Search

A two-step strategy to improve the thermoplasticity of bamboo powder (BP) by the combination of hydrothermal pretreatment (BP-LHW) and propargyl modification (BP-PB/BP-LHW-PB) in a heterogeneous system was developed in this research. It was observed that the hydrothermal pretreatment has a positive impact on the alkyne-functionalized BP-LHW, resulting in substantial change including the etherification of BP-LHW with propargyl bromide, breaking of crystalline phase of the cellulose fraction. Besides, the modified sample is significantly changed in the apparent morphology and reduced in the thermal stability and glass transition temperature (Tg). The Tg is attributed to the increase of free volume due to the increase of propargyl concentration in the modified samples. These results revealed that the combination of propargyl group into pretreated BP is an efficacious way to ameliorate the thermoplasticity. Notably, the thermoplasticity of BP-LHW-PB with high concentration of propargyl is significantly enhanced compared to BP-PB, which is owed to the enhanced molecular mobility resulting from the reduced interaction forces between the cellulose molecular. Herein, the application way that the building a "clickable" alkyne platform in BP to obtain multifunctional materials will be broadened in bamboo-based materials. The bio-based material with improved thermoplasticity was prepared by grafting propargyl bromide onto bamboo powder.

Soft lithography is one of the most promising nanofabrication technologies for scalable nanomanufacturing. It uses flexible molds or stamps to fabricate extremely high-resolution nanopatterns in a low cost and rapid fashion on both flat and curved surfaces. Although two-dimensional soft lithography has been widely investigated and applied for some applications, there is a lack of quantitative research on using nanometer scale 3D patterns fabricated by atomic force microscope (AFM) for 3D soft lithography. In this paper, we demonstrated the effectiveness of ultrasonic vibration assisted AFM-based nanomachining in fabricating 3D master nanotemplates for 3D soft lithography. We successfully applied Polydimethylsiloxane (PDMS) daughter molds, casted from a nanometer scale 3D master template, using a soft lithography technique solvent-assisted micromolding. In addition, we investigated the quality and reusability of the master nanotemplates, and the quality of the PDMS patterns by quantifying the volume differences using an automatic imaging registration algorithm. Results show that there are zero or little PDMS residuals in the polymethyl methacrylate (PMMA) master nanotemplate with a simple contour for the first and second daughter mold casting, but 7% residuals for the third casting. And a more complex master nanotemplate shows slightly higher residual levels.

The mechanisms of brain injury after intracerebral hemorrhage (ICH) involve mass effect-induced primary injury and secondary injury caused by a pathologic response to the hematoma. Considerable attentions have recently been paid to the mechanisms and therapeutic strategy for secondary brain injury due to no overall benefit from early surgery compared with initial conservative treatment. However, it is unclear whether there is a causal relationship between mass effect and secondary brain injury. Here, the role of mass effect on early erythrolysis after experimental ICH was investigated based on the poly(N-isopropylacrylamide) (PNIPAM) ICH model. Autologous blood and PNIPAM hydrogel were co-injected into the right basal ganglia of rats to induce different degrees of mass effect, but with a constant hematoma. The influences of different mass effect and time courses on erythrolysis and brain damages after ICH were investigated. Furthermore, the protective effect of trehalose against erythrolysis after ICH was evaluated. The results showed that mass effect caused erythrocyte morphological change at 24 hr after ICH. The released hemoglobin was quantitatively evaluated by a polynomial concerning with the mass effect, the volume of hematoma, and the time of ICH. An obvious increase in heme oxygenase-1 (HO-1) and ionized calcium binding adaptor molecule-1 (Iba-1) expression, iron deposition, cell death, and neurological deficits was observed with increasing mass effect. Moreover, trehalose alleviated brain injury by inhibiting erythrolysis after ICH. These data demonstrated that mass effect accelerated the erythrolysis and brain damages after ICH, which could be relieved through trehalose therapy.

Saponins from Camellia fascicularis leaves, which ultrasonic-assisted extraction process parameters were optimized with Box–Behnken design and antioxidant activities were assessed, were reported in this study. The highest yield of crude saponins was up to 3.68% when the optimal extraction conditions were ratio of solvent to solid of 52.1 mL/g, methanol concentration of 71.1%, and ultrasonic temperature of 50.3 °C. The crude saponins from C. fascicularis leaves were purified using HP-20 macroporous resin with methanol and three fractions (SCF-1, SCF-2 and SCF-3) were obtained. Subsequently, the in vitro scavenging activity assay showed that the fractions proved significant antioxidant capacities as dose-dependent manner on 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl radical and azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS). SCF-1 possessed significantly higher antioxidant activity than that SCF-2 and SCF-3. Overall, ultrasonic-assisted extraction could be effectively used to extract C. fascicularis leaves saponins, which possessed potential antioxidant capabilities and is expected to be developed as food materials.

A novel adsorbent of magnetic graphene oxide/chitosan (MGOC) composite has been prepared via chemical cross-linking method, and exhibits an extraordinary sorption capacity (about 59.82 mg/g) towards cobalt ions. The batch experiments revealed that MGOC is weakly affected by ionic strength and pH-dependent for cobalt ions sorption. The sorption process is spontaneous and endothermic according to thermodynamic parameters, following the pseudo-second-order model. In view of low price, high adsorption capacity, great saturation magnetization and perfect reusability, the MGOC composite maybe has a potential value in treatment of radiocobalt-containing wastewater.

The local microenvironment may influence the success of stem cell therapy. Iron overload occurs in many hemorrhagic injuries due to hemolysis and hemoglobin degradation, which not only mediates local cell injury, but also induces damage to the transplanted cells. Here, an injectable nanoparticle encapsulated core-shell hydrogel was fabricated for simultaneous iron overload clearance and bone marrow mesenchymal stem cells (BMSCs) transplantation following intracerebral hemorrhage (ICH). The iron chelator-loaded low-molecular-weight keratin hydrogel with quick degradation property was selected as the outer shell to eliminate iron overload, and BMSCs implantation with high-molecular-weight keratin hydrogel was selected as the inner core. The epidermal growth factor and the basic fibroblast growth factor were entrapped within the poly (lactic-co-glycolic acid) (PLGA) nanoparticle, which was then encapsulated into the core hydrogel to support the BMSC growth and differentiation. The core-shell hydrogel can be easily formed by programmed injections, and the core-shell hydrogel displayed a strong protective effect against the toxicity of hemoglobin in cell experiments. Furthermore, more BMSCs survived in the core-shell hydrogel group in vivo as compared to that in the core hydrogel group and the vehicle group. Less iron deposition and ventricular enlargement, lower brain water content, and faster neurological recovery were also observed. The data demonstrated that this core-shell hydrogel is an effective strategy for promoting transplanted cell survival under the condition of an iron overload.

Objectives To assess the recall of a deep learning (DL) method to automatically detect kidney stones composition from digital photographs of stones. Materials and methods A total of 63 human kidney stones of varied compositions were obtained from a stone laboratory including calcium oxalate monohydrate (COM), uric acid (UA), magnesium ammonium phosphate hexahydrate (MAPH/struvite), calcium hydrogen phosphate dihydrate (CHPD/brushite), and cystine stones. At least two images of the stones, both surface and inner core, were captured on a digital camera for all stones. A deep convolutional neural network (CNN), ResNet-101 (ResNet, Microsoft), was applied as a multi-class classification model, to each image. This model was assessed using leave-one-out cross-validation with the primary outcome being network prediction recall. Results The composition prediction recall for each composition was as follows: UA 94% (n = 17), COM 90% (n = 21), MAPH/struvite 86% (n = 7), cystine 75% (n = 4), CHPD/brushite 71% (n = 14). The overall weighted recall of the CNNs composition analysis was 85% for the entire cohort. Specificity and precision for each stone type were as follows: UA (97.83%, 94.12%), COM (97.62%, 95%), struvite (91.84%, 71.43%), cystine (98.31%, 75%), and brushite (96.43%, 75%). Conclusion Deep CNNs can be used to identify kidney stone composition from digital photographs with good recall. Future work is needed to see if DL can be used for detecting stone composition during digital endoscopy. This technology may enable integrated endoscopic and laser systems that automatically provide laser settings based on stone composition recognition with the goal to improve surgical efficiency.

Thermal atomic force microscope (AFM) nanolithography enables many nanofabrication applications, but it requires special thermal probes. In this paper, we developed a vibration-assisted sample heating approach to implement the nanomachining of poly(methyl methacrylate) (PMMA) with a regular AFM probe with low stiffness (~0.16 N/m). The joule heating softens the PMMA, which lowers the normal force. The in-plane vibration with high frequency was applied to reduce the adhesion force between the AFM tip and the PMMA with elevated temperature, which enhances nanomachining performances. By using this approach, uniform nanopatterns with controllable dimensions were fabricated on PMMA films with small setpoint force.

Porous grafted copolymer with excellent thermal stability and swelling capacity was synthesized from water soluble Prunus cerasifera gum polysaccharide (PG) and acrylamide (AM). The monosaccharide compositions and the structure of Prunus cerasifera tree gum were detected by a high-performance anion exchange chromatography (HPAEC) system and 1H NMR and 13C NMR, and the obtained PG-AM copolymer was characterized by Fourier transform infrared (FT-IR), scanning electron microscope (SEM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively. The results indicated that the water soluble polysaccharides obtained from Prunus cerasifera tree gum were mainly composed of l-arabinose (39.78%) and d-galactose (40.59%) with minor amount of xylose, mannose and uronic acids. The maximum percent and the grafting efficiency of grafting acrylamide (AM) onto PG to form PG-AM were obtained by copolymerization between polysaccharide and 3 times (weight) acrylamide with 3 mmol/L potassium persulfate initiator at 50 °C for 1 h. In addition, lots of isolated and conjoint pores were observed in the prepared PG-AM materials, with a diameters distribution between 2 and 10 μm. Compared with PG, the synthesized copolymer PG-AM showed an excellent performance in thermal stability and swelling capacity. The detailed structural characteristic together with excellent thermal stability and swelling properties will benefit efficient utilization of the synthesized copolymer as a precursor for preparation of large-scale environmentally friendly advanced materials with various potential applications.

Milled wood lignin (MWL) was isolated from Dendrocalamus sinicus, an abundant bamboo variety in the earth, using Bjorkman method. Elucidation and quantification of the chemical structures for the isolated MWL have been facilitated by employing FT-IR and NMR techniques. The obtained results showed that the MWL consists of syringyl (S), guaiacyl (G), and p-hydroxyphenyl (H) units, indicating it as grass type (HGS) lignin. There is no significant change in structure (i.e. cleavage at α-O-4′ and β-O-4′ linkage) was observed. NMR techniques indicated that the isolated lignin was rich in β-O-4′ aryl ether substructures and syringyl (S) units. Furthermore, the sufficient understanding of the chemical structure of the lignin benefits their effective utilization towards the production of renewable biomass and biofuels.

This study was to evaluate the effect of graft copolymer (CTS-g-SA) of chitosan (CTS) and salicylic acid (SA) on the storability of grapefruit fruits during postharvest storage. Results indicate that the graft copolymer treatment significantly depressed green mold caused by Penicillium digitatum. The graft copolymer application kept fruit firmness without impairing the fruit quality. Moreover, the graft copolymer treatment inhibited the activity and gene expression of cell wall-modifying enzymes such as polygalacturonase, cellulase, pectin methylesterase, α-l-arabinofuranosidase, β-galactosidase, and suppressed the modification of cell wall components including covalently bound polysaccharide (sodium carbonate soluble pectin, 24% KOH-soluble fraction), which were associated with fruit softening. These results suggested that graft copolymer application can be recognized as a postharvest technique to suppress rotting and delay softening through inhibiting solubilization of cell wall polysaccharides.

Urea accounts for over half of the global ammonia volatilization from synthetic nitrogen fertilization. Process-oriented models, such as the widely applied DeNitrification DeComposition 9.5 version (DNDC95), are expected to predict ammonia volatilization from agricultural urea applications under various conditions. However, compared to the wind-tunnel ammonia observations of a nationwide, seven-site/ten-case network in the United Kingdom, the DNDC95 greatly underestimated the ammonia volatilization from winter cereal fields applied with urea at a constant dose. The model was revised in this study mainly through (i) newly parameterizing the effects of clay fraction, plant standings and canopy wetting on ammonia release from the soil solution, and (ii) re-calibrating the parameters of the urea hydrolysis function and the original parameterizations of wind, soil temperature and moisture effects on ammonia volatilization using the observations in one case of the network. Next, the performances of the revised model (DNDC95_NH3) in simulating grain yield, full crop nitrogen uptake, cumulative ammonia volatilization (CAV) and daily ammonia fluxes were evaluated using the observations of these variables in the other nine network cases. The DNDC95_NH3 performed considerably better than the DNDC95. Particularly, the slopes of the zero-intercept regression for the observations versus simulations decreased from 1.97 to 0.86 and 1.65 to 0.75 for the CAV and daily ammonia fluxes, respectively. In addition, the number of the cases with significant discrepancies between simulated and observed CAV was reduced from six of the nine network cases to only two. The simulations by the revised model for these two cases showed a significant underestimation and an extremely large overestimation, respectively. However, reasons especially for the significant overestimation still remain unclear. Future studies still need to diagnose and solve the other existing problems so as to further improve the model's performance.

Accelerating and regulating collagen formation during wound healing repair is key issues for skin regeneration. Insulin can promote the healing of damaged skin by stimulating cellular migration and angiogenesis. Here, human hair keratin-conjugated insulin was synthesized to enhance full-thickness skin regeneration based on the excellent wound healing and hemostatic effects of keratin and the collagen deposition regulation ability of insulin. The insulin-conjugated keratin (Ins-K) was synthesized through the EDC/NHS reaction, which can supply a sustained release of insulin. The Ins-K hydrogel displayed similar water absorption, porosity and rheology properties to those of the keratin hydrogel. However, the Ins-K hydrogel shows a stronger hemostatic ability than the keratin hydrogel group, with a stronger wound healing effect found for the Ins-K hydrogel in the early regeneration stage (first 2 weeks) than for the keratin hydrogel treatment, resulting in smoother skin tissues at an excision section realized by regulating transforming growth factor β1 (TGF-β1) and hydroxyproline (HYP) expression. The results demonstrate that keratin promotes hemostasis and wound healing after insulin conjugation, which highlights the potential of keratin-based materials in tissue regeneration applications.

To reveal the structural characteristics and physicochemical properties of perennial ryegrass lignin, sequential alkali extractions or double ball-milling and enzymatic hydrolysis on the basis of ultrasonic and hydrothermal pretreatments were proposed in this study. Results revealed that sequential alkali extractions released 89.4% of original lignin from the ryegrass cell walls and 0.75-4.16% of associated carbohydrates as compared to the double ball-milling and enzymatic hydrolysis (96.0% and 18.39%). It was observed that the two types of lignin prepared were SGH-type and had different amounts of p-coumarates and ferulates, and primarily consisted of β-O-4' linkages combined with minor amounts of β-β' and β-5' linkages. Besides, alkali-soluble lignins exhibited relatively fewer β-O-4' linkages, higher S/G ratios and H-type units, and abundant phenolic OH groups as compared to the double enzymatic lignin. Overall, the deeper investigation of the lignin structure of ryegrass will provide useful information for the efficient utilization of lignin macromolecules in biorefineries.

Age-related level changes of hormones, endocannabinoids and their ratios are of pathophysiological significance for understanding functions, activities and interactions of the endocrine systems, including the hypothalamic-pituitaryadrenal (HPA), hypothalamic-pituitary-gonadal (HPG) axes and endogenous cannabinoid system (ECS). The present study aimed to investigate the age-dependent fluctuations of glucocorticoids, gonadal steroids, endocannabinoids and their ratios from 21 days to 10 months in both plasma and hair from the male C57BL/6 mice. A novel framework based on the liquid chromatography-tandem mass spectrometry was developed to simultaneously determine ten hormones and two endocannabinoids in plasma and hair. Results showed that glucocorticoids, corticosterone (CORT), aldosterone (ALD), 11-dehydrocorticosterone (11-DHC), gonadal steroids, progesterone (P), dehydroepiandrosterone (DHEA), testosterone (T) and dihydrotestosterone (DHT) in plasma were unimodally fluctuated (ps < 0.001) along age with the maximum value at 2.7-month-old. In contrast, the other two gonadal steroids, estrone (E1) and estradiol (E2) were declined with age (ps < 0.001). Differently, endocannabinoids, N-arachidonoyl-ethanolamine (AEA) and 1-arachydonoyl glycerol (1-AG) showed nadir and zenith values at 2.7-month-old and 3.4-month-old, respectively (ps < 0.001). Additionally, the ratios of CORT to 11-DHC and ALD in plasma were dropped similarly with age (ps < 0.001). The ratios of 1-AG to AEA, and of T to A4 and DHT, and of DHEA to A4 were unimodally changed (ps < 0.001) along age with maximum value at 2.7- or 3.4-month-old. In contrast, the ratios of E2 to T and E1 to A4 were decreased with age (ps < 0.05). The rest six ratios that reflected the interactions among the three endocrine systems, were similar age-dependent and showed nadir and zenith values at 2.7-month-old and 3.4-month-old, respectively (ps < 0.05). Most importantly, these findings in light of age-related changing patterns in plasma were repeated in hair, suggesting that the fi41-ndings in the two matrices were mutually validated. However, it was worth noting that their magnitude of levels in the two bio-matrices were markedly different. The current findings could provide reliable hormone and endocannabinoid signatures with age on neuroendocrine profiles as well as their ratios for the male C57BL/6 mice.

Background Lidocaine is a commonly used local anesthetic, and low-dose lidocaine has neuroprotective effects on cerebral ischemia/reperfusion (CI/R) injury; the mechanism for this, however, is still unclear. The aim of this study was to investigate the role and the possible mechanisms of lidocaine on CI/R injury in rats. Methods We constructed a rat (male Sprague-Dawley rats, 6-8 weeks old) model of CI/R injury induced by middle cerebral artery occlusion (MCAO). Histopathology, neuronal apoptosis, oxidative stress, and inflammatory response were evaluated using hematoxylin and eosin (HE) staining, Nissl staining, enzyme-linked immunosorbent assay (ELISA) and western blotting, respectively. In addition, brain water content, infarct volume, neurological deficit score each evaluated. Results The findings showed that lidocaine improved spatial learning and memory impairment, protected I/R-induced brain injury and attenuated neuronal death and apoptosis. Furthermore, lidocaine also regulated the levels of malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), IL-6, IL-10, iNOS, and IL-4.Notably, lidocaine markedly inhibited the expression of p65 and p38. Conclusions The results indicate that lidocaine protects against cerebral injury induced by I/R in rats via the nuclear factor kappa-B (NF-κB) p65 and p38 mitogen-activated protein kinase (MAPK) signaling pathway, it provided a candidate for the treatment of CI/R-induced injury.

Quantification of nitrogen losses and net greenhouse gas (GHG) emissions from catchments is essential for evaluating the sustainability of ecosystems. However, the hydrologic processes without lateral flows hinder the application of biogeochemical models to this challenging task. To solve this issue, we developed a coupled hydrological and biogeochemical model, Catchment Nutrients Management Model - DeNitrification-DeComposition Model (CNMM-DNDC), to include both vertical and lateral mass flows. By incorporating the core biogeochemical processes (including decomposition, nitrification, denitrification and fermentation) of the DNDC into the spatially distributed hydrologic framework of the CNMM, the simulation of lateral water flows and their influences on nitrogen transportation can be realized. The CNMM-DNDC was then calibrated and validated in a small subtropical catchment belonged to Yanting station with comprehensive field observations. Except for the calibration of water flows (surface runoff and leaching water) in 2005, stream discharges of water and nitrate in 2007, the model validations of soil temperature, soil moisture, crop yield, water flows in 2006 and associated nitrate loss, fluxes of methane, ammonia, nitric oxide and nitrous oxide, and stream discharges of water and nitrate in 2008 were statistically in good agreement with the observations. Meanwhile, our initial simulation of the catchment showed scientific predictions. For instance, it revealed the following: (i) dominant ammonia volatilization among the losses of nitrogenous gases (accounting for 11-21% of the applied annual fertilizer nitrogen in croplands); (ii) hotspots of nitrate leaching near the main stream; and (iii) a net GHG sink function of the catchment. These results implicate the model's promising capability of predicting ecosystem productivity, hydrologic nitrogen loads, losses of gaseous nitrogen and emissions of GHGs, which could be used to provide strategies for establishing sustainable catchments. In addition, the model's capability would be further proved by applying in other catchments with different backgrounds.

Green mold caused by Penicillium digitatum is critical diseases for grapefruit fruit. In this study, the alone or combined effects of chitosan and salicylic acid on the control of green mold decay in grapefruit fruits were investigated. The results showed that combination of chitosan with SA treatment provided a more effective control of green mold than alone applying chitosan or SA. chitosan plus SA significantly reduced lesion diameter, disease incidence, while the content of endogenous SA much higher than those in treatment alone or control fruit. The combined treatment enhanced the chitinase, β-1,3-glucanase, peroxidase, phenylalanine ammonia-lyase and polyphenoloxidase activities and stimulated the synthesis of total phenolic compounds content. Moreover, the applications of alone or combined did not impair fruit postharvest quality such as firmness, weight loss and TA, while increased ascorbic acid and total soluble solids contents in grapefruit fruits. These result suggest that the use of chitosan combined SA treatment was effective in activating disease resistance against green mold, and providing a longer storage life with acceptable postharvest quality in grapefruit fruit.

Atomic hydrogen (H•) is highly reactive for the hydrodechlorination of trichloroethylene (TCE). In this work, we found that the coprecipitation of Ni2+ and Fe2+ at neutral pH led to an unprecedented catalytic generation of H•. The generated H• effectively dechlorinate TCE to nontoxic ethylene and ethane, and Fe2+ is the only electron donor. The abundant adsorbed H• produced with a Ni/Fe ratio of 0.4 enhances hydrogen evolution reaction causing a low efficiency for hydrodechlorination. In contrast, the active absorbed H• is generated in the crystal lattice of Ni-Fe hydroxides with a Ni/Fe ratio of 3.0 causing highly efficient hydrodechlorination of TCE. This work not only reveals the mechanism of catalytic hydrodechlorination by Ni-Fe hydroxides at neutral pH, but also provides a novel approach to detoxify TCE in contaminated water using facile precipitated Ni-Fe hydroxides.

Trichloroethylene (TCE), one of the most frequently detected chlorinated organic pollutants (COPs) in groundwater, has potential risks to human health. The bimetallic system consisting of zero-valent iron (ZVI) and a second catalytic metal has been widely investigated for reductive dechlorination of COPs. However, the passivation layer of ZVI inhibits the electron transfer causing a low dechlorination efficiency. In this work, we designed a novel bimetallic system using Fe(OH)2 and Ni for fast dechlorination of TCE. The reduction efficiency of TCE reaches 94.8 % after 5 h of reaction in the Fe(OH)2/Ni system. TCE was completely dechlorinated to nontoxic gas products including ethylene and ethane, which was attributed to the generation of active hydrogen species (H*) in the system. The Ni2+ cations undergo the process of hydroxylation and olation. Subsequently, electrons of Fe(OH)2 were transferred to Ni(II) causing the formation of Ni(0). The catalytic Ni(0) sites generate H* for TCE dechlorination via catalytic reduction of H2O/H+. A part of Fe(II) in the Fe hydroxide layer of Fe(OH)2 was oxidized to Fe(III) leading to the formation of green rust with a hexagonal structure. Our work demonstrates Fe(OH)2/Ni is a promising composite material for the remediation of TCE-contaminated groundwater.

Electrochemical dechlorination is a prospective strategy to remediate trichloroethylene (TCE)-contaminated groundwater. In this work, iron-nitrogen-doped carbon (FeNC) mimicking microbiological dechlorination coenzymes was developed for TCE removal under environmentally related conditions. The biomimetic FeNC-900, FeNC-1000, and FeNC-1100 materials were synthesized via pyrolysis at different temperatures (900, 1000, and 1100 °C). Due to the synergistic effect of Fe–N4 active sites and graphitic N sites, FeNC-1000 had the highest electron transfer efficiency and the largest electrochemical active surface area among the as-synthesized FeNC catalysts. The pseudo-first-order rate constants for TCE reduction using FeNC-1000 catalyst are 0.19, 0.28 and 0.36 h−1 at potentials of −0.8 V, −1.0 V and −1.2 V, respectively. Active hydrogen and direct electrons transfer both contribute to the dechlorination from TCE to C2H4 and C2H6. FeNC maintain a high reactivity after five reuse cycles. Our study provides a novel approach for the dechlorination of chlorinated organic contaminants in groundwater.

U.S. Department of Energy [DE-SC0004632, DE-SC0010580]; U.S. National Science Foundation (MacroSystems Biology) [1241937]; Northern Ecosystems Research for undergraduates REU Site (NSF EAR) [1063037]; Vetenskapradet (DR) [2007-4547, 2013-5562]

The purpose of this study was to discriminate the release behavior from three differently formulated racecadotril (BCS II) granules and to establish an in vitro-in vivo correlation. Three granule formulations of the lipophilic drug were prepared with equivalent composition but prepared with different manufacturing processes (dry granulation, wet granulation with or without binder). In vitro release of the three granules was investigated using a biphasic dissolution system (phosphate buffer pH6.8 and octanol) and compared to the conventional single phase USP II dissolution test performed under sink and non-sink conditions. In vivo studies with each granule formulation were performed in rats. Interestingly, the granule formulations exhibited pronouncedly different behavior in the different dissolution systems depending on different wetting and dissolution conditions. Single phase USP II dissolution tests lacked discrimination. In contrast, remarkable discrimination between the granule formulations was observed in the octanol phase of biphasic dissolution system with a rank order of release from granules prepared by wet granulation with binder>wet granulation without binder>dry granulation. This release order correlated well with the wettability of these granules. An excellent correlation was also established between in vitro release in the octanol phase of the biphasic test and in vivo data (R2=0.999). Compared to conventional dissolution methods, the biphasic method provides great potential to discriminate between only minor formulation and process changes within the same dosage form for poorly soluble drugs.

The contents of steroids and endocannabinoids along with the ratios between them would be candidate biomarkers for sensitively and comprehensively assessing the role of testosterone in regulating the activities of the hypothalamus-pituitary-gonadal (HPG) axis, the hypothalamus-pituitaryadrenal (HPA) axis and endogenous cannabinoid system (ECS). However, previous studies mostly used the contents rather than the ratios as biomarkers. This study aimed to systematically screen and identify sensitive biomarkers from 21 candidates including both the contents of nine steroids and one endocannabinoid and their ratios in saliva. Three screening criteria were whether there were intergroup differences, time-dependent changes and considerable relative stability during a 4-h period after exogenous testosterone administration. This study used LC-APCI+-MS/MS to determine the salivary levels of the candidate biomarkers on 62 male healthy undergraduates who were divided into testosterone administration and placebo control groups. The results revealed that salivary testosterone, androstenedione, DHEA and the ratios of testosterone to estradiol and AEA, and of cortisol to testosterone and DHEA were sensitive biomarkers for assessing the effects of testosterone administration on the three neuroendocrine systems because they all showed significant intergroup differences and time-dependent changes and good relative stability. Salivary cortisol, cortisone and the ratios of testosterone to androstenedione and DHEA and of androstenedione to estrone, and of cortisol to cortisone, androstenedione and AEA might be suitable biomarkers because they met only two of the three criteria, but needed to be validated in the future. The rest biomarkers were unsuitable because they mostly showed no significant intergroup differences, blunt time-dependent changes and poor relative stability.

The increasing trend of adopting organic fertilization in rice production can impact grain yields and soil methane (CH4) emissions. To simulate these impacts in the absence of long-term field data, a process-based biogeochemical model, Denitrification and Decomposition (DNDC version 9.5) was used. The model was calibrated against a single year greenhouse study and validated using a previously published one-year field trial from 1990, both comparing varying fertilization systems in rice production in southeast Texas, USA. In both the greenhouse and the field studies, lower grain yield and greater soil CH4 emissions were observed in organically fertilized systems. Calibrated model simulations of the greenhouse study correlated with the observed daily CH4 emissions (conventional r2 = 0.87; organic r2 = 0.91) and SOC (r2 = 0.83); but, the model overestimated yield of conventional systems (slope = 1.2) and underestimated yield of organic systems (slope = 0.68). For the field study, agreement between simulated and observed yields and CH4 emissions resulted in slopes close to 1. A simple organic system with urea and straw amendment from the field study was an input available in DNDC whereas the slow release, pelletized organic fertilizer used in the greenhouse study, Nature Safe, was not modeled well by DNDC. The validated model was used to simulate 22 years of rice production and predicted that the differences in yield and CH4 emissions between treatments would diminish with time. In the model simulations, the overall soil health was enhanced when managed with organic fertilization compared to conventional inorganic fertilizers. Model simulations could be improved further by including site-specific calibration of soil organic C, and soil carbon dioxide (CO2) emissions.

Lignin is the second most abundant biopolymer and the main source of aromatic structures on the earth. As a by-product of cellulose in the paper pulp production, lignin has rather low added-value applications. Sub-micro and nano- lignin materials maybe open promising high added-value applications. These new fields have brought about renewed interest for lignin. In this paper, the current developments of sub-micro and nano-lignin materials were reviewed. The synthetic routes between sub-micro and nano- lignin materials were summarized. All the different shapes, microstructures, and properties of these sub-micro and nano- lignin materials were compared with that of conventional lignin. The future trend toward micro- and nanostructured lignin-based materials is also suggested. It is expected that the small size of sub-micro and nano-lignin materials displays great progress, which are promising applications of various fields in the near future.

The transformation of green rust (GR) to form ferric oxyhydroxide at the oxic/anoxic interface, is an important process of iron cycles in subsurface environments. However, little is known in its electron transfer process and environmental impacts. Herein, we demonstrate that the GR oxygenation can generate hydroxyl radical (•OH; 1.6 μM) with a low rate of 0.012 μM/min. Interestingly, a strong correlation between the adsorbed phosphate on GR and the •OH generation is found; the presence of 20 mM phosphate significantly enhance the generation rate of •OH up to 0.13 μM/min, and a high cumulative concentration up to 20.9 μM. Our results demonstrate that the formation of iron-phosphate complexes is likely a key species determining •OH generation. Electrochemical analysis and DFT calculations indicate that phosphate can decrease the electron utilization ratio of GR but notably increase the electron selectivity for •OH production under oxic conditions. Subsequently, the generation of •OH radicals plays a role in oxidatively detoxifying diverse organic pollutants (e.g. chlorophenol and pharmaceuticals). Our findings provide new insights into the important role of oxyanions such as phosphate in determining electron transfer during iron cycles and consequently the fate of pollutants in subsurface environments.

In this report, three metal-organic frameworks (MOFs) were synthesized by hydrothermal reactions with 4,4′,4″-nitrilotribenzoic acid (H3NTB), 1,10-phenanthroline (phen) and water by introducing Zn(Ⅱ), Mn(Ⅱ) and Cu(Ⅱ) center ions, namely, [Zn(HNTB)(phen)]n (Ⅰ), [Mn(HNTB)(phen)•H2O]n (Ⅱ) and {[Cu(HNTB)(phen)•H2O]•H2O}n (Ⅲ). Single-crystal X-ray diffraction data analyses demonstrate that Ⅰ-Ⅲ are assembled into three-dimensional frameworks based on the building blocks of {ZnO4N2}, {MnO3N2} and {CuO4N2} through the connections of HNTB2−, intermolecular hydrogen bonds and the π … π interactions between pyridine rings, respectively. The fluorescent properties of Ⅰ-Ⅲ have been systematically studied in different solutions containing certain metal ions and organic molecules. As a result, Zn-MOF (I) exhibits a dual-responsive fluorescent sensor toward nitrobenzene (NB) and Fe3+ with high selectivity, stability and anti-interference ability at the existence of other corresponding analytes originating from its excellent fluorescent quenching efficiency. Moreover, the possible sensing mechanisms for the above analytes have also been elucidated, which are testified by PXRD analysis, ICP-AES, UV–vis spectra, XPS and the density functional theory (DFT).

Layered double hydroxide (LDH) was a kind of layer materials with multi-metal elements and good catalytic performance, but the metals can be dissolved during catalysis. Graphene oxide (GO) was a two-dimensional structure with abundant anionic groups with the potential of immobilizing metals. However, LDH combined with GO (LDH/GO) was few reported in the treatment of pharmaceuticals and personal care products (PPCPs). In this work, CoFeNi LDH/GO composites were designed and synthesized for activating peroxymonosulfate (PMS). Meanwhile, gatifloxacin (GAT), a typical antibiotic, was used to assess the performance of LDH/GO + PMS system. The characterization of LDH/GO using various measures showed that the adding GO was inserted the layer structure of LDH and the surface functional group of GO was immobilized in LDH well. GAT could be degraded completely after 45 min under the reaction conditions of pH 7.0, 38 mg L−1 GAT, 40 mg L−1 LDH/GO and 400 mg L−1 PMS. The removal of total organic carbon and defluorination reached 55.5% and 78.0% after 5 h reaction, respectively. Quenching tests suggested that the main radicals responsible for GAT degradation and mineralization was sulfate radical (SO4− ). The redox cycle made the catalysis of the LDH/GO composites work continuously. Compared with LDH + PMS system, the concentration of dissolved metals decreased 60.6%-74.3% at pH 3.0–11.0 in LDH/GO + PMS system. The reusability test indicates that LDH/GO has stable catalytic performance in removing PPCPs from wastewater.

Greenhouse vegetable (GV) fields with intensive nitrogen application and frequent flood irrigation may substantially contribute to reactive nitrogen (Nr) losses, such as nitrous oxide (N2O) emissions and nitrate (NO3−) leaching. In this study, we applied a biogeochemical model, Denitrification-Decomposition (DNDC), to assess impacts of N management on vegetable yields, N2O emissions, and NO3−-N leaching from GV systems. The model was evaluated using multi-year (2011–2013) field measurements of vegetable yields, N2O emissions, and NO3−-N concentrations in the surface soil layer and soil leachate under three treatments with different N management. The model evaluations demonstrated that the simulations of the vegetable yields and seasonal cumulative N2O emissions were consistent with the corresponding observations after calibration. In addition, DNDC generally captured the seasonal variations of the N2O fluxes and NO3−-N concentrations in the surface soil layer and the seasonal patterns and magnitudes of the measured NO3−-N concentrations in soil leachate in 2011. We then assessed impacts on the vegetable yields, N2O emissions, and NO3−-N leaching of different N management practices by conducting simulations under scenarios with changes in rate of the applied N-fertilizers and the application of nitrification inhibitor (NI). The results suggested that 1) the increasing of organic or synthetic N application rate generally increased the N2O emissions and NO3−-N leaching, but did not persistently increase the vegetable yields, 2) urea N application could induce more N2O emissions and NO3−-N leaching in comparison with organic N amendment, and 3) the NI application could decrease the N2O emissions and NO3−-N leaching while maintaining the vegetable yields at the GV fields. The optimum management practice identified in this study was applying organic manure at a rate of 320 kg N ha−1 four season−1 and urea at a rate of 334 kg N ha−1 four season−1, combined with the NI application. The optimum management practice reduced the rates of organic manure (1600 kg N ha−1 four season−1) and urea (1670 kg N ha−1 four season−1) under the farm's conventional practice by 80%. This practice maintained or slightly increased the yields and mitigated the N2O emissions and NO3−-N leaching by 81% to 90% and 92% to 95%, respectively, among different vegetable growing seasons.

The adsorption of iodine anions (iodide and iodate) on the sulfur terminated (001) chalcopyrite surface has been systematically investigated combining first-principles calculations based on density functional theory (DFT) with X-ray photoelectron spectroscopy (XPS) measurements. Based on the total energy calculations and geometric optimization, the thermodynamically preferred site was copper atom for iodide adsorption and iron atom for iodate adsorption, respectively. In the case of Cu site mode, the iodate underwent a dissociative adsorption, where one I O bond of iodate ion was broken and the dissociative oxygen atom adsorbed on the adjacent sulphur site. Projected density of states (PDOS) analysis further clarified the interaction mechanism between active sites of chalcopyrite surface and adsorbates. In addition, full-range XPS spectra qualitatively revealed the presence of iodine on chalcopyrite surface. High resolution XPS spectra of the I 3d peaks after adsorption verified the chemical environment of iodine. The binding energies of 618.8 eV and 623.5 eV for I 3d5/2 peaks unveiled that the adsorption of iodide and iodate ions on copper-iron sulfide minerals was the result of formation of low solubility metal iodides precipitate. Also two I 3d peaks with low intensity around 618 eV and 630 eV might be related to the inorganic reduction of iodate to iodide by reducing S2− ion of chalcopyrite.

The effect of gut microbiota on the activity of the HPA and HPG axes and ECS is a short-term or long-lasting process remains unclear in rodents. However, the extant studies focused only on its short-term effect on the HPA activity because there is lack of reliable biomarkers characterizing short-term activity of the HPG axis and ECS and long-term activities of the three endocrine systems. The endogenous levels of aldosterone (ALD), 11-dehydrocorticosterone (11-DHC), estradiol (E2), estrone (E1), androstenedione (A4), dihydrotestosterone (DHT), corticosterone (CORT), dehydroepiandrosterone (DHEA), testosterone (T), progesterone (P), N-arachidonoyl ethanoamide (AEA) and 1-arachydonoyl glycerol (1-AG) in hair and plasma are the potential long-term and short-term biomarkers of the three systems. This study aimed to develop the sensitive and selective methods for simultaneous quantitation of the twelve compounds in rodent’s hair and plasma. Then the methods were used to explore the differences in the hair levels of the twelve compounds between the mice in XZ group possibly having gut microbiota with more diversity and SPF group possibly having gut microbiota with less diversity and the inter-group differences in the plasma levels in the response to 1-h restraint stress. The methods were based on high performance liquid chromatography tandem mass spectrometry with atmospheric pressure chemical ionization in positive mode. The methods were adopted for 20 mg hair and 100 μL plasma, respectively. Hair samples were incubated in methanol at 40 ℃ for 24 h, and were performed by solid phase extraction. Plasma samples were implemented by liquid-liquid extraction with ethyl acetate. The methods showed limit of quantification at 0.06–1.3 pg/mg and 0.03-0.6 ng/mL and recovery ranging between 87.7–115.1 % and 86.1–114.6 % for all compounds in rodent’s hair and plasma, and the intra-day and inter-day coefficients of variation less than 15 %, and good freeze/thaw and short-term stability. The present methods also had good reliability as demonstrated by the sex difference in the testosterone levels in hair and plasma. The inter-group comparison revealed that the mice in XZ group showed significantly higher hair levels than those in SPF group for 1-AG and most of hormones except for T and P. The non-stressed female mice in SPF showed significantly higher plasma levels than those in XZ for AEA and most of hormones except for E2, A4, DHT, T and 1-AG, but there were no inter-group differences for the stressed mice except for DHEA and 11-DHC and for the non-stressed male mice. Additionally, the stressed mice showed significantly higher corticosterone level in plasma than controls for male and female mice in XZ and male mice in SPF, but it was not true for female mice in SPF.

Soil carbon dioxide (CO2) and nitrous oxide (N2O) emissions and carbon (C) sequestration are important processes for determining net greenhouse gas (GHG) emissions from maize fields. Farming management practices (FMPs) substantially affect crop productivity, soil organic carbon (SOC), and N2O emissions. However, relative knowledge is not sufficient, and further research is required for sustainable agriculture development. A multi-year experiment was performed on a spring maize field in the North China Plain (NCP) to quantify changes in SOC stocks, N2O emissions, and maize yields. Seven treatments were involved in the experiment, including no N fertilization (CK), farmers’ conventional N fertilization (FP), sole application of manure N (M), a combination of M and FP (MFP), FP combined with returned maize straw (SFP), fertilization with reduced synthetic N amount (RN), and fertilization with both reduced synthetic and manure N (RMN). The field measurements demonstrated that urea applications and returned maize straw increased N2O emission. The seasonal total N2O emissions under FP were significantly (P

Isolation of earth abundant biopolymer, Lignin, from Dendrocalamus sinicus and their structural properties were investigated to achieve its large-scale practical applications in value-added products. Two lignin fractions (MWL, DSL) were isolated with successive treatments of dioxane and dimethylsulfoxide (DMSO) from dewaxed and ball milled bamboo (D. sinicus) sample. The two-step treatments yielded 52.1% lignin based on the total lignin content in the dewaxed bamboo sample. Spectroscopy analyses indicated that the isolated bamboo lignin was a typical grass lignin, consisting of p-hydroxyphenyl, guaiacyl, and syringyl units. The major interunit linkages presented in the obtained bamboo lignin were β-O-4' aryl ether linkages, together with lower amounts of β-β', β-5', and β-1' linkages. The tricin was detected to be linked to lignin polymer through the β-O-4' linkage in the bamboo. In addition, phenyl glycoside and benzyl ether lignin-carbohydrate complexes (LCC) linkages were clearly detected in bamboo (D. sinicus), whereas the γ-ester LCC linkages were ambiguous due to the overlapping NMR signals with other substructures. The detailed structural properties of the obtained lignin fraction together with the light-weight will benefit efficient utilization of natural polymers as a possibly large-scale bio-based precursor for making polymeric materials, biochemicals, functional carbon and biofuels, and multifunctional polymer nanocomposites.

Altering recalcitrant structures of bamboo is essential to obtain high yield of bioethanol via bioconversion process. With the goal of improving cell wall digestibility, alkaline liquid hot water was used to pretreat N. affinis. The effects of temperature and alkali dosage on structural alterations were determined by chemical composition, Brunauer Emmett Teller (BET) and gel permeation chromatography (GPC). The relationship between these changes and substrate digestibility was addressed by separate enzymatic hydrolysis and fermentation (SHF). The results indicated that pretreatments partly removed and degraded hemicelluloses and lignin, reducing yields of substrates and molecular weights of carbohydrates. With the change of cell wall structure, specific surface area of materials increased after LHW pretreatment but decreased with further removal of lignin and hemicellulosic fractions. Maximum bioconversion was obtained by pretreatment with 0.5% NaOH aqueous at 170 °C and SHF, yielding 4.8 g/L ethanol.

Polysaccharide fractions were prepared from peach gum exudates by treatments with alkaline hydrogen peroxide (AHP) and liquid hot water (LHW). The structural characteristics and activities of the polysaccharide fractions were comparatively studied. The results suggested that arabinogalactans substituted with xylose and uronic acids were the main structure of all polysaccharide fractions. AHP and LHW treatments introduced the degradation of the polysaccharides, reducing the molecular weight of polysaccharides from 182500 g/mol to 78450 g/mol and 68420 g/mol, respectively. The decreasement of molecular weights responded to the decrease of thermal stability of polysaccharide fractions. However, AHP and LHW treatments removed most of the nonsugar composition, increasing the DPPH•- and ABTS•+-scavenging activity of polysaccharides. Polysaccharide fractions obtained from LHW treatment showed favorable DPPH•- and ABTS•+-scavenging activity at 22.9% and 34.3%, respectively, at concentration of 1000 μg/mL.

Nitrogen (N) losses and greenhouse gas (GHG) emissions from paddy rice fields contaminate water bodies and atmospheric environment. A 2-year (2012–2013) field experiment was conducted at a typical paddy rice field in a rural suburb of Shanghai, China. N losses and GHG emissions from the paddy field with alternative fertilizer management practices were simultaneously measured. Four treatments were tested in the experiment: applications of only chemical synthetic fertilizer urea (CT), only organic manure (OT), a combination of the two types of fertilizers (MT) and a control (CK). Results from the field study indicated that CT produced the highest seasonal N loading rate (18.79 kg N/ha) and N2O emissions (1.81 kg N2O/ha) but with the lowest seasonal CH4 emissions (69.09 kg CH4/ha). With organic manure applied, MT and OT respectively reduced N loading by 21.86% and 30.41%, reduced N2O emissions by 28.34% and 69.41%, but increased CH4 emissions by 137% and 310% in comparison with CT. However, the net impact of CH4 and N2O emissions on global warming was enhanced when organic manure was applied. In addition, CT and MT produced the optimal rice yield during the experimental period, while OT treatment led to a yield reduction by 9.29% compared with CT. In conclusion, the impacts of alternative fertilizer management practices on ecosystem services ought to be assessed specifically due to the great variations across rice yields, N loss and GHG emissions.

Oestrogen (E) and progestogen (P) exert regulatory effects on the epithelial Na(+) channel (ENaC) in the kidneys and the colon. However, the effects of E and P on the ENaC and on alveolar fluid clearance (AFC) remain unclear, and the mechanisms of action of these hormones are unknown. In this study, we showed that E and/or P administration increased AFC by more than 25% and increased the expression of the α and γ subunits of ENaC by approximately 35% in rats subjected to oleic acid-induced acute lung injury (ALI). A similar effect was observed in the dexamethasone-treated group. Furthermore, E and/or P treatment inhibited 11β-hydroxysteroid dehydrogenase (HSD) type 2 (11β-HSD2) activity, increased corticosterone expression and decreased the serum adrenocorticotrophic hormone (ACTH) levels. These effects were similar to those observed following treatment with carbenoxolone (CBX), a nonspecific HSD inhibitor. Further investigation showed that CBX further significantly increased AFC and α-ENaC expression after treatment with a low dose of E and/or P. In vitro, E or P alone inhibited 11β-HSD2 activity in a dose-dependent manner and increased α-ENaC expression by at least 50%, and E combined with P increased α-ENaC expression by more than 80%. Thus, E and P may augment the expression of α-ENaC, enhance AFC, attenuate pulmonary oedema by inhibiting 11β-HSD2 activity, and increase the active glucocorticoid levels in vivo and in vitro.

The greenhouse vegetable (GV) field is an important agricultural system in China. It may also be a hot spot of nitrous oxide (N2O) emissions. However, knowledge on N2O emission from GV fields and its mitigation are limited due to considerable variations of N2O emissions. In this study, we performed a multi-year experiment at a GV field in Beijing, China, using the static opaque chamber method, to quantify N2O emissions from GV fields and evaluated N2O mitigation efficiency of alternative nitrogen (N) managements. The experiment period spanned three rotation periods and included seven vegetable growing seasons. We measured N2O emissions under four treatments, including no N fertilizer use (CK), farmers' conventional fertilizer application (FP), reduced N fertilizer rate (R), and R combined with the nitrification inhibitor "dicyandiamide (DCD)" (R+DCD). The seasonal cumulative N2O emissions ranged between 2.09 and 19.66, 1.13 and 11.33, 0.94 and 9.46, and 0.15 and 3.27kgNha-1 for FP, R, R+DCD, and CK, respectively. The cumulative N2O emissions of three rotational periods varied from 18.71 to 26.58 (FP), 9.58 to 15.96 (R), 7.11 to 13.42 (R+DCD), and 1.66 to 3.73kgNha-1 (CK). The R and R+DCD treatments significantly (P

In the present study, the electrospray deposition was successfully applied to prepare the porous poly(lactic-co-glycolic acid) (PLGA) microparticles by one-step processing. Metronidazole was selected as the model drug. The porous PLGA microparticles had high drug loading and low density, and the porous structure can be observed by scanning electron microscope (SEM) and transmission electron microscopy (TEM). The production time has been shortened considerably compared with that of the traditional multi-emulsion method. In addition, no chemical reaction occurred between the drug and polymer in the preparation of porous microparticles, and the crystal structure of drug did not change after entrapment into the porous microparticles. The porous microparticles showed a sustained release in the simulated gastric fluid, and the release followed non-Fickian or case II transport. Furthermore, porous microparticles showed a slight cytotoxicity in vitro. The results indicated that electrospray deposition is a good technique for preparation of porous microparticles, and the low-density porous PLGA microparticles has a potential for the development of gastroretentive systems or for pulmonary drug delivery.

Intensive nitrogen (N) fertilizer application in the vegetable fields of China has commonly occurred during recent decades and may substantially increase both nitrous oxide (N2O) and nitric oxide (NO) emissions. However, the quantification of N2O and NO emissions from vegetable fields has been rare due to both the lack of long-term field measurements and reliable methods for extrapolating these measurements. Using a unique dataset from a four-year measurement study of an intensively managed conventional vegetable field in southeastern China, we tested a process-based biogeochemical model, denitrification-decomposition (DNDC), for its applicability for quantifying the impact of fertilizer management practices on emissions of N trace gases from vegetable production. The results from the model validation indicate that the simulations of vegetable yields and seasonal cumulative N2O and NO emissions are consistent with the observations. In addition, DNDC can generally capture the measured temporal pattern of daily N2O and NO fluxes. The modeled impacts of fertilization alternatives can be summarized as follows: (a) both the type and application rate of N fertilizers play important roles in regulating N2O and NO emissions as well as vegetable growth; (b) reducing the N application rate to 75% of the conventional amount decreased N2O and NO emissions by 31% and showed little impact on vegetable biomasses, suggesting that reducing the N dose to a reasonable level would be advisable for both the mitigation of N gases emissions and the maintenance of vegetable production; and (c) replacing synthetic fertilizer under the conventional management practices with organic manure may significantly stimulate N2O emission by 62% while decreasing vegetable yields. The results from this modeling study may provide useful information for the ongoing debate regarding the optimization of fertilizer use strategies in China. This study also demonstrates the potential of utilizing process-based models, such as DNDC, to quantify and mitigate N2O and NO emissions from intensive vegetable production through interpreting, integrating, and extrapolating field observations.

Given the common problem of fertilizer overuse, agronomists are calling for a reduction of the high nitrogen dose by 1/3. We carried out a field experiment over two full winter wheat–summer maize rotations in the North China Plain (NCP) to determine whether this degree of nitrogen reduction will significantly reduce the emissions of nitrous oxide (N2O) and nitric oxide (NO). Three treatments were investigated in the field trial: a control with no nitrogen application, the conventional practice with nitrogen over-application and the optimal practice with a reduced dose of nitrogen by 1/3. Our observations across all treatments over the experimental period reveal significant correlations of the fluxes of either gas with soil temperature and moisture as well as the concentrations of soil ammonium, nitrate and dissolvable organic carbon. There were strong correlations within the functions of the dual Arrhenius and Michaelis–Menten kinetics, giving apparent activation energy values of 40–97 and 59–92 kJ mol−1 for N2O and NO fluxes, respectively. Our results provide annual direct emission factors of 0.48–0.96% for N2O and 0.15–0.47% for NO and demonstrate a significant correlation between N2O emission induced by fertilization and fertilizer nitrogen use efficiency (NUE). The correlation indicates a significant potential of N2O mitigation via enhancing NUEs. A reduction in the nitrogen dose did not obviously mitigate either the annual NO emission in both rotations or the annual N2O emission in the second one. However, nitrogen reduction significantly decreased the annual total N2O emission by 38% during the first rotation. These inconsistencies in the responses of N2O emission to the reduced nitrogen dose can be attributed to improper fertilization practices, such as broadcasting urea prior to heavy rainfalls or irrigation events during the maize season, which implies a need for further fertilization practice options/techniques in addition to the reduction of nitrogen doses.

Dendrocalamus sinicus, which is the largest bamboo species in the world, has broad prospects in the fields of bioenergy and biorefinery application. In this study, dewaxed D. sinicus samples were sequentially treated with 80 % ethanol containing 0.025 M HCl, 80 % ethanol containing 0.5 % NaOH, and aqueous alkaline solutions (containing 2.0, 5.0, and 8.0 % NaOH, respectively) at 75 °C for 4 h, in which 9.63, 8.71, 21.83, 21.09, and 13.09 % of the original lignin were isolated, respectively. The lignin fractions obtained were comparatively characterized by chemical composition, molecular weights, and structural features by wet chemical and instrumental analysis methods. It was found that the bamboo lignin fractions isolated by ethanol had lower weight-average molecular weights (1,360–1,380 g mol−1) and contained much higher amounts of associated hemicelluloses, while the lignin fractions isolated by aqueous alkaline solutions had higher weight-average molecular weights (5,300–6,040 g mol−1) and contained lower amounts of associated hemicelluloses. Spectroscopy analyses indicated that the bamboo lignin was a typical grass lignin, consisting of p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) units. A small percentage of the lignin side-chain was found to be acetylated at the γ-carbon, predominantly at syringyl units. The major interunit linkages present in the bamboo lignin obtained were β-O-4′ aryl ether linkages, together with lower amounts of β-β′, β-5′, and β-1′ linkages.

Zinc porphyrins and its analogs showing many excellent properties such as good potosensitivity, non-toxicity, high stability and facile preparation attract more and more attention of scientists. Here, a novel zinc porphyrazine, namely zinc(II) tetracarboxyl- tetra(1,4-dithiin) porphyrazine [abbreviated as ZnPz(dtn-COOH)4] was successfully synthesized and its potocatalytic activity was studied. The ZnPz(dtn-COOH)4 supported on an Amberlite CG-400 resin was used as a biomimetic catalyst for the activation of molecular oxygen under visible light to degrade a probe dye compound Rhodamine B (RhB) in aqueous solution. Interestingly, the mechanism for the oxidative degradation of RhB involves both 1O2 and HO (Type II and Type I mechanisms, respectively). More hydroxyl radicals were produced at pH 3, which was responded for the highest degradation ratio. The catalyst can be reused several times without losing its catalytic activity, with an average RhB degradation ratio around 80% for 12 h. The most probable mechanism of RhB degradation in this study was that N,N-diehyl-N-ethyl-rhodamine was the main intermediate, which was then cleaved to small molecule by reactive oxidizing species. This study demonstrated a promising approach for the activation of molecular oxygen by the newly developed biomimetic catalyst, in which the central metal to be unchangeable valence, for environmental remediation and oxidation catalysis.

Five soluble polysaccharide fractions were sequentially extracted with water, EDTA, Na2CO3, 4% KOH, and 14% KOH solutions at room temperature for 4 h from cell wall material of rabbiteye blueberry (Vaccinium ashei) fruits, and their physicochemical properties were examined. The sequential treatments yielded a total 36.02% soluble polysaccharides of the dry cell wall material. HPAEC and spectroscopy (FT-IR, NMR) analyses indicated that water-, EDTA-, and Na2CO3-soluble polysaccharide fractions were mainly composed of pectins, followed by lower amounts of arabinogalactans and glucans, while the two KOH-soluble fractions were mainly composed of hemicelluloses. Homogalacturonan was proven to be the predominant component in the isolated blueberry fruit pectic substance. The isolated blueberry fruit hemicelluloses could be defined as a linear β-(1→4)-linked-xylopyranosyl, in which xylose was the predominant neutral sugar (69.98 to 77.16%), followed by lower amounts of galactose, glucose, arabinose, and mannose.