiotic resistance and biofilms when treating infection and provide selected examples of how nanomaterials are being used to address these challenges.

Effect of Two Substrate Types on Feeding Efficiency by Juvenile Chinese Sturgeon Acipenser sinensis on Barcheek Goby Rhinogobius giurinus

We conducted experiments in an artificial stream tank with wild juvenile Chinese sturgeon Acipenser sinensis captured in the Yangtze Estuary to test the null hypothesis that their feeding efficiency on Barcheek goby Rhinogobius giurinus was not affected by sand vs. smooth glass substrate. Gobies are among the most common prey eaten by wild juvenile A. sinensis in the estuary. Test results found neither substrate type significantly affected feeding efficiency by juveniles. Previous research found a strong innate habitat preference of A. sinensis for sand substrate. The present results indicate that the preference for sand is not related to efficiently capturing R. giurinus on sand, but is an adaptation predisposing juvenile A. sinensis to seek sandy substrate where R. giurinus and other benthic forage are the most abundant in the Yangtze Estuary.

Spatial Variability of Nutrient Properties in Black Soil of Northeast China

A total of 1400 soil samples from the plow layer （0-20 cm） at an approximate interval of 5 km were collected in the autumn of 2002 over the entire black soil arable crops region to determine the spatial variability of seven variables, such as total organic matter content （OMC）, total N, total P, total K, alkali-dissolvable N （AN）, available P （AP） and available K （AK）, with classical statistics and geostatistical analysis across the entire black soil area in Northeast China. In nonsampled areas ordinary kriging was utilized for interpolation of estimated nutrient determinations. Classical statistics revealed highly significant （P ≤ 0.01） correlations with all seven of the soil properties, except for OMC with AP and total K with AK. In addition, using coefficients of variation, all soil properties, except for total K, were moderately variable. A geostatistical analysis indicated that structural factors, such as parent material, terrain, and water table, were the main causes of the spatial correlations. Strong spatial correlations were noted with OMC, total N, total P, AN, and AP, while they were moderate for total K and AK. The effective spatial autocorrelation of OMC, total N, total P, and AN ranged from 1 037 to 1353 km, whereas the ranges of total K, AP, and AK were only from 6 to 138 km. The fit of the experimental scmi-variograms to the theoretical models indicated that except for AN, kriging could successfully interpolate other six variables. Thns, the geostatistical method used on a large scale could accurately evaluate the spatial variability of most black soil nutrient properties in Northeast China.

Microbial Community Characteristics in a Degraded Wetland of the Yellow River Delta

Five different sites with a soluble salt gradient of 3.0-17.7 g kg^-1 dry soil from the coast to the inland were selected, and the microbial population size, activity and diversity in the rhizospheres of five common plant species and the adjacent bulk soils （non-rhizosphere） were compared in a degraded wetland of the Yellow River Delta, Shandong Province, China to study the effects of soil environment （salinity, seasonality, depth, and rhizosphere） on microbial communities and the wetland＇s ecological function, thus providing basic data for the bioremediation of degraded wetlands. There was a significant negative linear relationship between the salinity and the total number of microorganisms, overall microbial activity, or culturable microbial diversity. Salinity adversely affected the microbial community, and higher salinity levels resulted in smaller and less active microbial communities. Seasonal changes were observed in microbial activity but did not occur in the size and diversity. The microbial size, activity and diversity decreased with increasing soil depth. The size, activity and diversity of culturable microorganisms increased in the rhizospheres. All rhizospheres had positive effects on the microbial communities, and common seepweed had the highest rhizosphere effect. Three halophilic bacteria （Pseudomonas mendocina, Burkholderia glumae, and Acinetobacter johnsonii） were separated through BIOLOG identification, and common seepweed could be recommended for bioremediation of degraded wetlands in the Yellow River Delta.

Effect of sub-acute exposure to TiO_2 nanoparticles on oxidative stress and histopathological changes in Juvenile Carp (Cyprinus carpio)

Increasing application of nanotechnology highlights the need to clarify and understand nanotoxicity. Mammalian and in vitro studies have raised concerns about the toxicity of titanium dioxide nanoparticles （TiO2-NPs）, but there are limited data on ecotoxicity to aquatic organisms. In this work, the sub-acute toxicity of TiO2-NPs to carp （Cyprinus carpio） was assessed. Superoxide dismutase （SOD）, catalase （CAT） and peroxidase （POD） activities and lipid peroxidation （LPO） levels in liver, gill and brain tissues of carps varied with concentration of TiO2-NPs suspensions and exposure time （up to 8 d）. As a result, 100 and 200 mg/L TiO2-NPs caused statistically significant decrease in SOD, CAT and POD activities and significant increase in LPO levels in tissues （P 〈 0.05）, suggesting that the fish exposed to these two concentrations of TiO2-NPs suffered from the oxidative stress. The extent of depletion of antioxidant enzymes activities and the elevation of LPO in the liver was the greatest, indicating that the liver might be the most susceptible organ to TiO2-NPs exposure. In addition, carps had gill pathologies including edema and thickening of gill lamellae as well as gill filaments, and liver pathologies including necrotic and apoptosis hepatocytes after exposed to 100 and 200 mg/L TiO2-NPs for 20 d. These results indicated a potential risk from TiO2-NPs released into the aqueous environment.

Sorption and Fractionation of a Peat Derived Humic Acid by Kaolinite, Montmorillonite, and Goethite

Sorption of humic acid （HA） on mineral surfaces has a profound interest regarding the fate of hydrophobic organic contaminants （HOCs） and carbon sequestration in soils. The objective of our study is to determine the fractionation behavior of HA upon sorption on mineral surfaces with varying surface properties. HA was coated sequentially on kaolinite （1：1 clay）, montmorillonite （2：1 clay）, and goethite （iron oxide） for four times. The unadsorbed HA fractions were characterized by elemental analysis, diffuse reflectance infrared Fourier transform spectroscopy （DRIFT）, and solid state 13C nuclear magnetic resonance spectroscopy （NMR）. The mineral-HA complexes were characterized by DRIFT. Polarity index [（N＋O）/C] revealed higher polarity of the unadsorbed HA fractions after coating on kaolinite, reflecting that relatively higher polarity fractions of HA remain unadsorbed. Sorption of aiiphatic alcohol fraction along with carbohydrate was prominent on kaolinite surface. DRIFT results of the unadsorbed HA fractions indicated more sorption of aiiphatic moieties on both kaolinite and montmorillonite. DRIFT results of the unadsorbed HA fractions after sorption on kaolinite and goethite showed the sorption of the proteinaceons fractions of HA. The HA fractions obtained after coating on goethite showed significant sorption of carboxylic moieties. The results mentioned above comply reasonably well with the DRIFT spectra of the minerai-HA complexes. ^13C NMR results showed higher sorption of anomeric C on kaolinite surface. Higher sorption of paraffinic fraction waS observed on montmorillonite. NMR data inferred the sorption of carboxylic moieties on goethite surface. Overall, this study showed that aliphatic moieties of HA preferentially sorbed on kaolinite and montmorillonite, while carboxylic functional groups play a significant role in sorption of HA on goethite. The sorbed fractions of HA may modify the mineral surface properties, and thus, the interaction with organic contaminants.

Interactive effects of drought stress and chitosan application on physiological characteristics and essential oil yield of Thymus daenensis Celak

Thymus daenensis, a perennial herb, is often grown in areas that experience drought conditions during its growing period. Application of chitosan may compensate for the negative impact of drought stress on the yield of oil and secondary metabolites in Thymus.The interactive effects of foliar application of chitosan and drought stress on dry matter,essential oil yield, and selected physiological characteristics including photosynthetic pigments, osmotic adjustment, and lipid peroxidation of Thymus were investigated in a two-year study from 2014 to 2015. Treatments consisted of 0, 200, and 400(iL L'1 chitosan applied to plants grown under field capacity, mild drought stress(50% field capacity), and severe drought stress(25% field capacity). Dry matter yield decreased substantially as drought stress intensified. However, essential oil content increased under stress conditions,with the highest essential oil yield obtained from plants under mild drought stress. Foliar application of chitosan compensated to some extent for dry matter and oil yield reduction of plants grown under drought stress. The highest essential oil yield(1.52 g plant-1) was obtained by application of 400 \iL L_1 chitosan under the mild stress condition in 2015 when plants were mature. The compensatory effect of chitosan in reducing the negative impact of stress conditions on dry matter and oil yield was due mainly to stimulation of osmotic adjustment through proline accumulation and reduction of lipid peroxidase level, which increased the integrity of cell membranes of thyme leaves.

Petroleum Hydrocarbon Degradation Potential of Soil Bacteria Native to the Yellow River Delta

The bioremediation potential of bacteria indigenous to soils of the Yellow River Delta in China was evaluated as a treatment option for soil remediation. Petroleum hydrocarbon degraders were isolated from contaminated soil samples from the Yellow River Delta. Four microbial communities and eight isolates were obtained. The optimal temperature, salinity, pH, and the ratios of C, N, and P (C:N:P) for the maximum biodegradation of diesel oil, crude oil, n-alkanes, and polyaromatic hydrocarbons by indigenous bacteria were determined, and the kinetics changes in microbial communities were monitored. In general, the mixed microbial consortia demonstrated wider catabolic versatility and faster overall rate of hydrocarbon degradation than individual isolates. Our experimental results demonstrated the feasibility of biodegradation of petroleum hydrocarbon by indigenous bacteria for soil remediation in the Yellow River Delta.

Temporal and Spatial Dynamics of Bacterial Community in the Rhizosphere of Soybean Genotypes Grown in a Black Soil

The dynamics of rhizosphere microbial communities is important for plant health and productivity, and can be influenced by soil type, plant species or genotype, and plant growth stage. A pot experiment was carried out to examine the dynamics of microbial communities in the rhizosphere of two soybean genotypes grown in a black soil in Northeast China with a long history of soybean cultivation. The two soybean genotypes, Beifeng 11 and Hai 9731, differing in productivity were grown in a mixture of black soil and siliceous sand. The bacterial communities were compared at three zone locations including rhizoplane, rhizosphere, and bulk soil at the third node （V3）, early flowering （R1）, and early pod （R3） stages using polymerase chain reaction-denaturing gradient gel electrophoresis （PCR-DCGE） of 16S rDNA. The results of principal component analyses （PCA） showed that the bacterial community structure changed with growth stage. Spatially, the bacterial communities in the rhizoplane and rhizosphere were significantly different from those in the bulk soil. Nevertheless, the bacterial communities in the rhizoplane were distinct from those in the rhizosphere at the V3 stage, while no obvious differences were found at the R1 and R3 stages. For the two genotypes, the bacterial community structure was similar at the V3 stage, but differed at the R1 and R3 stages. In other words, some bacterial populations became dominant and some others recessive at the two later stages, which contributed to the variation of the bacterial community between the two genotypes. These results suggest that soybean plants can modify the rhizosphere bacterial communities in the black soil, and there existed genotype-specific bacterial populations in the rhizospbere, which may be related to soybean productivity.

Unifying the Software Process Spectrum

Software Process Workshop (SPW 2005) was held in Beijing on May 25-27, 2005. This paper introduces the motivation of organizing such a workshop, as well as its theme and paper gathering and review; and summarizes the main content and insights of 11 keynote speeches, 30 regular papers in five sessions of “Process Content”, “Process Tools and Metrics”, “Process Management”, “Process Representation and Analysis”, and “Experience Reports”, 8 software development support tools demonstration, and the ending panel “Where Are We Now? Where Should We Go Next?”.

Metabolic integration during the evolutionary origin of mitochondria

Although mitochondria provide eukaryotic cells with certain metabolic advantages, in other ways they may be disadvantageous. For example, mitochondria produce reactive oxygen species that damage both nucleocytoplasm and mitochondria, resulting in mutations, diseases, and aging. The relationship of mitochondria to the cytoplasm is best understood in the context of evolutionary history. Although it is clear that mitochondria evolved from symbiotic bacteria, the exact nature of the initial symbiosis is a matter of continuing debate. The exchange of nutrients between host and symbiont may have differed from that between the cytoplasm and mitochondria in modern cells. Speculations about the initial relationships include the following. (1) The pre-mitochondrion may have been an invasive, parasitic bacterium. The host did not benefit. (2) The relationship was a nutritional syntrophy based upon transfer of organic acids from host to symbiont. (3) The relationship was a syntrophy based upon H2 transfer from symbiont to host, where the host was a methanogen. (4) There was a syntrophy based upon reciprocal exchange of sulfur compounds.The last conjecture receives support from our detection in eukaryotic cells of substantial H2S-oxidizing activity in mitochondria, and sulfur-reducing activity in the cytoplasm.

Micromechanical analysis of the behavior of stiffclay

Cementations formed in geological timescale are observed in various stiff clays.A micromechanical stress strain model is developed for modeling the effect of cementation on the deformation behavior of stiff clay.The proposed approach considers explicitly cementations at intercluster contacts,which is different from conventional model.The concept of inter-cluster bonding is introduced to account for an additional cohesion in shear sliding and a higher yield stress in normal compression.A damage law for inter-cluster bonding is proposed at cluster contacts for the debonding process during mechanical loading.The model is used to simulate numerous stress-path tests on Vallericca stiff clay.The applicability of the present model is evaluated through comparisons between the predicted and the measured results.In order to explain the stress-induced anisotropy arising from externally applied load,the evolution of local stresses and local strains at inter-cluster planes are discussed.

Use of recycled gypsum in the cement-based stabilization of very soft clays and its micro-mechanism

This paper presents an experimental study and micro-mechanism discussion on gypsum role in the mechanical improvements of cement-based stabilized clay(CBSC).A soft marine clay at two initial water contents(i.e.50%and 70%)was treated by reconstituted cementitious binders with varying gypsum to clinker(G/C)ratios and added metakaolin to facilitate the formation of ettringite,followed by the measurements of final water contents,dry densities and strengths in accordance with ASTM standards as well as microstructure by mercury intrusion porosimetry(MIP)and scanning electron microscopy(SEM).Results reveal that the gypsum fraction has a significant influence on the index and mechanical properties of the CBSC,and there exists a threshold of the G/C ratio,which is 10%and 15%for clays with 50%and 70%initial water contents,respectively.Beyond which adding excessive gypsum cannot improve the strength further,eliminating the beneficial role.At these thresholds of the G/C ratio,the unconfined compressive strength(UCS)values for clays with 50%and 70%initial water contents are 1.74 MPa and 1.53 MPa at 60 d of curing,respectively.Microstructure characterization shows that,besides the common cementation-induced strengthening,newly formed ettringite also acts as significant pore infills,and the associated remarkable volumetric expansion is responsible,and may be the primary factor,for the beneficial strength gain due to the added gypsum.Moreover,pore-filling ettringite also leads to the conversion of relatively large inter-aggregate to smaller intra-aggregate pores,thereby causing a more homogeneous matrix or solid skeleton with higher strength.Overall,added gypsum plays a vital beneficial role in the strength development of the CBSC,especially for very soft clays.