Application of optimized LSTM in prediction of the cumulative confirmed cases of COVID-19

This paper proposes an optimized Long Short-Term Memory (LSTM+) model for predicting cumulative confirmed cases of COVID-19 in Germany, the UK, Italy, and Japan. The LSTM+ model incorporates two key optimizations: (1) fine-adjustment of parameters and (2) a 're-prediction' process that utilizes the latest prediction results from the previous iteration. The performance of the LSTM+ model is evaluated and compared with that of Backpropagation (BP) and traditional LSTM models. The results demonstrate that the LSTM+ model significantly outperforms both BP and LSTM models, achieving a Mean Absolute Percentage Error (MAPE) of less than 0.6%. Additionally, two illustrative examples employing the LSTM+ model further validate its general applicability and practical performance for predicting cumulative confirmed COVID-19 cases.

The covalent NLRP3-inflammasome inhibitor Oridonin relieves myocardial infarction induced myocardial fibrosis and cardiac remodeling in mice

BACKGROUND

Myocardial infarction (MI) triggers a strong inflammatory response that is associated with myocardial fibrosis and cardiac remodeling. Interleukin (IL)-1β and IL-18 are key players in this response and are controlled by NLRP3-inflammatory bodies. Oridonin is a newly reported NLRP3 inhibitor with strong anti-inflammatory activity. We hypothesized that the covalent NLRP3 inhibitor Oridonin could reduce IL-1β and IL-18 expression and ameliorate myocardial fibrosis after myocardial infarction in mice, improve poor heart remodeling, and preserve heart function.

METHODS

Male C57BL/6 mice were subjected to left coronary artery ligation to induce MI and then treated with Oridonin (1, 3, or 6 mg/kg), MCC950 (10 mg/kg), CY-09 (5 mg/kg) or saline three times a week for two weeks. Four weeks after MI, cardiac function and myocardial fibrosis were assessed. In addition, myocardial expressions of inflammatory factors and fibrotic markers were analyzed by western blot, immunofluorescence, enzyme-linked immunosorbent assay, and quantitative real-time polymerase chain reaction.

RESULTS

Oridonin treatment preserved left ventricular ejection fraction and fractional shortening, and markedly limited the myocardial infarct size in treated mice. The myocardial fibrosis was lower in the 1 mg/kg group (15.98 ± 1.64)%, 3 mg/kg group (17.39 ± 2.45)%, and 6 mg/kg group (16.76 ± 3.06)% compared to the control group (23.38 ± 1.65)%. Moreover, similar with the results of Oridonin, MCC950 and CY-09 also preserved cardiac function and reduced myocardial fibrosis. The expression levels of NLRP3, IL-1β and IL-18 were decreased in the Oridonin treatment group compared to non-treated group. In addition, myocardial macrophage and neutrophil influxes were attenuated in the Oridonin treated group.

CONCLUSIONS

The covalent NLRP3-inflammasome inhibitor Oridonin reduces myocardial fibrosis and preserves cardiac function in a mouse MI model, which indicates potential therapeutic effect of Oridonin on acute MI patients.

[Research progress of prognostic biomarkers in diffuse large B-cell lymphoma]

Diffuse large B-cell lymphoma (DLBCL) is a highly heterogeneous malignancy. A variety of indicators have been identified to predict the prognosis of DLBCL. However, with the emerging new drugs and new therapeutic options in recent years, the prognostic value of these risk prediction models becomes limited, failing to accurately guide treatment. The rapid development of high throughput technologies has led to dramatic improvement in understanding of the biology of DLBCL. The emergence of various new biomarkers contributes to further understanding the pathogenesis, treatment optimization and prognostic stratification of this disease. This review summarizes the prognostic biomarkers related to DLBCL, which mainly covers the hematological, genetic and tumor microenvironment factors, aiming to provide some theoretical basis for the precision treatment of DLBCL.

[Four-steps surgery for infected pancreatic necrosis based on "Step-up" strategy: a retrospective study]

Objective: To examine the effect of the "four-steps" treatment on infectious pancreatic necrosis(IPN). Methods: The data of 207 patients who were diagnosed with IPN from January 2013 to December 2017 at Department of Pancreaticobiliary Surgery, the First Affiliated Hospital of Harbin Medical University were analyzed retrospectively. Among 207 patients, 132(63.8%) were males and 75(36.2%) were females. The median age was 45 years old (range: 19 to 80 years old). One hundred and fifty-eight patients(76.3%) suffered severe acute pancreatitis and 49 patients(23.7%) suffered moderately severe acute pancreatitis. Percutaneous catheter drainage(PCD) was performed on all the patients(Step 1). Patients received "four-steps" minimally invasive treatment strategy in step-up group(173 patients). The following steps after PCD were mini-incision access pancreatic necrosectomy(MIAPN) (Step 2), sinus tract endoscopic debridement and(or) PCD for residual infections(Step 3) and finally conventional open pancreatic necrosectomy(OPN) (Step 4). Patients(34 cases) received conventional open pancreatic necrosectomy after invalided PCD in OPN group. The perioperative parameters and prognosis were compared between Step-up group and OPN group. Normally distributed quantitative variables were analyzed by t-test, non-normally distributed quantitative variables were analyzed by Wilcoxon chi-square test and categorical variables were analyzed by χ(2) test or Fisher exact test, respectively. Results: The basic characteristics of the two groups of patients were similar, but the referral rate of patients and the rate of preoperative 3 days organ failure in the OPN group were significantly higher than those of step-up group patients(47.1% vs. 28.9%, χ(2)=4.313, P=0.038; 26.5% vs. 9.2%, χ(2)=2.819, P=0.011). The frequency of PCD and the number of PCD tube (root) were less than those in the step-up group(1(1) vs. 2(1), Z=-3.373, P=0.018; 2(1) vs. 3(2), Z=-2.208, P=0.027). Compared with the OPN group, the interval time from onset to surgery and the MIAPN operation time were significantly shorter in the step-up group(29(15) days vs. 36(17)days, Z=-0.567, P=0.008; 58(27)minutes vs. 90(56)minutes, Z=-3.908, P<0.01); postoperative mortality was lower(5.8% vs.17.6%, χ(2)=4.070, P=0.044); the overall incidence of postoperative complications was reduced(23.1% vs. 55.9%, χ(2)=14.960, P<0.01) and the incidence of new-onset organ failure was decreased after operation in the step-up group(37.5% vs.47.4%, χ(2)=7.133, P=0.007). The incidence of local abdominal complications (pancreatic fistula, intra-abdominal hemorrhage, gastrointestinal fistula) showed no significant difference between the two groups (P>0.05). Fewer patients required ICU treatment after operation in the step-up group compared with OPN group(22.0% vs. 44.1%, χ(2)=6.204, P=0.013). Patients in the Step-up group has shorter hospital stay than patients in OPN group (46(13) days vs. 52(13)days, Z=-1.993, P=0.046). Conclusions: The clinical effects of "four-steps" exhibited the superiority of minimally invasive treatment of IPN.And MIAPN is a simple, safe and effective procedure to remove pancreatic necrotic tissue and decrease complications.

Actin filaments altered distribution in wheat (Triticum aestivum) "Bending Root" to respond to enhanced Ultraviolet-B radiation

Plants adjust their shoot growth to acclimate to changing environmental factors, such as to enhanced Ultraviolet-B (UV-B) radiation. However, people have ignored that plant roots can also respond to UV-B light. Here, we find the morphology curled wheat roots under UV-B radiation, that we call, "bending roots." The curly region is the transition zone of the root after observed at the cellular level. After exposed to enhanced UV-B radiation for 2 d (10.08 KJ/m2/d), cell size decreased and actin filaments gathered in wheat roots. We also find that H2O2 production increased and that content of the indole-3-acetic acid (IAA) increased remarkably. The pharmacological experiment revealed that actin filaments gathered and polymerized into bundles in the wheat root cells after irrigated H2O2 and IAA. These results indicated that actin filaments changed their distribution and formed the "bending root," which was related to H2O2 production and increase in IAA. Overall, actin filaments in wheat root cells could be a subcellular target of UV-B radiation, and its disruption determines root morphology.

[Research advances on the therapy of pancreatic fistula after pancreatic surgery]

Pancreatic fistula is a common and serious complication after pancreatic surgery. Pancreatic fistula, intra-abdominal infection and hemorrhage are known as the " lethal triad" after pancreatic surgery, which seriously affect the curative efficacy of operation. Although the incidence of pancreatic fistula has not been significantly reduced, there have been a large number of studies on the risk factors of pancreatic fistula and the means of prevention and therapy, which try to minimize the harm of pancreatic fistula. In this article we review the recent development of the latest definition, high risk factors and treatment of postoperative pancreatic fistula according to relevant literatures at home and abroad, aiming at summarizing the research advances on the therapy of pancreatic fistula after pancreatic surgery.

Two-steps gas double-dynamic solid-state fermentation enhances growth and spore production of Conithyrium minitans

Gas double-dynamic solid-state fermentation (SSF) is a promising strategy with the potential in transforming open-pattern fermentation into closed-pattern fermentation. This paper investigated gas double-dynamic SSF performance in cultivating Coniothyrium minitans (C. minitans), as well as its effect on physiology of C. minitans. Results showed that gas double-dynamic increased biomass content by 48.6%. High temperature impeded pycnidia formation and increased glycine production. More pycnidia formed in solid matrix at 20 °C, which was responsible for higher conidia production (1.5 (±0.03) × 10¹⁰ spores/g dry mass), indicating decisive role of high temperature in pycnidia formation of C. minitans in solid-state fermentation. Higher glycine content may be the response of high temperature stress which has close relationship with pycnidia and conidia production. Based on the findings, a two-step strategy for gas double-dynamic SSF was proposed and an satisfactory conidia production was obtained while fermentation period shortened.

[Clinicopathological features of thyroid papillary microcarcinoma of which the maximum diameter is less than 5 mm: a series of 487 cases]

Objective: To analyze the clinical and pathological features of papillary thyroid microcarcinoma(PTMC) of which the maximum diameter is less than 5 mm. Methods: Clinical data of 487 PTMC (≤5 mm) patients who underwent primary surgery by the same team of doctors between March 2013 to March 2016 at Department of Surgery, Ruijin Hospital, School of Medicine, Shanghai Jiaotong University were analyzed retrospectively. Female patients accounted for 77.4%(377/487). The age ranged from 22 to 80 years, with an average of (46±11) years.χ² test and multivariate Logistic regression analysis were used to analyze risk factors. Results: There were 93.6% (456/487) of the patients with preoperative definite diagnosis. There were 92.6% (452/487) of the patients underwent unilateral thyroid lobectomy with isthmectomy and ipsilateral central lymph node dissection. Multifocal carcinoma accounted for 20.3% (99/487), Ⅲ to Ⅳ phase cases accounted for 12.3% (60/487), patients with low risk of recurrence accounted for 67.6% (329/487). The central lymph node metastasis rate was 34.9% (170/487). Male (OR=2.149, 95%CI: 1.367 to 3.381), age<45 years (OR=0.451, 95%CI: 0.303 to 0.672), multifocal carcinoma (OR=1.798, 95%CI: 1.116 to 2.898), and capsular invasion (OR=3.678, 95%CI: 1.406 to 9.622) were the independent risk factors for lymph node metastasis (P<0.05). Conclusion: Regardless of tumor size, PTMC still needs to be taken seriously, especially male, age < 45 years, capsular invasion, or multifocal carcinoma patients.

Two-step size reduction and post-washing of steam exploded corn stover improving simultaneous saccharification and fermentation for ethanol production

The simultaneous saccharification and fermentation (SSF) of corn stover biomass for ethanol production was performed by integrating steam explosion (SE) pretreatment, hydrolysis and fermentation. Higher SE pretreatment severity and two-step size reduction increased the specific surface area, swollen volume and water holding capacity of steam exploded corn stover (SECS) and hence facilitated the efficiency of hydrolysis and fermentation. The ethanol production and yield in SSF increased with the decrease of particle size and post-washing of SECS prior to fermentation to remove the inhibitors. Under the SE conditions of 1.5MPa and 9min using 2.0cm particle size, glucan recovery and conversion to glucose by enzymes were 86.2% and 87.2%, respectively. The ethanol concentration and yield were 45.0g/L and 85.6%, respectively. With this two-step size reduction and post-washing strategy, the water utilization efficiency, sugar recovery and conversion, and ethanol concentration and yield by the SSF process were improved.

Enzymatic hydrolysis of lignocellulosic biomass from low to high solids loading

Solid state enzymatic hydrolysis (SSEH) has many advantages, such as higher sugar concentration, lower operating costs, and less energy input. It should be a potential approach for the industrial application of lignocellulosic ethanol. The purpose of this work is to review the enzymatic hydrolysis of lignocellulosic biomass from low to high solids loading and introduce its both challenges and perspectives. The limitations of SSEH, including inhibition effects, water constraint, and rheology characteristic, are summarized firstly. Various strategies for overcoming these limitations are proposed correspondingly. Fed batch process and its feeding strategy to improve the SSEH efficiency are then discussed. Finally, several intensification methods, hydrolysis reactor, and pilot- and demonstration-scale operations of SSEH are described. In-depth analysis of main limitations and development of novel intensification methods and reactors should provide an effective way to achieve large-scale implementation of SSEH.

Mechanical property of different corn stover morphological fractions and its correlations with high solids enzymatic hydrolysis by periodic peristalsis

Selective structure fractionation combined with periodic peristalsis was exploited to improve the conversion performance of corn stover. The increase of glucan and lignin content and the decrease of xylan content in stem pith were highest after SE, whereas they were lowest in stem node. Glucan conversion increased in this order: steam node<stem rind<whole corn stover (WCS)<stem pith<leaf sheath<leaf. Glucan conversion using periodic peristalsis increased by 10-17% before 24h compared with that using incubator shaker. Stem pith, leaf sheath, leaf, and WCS showed lower hardness and total work in texture profile analysis, resulting in higher glucan conversion compared with stem node and stem rind. Periodic peristalsis reduced hardness and total work before 24h, which was consistent with increased glucan conversion. Periodic peristalsis was an effective strategy to increase high solids enzymatic hydrolysis efficiency of different corn stover morphological fractions.

Enzymatic Pretreatment Coupled with the Addition of p-Hydroxyanisole Increased Levulinic Acid Production from Steam-Exploded Rice Straw Short Fiber

Levulinic acid production, directly from lignocellulosic biomass, resulted in low yields due to the poor substrate accessibility and occurrence of side reactions. The effects of reaction conditions, enzymatic pretreatment, and inhibitor addition on the conversion of steam-exploded rice straw (SERS) short fiber to levulinic acid catalyzed by solid superacid were investigated systematically. The results indicated that the optimal reaction conditions were temperature, time, and solid superacid concentration combinations of 200 °C, 15 min, and 7.5 %. Enzymatic pretreatment improved the substrate accessibility to solid superacid catalyst, and p-hydroxyanisole inhibitor reduced the side reactions during reaction processes, which helped to increase levulinic acid yield. The levulinic acid yield reached 25.2 % under the optimal conditions, which was 61.5 % higher than that without enzymatic pretreatment and inhibitor addition. Therefore, enzymatic pretreatment coupled with the addition of p-hydroxyanisole increased levulinic acid production effectively, which contributed to the value-added utilization of lignocellulosic biomass.

Computed tomography findings of hepatic veno-occlusive disease caused by Sedum aizoon with histopathological correlation

This study investigated the value of computed tomography (CT) in the diagnosis and treatment of hepatic veno-occlusive disease (HVOD) caused by Sedum aizoon (SA). The clinical manifestations, treatment results, imaging findings, and histological findings of the liver were analyzed in 39 patients with HVOD caused by SA. Hepatomegaly, liver dysfunction, abdominal effusion, and geographic density changes on liver CT scans were found in all 39 patients. The pathological findings of histological liver examination included swelling and point-like necrosis of liver cells, significant expansion and congestion of the sinuses, endothelial swelling, and wall thickening with incomplete lumen occlusion of small liver vessels. CT geographic density changes were confirmed by histological examination of the liver in 18 patients. Sixteen patients with small amounts of ascites that started within 4 weeks of treatment recovered completely or significantly improved after symptomatic and supportive treatment. However, only 43.75% of the patients with larger amounts of ascites improved following symptomatic and supportive treatment. In conclusion, liver CT examination is a valuable, safe, and noninvasive tool for the diagnosis of HVOD caused by SA. In selected cases, liver CT examination may replace liver biopsy and histological analysis.

Periodic peristalsis releasing constrained water in high solids enzymatic hydrolysis of steam exploded corn stover

Periodic peristalsis was used to release water constraint and increase high solids enzymatic hydrolysis efficiency. Glucan and xylan conversion in periodic peristalsis enzymatic hydrolysis (PPEH) at 21% solid loading increased by 5.2-6.4% and 6.8-8.8% compared with that in incubator shaker enzymatic hydrolysis (ISEH), respectively. Hydrolysis kinetics suggested that sugars conversion significantly increased within 24h in PPEH compared with ISEH. The peak height of main water pool increased by 7.7-43.1% within 24h in PPEH compared with ISEH. The increases in peak height of main water pool were consistent with the increases in glucan conversion. Submicroscopic particulates and macro granule residues contributed greatly to water constraint compared with glucose, xylose, ethanol, and Tween 80. Smaller particle size and longer residence time resulted in lower water constraint and facilitated the enzymatic hydrolysis performance. Periodic peristalsis was an effective method to reduce water constraint and increase high solids enzymatic hydrolysis efficiency.

Physical structure changes of solid medium by steam explosion sterilization

Physical structure changes of solid medium were investigated to reveal effects of steam explosion sterilization on solid-state fermentation (SSF). Results indicated that steam explosion changed the structure of solid medium at both molecular and three-dimensional structural levels, which exposed hydrophilic groups and enlarged pores and cavities. It was interesting to find that pores where capillary water located were the active sites for SSF, due to the close relationship among capillary water relaxation time, specific surface area and fermentation performance. Therefore, steam explosion sterilization increased the effective contact area for microbial cells on solid medium, which contributed to improving SSF performance. Combined with the previous research, mechanisms of SSF improvement by steam explosion sterilization contained both chemical and physical effects.

Simultaneous saccharification and co-fermentation for improving the xylose utilization of steam exploded corn stover at high solid loading

Simultaneous saccharification and co-fermentation (SSCF) of steam exploded corn stover (SECS) was investigated at 5-25% solid loadings compared with other conversion processes. SECS was washed with a 15-fold excess of deionized water to remove inhibitors of hydrolysis and fermentation. The concentration, yield, and productivity of ethanol was 34.3g/L, 90.0%, 2.61g/L/h in the co-fermentation of 60g/L glucose and 10g/L xylose by Saccharomyces cerevisiae IPE003. Ethanol concentration and productivity increased with increasing solid loading while ethanol yield decreased in all conversion processes of SECS. Glucan and xylan conversion was 82.0% and 82.1% in SSCF at 20% solid loading, respectively, while the concentration, yield and productivity of ethanol was 60.8g/L, 75.3% and 0.63g/L/h. The feeding strategy of SECS addition within 24h improved the SSCF performance. Therefore, SSCF increased ethanol productivity and was an effective conversion process for ethanol production at high solid loading.

Erratum to: A novel solid state fermentation coupled with gas stripping enhancing the sweet sorghum stalk conversion performance for bioethanol

[This corrects the article DOI: 10.1186/1754-6834-7-53.].

Xylose production from corn stover biomass by steam explosion combined with enzymatic digestibility

A novel conversion process using steam explosion combined with enzymatic digestibility was exploited to increase sugar yield. Results showed that glucan and xylan recovery decreased with the increase of holding temperature and residence time in SE, respectively, while glucan and xylan conversion exhibited an opposite trend. The optimal conditions of steam explosion were 160 °C and 48 min, under which glucan and xylan recovery was 93.4% and 71.6%, respectively. Glucan and xylan conversion at 18% solid loading by periodic peristalsis increased by 3.4-5.8% and 4.5-6.2%, respectively, compared with that by water baths shaker. In the whole process, glucose, xylose and total sugar yield reached to 77.3%, 62.8% and 72.3%, respectively. The yield of hydroxymethyl furfural, furfural and lignin-derived products was 6.3 × 10(-2), 7.5 × 10(-2) and less than 3.7 × 10(-2) g/100 g feedstock, respectively. This novel conversion process increased sugar recovery, reduced degradation products formation, improved digestibility efficiency, and hence increased sugar yield.

A novel steam explosion sterilization improving solid-state fermentation performance

Traditional sterilization of solid medium (SM) requires lengthy time, degrades nutrients, and even sterilizes inadequately compared with that of liquid medium due to its low thermal conductivity. A novel sterilization strategy, high-temperature and short-time steam explosion (SE), was exploited for SM sterilization in this study. Results showed that SE conditions for complete sterilization were 172 °C for 2 min and 128 °C for 5 min. Glucose and xylose contents in medium after SE sterilization increased by 157% and 93% respectively compared with those after conventional sterilization (121 °C, 20 min) while fermentation inhibitors were not detected. FTIR spectra revealed that the mild SE conditions helped to release monosaccharides from the polysaccharides. Bacillus subtilis fermentation productivity on medium after SE sterilization was 3.83 times of that after conventional sterilization. Therefore, SE shortened sterilization time and improved SM nutrition, which facilitated fermentability of SM and should promote economy of solid-state fermentation.

A novel solid state fermentation coupled with gas stripping enhancing the sweet sorghum stalk conversion performance for bioethanol

BACKGROUND

Bioethanol production from biomass is becoming a hot topic internationally. Traditional static solid state fermentation (TS-SSF) for bioethanol production is similar to the traditional method of intermittent operation. The main problems of its large-scale intensive production are the low efficiency of mass and heat transfer and the high ethanol inhibition effect. In order to achieve continuous production and high conversion efficiency, gas stripping solid state fermentation (GS-SSF) for bioethanol production from sweet sorghum stalk (SSS) was systematically investigated in the present study.

RESULTS

TS-SSF and GS-SSF were conducted and evaluated based on different SSS particle thicknesses under identical conditions. The ethanol yield reached 22.7 g/100 g dry SSS during GS-SSF, which was obviously higher than that during TS-SSF. The optimal initial gas stripping time, gas stripping temperature, fermentation time, and particle thickness of GS-SSF were 10 h, 35°C, 28 h, and 0.15 cm, respectively, and the corresponding ethanol stripping efficiency was 77.5%. The ethanol yield apparently increased by 30% with the particle thickness decreasing from 0.4 cm to 0.05 cm during GS-SSF. Meanwhile, the ethanol yield increased by 6% to 10% during GS-SSF compared with that during TS-SSF under the same particle thickness. The results revealed that gas stripping removed the ethanol inhibition effect and improved the mass and heat transfer efficiency, and hence strongly enhanced the solid state fermentation (SSF) performance of SSS. GS-SSF also eliminated the need for separate reactors and further simplified the bioethanol production process from SSS. As a result, a continuous conversion process of SSS and online separation of bioethanol were achieved by GS-SSF.

CONCLUSIONS

SSF coupled with gas stripping meet the requirements of high yield and efficient industrial bioethanol production. It should be a novel bioconversion process for bioethanol production from SSS biomass.

Multilevel composition fractionation process for high-value utilization of wheat straw cellulose

BACKGROUND

Biomass refining into multiple products has gained considerable momentum due to its potential benefits for economic and environmental sustainability. However, the recalcitrance of biomass is a major challenge in bio-based product production. Multilevel composition fractionation processes should be beneficial in overcoming biomass recalcitrance and achieving effective conversion of multiple compositions of biomass. The present study concerns the fractionation of wheat straw using steam explosion, coupled with ethanol extraction, and that this facilitates the establishment of sugars and lignin platform and enables the production of regenerated cellulose films.

RESULTS

The results showed that the hemicellulose fractionation yield was 73% under steam explosion at 1.6 MPa for 5.2 minutes, while the lignin fractionation yield was 90% by ethanol extraction at 160°C for 2 hours and with 60% ethanol (v/v). The cellulose yield reached up to 93% after steam explosion coupled with ethanol extraction. Therefore, cellulose sugar, hemicellulose sugar, and lignin platform were established effectively in the present study. Long fibers (retained by a 40-mesh screening) accounted for 90% of the total cellulose fibers, and the glucan conversion of short fibers was 90% at 9.0 hours with a cellulase loading of 25 filter paper units/g cellulose in enzymatic hydrolysis. Regenerated cellulose film was prepared from long fibers using [bmim]Cl, and the tensile strength and breaking elongation was 120 MPa and 4.8%, respectively. The cross-section of regenerated cellulose film prepared by [bmim]Cl displayed homogeneous structure, which indicated a dense architecture and a better mechanical performance.

CONCLUSIONS

Multilevel composition fractionation process using steam explosion followed by ethanol extraction was shown to be an effective process by which wheat straw could be fractionated into different polymeric fractions with high yields. High-value utilization of wheat straw cellulose was achieved by preparing regenerated cellulose film using [bmim]Cl.

Improved efficiency of butanol production by absorbent fermentation with a renewable carrier

BACKGROUND

Biobutanol production is still not economically competitive because of some principal drawbacks including high cost in feedstock consumption, low butanol concentration in the fermentation broth caused by severe product inhibition. An alternative fermentation mode is becoming an urgent requirement to solve these problems. Biobutanol production by absorbent fermentation with a renewable carrier, i.e. pretreated straw materials, is studied in this paper.

RESULTS

Compared with other types of porous media, alkali-treated steam-exploded straw was proved to be a suitable carrier for absorbent fermentation of butanol. The Acetone-Butanol-Ethanol (ABE) concentration increased by 52% compared with submerged culture at an initial glucose concentration of 65 g/L. The adsorption of ABE solvent on substrate and increased bacterial concentration alleviated the end product inhibition and partly explained this positive effect. The steam pretreatment conditions, solid-liquid ratio, substrate types and substrate concentration were also investigated. Steam-explosion at 1.1 MPa for 4 min and solid-liquid ratio of 1:10 was shown to be the optimum. Glucose showed a great advantage over xylose, and higher glucose content was more conducive to biobutanol production. However, the yield of solvent decreased with the increased initial sugar concentration. Considering comprehensively, 100 g/L initial glucose was considered to be the optimum.

CONCLUSIONS

This work demonstrated an effective approach of improved butanol fermentation and its probable mechanisms of this positive effect, i.e. the adsorption of ABE solvent and the adhesion of bacteria on porous substrate accounted for the production improvement and the proportional variation of solvent constituents.

Manufacture of dissolving pulps from cornstalk by novel method coupling steam explosion and mechanical carding fractionation

In order to solve the inhomogeneity of cornstalk as fiber material to manufacture dissolving pulp, a novel method of steam explosion coupling mechanical carding was put forward to fractionate cornstalk long fiber for the production of cornstalk dissolving pulp. The fractionated long fiber had homogeneous structure and low hemicellulose and ash content. The fiber cell content was up to 85% in area, and the hemicellulose and ash content was 8.34% and 1.10% respectively. The α-cellulose content of cornstalk dissolving pulps was up to 93.10-97.10%, the viscosity was 14.37-23.96 mPas, and the yields of cornstalk dissolving pulps were from 10.11% to 12.44%. In addition, the fractionated short fiber was to be hydrolyzed by enzyme to build sugar platform. The constructed method of steam explosion coupling mechanical carding achieved the fractionation of cornstalk into long fiber and short fiber cleanly and effectively, and provided a new way for cornstalk integrated refinery.

Gate dependent photo-responses of carbon nanotube field effect phototransistors

Gate dependent photoconductivity of carbon nanotube (CNT) field effect phototransistors (FEPs) was systematically investigated in this study. The photo-response comparisons of CNT FEPs with symmetric and asymmetric metal structures connecting to the same CNT revealed that the gate effect contributed to a sensitivity improvement with a lower dark current, a higher photocurrent, and an enhanced photovoltage. A functionalized asymmetric FEP, fabricated by partially doping the CNT utilizing a polyethylene imine (PEI) polymer, verified that FEPs delivered a better performance by using asymmetric structures. A multi-gate FEP, with three pairs of side-gates that can electrostatically dope different sections of a CNT independently, was fabricated to examine the gate structure dependent photo-responses. Experimental measurements showed an unconventional photocurrent improvement that was weakly dependent on the gate location, which was attributed to the unique charge distribution of one-dimensional semiconductors.

Successful organ donation from brain dead donors in a Chinese organ transplantation center

Solid organ transplantation is an effective treatment for patients with end-stage organ failure. Donation after brain death (DBD) is a means of addressing the inadequate supply of acceptable donor organs but has only gradually begun to be accepted in mainland China. A major barrier has been the absence of brain death and organ transplant legislation. This paper describes our initial experience with organ transplantation using organs from brain dead donors and discusses strategies for encouraging organ transplantation and brain death legislation in China. Six patients underwent renal transplantation and two patients underwent liver transplantation with organs procured from three brain dead donors at the Organ Transplantation Center, the 181st Hospital. All patients are alive with excellent graft function. DBD is an important means of increasing the number of organs available for transplantation and its widespread implementation in China should be encouraged. Brain death and organ transplantation legislation is necessary to ensure the rights and obligations of donors, recipients and medical institutions.

Membrane penetrating peptides greatly enhance baculovirus transduction efficiency into mammalian cells

The baculovirus group of insect viruses is widely used for foreign gene introduction into mammalian cells for gene expression and protein production; however, the efficiency of baculovirus entry into mammalian cells is in general still low. In this study, two recombinant baculoviruses were engineered and their ability to improve viral entry was examined: (1) cytoplasmic transduction peptide (CTP) was fused with baculovirus envelope protein, GP64, to produce a cytoplasmic membrane penetrating baculovirus (vE-CTP); and (2) the protein transduction domain (PTD) of HIV TAT protein was fused with the baculovirus capsid protein VP39 to form a nuclear membrane penetrating baculovirus (vE-PTD). Transduction experiments showed that both viruses had better transduction efficiency than vE, a control virus that only expresses EGFP in mammalian cells. Interestingly, vE-CTP and vE-PTD were also able to improve the transduction efficiency of a co-transduced baculovirus, resulting in higher levels of gene expression. Our results have described new routes to further enhance the development of baculovirus as a tool for gene delivery into mammalian cells.

Anaerobic digestibility and fiber composition of bulrush in response to steam explosion

Steam explosion, one potential commercial pretreatment method for lignocellulosic wastes, was used to improve methane production of bulrush. Steam exploded bulrush showed a higher methane yield than the raw sample. The effects of steam pressure, moisture content and residence time on the concentration of neutral detergent fiber (NDF) and methane yield were described using a second order polynomial equation. A minimum NDF content of 30.6% was achieved under pretreatment condition with moisture content of 16.55%, steam pressure of 1.52 MPa and residence time of 5.17 min. A maximum methane yield of 205.3 ml per degradable volatile solid was obtained at 11.0% moisture, 1.72 MPa steam pressure, and 8.14 min residence time. The breakage and disruption of rigid lignin structure by steam explosion was confirmed by thermogravimetric analysis.

Unique histological features of the left atrial posterior wall

The left atrial posterior wall (LAPW) plays a critical role in atrial fibrillation, but the underlying mechanism remains unclear. In the present study, we sought to characterize the histological features of the LAPW. Different atrial regions were dissected from hearts of normal Sprague-Dawley rats and humans. Haematoxylin/eosin and van Gieson staining were used to analyse atrial cardiomyocyte arrangement and collagen distribution, respectively. Intercellular junctions were evaluated by transmission electron microscopy. In contrast with other atrial regions, the LAPW exhibited more disorganized cardiomyocytes, larger intercellular spaces and variable myocardial fibre arrangement. The proportion of collagen was significantly higher in the LAPW than in other atrial regions. Interestingly, desmosomes were sparse along with intercellular gaps in the LAPW. In summary, distinct disarrangement of cardiomyocytes and an abundance of collagen exist in the LAPW. The sparsity of desmosomes in the LAPW may be related to the heterogeneous distribution and separation of atrial myocytes.

Air pressure pulsation solid state fermentation of feruloyl esterase by Aspergillus niger

Air pressure pulsation solid state fermentation (APP-SSF) was applied to produce feruloyl esterase (FAE) by Aspergillus niger. With the optimization of some variables by orthogonal design, the optimal condition obtained was 0.2 MPa (gauge pressure) of high pressure intensity, 30 min of low pressure duration and 20s of high pressure duration. Based on the optimized condition, the APP-SSF achieved the reasonable enzyme yield of 881 mU/g at 48 h, which was 58% more than that by static solid state fermentation (static SSF) at 72 h. By comparison of two fermentation methods in temperature, O(2) and CO(2) concentration, and respiration intensity, it was concluded that APP-SSF enhanced heat and mass transfer of fermentation system and strengthened the metabolism of microorganisms. The APP-SSF had a greatly positive effect on FAE production by A. niger, by enhancing mass and heat transfer and activating growth and metabolism.

Surgical treatment of esophageal leiomyoma located near or at the esophagogastric junction via a thoracoscopic approach

Esophageal leiomyoma can be enucleated safely and effectively by minimally invasive surgery. The laparoscopic approach has been a conventional option for this kind of tumor located near or at the esophagogastric (EG) junction. The aims of this study were to evaluate the surgical outcome of thoracoscopic resection of leiomyoma at the EG junction, and discuss factors affecting the incidence of postoperative gastroesophageal reflux. Fourteen patients who underwent thoracoscopic resection of esophageal leiomyoma located near or at the EG junction (<4 cm above the esophageal hiatus) from January 2002 to August 2007 were reviewed retrospectively. Tumor characteristics, surgical methods, and postoperative outcomes were evaluated. A left approach of video-assisted thoracoscopy was used in 13 patients; a right approach was used for the other patient, whose multiple tumors were located in the EG junction and mid-esophagus. Postoperative recovery was uneventful in all patients, with no mucosa leakage or other significant complications. Mean tumor size was 3.2 cm (1.2-6.0 cm). Of the 14 patients, two had serpiginous leiomyoma, two had multiple tumors, and the others had solitary tumors. Mean postoperative stay in hospital was 7 days (4-11 days). Postoperative dysphagia was not reported, although gastroesophageal reflux was noted in one patient. Thoracoscopic resection of esophageal leiomyomas near or at the EG junction is feasible, with a low prevalence of postoperative gastroesophageal reflux.

[FTIR spectra analysis of the reactive activity of lignin when modified by laccase]

In company with the development of nonaqueous enzymology, the enzymatic modification of lignin has gained increasing interests, especially in the synthesis of high molecular material. In the present article, the enzymatic modification of spruce alkali lignin in cetyltrimethylammonium bromide (CTAB) reversed micelles (100 mmol x L(-1) 1, pH 6.0, W/O = 40), alcohol lignin in ethanol solution (50%), lignin sulphonate in sodium phosphate buffer (pH 5.8, 20 mmol x L(-1)) and steam-explosion wheat straw alkali lignin in alkaline solution (pH 10.0, 20 mmol x L(-1) NaOH) by mycelia sterilia YY-5 laccase was studied. Laccase was isolated from Mycelia Sterilia YY-5 (CGMCC-1462) which was an entophytic fungus of Rhus Chinensis Mill. FTIR spectrum was used to assay the structure of lignins and gel permeation chromatography (GPC) was used to determine the molecular weight and molecular weight polydispersity of lignins. Bands of lignin in FTIR spectra of all lignins changed obviously after treated with YY-5 laccase, which indicated that some bond breakage or rearrangement occurred to lignin. The shift of non-conjugated C=O and conjugated carbonyl groups (alpha-carbonyl groups) stretching vibration, the decrease of phenol hydroxyl stretching vibration and the increase of C--O--C stretching vibration of ester bond proved that phenolic hydroxyl, carbonyl group and side chain substituent all might participate in the laccase modification reactions of lignin. Meanwhile, the results of GPC indicated that the molecular of lignins all have certain increase and molecular polydispersity decreased. From the point of the molecular mass polydispersity, the modification effect of YY-5 laccase on steam-exploded wheat straw alkali lignin and spruce alkali lignin was more significantly than other two lignins. The molecular mass polydispersity for steam-exploded wheat straw alkali lignin and spruce alkali lignin was 1.211 and 1.375 respectively, which might contribute to the alkali-stable enzyme for YY-5 laccase. Correspondingly, alkali solution was chosen as the optimum medium for YY-5 laccase to modify lignins.

Temperature cycling to improve the ethanol production with solid state simultaneous saccharification and fermentation

Simultaneous saccharification and fermentation (SSF) widely used in submerged state could be effective in solid state. Solid state SSF was first compared with solid state separate hydrolysis and fermentation on ethanol production. Ethanol yield using solid state separate hydrolysis and fermentation (SHF) in 5 days was only half of that in solid state SSF in 3 days. In solid state SSF, the ethanol concentration using temperature cycling (10 h at 37 degrees C followed by 15 min at 42 degrees C) was 2 times that using constant 37 degrees C within 72 h, reached 5.2%.

Study of PMS777, a new type of acetylcholinesterase inhibitor, in human HepG2 cells. Comparison with tacrine and galanthamine on oxidative stress and mitochondrial impairment

Acetylcholinesterase inhibitors are commonly used as cognitive enhancers for dementia in aged people. Among them, tacrine (THA) but not galanthamine, was shown to exhibit hepatotoxicity which reduces its clinical use. PMS777, both a PAF antagonist and a new potent acetylcholinesterase inhibitor was recently demonstrated to reverse scopolamine-induced amnesia in mice without toxicity. In the present study, the effects of THA, galanthamine and PMS777 were compared in HepG2 cells on the oxidative parameters involved in the reported hepatotoxicity of THA. THA (> or = 10 microM) induced an oxidative stress as shown by elevated ROS and MDA production and by a decrease in GSH level. Moreover, mitochondrial membrane potential and redox status were decreased. At low concentrations (< or =10 microM), there was no significant disturbance. None of the oxidative stress markers was affected by PMS777 up to the maximum concentration tested and it is suggested that PMS777 is not cytotoxic for HepG2 cells. Galanthamine was also without cytotoxicity. Our results suggest that the toxic effect of THA above 10 microM may be caused by drug-induced mitochondrial energization impairment and destabilisation of membrane phospholipids associated with an oxidative stress. In contrast by preventing these dysfunctions, PMS777 could be safer than THA.

Effect of Straw Apoplast Protein on Cellulase Activity

We studied the alteration of the maize straw apoplast proteins in the process of preservation, and analyzed the effects of apoplast proteins on Penicillum expansum cellulase activities. The results show that: the extractable apoplast proteins are gradually decreased during the preservation of maize straw. Meanwhile, their synergistic effects on P. expensum cellulose are also attenuated. The apoplast proteins extracted from fresh maize straw possess endogenous EG activities, which is unstable and completely vanished after 6 months preservation. The apoplast proteins from the preserved straw exhibit significant synergistic effect on FPA, cotton lyase and beta-glucosidase. The maximal synergistic values are 95.32%, 102.06% and 96.6%, respectively. But interestingly, they inhibit the CMCase activity (max. 49.52%). Apoplast proteins show distinctive synergy with betaG and EG, but have no effect on CBH activity. After eliminating the effect of endogenous EG, the apoplast proteins from fresh maize straw have enhanced synergistic or inhibiting effects on FPA, Cotton lyase, betaG and CMCase than those extracted from the preserved straw. Based on our observation, the apoplast proteins play important roles in regulating the cellulase activities. The detailed analysis of the related mechanisms will greatly benefit the studies of the natural biomaterials hydrolysis.

[Enzymatic hydrolysis of steam-exploded rice straw in membrane bioreactor]

An ultrafiltration membrane bioreactor consisted of 1 - 6 enzymatic vessel was used to increase the reducing sugar concentration. The effects of enzyme loading, the number of enzymatic vessel and the dilution rate on enzymatic hydrolysis of steam-exploded rice straw were studied. The results show that the best condition is: 20FPU/g, four enzymatic vessels and 0.075/h (D). Compared with traditional batch reaction, the conversion of substrate increased significantly from 18% - 21% to 39.5%. Compared with the ultrafiltration membrane bioreactor consisted of one enzymatic vessel, the production of reducing sugar increased from 0.25 g/ g to 0.4g/g, and the final reducing sugar concentration in the product stream increased from 4.56g/L to 27.23g/L.

[The periodic change of environment factors in solid state fermentation and effect on microorganism fermentation]

The periodic change of environment factors in air pressure oscillation solid state fermentation bioreactor was studied. Based this research the effect of the periodic environment stimulations on Penicillium decumbens JUA10 cultured in solid state substrate was researched too. The research results showed that in this bioreactor air temperature and relative humidity had large amplitude periodic change drived by air pressure oscillation. The changes had same frequency with the air pressure Oscillation and had amplitude that increased with the air pressure increased. When the press lower limit and upper limit were 0.0MPa and 0.2MPa respectively, pulsating period was 20 min, contrast to the period gather breath solid state fermentation, the air press pulsating SSF had a 2.29 times total CO2 production increase, 3.2 times enzyme activity increase and 1.04 times biomass increase. The data suggested air press pulsating stimulation not only increased biomass but also the metabolic activity.