Improving prediction of N2O emissions during composting using model-agnostic meta-learning.

Nitrous oxide (N2O) represents a significant environmental challenge as a harmful, long-lived greenhouse gas that contributes to the depletion of stratospheric ozone and exacerbates global anthropogenic greenhouse warming. Composting is considered a promising and economically feasible strategy for the treatment of organic waste. However, recent research indicates that composting is a source of N2O, contributing to atmospheric pollution and greenhouse effect. Consequently, there is a need for the development of effective, cost-efficient methodologies to quantify N2O emissions accurately. In this study, we employed the model-agnostic meta-learning (MAML) method to improve the performance of N2O emissions prediction during manure composting. The highest R2 and lowest root mean squared error (RMSE) values achieved were 0.939 and 18.42 mg d-1, respectively. Five machine learning methods including the backpropagation neural network, extreme learning machine, integrated machine learning method based on ELM and random forest, gradient boosting decision tree, and extreme gradient boosting were adopted for comparison to further demonstrate the effectiveness of the MAML prediction model. Feature analysis showed that moisture content of structure material and ammonium concentration during composting process were the two most significant features affecting N2O emissions. This study serves as proof of the application of MAML during N2O emissions prediction, further giving new insights into the effects of manure material properties and composting process data on N2O emissions. This approach helps determining the strategies for mitigating N2O emissions.

Investigation of underlying links between nitrogen transformation and microorganisms' network modularity in the novel static aerobic composting of dairy manure by "stepwise verification interaction analysis".

Conventional composting is a viable method treating agricultural solid waste, and microorganisms and nitrogen transformation are the two major components of this proces. Unfortunately, conventional composting is time-consuming and laborious, and limited efforts have been made to mitigate these problems. Herein, a novel static aerobic composting technology (NSACT) was developed and employed for the composting of cow manure and rice straw mixtures. During the composting process, physicochemical parameters were analyzed to evaluate the quality of compost products, and microbial abundance dynamics were determined using high-throughput sequencing technique. The results showed that NSACT achieved compost maturity within 17 days as the thermophilic stage (≥55 °C) lasted for 11 days. GI, pH, and C/N were 98.71 %, 8.38, and 19.67 in the top layer, 92.32 %, 8.24, and 22.38 in the middle layer, 102.08 %, 8.33, and 19.95 in the bottom layer. These observations indicate compost products maturated and met the requirements of current legislation. Compared with fungi, bacterial communities dominated NSACT composting system. Based on the stepwise verification interaction analysis (SVIA), the novel combination utilization of multiple statistical analyses (Spearman, RDA/CCA, Network modularity, and Path analyses), bacterial genera Norank Anaerolineaceae (-0.9279*), norank Gemmatimonadetes (1.1959*), norank Acidobacteria (0.6137**) and unclassified Proteobacteria (-0.7998*), and fungi genera Myriococcum thermophilum (-0.0445), unclassified Sordariales (-0.0828*), unclassified Lasiosphaeriaceae (-0.4174**), and Coprinopsis calospora (-0.3453*) were the identified key microbial taxa affecting NH4+-N, NO3--N, TKN and C/N transformation in the NSACT composting matrix respectively. This work revealed that NSACT successfully managed cow manure-rice straw wastes and significantly shorten the composting period. Interestingly, most microorganisms observed in this composting matrix acted in a synergistic manner, promoting nitrogen transformation.

Optimal nitrogen fertilizer, which determines straw properties, and pyrolysis temperatures produce desired-biochars that can be used as a soil amendment.

This study investigated the straw harvested after nitrogen (N) fertilizer application levels (0, 75, 150 and 225 kg N hm-2). The N fertilizer increased straw yield by 115.4-190.6%. In addition to N fertility, the pyrolysis temperatures (300, 500 and 700 °C) induced significant changes of the straw-derived biochar samples. The yield reduced from 41.4 wt% to 23.2 wt%, the residence time increased from 272 yr to 2194 yr, and the residual coefficient of organic C (Fperm) increased from 0.65 to 0.93 for the biochar samples as the temperature rising. The parameters of C sequestration were mainly affected by pyrolysis temperature. The N + P2O5+K2O content (5.6-8.8%) of the biochar samples was more in the 500 °C treatment. The characteristics of nutrient supply were affected by both the N fertility and pyrolysis temperature. The N fertilizer rate of 150 kg N hm-2 in the soil for wheat straw, together with the 500 °C treatment induces the best nutrient donor and C sequestration after biochar incorporation into the soil.

Optical-Relayed Entanglement Distribution Using Drones as Mobile Nodes.

Entanglement distribution has been accomplished using a flying drone, and this mobile platform can be generalized for multiple mobile nodes with optical relay among them. Here we develop the first optical relay to reshape the wave front of photons for their low diffraction loss in free-space transmission. Using two drones, where one distributes the entangled photons and the other serves as relay node, we achieve entanglement distribution with Clauser-Horne-Shimony-Holt S parameter of 2.59±0.11 at 1 km distance. Key components for entangled source, tracking, and relay are developed with high performance and are lightweight, constructing a scalable airborne system for multinode connectio and toward mobile quantum networks.

Challenges and growth opportunities: the landscape of Chinese medical publication professionals in the global context: a questionnaire-based survey.

OBJECTIVE: The Chinese healthcare industry has immense potential for innovation and requires competent publication professionals for global reach. Changes in regulatory landscape of China necessitates pharmaceutical industries to collaborate with medical professionals who are capable of keeping up with both changes in regulations and innovative medicine. METHODS: We initiated an online questionnaire-based survey via WeChat from August 3 to August 14, 2019 which focused on experience level, challenges, career development, and training requirements of survey participants. RESULTS: A total of 53 medical publication professionals participated in this survey. Contrary to global trends, 77% of participants had <5 years of professional experience in publication, although only 36% of participants had <5 years of experience in healthcare industry. In all, 63% of respondents spent <50% of their time in publication-related activities, contributing to <10 manuscripts per year. Their expertise in manuscripts spanned clinical studies (68%), post-marketing studies (62%), and reviews (38%). Poor research design and data quality, limited medical writing skill, and inefficient communication with authors were major challenges for developing high-quality publications. Awareness of good publication practices guidelines was high (49%) and 15% of respondents were Certified Medical Publication Professionals. Strategic publication planning (72%), industry trends (66%), and best practices (55%) were some of training requirements identified to increase competencies among respondents. CONCLUSIONS: Although the Chinese medical publication professional industry is at a nascent stage, an attempt is being made to provide opportunities for its publication professionals to develop their competencies to match global standards.

Bayesian hierarchical spatial count modeling of taxi speeding events based on GPS trajectory data.

Speeding behavior, especially serious speeding, is more common in taxi driver than other driving population due to their high exposure under traffic environment, which increases the risk of being involved in crashes. In order to prevent the taxi and other road users from speed-related crash, previous studies have revealed contributors of demographic and driving operation affecting taxi speeding frequency. However, researches regarding road factors, and spatial effect are typically rare. For this sake, the current study explores the contributions of 10 types of road characteristics and two kinds of spatial effects (spatial correlation and spatial heterogeneity) on taxi total speeding and serious speeding frequency. Taxi GPS trajectory data in a Chinese metropolis were used to identify speeding event. The study then established four kinds of Bayesian hierarchical count models base on Poisson and negative binominal distribution to estimate the contributor impacts, respectively. Results show that Bayesian hierarchical spatial Poisson log-linear model is optimum for fitting both total and serious speeding frequency. For the analysis, it is found that drivers are more likely to commit speeding on long multilane road with median strip, and road with non-motorized vehicle lane, bus-only lane and viaduct or road tunnel. Roads with low speed limit, and work zone are associated with increasing speeding as well. In terms of serious speeding, bus-only lane is not a contributor, while road speed camera number and one-way organization are significantly positive to the speeding frequency. Furthermore, it reveals that two spatial effects significantly increase the occurrence of speeding events; the impact of spatial heterogeneity is more critical.

Nutrient removal, methane and nitrous oxide emissions in a hybrid constructed wetland treating anaerobic digestate.

A pilot hybrid constructed wetland (CW) planted with reeds (Phragmite australis) and rice (Oryza sativa L.) was designed to treat liquid anaerobic digestate in the Yangtze River Delta, China. The hybrid CW system was composed of four stages: two reed vegetated vertical subsurface flow beds (VSSF: U1 and U2) in sequence, followed by a reed vegetated horizontal subsurface flow bed (HSSF: U3) and a rice vegetated surface flow bed (SF: U4). The average loading rate of digestate was 3.6 m3 per day during the experimental period. The average concentrations of TN and TP in the influent were 379 ± 58 mg L-1 and 29.6 ± 9.2 mg L-1, while the average removal efficiencies of TN and TP were 94.6% and 88.4%. Both TN and TP removal efficiencies in the second VSSF containing zeolite gave the highest removal performance, in which the mass removal rates were 21.3 ± 8.0 g-N m-2 d-1 and 0.99 ± 0.69 g-P m-2 d-1, respectively. Similarly, the highest removal performance for COD was also observed in the second VSSF with a mass removal rate of 79.9 ± 72.4 g-COD m-2 d-1. On the other hand, the average CH4 and N2O fluxes were highest in the first VSSF, at 31.8 ± 12.9 mg m-2 h-1 and 3.7 ± 2.8 mg m-2 h-1, respectively. There was a significant linear relationship between CH4 flux and DOC concentration in the pore water as well as a correlation between N2O flux and TN concentration. Total GWP of the hybrid CWs, derived from CH4 and N2O emissions, was 792.4 kg CO2-eq, of which CH4 and N2O emissions accounted for 66.0% and 34.0%, respectively. Consequently, the hybrid CWs emitted on average 0.93 kg CO2-eq to remove 1 kg COD while the average EF of TNin was 0.34%, suggesting that the use of multistage hybrid CWs could be efficiency-wise and environmentally a promising strategy for anaerobic digestate treatment.

The soluble fraction from straw-derived biochar supplies nutrients and affects carbon storage of coastal mudflat soil in rice paddy.

Incorporation of biochar into soil has been proposed as a strategy for enhancing soil fertility and rice production. A pot trial was carried out to investigate the effects of the dissolvable fraction of biochar in the Yangtze River estuary, China. Soil in plastic pots was incorporated with straw biochar at five different rates: 0%, 5%, 10%, 15%, and 20% (w/wet weight). The rice height, tiller number, and grain yield were recorded; soils and surface water were sampled, and key chemical properties were investigated. Rice grain yield was improved by 29.1-34.2%, and the grain-to-straw ratio was promoted by 8.0-26.1% in the treatments with 10-15% biochar incorporated compared with the control. Soil total organic carbon and total nitrogen contents increased 65.7-242.8% and 22.9-75.3% in the biochar-amended treatments, respectively. Meanwhile, the soil dissolved organic carbon contents increased by 13.4-25.3% in biochar-amended treatments. Higher amounts of added biochar resulted in increased soil electrical conductivity but had no significant effect on soil pH. The major anion was Cl-, and the main cations were K+ and Na+ in the mudflat soil. Addition of 10-15% straw biochar to soil for agronomic purposes is a potentially sustainable ecologically technology.

Year-to-year climate variability affects methane emission from paddy fields under irrigated conditions.

A field experiment in Yangtze River delta of China was conducted to investigate the effects of four treatments (conventional chemical fertilizers (CF), chemical fertilizers incorporated with wheat straw (CF-WS), slow-release urea fertilizer incorporated with wheat straw (SCF-WS), and no fertilizers (Non-F)) on methane emission, rice grain yield, and straw biomass in three (2013, 2014, and 2015) consecutive growing seasons. Similar air temperature and precipitation were recorded in 2014 and 2015 normal seasons; however, the 2013 season with a 2.1-2.3 °C higher mean air temperature and a 61-64% lower precipitation than the normal seasons was considered as a warm-and-dry season.No significant differences in seasonal total methane emissions across all treatments were observed in 2014 and 2015 seasons. Seasonal total methane emissions were 58-294% higher in 2013 season compared to 2014 and 2015 seasons, which suggests that higher ambient temperatures increase methane emissions from paddy fields. The enhanced methane emission was seen mainly during the mid-to-late growth stages after mid-season drainage. CF-WS and SCF-WS significantly increased methane emissions before mid-season drainage relative to CF, and thereby enhanced methane emissions in both normal and warm-and-dry seasons in a seasonal scale.While rice grain yield in each treatment in 2013 season was close to or lower than that in 2014 and 2015 seasons, straw biomass in CF, CF-WS, and SCF-WS in 2013 season were significantly higher than those in 2014 and 2015 seasons, by both 29%, 33-41%, and 15-16%, respectively. Enhancements in methane emissions at higher air temperatures were significantly correlated to its greater straw biomass. Furthermore, combination of slow-release urea fertilizer and straw by ploughing can significantly increase above-ground biomass yields and nitrogen use efficiency in both normal and warm-and-dry seasons.

Drone-based entanglement distribution towards mobile quantum networks.

Satellites have shown free-space quantum-communication ability; however, they are orbit-limited from full-time all-location coverage. Meanwhile, practical quantum networks require satellite constellations, which are complicated and expensive, whereas the airborne mobile quantum communication may be a practical alternative to offering full-time all-location multi-weather coverage in a cost-effective way. Here, we demonstrate the first mobile entanglement distribution based on drones, realizing multi-weather operation including daytime and rainy nights, with a Clauser-Horne-Shimony-Holt S-parameter measured to be 2.41 ± 0.14 and 2.49 ± 0.06, respectively. Such a system shows unparalleled mobility, flexibility and reconfigurability compared to the existing satellite and fiber-based quantum communication, and reveals its potential to establish a multinode quantum network, with a scalable design using symmetrical lens diameter and single-mode-fiber coupling. All key technologies have been developed to pack quantum nodes into lightweight mobile platforms for local-area coverage, and arouse further technical improvements to establish wide-area quantum networks with high-altitude mobile communication.

Effect of moisture gradient on rice yields and greenhouse gas emissions from rice paddies.

Fluxes of methane (CH4) and nitrous oxide (N2O) from two rice varieties, Huayou 14 and Hanyou 8, were monitored using closed chamber/gas chromatography method. Huayou 14 is a commonly grown variety of rice whereas Hanyou 8 is a water-saving and drought-resistant rice (WDR) variety. Low soil volumetric water content (VWC) existed in the treatments on the slope (W5 < W4 < W3 < W2). On the slope, rice yields of Hanyou 8 decreased by 12-39%, and Huayou 14 by 11-46% as compared to the plots on the flat. The total compatible solutes in Hanyou 8 had a greater variational range than Huayou 14. Compared to W1, CH4 emissions from W2-W5 decreased by 58-86% in Hanyou 8 and 38-86% in Huayou 14, whereas those of N2O increased by 26-121% in Hanyou 8 and 49-189% in Huayou 14 across both two seasons, which was mainly because the VWC varied in W2-W5 treatment. Under the treatments in the slope (W2, W3, W4, and W5), the global warming potential (GWP) was dominated by N2O emissions, which accounted for 69-90% of the GWP. Hanyou 8 had greater tolerance for water stress than Huayou 14 did, as evident from the smaller reductions in rice yield and greater variational range of total compatible solutes content. Water stress could reduce CH4 emissions but decrease N2O emissions for both rice varieties. This results suggest that planting WDR varieties under water shortage irrigation (such as W4, W5) will be able to maintain rice yields and reduce the GWP with less water.

Three-year rice grain yield responses to coastal mudflat soil properties amended with straw biochar.

Biochar application is a promising management strategy for enhancing soil fertility and carbon sequestration. A 3-year pot trial was conducted to demonstrate the relationship between rice grain yield and biochar-amended soil properties together with carbon storage in the Yangtze River estuary, China. Straw biochar was incorporated once into soil in pots at five different rates: 0%, 5%, 10%, 15%, and 20% (dry biochar weight/wet soil weight). Compared to yields from the control treatment with no biochar, rice grain yield was improved by 29.1-34.2% in the treatments with 10-15% biochar in the first year following biochar application. In the second year following biochar application, the rice yield was increased by 51.8-96.0% in the treatments with 15-20% biochar. However, compared to the control treatment, hardly any yield increase occurred in any of the biochar treatments in the third year following biochar application. Higher amounts of added biochar increased the soil organic carbon (SOC) and total nitrogen (TN). SOC contents were invariable and increased nearly 60-250% annually in the biochar treatments compared with the control. Biochar increased soil TN 22.9-75.3%, 24.0-60.9% and 13.8-51.2%, respectively, in each of three consecutive years. Biochar increased the mean concentrations of EC, RAP, RAK and DOC by 8.8-44.8%, 10.0-61.1%, 65.6-310.1% and 9.1-20.0%, respectively, during the three rice-growing seasons. The addition of 10-15% straw biochar to soil and regular annual biochar supplements for agronomic purposes is a potentially sustainable management technology to enhance coastal mudflat soil properties and improve rice yields therefrom.

Novel multipurpose pod-intravaginal ring for the prevention of HIV, HSV, and unintended pregnancy: Pharmacokinetic evaluation in a macaque model.

Globally, women bear an uneven burden for sexual HIV acquisition. Results from two clinical trials evaluating intravaginal rings (IVRs) delivering the antiretroviral agent dapivirine have shown that protection from HIV infection can be achieved with this modality, but high adherence is essential. Multipurpose prevention technologies (MPTs) can potentially increase product adherence by offering protection against multiple vaginally transmitted infections and unintended pregnancy. Here we describe a coitally independent, long-acting pod-IVR MPT that could potentially prevent HIV and HSV infection as well as unintended pregnancy. The pharmacokinetics of MPT pod-IVRs delivering tenofovir alafenamide hemifumarate (TAF2) to prevent HIV, acyclovir (ACV) to prevent HSV, and etonogestrel (ENG) in combination with ethinyl estradiol (EE), FDA-approved hormonal contraceptives, were evaluated in pigtailed macaques (N = 6) over 35 days. Pod IVRs were exchanged at 14 days with the only modification being lower ENG release rates in the second IVR. Plasma progesterone was monitored weekly to determine the effect of ENG/EE on menstrual cycle. The mean in vivo release rates (mg d-1) for the two formulations over 30 days ranged as follows: TAF2 0.35-0.40; ACV 0.56-0.70; EE 0.03-0.08; ENG (high releasing) 0.63; and ENG (low releasing) 0.05. Mean peak progesterone levels were 4.4 ± 1.8 ng mL-1 prior to IVR insertion and 0.075 ± 0.064 ng mL-1 for 5 weeks after insertion, suggesting that systemic EE/ENG levels were sufficient to suppress menstruation. The TAF2 and ACV release rates and resulting vaginal tissue drug concentrations (medians: TFV, 2.4 ng mg-1; ACV, 0.2 ng mg-1) may be sufficient to protect against HIV and HSV infection, respectively. This proof of principle study demonstrates that MPT-pod IVRs could serve as a potent biomedical prevention tool to protect women's sexual and reproductive health and may increase adherence to HIV PrEP even among younger high-risk populations.

A Dose Ranging Pharmacokinetic Evaluation of IQP-0528 Released from Intravaginal Rings in Non-Human Primates.

PURPOSE: Design of intravaginal rings (IVRs) for delivery of antiretrovirals is often guided by in vitro release under sink conditions, based on the assumption that in vivo release will follow a similar release profile. METHODS: We conducted a dose-ranging study in the female reproductive tract of pigtail macaques using matrix IVRs containing IQP-0528, a poorly soluble but highly potent antiretroviral drug with an IC90 of 146 ng/mL. These IVRs consisted of drug-loaded segments, 15.6% IQP-0528 in Tecoflex 85A, comprising either all, half, or a quarter of the entire ring. RESULTS: In vitro release under sink conditions demonstrates loading-proportional release, with a cumulative 30-day release of 48.5 ± 2.2 mg for our 100% loaded ring, 24.8 ± .36 mg from our 50% loaded ring, and 13.99 ± 1.58 mg from our 25% loaded ring. In vivo, while drug concentration in vaginal fluid is well in excess of IQP-0528's EC90, we find no statistical difference between the different ring loadings in either swab drug levels or drug released from our rings. CONCLUSIONS: We show that in vitro release may not accurately reflect in vivo release, particularly for poorly soluble drugs. All tested loadings of our IVRs are capable of delivering IQP-0528 well in excess of the IC90.

Repeated administration of high-dose depot medroxyprogesterone acetate does not alter SHIVSF162p3 viral kinetics and tenofovir pharmacokinetics when delivered via intravaginal rings.

BACKGROUND: Intravaginal rings (IVR) for HIV prevention will likely be used by women on depot medroxyprogesterone acetate (DMPA) hormonal contraception. We used pigtailed macaques to evaluate the effects of DMPA on tenofovir disoproxil fumarate (TDF) IVR pharmacokinetics and viral shedding. METHODS: Mucosal tenofovir (TFV) levels were compared in SHIVSF162p3 -negative DMPA-treated (n=4) and normally cycling (n=6) macaques receiving TDF IVRs. Plasma viremia and vaginal shedding were determined in groups of SHIVSF162p3 -positive DMPA-treated (n=6) and normally cycling (n=5) macaques. RESULTS: Similar median vaginal fluid TFV concentrations were observed in the DMPA-treated and cycling macaques over 4 weeks (1.2×105 and 1.1.×105  ng/mL, respectively). Median plasma viremia and vaginal shedding AUC of the DMPA-treated (2.73×107 and 8.15×104 copies/mL, respectively) and cycling macaques (3.98×107 and 1.47×103 copies/mL, respectively) were statistically similar. CONCLUSIONS: DMPA does not affect TDF IVR pharmacokinetics or SHIV shedding.

Topical Delivery of Tenofovir Disoproxil Fumarate and Emtricitabine from Pod-Intravaginal Rings Protects Macaques from Multiple SHIV Exposures.

Topical preexposure prophylaxis (PrEP) against HIV has been marginally successful in recent clinical trials with low adherence rates being a primary factor for failure. Controlled, sustained release of antiretroviral (ARV) drugs may help overcome these low adherence rates if the product is protective for extended periods of time. The oral combination of tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) is currently the only FDA-approved ARV drug for HIV PrEP. A novel pod-intravaginal ring (IVR) delivering TDF and FTC at independently controlled rates was evaluated for efficacy at preventing SHIV162p3 infection in a rigorous, repeat low-dose vaginal exposure model using normally cycling female pigtailed macaques. Six macaques received pod-IVRs containing TDF (65 mg) and FTC (68 mg) every two weeks, and weekly vaginal exposures to 50 TCID50 of SHIV162p3 began one week after the first pod-IVR insertion. All pod-IVR-treated macaques were fully protected throughout the study (P = 0.0002, Log-rank test), whereas all control animals became infected with a median of 4 exposures to infection. The topical, sustained release of TDF and FTC from the pod-IVR maintained protective drug levels in macaques over four months of virus exposures. This novel and versatile delivery system has the capacity to deliver and maintain protective levels of multiple drugs and the protection observed here warrants clinical evaluation of this pod-IVR design.

Safety and Pharmacokinetics of Quick-Dissolving Polymeric Vaginal Films Delivering the Antiretroviral IQP-0528 for Preexposure Prophylaxis.

For human immunodeficiency virus (HIV) prevention, microbicides or drugs delivered as quick-dissolving films may be more acceptable to women than gels because of their compact size, minimal waste, lack of an applicator, and easier storage and transport. This has the potential to improve adherence to promising products for preexposure prophylaxis. Vaginal films containing IQP-0528, a nonnucleoside reverse transcriptase inhibitor, were evaluated for their pharmacokinetics in pigtailed macaques. Polymeric films (22 by 44 by 0.1 mm; providing 75% of a human dose) containing IQP-0528 (1.5%, wt/wt) with and without poly(lactic-co-glycolic acid) (PLGA) nanoparticle encapsulation were inserted vaginally into pigtailed macaques in a crossover study design (n = 6). With unencapsulated drug, the median (range) vaginal fluid concentrations of IQP-0528 were 160.97 (2.73 to 2,104), 181.79 (1.86 to 15,800), and 484.50 (8.26 to 4,045) µg/ml at 1, 4, and 24 h after film application, respectively. Median vaginal tissue IQP-0528 concentrations at 24 h were 3.10 (0.03 to 222.58) µg/g. The values were similar at locations proximal, medial, and distal to the cervix. The IQP-0528 nanoparticle-formulated films delivered IQP-0528 in vaginal tissue and secretions at levels similar to those obtained with the unencapsulated formulation. A single application of either formulation did not disturb the vaginal microflora or the pH (7.24 ± 0.84 [mean ± standard deviation]). The high mucosal IQP-0528 levels delivered by both vaginal film formulations were between 1 and 5 log higher than the in vitro 90% inhibitory concentration (IC90) of 0.146 µg/ml. The excellent coverage and high mucosal levels of IQP-0528, well above the IC90, suggest that the films may be protective and warrant further evaluation in a vaginal repeated low dose simian-human immunodeficiency virus (SHIV) transmission study in macaques and clinically in women.

Variation of the microbial community in thermophilic anaerobic digestion of pig manure mixed with different ratios of rice straw.

The effect of pig manure mixed with rice straw on methane yield and the microbial community involved in a thermophilic (55°C) anaerobic digestion process was investigated. Three substrates composed of mixed pig manure and rice straw at different ratios (95:5; 78:22 and 65:35 w/w, which resulted in C/N ratios of 10:1, 20:1 and 30:1) were used for the experiment. The substrate type had a major influence on the total bacterial community, while the methanogens were less affected. The members of the class Clostridia (phylum Firmicutes) were predominant regardless of mixture ratio (C/N ratio), but at species level there was a major difference between the low and high C/N ratio samples. The hydrogenotrophic methanogenic genus of Methanothermobacter was predominant in all samples but higher C/N ratio sequences affiliated to the genus Methanosarcina were also detected. The appearance of Methanosarcina sp. is most likely due to the less inhibition of ammonia during the anaerobic digestion.

The filamentous fungal pellet and forces driving its formation.

Filamentous fungi play an important role not only in the bio-manufacturing of value-added products, but also in bioenergy and environmental research. The bioprocess manipulation of filamentous fungi is more difficult than that of other microbial species because of their different pellet morphologies and the presence of tangled mycelia under different cultivation conditions. Fungal pellets, which have the advantages of harvest ease, low fermentation broth viscosity and high yield of some proteins, have been used for a long time. Many attempts have been made to establish the relationship between pellet and product yield using quantitative approaches. Fungal pellet formation is attributed to the combination of electrostatic interactions, hydrophobicity and specific interactions from spore wall components. Electrostatic interactions result from van der Waals forces and negative charge repulsion from carboxyl groups in the spore wall structure. Electrostatic interactions are also affected by counter-ions (cations) and the physiologic conditions of spores that modify the carboxyl groups. Fungal aggregates are promoted by the hydrophobicity generated by hydrophobins, which form a hydrophobic coat that covers the spore. The specific interactions of spore wall components contribute to spore aggregation through salt bridging. A model of spore aggregation was proposed based on these forces. Additionally, some challenges were addressed, including the limitations of research techniques, the quantitative determination of forces and the complex information of biological systems, to clarify the mechanism of fungal pellet formation.

Straw biochar hastens organic matter degradation and produces nutrient-rich compost.

Biochar derived from wheat straw was added to pig manure in amounts equivalent to 5%, 10%, or 15% (w/w, wet weight). The ratios of NH4(+)/NO3(-) and of UV light absorption at a wavelength of 254nm (SUV254) and dissolved organic carbon (DOC) indicated that compost with 10-15% biochar became more mature and more humified within 42days of composting, and the content of DOC and the concentration of NH4(+) in such compost decreased by 37.5-62.0% and 4.0-20.9%, respectively, compared to the corresponding levels in the control. Addition of biochar lowered the pH and increased electrical conductivity by 7.0-37.5% compared to the control and also increased the concentrations of water-soluble nutrients including PO4(3-) (5.6-7.4%), K(+) (14.2-58.6%), and Ca(2+) (0-12.5%). It is therefore recommended that straw biochar be added to pig manure at 10-15% by weight.