Optical amplification-free deep reservoir computing-assisted high-baudrate short-reach communication.

An optical amplification-free deep reservoir computing (RC)-assisted high-baudrate intensity modulation direct detection (IM/DD) system is experimentally demonstrated using a 100G externally modulated laser operated in C-band. We transmit 112 Gbaud 4-level pulse amplitude modulation (PAM4) and 100 Gbaud 6-level PAM (PAM6) signals over a 200-m single-mode fiber (SMF) link without any optical amplification. The decision feedback equalizer (DFE), shallow RC, and deep RC are adopted in the IM/DD system to mitigate impairment and improve transmission performance. Both PAM transmissions over a 200-m SMF with bit error rate (BER) performance below 6.25% overhead hard-decision forward error correction (HD-FEC) threshold are achieved. In addition, the BER of the PAM4 signal is below the KP4-FEC limit after 200-m SMF transmission enabled by the RC schemes. Thanks to the use of a multiple-layer structure, the number of weights in deep RC has been reduced by approximately 50% compared with the shallow RC, whereas the performance is comparable. We believe that the optical amplification-free deep RC-assisted high-baudrate link has a promising application in intra-data center communications.

Recycling silage leachate and biochar for improving nitrate removal by woodchip bioreactor.

Woodchip bioreactor (WBR) is commonly used to remove nitrate from drainage and runoff. However, the efficiency of nitrate removal in WBR is highly variable due to the properties of filling materials. In this study, we investigated the potential of recycling two waste materials, biochar (B) and silage leachate (SL), to enhance nitrate removal by providing a better living habitat and extra available carbon for denitrification. We constructed twelve lab-scale bioreactors with different filling materials (WBR, WBR + B, WBR + SL, WBR + B + SL), hydraulic retention times (HRT: 0.5-24 h), and nitrate concentrations (5.4-33 mg L-1) to test nitrate removal efficiency (NRE) and nitrate removal rate (NRR). Our results showed that the combination of biochar and silage leachate led to the highest NRE and NRR, with improvements of 23% and 48%, respectively, compared to WBR alone. However, the benefits of adding biochar and silage leachate were less apparent at longer HRTs. According to the results of our structural equation modeling (SEM), we have attributed the improved denitrification to several factors. These factors include the decrease in dissolved oxygen, saturated hydraulic conductivity, and pH value, as well as an increase in dissolved organic carbon after the addition of silage leachate. Therefore, our study provides evidence that recycling biochar and silage leachate as an additive to WBR could be a beneficial strategy for enhancing nitrate removal. Overall, this study highlights the potential of a win-win solution to improve the efficiency of nitrate removal in water treatment processes.

Simultaneous modulation format identification and OSNR monitoring based on optoelectronic reservoir computing.

An approach for simultaneous modulation format identification (MFI) and optical signal-to-noise ratio (OSNR) monitoring in digital coherent optical communications is proposed based on optoelectronic reservoir computing (RC) and the signal's amplitude histograms (AHs) obtained after the adaptive post-equalization. The optoelectronic RC is implemented using a Mach-Zehnder modulator and optoelectronic delay feedback loop. We investigate the performance of the proposed model with the number of symbols, bins of AHs and the hyperparameters of optoelectronic RC. The results show that 100% MFI accuracy can be achieved simultaneously with accurate OSNR estimation for different modulation formats under study. The lowest achievable OSNR estimation mean absolute errors for the dual-polarization (DP)-quadrature phase-shift keying signal, the DP-16-ary quadrature amplitude modulation (16QAM) signal, and the DP-64QAM signal are 0.2 dB, 0.32 dB and 0.53 dB, respectively. The robustness of the proposed scheme is also evaluated when the optoelectronic RC is in presence of additive white Gaussian noises. Then, a proof of concept experiment is demonstrated to further verify our proposed method. The proposed approach offers a potential solution for next-generation intelligent optical performance monitoring in the physical layer.

Soil organic carbon dynamics shift by incorporating wheat straw in paddy soil in China.

The objective of this study was to explore the effects of unfertilized control (CK), mineral NPK fertilizer (NPK), NPK plus medium-rate wheat straw (MSNPK), and NPK plus high-rate wheat straw (HSNPK) on soil organic carbon (SOC) fractions and C-cycle enzymes at distinct depths (0-5, 5-10, 10-20, 20-30, and 30-50 cm) in paddy soil. The SOC content at 0-50 cm depth ranged from 8.50 to 21.15 g kg-1 , following the trend HSNPK > MSNPK > NPK > CK. Correspondingly, the content of water-soluble organic carbon (WSOC), microbial biomass carbon (MBC), particulate organic carbon (POC), and easily oxidizable carbon (EOC) ranged from 0.08 to 0.27 g kg-1 , 0.11 to 0.53 g kg-1 , 1.48 to 8.29 g kg-1 , and 3.25 to 7.33 g kg-1 , respectively, and HSNPK exhibited the highest values for these parameters among all treatments and soil depths, with significant differences observed compared to NPK and CK (p < 0.05). The cellulase activity of HSNPK was significantly (p < 0.05) higher by 6.12%-13.30% compared to the CK at 0-30 cm depth; while the activity of invertase and ß-glucosidase of HSNPK were significantly (p < 0.05) higher by 34.09%-433.43% and 26.61%-130.50%, respectively, compared to the CK at 0-50 cm depth. Enzyme activities were significantly (p < 0.05) correlated with SOC fractions and the dominant factors driving changes in enzyme activities were WSOC, POC, and EOC. HSNPK was associated with the highest SOC fractions and enzyme activities, indicating that it was the most favorable management practice for promoting soil quality in rice paddy fields.

Antitumor synergism between PAK4 silencing and immunogenic phototherapy of engineered extracellular vesicles.

Immunotherapy has revolutionized the landscape of cancer treatment. However, single immunotherapy only works well in a small subset of patients. Combined immunotherapy with antitumor synergism holds considerable potential to boost the therapeutic outcome. Nevertheless, the synergistic, additive or antagonistic antitumor effects of combined immunotherapies have been rarely explored. Herein, we established a novel combined cancer treatment modality by synergizing p21-activated kinase 4 (PAK4) silencing with immunogenic phototherapy in engineered extracellular vesicles (EVs) that were fabricated by coating M1 macrophage-derived EVs on the surface of the nano-complex cores assembled with siRNA against PAK4 and a photoactivatable polyethyleneimine. The engineered EVs induced potent PAK4 silencing and robust immunogenic phototherapy, thus contributing to effective antitumor effects in vitro and in vivo. Moreover, the antitumor synergism of the combined treatment was quantitatively determined by the CompuSyn method. The combination index (CI) and isobologram results confirmed that there was an antitumor synergism for the combined treatment. Furthermore, the dose reduction index (DRI) showed favorable dose reduction, revealing lower toxicity and higher biocompatibility of the engineered EVs. Collectively, the study presents a synergistically potentiated cancer treatment modality by combining PAK4 silencing with immunogenic phototherapy in engineered EVs, which is promising for boosting the therapeutic outcome of cancer immunotherapy.

The global significance of abiotic factors affecting nitrate removal in woodchip bioreactors.

Woodchip bioreactor (WBR) is one of the green infrastructures in the agriculture system to reduce nitrate from agricultural drainage and stormwater. A lot of abiotic factors have been reported that affect nitrate removal lacking a comprehensive understanding. In this study, we studied eight important abiotic factors, including media age, hydraulic retention time (HRT), influent nitrate concentration (Cin), temperature, dissolved organic carbon (DOC), dissolved oxygen (DO), pH, and effective porosity (ρe) of WBR-filling materials. Based on a database that included 10,179 sets of data from 63 peer-reviewed articles, the nitrate removal rate (NRR) and nitrate removal efficiency (NRE) corresponding to the eight abiotic factors by different categories were comprehensively reported. According to this database, this study found the optimal range of abiotic factors for NRR and NRE in WBR were different. Regarding NRR, the optimal range of media age, HRT, Cin, temperature, effluent DOC, DO, pH, and ρe were in the first year, 0-5 h, 10-20 mg L-1, 20-25 °C, 0-5 mg L-1, 0-0.5 mg L-1, 7-8, and 0.6-0.7, respectively. For NRE, the optimal range of media age, HRT, Cin, temperature, effluent DOC, DO, pH, and ρe were in the first year, 500-3000 h, 0-10 mg L-1, 10-15 °C, >50 mg L-1, 0-0.5 mg L-1, 4-5, and 0.4-0.5, respectively. Moreover, the principal component analysis (PCA) indicated the field studies' principal components were different from laboratory studies. Furthermore, the structural equation modeling (SEM) also revealed the causal relationship of the eight abiotic factors on NRR and NRE is totally different. Lessons from this study can be incorporated into DNBR designs, especially improving nitrate removal rates by optimizing different abiotic factors. It also provides insights regarding the contributions of different abiotic factors for NRR and NRE independently and comprehensively.

The Mechanisms Responsible for N Deficiency in Well-Watered Wheat Under Elevated CO2.

Elevated CO2 concentration [e(CO2)] often promotes plant growth with a decrease in tissue N concentration. In this study, three experiments, two under hydroponic and one in well-watered soil, including various levels or patterns of CO2, humidity, and N supply were conducted on wheat (Triticum aestivum L.) to explore the mechanisms of e[CO2]-induced N deficiency (ECIND). Under hydroponic conditions, N uptake remained constant even as transpiration was limited 40% by raising air relative humidity and only was reduced about 20% by supplying N during nighttime rather than daytime with a reduction of 85% in transpiration. Compared to ambient CO2 concentration, whether under hydroponic or well-watered soil conditions, and whether transpiration was kept stable or decreased to 12%, e[CO2] consistently led to more N uptake and higher biomass, while lower N concentration was observed in aboveground organs, especially leaves, as long as N supply was insufficient. These results show that, due to compensation caused by active uptake, N uptake can be uncoupled from water uptake under well-watered conditions, and changes in transpiration therefore do not account for ECIND. Similar or lower tissue NO 3 - -N concentration under e[CO2] indicated that NO 3 - assimilation was not limited and could therefore also be eliminated as a major cause of ECIND under our conditions. Active uptake has the potential to bridge the gap between N taken up passively and plant demand, but is limited by the energy required to drive it. Compared to ambient CO2 concentration, the increase in N uptake under e[CO2] failed to match the increase of carbohydrates, leading to N dilution in plant tissues, the apparent dominant mechanism explaining ECIND. Lower N concentration in leaves rather than roots under e[CO2] validated that ECIND was at least partially also related to changes in resource allocation, apparently to maintain root uptake activity and prevent more serious N deficiency.

Positive intervention of insoluble dietary fiber from defatted rice bran on hyperlipidemia in high fat diet fed rats.

Increasing dietary fiber intake is considered to be an effective way to prevent and relieve the diseases associated with high-income lifestyles. Compared with soluble dietary fiber, comprehensive evaluation about the effects of insoluble dietary fiber on hyperlipidemia is rarely studied. In the present study, the insoluble dietary fiber was extracted from defatted rice bran by enzymatic treatments (IDF-dRB), followed by investigation about the adsorption and antioxidant activities in vitro. Moreover, the alleviating effects of IDF-dRB on hyperlipidemia were evaluated and analyzed. As a result, IDF-dRB possessed good adsorption capacities of glucose and cholesterol, and also exhibited excellent properties in scavenging radicals. Furthermore, intervention with IDF-dRB significantly improved lipid and glucose metabolism and alleviated inflammation and oxidative stress in rats fed high-fat diet. It was also observed that IDF-dRB treatment could recover the decline in species of gut microbiota caused by high fat diet, increase the community richness, and modulate the metabolic function of gut microbiota. In conclusion, the results indicated that IDF-dRB could ameliorate hyperlipidemia from many aspects and offered some perspectives about the effects of diet intervention with insoluble dietary fiber. PRACTICAL APPLICATION: Rice bran and defatted rice bran are coproducts in the rice processing industry and potentially valuable for the preparation of insoluble dietary fiber. Here an insoluble dietary fiber IDF-dRB was extracted from defatted rice bran and showed good properties in improving lipid and glucose levels, alleviating inflammation and oxidative stress, and modulating gut microbiota in rats fed high-fat diet, suggesting the potential application in ameliorating hyperlipidemia.

Characterization and Interpretation of Cd (II) Adsorption by Different Modified Rice Straws under Contrasting Conditions.

Rice straw can adsorb Cd(II) from wastewater, and modification of rice straw may improve its adsorption efficiency. The rice straw powder (Sp) from the direct pulverization of rice straw was used as the control, the rice straw ash (Sa), biochar (Sa), and modified rice straw (Ms) were prepared by ashing, pyrolysis and citric acid modification, respectively, and all of them were examined as adsorbents for Cd(II) in this study. Batch adsorption experiments were adopted to systematically compare the adsorption capacities of rice straw materials prepared with different modification methods for Cd(II) from aqueous solution under different levels of initial Cd(II) concentration (0-800 mg·L-1), temperature (298, 308, and 318 K), contact time (0-1440 min), pH value (2-10), and ionic strength (0-0.6 mol·L-1). The results indicated that the modification method affected the adsorption of Cd(II) by changing the specific surface area (SSA), Si content, surface morphology, and O-containing functional group of rice straw. Compared with Sp, Ms held more surface O-H, aliphatic and aromatic groups, while Sa had more phenolic, C-O (or C-O-C), and Si-O groups, and Sb held more C-O (or C-O-C) and Si-O groups; besides, Sa, Sb, and Ms had larger SSA than Sp. Adsorption capacity of the four adsorbents for Cd(II) increased and gradually became saturated with the increase in the initial Cd(II) concentration (0-800 mg·L-1). The adsorption capacity of Cd(II) was significantly higher at 318 K than 298 K and 308 K, regardless of the adsorbent type. Sa had the largest SSA (192.38 m2·g-1) and the largest adsorption capacity for Cd(II). When the initial Cd2+ concentration was at 800 mg·L-1, the Cd(II) adsorption amount reached as high as 68.7 mg·g-1 with Sa at 318 K. However, the SSA of Sp was only 1.83 m2·g-1, and it had the least adsorption capacity for Cd(II). Only the adsorption of Cd(II) upon Sb at 298 K was spontaneous, and surprisingly, all other adsorptions were nonspontaneous. These adsorptions were all chemical, and were favorable, exothermic and order-increasing processes. The pseudo-second-order model showed a strong fit to the kinetics of Cd(II) adsorption by the four adsorbents. The adsorption capacities of Cd(II) by the adsorbents were less at low pH, and all were enhanced with the increase of initial pH value (2-10) in the solution. The inhibiting effect on Cd(II) adsorption due to the increase in ionic strength was greater with Sa, Sb, and Ms than that under Sp. The rice straw ash prepared by ashing unexpectedly had greater adsorption capacity for Cd(II) than the biochar and citric acid modified rice straw. The optimum condition for Cd(II) adsorption was established as the temperature of 318 K, initial Cd(II) concentration of 800 mg·L-1, contact time of 240 min, and no Na(I) interference regardless of absorbent. In conclusion, rice straw ash shows the greatest potential of being applied to paddy fields for the remediation of Cd(II) pollution so as to reduce the risk of Cd(II) enrichment in rice grains and straws.