Rational construction of multiple hollow silicalite-1 zeolite with enhanced quasi acidity for robust vapor-phase Beckmann rearrangement

Developing efficient and stable zeolites for vapor-phase Beckmann rearrangement of cyclohexanone oxime is still a great challenge to realizeε-caprolactam(CPL)green production.In this work,the hierarchical porous silicalite-1 zeolites with multiple hollow structure(S-1-M)are explored by in-situ desilication−recrystallization post-treatment of spongy highway-like zeolites(S-1-S),which are synthesized through silanization synthesis of conventional bulky silicalite-1(S-1).Compared to S-1,S-1-M achieves superior catalytic performance,with improving the CPL selectivity from 85.7%to 94.1%and prolonging the catalyst lifetime from 74 to 126 h at a weight hourly space velocity(WHSV)of 6 h^(−1).Comprehensive physiochemical studies demonstrate that the highly dispersed intracrystalline cavities within S-1-M endow greater mass diffusion and better quasi acidity inducing by the enhanced H-bonds among abundant H-bonded silanols,which is cooperatively responsible for its superior catalytic performance.

High rodent abundance increases seed removal but decreases scatter-hoarding and seedling recruitment along an elevational gradient

The distributions of small rodents in mountainous environments across different elevations can provide important information regarding the effects of climate change on the dispersal of plant species.However,few studies of oak forest ecosystems have compared the elevational patterns of sympatric rodent diversity,seed dispersal,seed bank,and seedling abundance.Thus,we tested the differences in the seed disperser composition and abundance,seed dispersal,seed bank abundance,and seedling recruitment for Quercus wutaishanica along 10 elevation levels in the Taihang Mountains,China.Our results provide strong evidence that complex asymmetric seed dispersal and seedling regeneration exist along an elevational gradient.The abundance of rodents had a significant negative correlation with the elevation and the seed removal rates peaked and then declined with increasing elevation.The seed removal rates were higher at middle and lower elevations than higher elevations but acorns were predated by 5 species of seed predators at middle and lower elevations,and thus,there was a lower likelihood of recruitment compared with those dropped beneath mother oaks at higher elevations.More importantly,the number of individual seeds in the seed bank and seedlings increased with the elevation,although dispersal services were reduced at sites lacking rodents.As conditional mutualists,the rodents could possibly act as antagonistic seed predators rather than mutualistic seed dispersers at low and middle elevations,thereby resulting in the asymmetric pattern of rodent and seedling abundance with increasing elevation to affect the community assembly and ecosystem functions on a large spatial scale.

Guidelines for burn rehabilitation in China

Quality of life and functional recovery after burn injury is the final goal of burn care,especially as most of burn patients survive the injury due to advanced medical science.However,dysfunction,disfigurement,contractures,psychological problems and other discomforts due to burns and the consequent scars are common,and physical therapy and occupational therapy provide alternative treatments for these problems of burn patients.This guideline,organized by the Chinese Burn Association and Chinese Association of Burn Surgeons aims to emphasize the importance of team work in burn care and provide a brief introduction of the outlines of physical and occupational therapies during burn treatment,which is suitable for the current medical circumstances of China.It can be used as the start of the tools for burn rehabilitation.

High population and dispersion of pentacoordinated Al~Ⅴ species on the surface of ?ame-made amorphous silica-alumina

Pentacoordinated Al(Al~Ⅴ)species in silica-alumina are promising to promote the formation of acid sites or act as surface defects for tailoring single-atom catalysts.However,pentahedral coordination(Al~Ⅴ)is rarely observed in conventionally prepared silica-alumina.Here,we show that high population and dispersion of Al~Ⅴ species on the surface of amorphous silica-alumina(ASA)can be achieved by means of flame spray pyrolysis.High resolution TEM/EDX,high magnetic-field NMR and DFT calculations are employed to characterize the structure of as-prepared ASAs.Solid-state ^(27)Al multi-quantum MAS NMR experiments show that most of the Al~Ⅴspecies are formed independently from the alumina phase and are accessible for guest molecules on the surface.Upon water adsorption,these Al~Ⅴ species are transformed to Al~Ⅵ species,structurally similar to surface Al~Ⅳ species,as confirmed by DFT calculations.The outstanding catalytic activity of as-synthesized ASA is demonstrated using the in situ H/D exchange reaction with deuterated benzene as an example.The Al~Ⅴ-rich ASA provides a much lower activation energy(～30 kJ/mol)than that reported for zeolite H-ZSM-5(～60 kJ/mol).The superior catalytic performance is attributed to the high Al~Ⅴcontent promoting the surface active sites in ASA.The knowledge gained on the synthesis of Al~Ⅴ-rich ASAs and the nature of aluminum coordination in these materials could pave the way to more efficient silica-alumina based catalysts.

Effects of masting on seedling establishment of a rodent-dispersed tree species in a warm-temperate region,northern China

Masting is an evolutionary strategy used by plants to promote seed survival and/or seed dispersal under animal predation,but its effects on seedling establishment in field condition are rarely tested by long-term experiments incorporating combined effects of seed and animal abundance.Here,we tracked seed production,rodent-mediated seed dispersal,and seedling establishment in Armeniaca sibirica from 2005 to 2014 in a warm-temperate forest in northern China,and examined the effects of seed abundance and per capita seed availability on seed fate and seedling recruitment rate.Our results showed that seed abundance or per capita seed availability generally benefited the seedling recruitment of A.sibirica through increasing dispersal intensity,supporting predator dispersal hypothesis.However,seedling recruitment showed satiated or even dome-shaped association with per capita seed availability,suggesting the benefit to trees would be decreased when seed abundance were too high as compared to rodent abundance(a satiated effect).Our results suggest that the predator dispersal and satiation effects of masting on seedling recruitment can operate together in one system and conditionally change with seed and animal abundance.

Visual landmark-directed scatter-hoarding of Siberian chipmunks Tamias sibiricus

Spatial memory of cached food items plays an important role in cache recovery by scatter-hoarding animals.However,whether scatter-hoarding animals intentionally select cache sites with respect to visual landmarks in the environment and then rely on them to recover their cached seeds for later use has not been extensively explored.Furthermore,there is a lack of evidence on whether there are sex differences in visual landmark-based food-hoarding behaviors in small rodents even though male and female animals exhibit different spatial abilities.In the present study,we used a scatter-hoarding animal,the Siberian chipmunk,Tamias sibiricus to explore these questions in semi-natural enclosures.Our results showed that T.sibiricus preferred to establish caches in the shallow pits labeled with visual landmarks(branches of Pinus sylvestris,leaves of Athyrium brevifrons and PVC tubes).In addition,visual landmarks of P.sylvestris facilitated cache recovery by T.sibiricus.We also found significant sex differences in visual landmark-based food-hoarding strategies in Siberian chipmunks.Males,rather than females,chipmunks tended to establish their caches with respect to the visual landmarks.Our studies show that T.sibiricus rely on visual landmarks to establish and recover their caches,and that sex differences exist in visual landmark-based food hoarding in Siberian chipmunks.

Covalently tethering disulfonic acid moieties onto polyoxometalate boosts acid strength and catalytic performance for hydroxyalkylation/alkylation reaction

Solid acid catalysts are widely used in the production of various high-value added and industrially important chemicals.Although the use of organosilicon compounds to modify the vacancy site has been extensively studied,the covalent tethering-SO_(3)H functionalized organosilicon modified polyoxometalates(POMs)has been rarely reported.In this work,two catalysts(TBA_(4)[SiW_(11)O_(39)(O(SiC_(3)H_(6)SO_(3)H)_(2))](compound 2)and TBA_(4)[SiW_(11)O_(39)(O(SiC_(8)H_(8)SO_(3)H)_(2))](compound 3))were synthesized successfully through covalently grafting different sulfonic acid(-SO_(3)H)groups onto[SiW_(11)O_(39)]^(8−)cluster,respectively.Compound 2 was achieved by surface grafting and in situ oxidation(3-mercaptopropyl)-trimethoxysilane,while compound 3 was achieved by surface grafting of 2-(4-chlorosulfonylphenyl)ethyltrimethoxysilane.Strong Brønsted acid strength of compounds 2 and 3 can be demonstrated by different methods including potentiometric titration,pyridine adsorption studies,and the ^(31)P trimethylphosphine oxides(TMPO)nuclear magnetic resonance(NMR).The systematic investigation of the relationship among POM structures,acid strength,and electron density was carried out based on density functional theory(DFT)calculation and experimental results,which revealed that covalent modification of compounds 2 and 3 decreased the electron density of the O-H bond,and promoted the release of H^(+).When applied in hydroxyalkylation/alkylation(HAA)reaction of 2-methylfuran(2-MF)with cyclohexanone,compound 2 exhibited better catalytic performance with conversion of ~93%,monocyclic fuel precursors(1a)yield of 79.9% and selectivity of 85.7% than compound 3,which can be attributed to strong Brønsted acid and the intramolecular hydrogen-bonding interactions between the neighboring -SO_(3)H moieties in compound 2.Finally,compound 2 also showed excellent catalytic activity in the HAA reaction of 2-MF with several different aldehydes and ketones(e.g.,furfuraldehyde,5-methylfurfuraldehyde,acetone,butyraldehyde and 4-methoxybenzaldehyde).This result opens a new pathway for design and fabrication of novel solid acid catalysts.

The effects of seed detectability and seed traits on hoarding preference of two rodent species

Seed traits play an important role in affecting seed preference and hoarding behaviors of small rodents.Despite greatly affected by seed traits,seed detectability of competitors represents pilfering risks and may also modify seed hoarding preference of animals.However,whether seed traits and seed detectability show consistent effects on seed hoarding preference of animals remain largely unknown.Here,we explored how seed traits and seed detectability correlate with seed hoarding preference of Leopoldamys edwardsi and Apodemus chevrieri in a subtropical forest.Despite the effects of seed coat thickness and caloric value on hoarding preference of L.edwardsi,we detected no significant effects of other seed traits on hording preference of the 2 rodent species.There was no correlation between larder-hoarding preference and inter-or intra-specific seed detectability of L.edwardsi;however,seed detectability of L.edwardsi was negatively correlated with its own scatter-hoarding preference.Although scatter-hoarding preference of A.chevrieri was not correlated with inter-and intra-specific seed detectability,larder-hoarding preference of A.chevrieri was positively correlated with intra-specific seed detectability.Our study may provide evidence that intra-specific seed detectability rather than seed traits and inter-specific pilfering risks play an important role in modifying seed hoarding preference of rodents.

Plant-animal interactions: patterns and mechanisms in terrestrial ecosystems

From the early work of Darwin,then Ehrlich and Raven(1964),to the recent novel contribution of mutualistic networks developed by Jordano and colleagues(Bascompte and Jordano 2007,Nuismer et al.2013,Guimarães et al.2017),it is clear that plant-animal interactions—especially those involving herbivory,seed dispersal,seed predation and pollination—are significant drivers of ecological processes and the evolution and maintenance of biodiversity.The vast majority of plant species,for example,are influenced by animal-mediated seed dispersal and pollination.

Radicle pruning by seed-eating animals helps oak seedlings absorb more soil nutrient

Although radicle pruning has well been observed in plant-animal interactions,research has not been conducted to determine how radicle pruning by seed-eating animals regulates nutrition mobilization of cotyledonary reserves and absorption of soil nutrients.We used stable nitrogen isotopes to test how acorns of early-germinating oak species(Quercus variabilis,Q.aliena,and Q.mogolica)trade off nutrients in the cotyledons and those in the soil in response to radicle pruning by seed-eating rodents.Radicle pruning by rodents resulted in root branching in the 3 early-germinating oak species.Moreover,radicle pruning increased shoot dry weight and substantially reduced the root-to-shoot ratio of oak species.Corresponding to the decreased dry weight of roots and root-to-shoot ratio,the dry weight of the remnant cotyledons was higher after radicle pruning in the 3 oak species.We provided first evidence that radicle pruning by seed-eating animals improved seedling performance of early-germinating oaks by increasing absorption of nutrients from soil.The results indicate that early-germinating oak seedlings trade off nutrition budget by altering nutrient absorption from soil and reserve mobilization from cotyledons in response to radicle pruning by seed-eating animals.Our study provided new insight into the nutrition allocation mechanism of young seedlings in response to radicle pruning by seed-eating animals,reflecting a mutualistic interaction between early-germinating oak and food-hoarding animals.

Olfaction alters spatial memory strategy of scatter-hoarding animals

Although it has been suggested that olfaction is closely interconnected with hippocampal systems,whether olfaction regulates spatial memory strategy remains never known.Furthermore,no study has examined how olfaction mediates spatial memory established on the external objects,for example,caches made by scatter-hoarding animals.Here,we experimentally induced nondestructive and reversible olfaction loss of a scatter-hoarding animal Leopoldamys edwardsi,to test whether and how olfaction regulates spatial memory to mediate cache recovery and pilferage.Our results showed that the normal L.edwardsi preferred to pilfer caches of others rather than to recover their own using accurate spatial memory(35.7%vs.18.6%).Anosmic L.edwardsi preferred to recover the caches they made prior to olfaction loss rather than to pilfer from others relied on spatial memory(54.2%vs.36.0%).However,L.edwardsi with anosmia showed no preference either to the caches they established after olfaction loss or caches made by others(25.8%vs.29.1%).These collectively indicate that olfaction loss has a potential to affect new memory formation but not previously established spatial memory on caches.Our study first showed that olfaction modified spatial memory strategy in cache recovery and pilferage behaviors of scatter-hoarding animals.We suggest that future studies pay more attention to the evolution of olfaction and its relationship with spatial memory strategy.

Exclusion of interspecific competition reduces scatter-hoarding of Siberian chipmunk Tamias sibiricus:A field study

Although food availability and the abundance of seed predators have been postulated to affect seed dispersal,it is not clear how seed-eating animals modify their scatter-hoarding strategies in response to different levels of interspecific competition.We placed paired germinated and ungerminated acorns of Quercus mongolica on 30-cm high platforms to exclude potential interspecific competition of the predominant larder hoarders Apodemus peninsulae and Myodes rufocanus,to investigate seed dispersal by a predominant scatter-hoarder,Tamias sibiricus,in the field in north-eastern China.Our results showed that T.sibiricus ate more acorns in situ in the absence of interspecific competition.In the presence of interspecific competition of A.peninsulae and C.rufocanus,however,more acorns were scatter-hoarded by T.sibiricus.Regardless of interspecific competition,germination of acorns showed no significant effects on seed dispersal patterns,inconsistent with the“seed perishability hypothesis”that animals avoid hoarding seeds with high perishability.Exclusion of interspecific competition,though relatively increasing the per capita seed abundance,appears to reduce seed dispersal,scatter-hoarding and seedling establishment.Therefore,we propose that moderate interspecific competition rather than competition exclusion may benefit seed scatter-hoarding and seedling establishment.

Visual and auditory cues facilitate cache pilferage of Siberian chipmunks(Tamias sibiricus)under indoor conditions

In the struggle for survival,scatter-hoarding rodents are known to cache food and pilfer the caches of others.The extent to which rodents utilize auditory/visual cues from conspecifics to improve cache-pilfering is un­known.Here,Siberian chipmunks(Tamias sibiricus)were allowed to search for caches of Corylus heterophyl­la seeds(man-made caches and animal-made caches)after experiencing cues from a conspecific’s cache-search­ing events.For each type of cache,3 experimental scenarios were presented:(1)alone(control);(2)auditory/visual(hearing and seeing conspecific’s cache-searching events);and(3)auditory only(hearing conspecific’s cache-searching events only)with random orders.The subjects located man-made caches faster,harvested more caches,and hoarded more seeds both in the auditory/visual and the auditory only treatments compared to the control,while scatter-hoarding more seeds in the auditory/visual treatment but larder-hoarding more seeds in the auditory only treatment.Compared to the control,the animals spent less time locating animal-made caches,har­vested more caches,ate fewer seeds,larder-hoarded more seeds and hoarded more seeds in total both in the au­ditory/visual and the auditory only treatments,while eating more seeds and hoarded fewer seeds in total in the auditory only treatment than in the auditory/visual treatment.The results also show that females spent less time locating the animal-made caches,but they scatter-hoarded fewer seeds than males in the auditory/visual treat­ment.To the best of our knowledge,this is the first report that visual and/or auditory cues of conspecifics im­prove cache-pilfering and hoarding in rodents.

Acorn size and tolerance to seed predators:the multiple roles of acorns as food for seed predators,fruit for dispersal and fuel for growth

Fitness of parents and offspring is affected by offspring size.In oaks(Quercus spp.),acorns vary considerably in size across,and within,species.Seed size influences dispersal and establishment of oaks,but it is not known whether size imparts tolerance to seed predators.Here,we examine the relative extent to which cotyledon size serves as both a means for sustaining partial consumption and energy reserves for developing seedlings during early stages of establishment.Acorns of 6 oak species were damaged to simulate acorn predation by vertebrate and invertebrate seed predators.Seedling germination/emergence and growth rates were used to assess seedling performance.We predicted that if cotyledons are important for dispersal,acorns should show tolerance to partial seed consumption.Alternatively,if the cotyledon functions primarily as an energy reserve,damage should significantly influence seedling performance.Acorns of each species germinated and produced seedlings even after removing>50%of the cotyledon.Seed mass explained only some of the variation in performance.Within species,larger acorns performed better than smaller acorns when damaged.Undamaged acorns performed as well or better than damaged acorns.There was no pattern among individual species with increasing amounts of damage.In some species,simulated invertebrate damage resulted in the poorest performance,suggesting alternative strategies of oaks to sustain damage.Large cotyledons in acorns may be important for attracting seed dispersers and sustaining partial damage,while also providing energy to young seedlings.Success of oak establishment may follow from the resilience of acorns to sustain damage at an early stage.