Search

Understanding consumer emotions arising from robot-customers encounters and shared through online reviews is critical for forecasting consumers’ intention to adopt service robots. Qualitative analysis has the advantage of generating rich insights from data, but it requires intensive manual work. Scholars have emphasized the benefits of using algorithms for recognizing and differentiating among emotions. This study critically addresses the advantages and disadvantages of qualitative analysis and machine learning methods by adopting a hybrid machine-human intelligence approach. We extracted a sample of 9707 customers reviews from two major social media platforms (Ctrip and TripAdvisor), encompassing 412 hotels in 8 countries. The results show that the customer experience with service robots is overwhelmingly positive, revealing that interacting with robots triggers emotions of joy, love, surprise, interest, and excitement. Discontent is mainly expressed when customers cannot use service robots due to malfunctioning. Service robots trigger more emotions when they move. The findings further reveal the potential moderation effect of culture on customer emotional reactions to service robots. The study highlights that the hybrid approach can take advantage of the scalability and efficiency of machine learning algorithms while overcoming its shortcomings, such as poor interpretative capacity and limited emotion categories.

Four representative pretreatment methods, water washing (WW), acid washing (AW), dilute acid hydrolysis (DH), and microwave assisted organosolv pretreatment (MOP), were adopted to alter eucalyptus ...

Persistent free radicals (PFRs) may cause negative impacts to human health and the environment because of the induced reactive oxygen species. We expect that PFRs could be generated in the condensable volatiles formed during lignocellulose biomass pyrolysis. Elucidating the structural origin and the formation mechanism of PFRs is important for an in-depth understanding of air pollutants from the pyrolysis or combustion of lignocellulose biomass. This work selected rice straw and pine sawdust to represent agricultural and forest biomass residues. The pyrolysis mechanism, volatile components, and PFR generation were discussed based on the analysis of thermogravimetry-Fourier transform infrared spectroscopy-mass spectrometry (MS), pyrolysis-gas chromatography/MS, and electron spin resonance (ESR). Levoglucosan, furans, and 2-methoxyphenols were the main pyrolytic compounds for cellulose (CL), hemicellulose (HC), and lignin (LG), respectively. Obvious ESR signals were detected in the condensable volatiles of LG, while no ESR signals were detected for those of CL and HC. Higher ESR signals were detected in lignocellulose with a higher content of LG. Therefore, LG was the main structural basis to generate PFRs in lignocellulose condensable volatiles, mostly attributed to the methoxyphenol components. This study provides useful information regarding the generation mechanisms of and the structures related to PFRs, which is essential to understand the risks of lignocellulose pyrolytic volatiles.

Purpose The use of Aspergillus ochraceus TCCC41060 for synthesis of 11α-OH-ethylgonendione, an important intermediate for synthesis of desogestrel-a major ingredient of the “third-generation” oral contraceptives, is hampered by its low regioselectivity of hydroxylation. In the present study, we sought to characterize gene(s) involved in steroid hydroxylation specificity in strain TCCC41060. Methods Taking advantage of the fact that expression of the 11α-hydroxylase, a member of the cytochrome P450 family, is highly induced by steroid substrates, we combined RNA-seq, qRT-PCR, and yeast functional expression to search for responsible steroid hydroxylase gene(s). Results Two highly inducible P450 genes (CYP68L8 and CYP68J5) were isolated and recombinant yeast cells expressing CYP68J5 were capable of 11α-hydroxylating both 16,17α-epoxyprogesterone and D-ethylgonendione. Disruption of CYP68J5 in strain TCCC41060 resulted in complete loss of hydroxylation activities towards D-ethylgonendione, indicating that CYP68J5 was solely responsible for hydroxylation activity on D-ethylgonendione in TCCC41060. Conclusion The above results demonstrated that low hydroxylation specificity of CYP68J5 on D-ethylgonendione fully accounted for high by-product contents in TCCC41060, thus pointing to a strategy to engineer 11α-hydroxylase variants with higher hydroxylation specificity.

Unlike healthy, non-transformed cells, the proteostasis network of cancer cells is taxed to produce proteins involved in tumor development. Cancer cells have a higher dependency on molecular chaperones to maintain proteostasis. The chaperonin T-complex protein ring complex (TRiC) contains eight paralogous subunits (CCT1-8), and assists the folding of as many as 10% of cytosolic proteome. TRiC is essential for the progression of some cancers, but the roles of TRiC subunits in osteosarcoma remain to be explored. Here, we show that CCT4/TRiC is significantly correlated in human osteosarcoma, and plays a critical role in osteosarcoma cell survival. We identify a compound anticarin

The ability to modulate the adhesion of soft materials on-demand is desired for broad applications ranging from tissue repair to soft robotics. Research effort has been focused on the chemistry and architecture of interfaces, leaving the mechanics of soft adhesives overlooked. Stimuli-responsive mechanisms of smart hydrogels could be leveraged for achieving stimuli-responsive hydrogel adhesives that respond mechanically to external stimuli. Such stimuli-responsive hydrogel adhesives involve complex chemomechanical coupling and interfacial fracture phenomena, calling for mechanistic understanding to enable rational design. Here, we combine experimental, computational, and analytical approaches to study a thermo-responsive hydrogel adhesive. Experimentally, we show that the adhesion and mechanical properties of a stimuli-responsive hydrogel adhesive are both enhanced by the application of a stimulus. Our analysis further reveals that the enhanced adhesion stems from the increased fracture energy of the bulk hydrogel and the insignificant residual stress on the adhesive-tissue interface. This study presents a framework for designing stimuli-responsive hydrogel adhesives based on the modulation of bulk properties and sheds light on the development of smart adhesives with tunable mechanics.

In this work, double cantilever beam specimens were used to investigate the rate-dependent fracture of a silicon/epoxy interface. Fracture experiments were conducted at 5 different separation rates, ranging from 0.042 to 8.5 mm/s. For each separation rate, the interfacial properties were extracted by a beam on elastic foundation model and an iterative method, assuming a bilinear traction-separation relation. Rate dependence is observed for the silicon/epoxy interface as both the interfacial toughness and strength increased with the separation rates, which is opposite to the rate dependent fracture behavior of the bulk epoxy in its glassy state. Motivated by this observation, a rate-dependent cohesive zone model is proposed based on a thermally activated bond rupture mechanism. This model relates the interfacial fracture to the breakage of molecular bonds at the interface, and the rate effect develops naturally from the kinetics of damage evolution via the statistical concept of bond survival probability. The double cantilever beam problem with the interfacial bond rupture kinetics was then solved numerically, and the model parameters were extracted by fitting the numerical results to the experimental data. Ideally, this model should be able to explain and predict the rate-dependent fracture of a specific interface (e.g., silicon/epoxy interface) with four parameters, including the bond energy, the critical stress, the initial stiffness and a time scale. However, in order to fit the experimental data, the critical stress had to be adjusted in the present study. Nevertheless, this mechanism-based cohesive zone model offers a promising approach for modeling the rate-dependent fracture, which may also incorporate other mechanisms in future studies.

Softwood is an abundantly available lignocelloluse feedstock which can be converted into chemical and liquid fuels via sugar-based platform molecules. However, cost-effective release of pyrolytic sugars from softwood is considerably hindered by the biomass recalcitrance related to its compositions and structures as well as the catalytic effect of alkali and alkaline earth metals. In order to address these challenges, a novel biorefinery based on H2SO4 assisted organosolvolysis of softwood (e.g. pine wood) in high boiling organic solvents coupled with subsequent fast pyrolysis is proposed. The experimental results demonstrated that H2SO4 assisted organosolvolysis could effectively deconstruct pine wood into pentose, organosolv lignin, cellulose-rich fraction, and simutaneously transfer alkali and alkaline earth metals to solutions, thus improving the yields of platform chemcials (levoglucosan and phenols) in subsequent fast pyrolysis. Moreover, different high boiling solvents showed obviously distinct performance for the deconstruction of pine wood and removal of alkali and alkaline earth metals, thus resulting in different yields of platform chemcials in the subsequent fast pyrolysis. The rank order of these solvents which are beneficial for improving the yield of pyrolytic sugars from pine wood was ethylene glycol > glycerin + ethylene glycol (mass ratio of 1:1) > glycerin > γ-valerolactone. The yield of levoglucosan increased drastically from 3.53 wt% of raw pine wood to 27.19 wt% of cellulose-rich fraction pretreated by ethylene glycol with 1 wt% H2SO4. It was found that the yield of levoglucosan from fast pyrolysis of feedstocks was subjecetd to the mutual effect of normalized total alkali and alkaline earth metals’ valencies and severity of delignification. These findings help to provide a simple and efficient process to selective production of platform chemicals from highly recalcitrant biomass.

Micro/nano-hierarchical textures play essential roles in realizing the functionalities of surfaces. Their friction and deformation behavior at the nanoscale, although important, are relatively unknown. In this study, through targeted friction tests inside a scanning electron microscope of individual micro/nano-hierarchical structures (micropillars covered with nanohairs) fabricated by two-photon lithography, we discovered the coupling between micropillar deformation and nanohair height. We also found that the bending of long nanohairs can provide assistive sliding forces, and lateral force can develop even under just normal load before sliding due to the buckling of the longer nanohairs. These findings, supported by finite element modeling of the tests, will shed light on the design of novel micro/nano-hierarchical textures to realize deformation-resistant functional surfaces with controlled friction.

Pressurization of thin elastomeric membranes has been exploited as a key actuation mechanism in soft robotics, leading to soft pneumatic actuators that can deform reversibly upon inflation and deflation. The contact mechanics of an inflated membrane with another object underlies several important functionalities of soft pneumatic actuators such as gripping, haptic feedback and locomotion. Motivated by the technological relevance, we study the contact between an inflated circular membrane consisting of incompressible neo-Hookean solid and a substrate that is: i) flat and rigid, ii) spherically curved and rigid, iii) flat and elastic, or iv) spherically curved and elastic. By assuming that the contact interface is adhesionless and frictionless and that the membrane is subjected to very large stretch ratios, we obtained approximate analytical solutions for the membrane’s deformation profile as well as the relationship between the applied force, displacement and contact radius. These solutions agree well with results of numerical simulations. In particular, when the substrate is elastic, we obtained a dimensionless parameter γ that captures the transition between two limiting cases, i.e., either the substrate or the inflated membrane is effectively rigid relative to the other component and thus experiences negligible deformation upon contact. The analytical solutions provided in this work can offer insights towards designing soft pneumatic actuators with desired contact compliance.

Softwood forestry waste is an abundantly available lignocellulosic feedstock which could be converted into value-added chemicals via fast pyrolysis. However, its prominent recalcitrant nature resulting from the tightly intertwining of cellulose, hemicellulose and lignin as well as the catalytic effect of alkaline and alkaline earth metals (AAEMs) in it make the valorization of target pyrolytic chemicals particularly challenging. Glycerol pretreatment is a novel process to disrupt the recalcitrant structure of lignocellulose by separating it into three fractions. However, pretreatment effect from conventional heating assisted glycerolysis is poor due to low heat transfer. Introduction of external fields such as ultrasonic and microwave radiation could effectively improve the pretreatment effect. Microwave heating enabled better pretreatment effect than conventional oil bath heating due to its rapid heat transfer and athermal effect. Turbulence effects of ultrasonic radiation enhanced uniformly mixing of feedstock with glycerol, therefore further improving the pretreatment effect. The optimal glycerol pretreatment effect was realized by ultrasonic radiation integrated with microwave heating process, with pine sawdust deconstructed into 53.09 wt.% cellulose-rich fraction, 14.64 wt.% hemicellulose-derived sugars and 12.46 wt.% organosolv lignin, simultaneously removing 91.7 wt.% AAEMs. This considerably facilitated the formation of target pyrolytic chemical (levoglucosan), whilst preventing the production of undesired low molecular weight oxygenates such as acids, ketones, aldehydes. The highest yield of levoglucosan reached up to 52.07 wt.%. Kinetic analysis revealed that, higher activation energy is required for the glycosidic cleavage-based concerted reactions of cellulose into levoglucosan than AAEM catalyzed ring-breaking into light oxygenates. This work introduces an efficient method to produce value-added chemicals from forestry waste whilst reducing its hazardous impact on environment.

An in-depth understanding of peanut shell pyrolysis reaction is essential for its efficient utilization. Detailed analysis of thermodynamics, kinetics, and reaction products can provide valuable information about pyrolysis reaction. In this work, pyrolytic reaction mechanism was elucidated with the analysis of thermogravimetric-mass spectrometry and the structural characterization of the derived biochar. The thermodynamic and kinetic parameters of three sub-stages were matched well in different model-free methods. The positive ΔH and ΔG values indicated that the pyrolysis reactions for three stages were endothermic and nonspontaneous. The reaction mechanism predicted by integral master-plots were F3 (f(α) = (1-α)3), F1 (f(α) = (1-α), and F3 (f(α) = (1-α)3) for the three sub-stages, respectively. The negative ΔS in the third stage was related to the reduced releasing of low-molecular weight gases and ordered graphite-like carbon structure. This study provides a prospective approach to understand the pyrolysis mechanism of biomass.

Fast pyrolysis is a promising method to convert cellulose and hemicellulose into anhydrosugars, but the current method is energy intensive and provides poor yield and selectivity for anhydrosugars. The possibility of using mineral acid pretreatment to achieve oriented pyrolysis of cellulose and xylan at low temperature was explored in this study. The pyrolysis behaviors and mechanism of cellulose and xylan were investigated by pyrolysis–gas chromatography/mass spectrometry and in-situ diffuse reflectance infrared Fourier transform spectroscopy combined with two-dimensional perturbation correlation infrared spectroscopy. The results showed that H2SO4-impregnation and HCl-demineralization achieved the oriented pyrolysis of cellulose and xylan into anhydrosugars at 300 °C. The highest yields of levoglucosan and levoglucosenone (33.3 and 9.7%) were obtained from pyrolysis of 0.1%H2SO4-impregnated cellulose at 300 °C, while those of xylosan and 1,5-anhydro-4-deoxypent-1-en-3-ulose (19.4 and 8.4%) were produced from pyrolysis of HCl-demineralized xylan at 300 °C. It is inferred that H2SO4 could promote the condensation of hydroxyls at C6 and C1 positions and the cleavage of glycosidic bonds to form levoglucosan. And AAEMs could inhibit the intra-molecular dehydration of C3 hydroxyl and C2 hydrogen atom of levoglucosan to form levoglucosenone. The demineralization of xylan could promote the cleavage of glycosidic bonds and dehydration reactions to form xylosan and 1,5-anhydro-4-deoxypent-1-en-3-ulose. These findings provide a simple method to achieve oriented pyrolysis of cellulose and xylan at low temperature.

Fast pyrolysis is a promising way to convert biomass waste into value-added chemicals, but current approaches give poor yield and selectivity for the desired chemicals (e.g. anhydrosugars). This study reported a novel two-staged controllable pyrolysis process consisting of torrefaction of H2SO4-impregnated eucalyptus waste and subsequent fast pyrolysis for achieving directional valorization of eucalyptus waste. Under different torrefaction temperature and holding time, the performance of two-staged controllable pyrolysis of 0.5%H2SO4-impregnated eucalyptus waste was evaluated. The highest total yield of levoglucosan (82.4%, based on cellulose) was obtained by torrefaction at 300 °C with a holding time of 240 s followed by fast pyrolysis at 550 °C, while the highest total yield of xylosan (17.0%, based on hemicellulose) was obtained from torrefaction at 280 °C with a holding time of 20 s combined with subsequent fast pyrolysis at 550 °C. It is demonstrated that H2SO4 impregnation can achieve the directional valorization of holocellulose into anhydrosugars during torrefaction at low temperature, while evidently inhibiting the degradation of lignin and the formation of non-condensable gas and C1-C4 light oxygenates. The unreacted holocellulose and lignin in torrefied eucalyptus waste can be further converted into anhydrosugars and phenols via subsequent fast pyrolysis. This study provides a very simple and efficient strategy to achieve staged and directional valorization of holocellulose and lignin in biomass waste into value-added chemicals.

Efficient fermentable sugar release from softwood biomass is considerably hampered by the recalcitrant nature of its plant cell wall. Here, we reported an ultrasonic and microwave assisted ethylene glycol pretreatment coupled with fast pyrolysis to make total utilization of softwood (pine sawdust) for pyrolytic sugar (levoglucosan), hemicellulosic sugar and phenol production. Compared with oil bath heating, fractionation of pine sawdust into cellulose rich fraction, hemicellulosic sugars and organosolv lignin was enhanced drastically after applying ultrasonic and microwave heating. Whereas, ultrasonic radiation prior to microwave heating turned out to slightly inhibit the fractionation due to oxygenation of sulfuric acid. Mechanistic insight into levoglucosan formation pathway revealed that microwave heating promoted the cleavage of covalent bonds, aromatic ether linkages and glycosidic bonds in lignocellulose, leading to significant improvement in biomass recalcitrance alleviation as well as alkaline and alkaline earth metal removal. This considerably facilitated the heterolytic cleavage of cellulose into levoglucosan, while inhibiting the formation of microorganism inhibitors (e.g. carboxylic acids and phenols) and other light oxygenates in the pyrolysate. Levoglucosan yield exhibited a drastic increase from 3.53 (pine sawdust) to 48.13 wt.% via single microwave heating at 240 W, which was further enhanced with increasing microwave power. Hemicellulosic sugar derived from organosolvolysis and phenol from fast pyrolysis of organosolv lignin also showed an increase in yields with increasing pretreatment severity. Ethylene glycol pretreatment via single microwave heating at 480 W was a preferable process for achieving high yields of levoglucosan (55.87 wt.%), hemicellulosic sugars (19.96 wt.%) and phenols (14.04 wt.%). These findings help to provide an efficient process for maximizing the conversion of recalcitrant softwood for the production of fermentable sugars and phenols.

Lignocellulosic biomass is an abundantly available feedstock for the sustainable production of chemicals and materials. However, total conversion of three major components within biomass (hemicellulose, cellulose and lignin) into chemicals and materials via single hydrolysis or fast pyrolysis remains a challenge because of the heterogeneous structure and recalcitrant nature of biomass, which is especially evident for softwood. In order to address these challenges, with ethylene glycol as solvent and different acids (HCl, HClO4, H2SO4, H3PO4,HCOOH, C3H6O3, or CH3COOH) as catalyst, an integrated process consisting of different acids-assisted organosolvolysis and subsequent fast pyrolysis was proposed for maximizing conversion of softwood into sugars (hemicellulosic and pyrolytic sugars) and ultrafine lignin. Mechanistic insight into acids-assisted organosolvolysis of recalcitrant pine indicated that, acid pKa and H+ concentrations were vital factors influencing the deconstruction of softwood into cellulose-rich fraction, hemicellulosic sugars and high purity ultrafine lignin. This considerably enhanced the heterolytic cleavage of cellulose into levoglucosan (LG) in subsequent fast pyrolysis. The highest LG yield of 44.45 wt% was realized by HCl due to its high pKa value and maximum H+ concentration. Total conversion efficiencies of strong acids-assisted integrated process were superior to those from medium strong and weak acids-assisted process with the highest total conversion efficiency of 61.61 wt% achieved by HClO4 and that of HCl and H2SO4 over 50.00 wt%. Moreover, prewashing feedstocks with HCl solution could effectively improve the total conversion efficiency as well as the purity and uniformity of ultrafine lignin. These findings help to provide an efficient process for maximizing the conversion efficiency of recalcitrant softwood for the production of sugars and ultrafine lignin.

The computation of radial integrals on the semi-infinite axis is an important computationally intensive feature of quantum chemistry computer codes with additional applications to physics and engineering. There have been numerous algorithms proposed to evaluate these integrals efficiently. Many of these approaches involve the transformation of the semi-infinite axis, $$r \in [0,\infty )$$ , to the finite interval, $$x \in [-1,1]$$ , and the use of the Gauss–Legendre or Gauss–Chebyshev quadratures to evaluate the integrals. These mappings redistribute the quadrature points in many different ways. The approach in this paper is to compute the radial integrals with the Gauss–Maxwell nonclassical quadrature defined by the weight function $$w(r)=r^2e^{-r^2}$$ appropriate for the semi-infinite interval and to also use scaling of the quadrature points. We carry out numerical experiments with simple model radial integrands and compare with the results of previous workers.

The aims of the present study were to determine the role of miR-214 on left ventricular remodeling of rat heart with acute myocardial infarction (AMI) and to further investigate the underlying mechanism of miR-214-mediated myocardial protection. AMI was induced in which adenovirus-expressing miR-214 (Ad-miR-214), anti-miR-214, or Ad-GFP had been delivered into rats hearts 4 days prior, while a phosphatase and tensin homolog (PTEN) inhibitor was administered via intra-peritoneal injection 30 minutes prior to AMI. Changes in hemodynamic parameters were detected and recorded. Left ventricular (LV) dimensions and LV/BW were measured. Quantitative RT-PCR was used to determine the miR-214 expression levels of the myocytes in the infarcted, border, and non-infarcted areas of the LV. Myocardial infarct size was also measured. Flow cytometry analysis was performed to examine cellular apoptosis. Western blot analysis was performed to examine PTEN expression. The results showed that miR-214 was upregulated in both border and infarcted areas. Myocardial cell apoptosis was decreased in the Ad-miR-214 group, but was increased in the anti-miR-214 group, while there were no differences among the Ad-GFP-group, PTEN-ad-miR-214 group, or PTEN-anti-miR-214 group. Myocardial infarct size, LV dimensions, heart rate (HR), and LV end-diastolic pressure (LVEDP) were decreased while the maximal rates of rise or decline in blood pressure in the ventricular chamber (± dp/dt) and LV systolic pressure (LVSP) were increased in the Ad-miR-214 group, all of which exhibited opposite changes in the anti-miR-214 group. PTEN was downregulated in the Ad-miR-214 group and upregulated in the anti-miR-214 group. PTEN was decreased in both the border and infarcted areas compared with non-infarcted areas. The study results suggest that Ad-miR-214 improves LV remodeling and decreases the apoptosis of myocardial cells through PTEN, suggesting a possible mechanism by which Ad-miR-214 functions in protecting against AMI injury.

Depression is one of the most common mental health problems worldwide. The diagnosis of depression is usually done by clinicians based on mental status questionnaires and patient's self-reporting. Not only do these methods highly depend on the current mood of the patient, but also people who experience mental illness are often reluctantly seeking help. Social networks have become a popular platform for people to express their feelings and thoughts with friends and family. With the substantial amount of data in social networks, there is an opportunity to try designing novel frameworks to identify those at risk of depression. Moreover, such frameworks can provide clinicians and hospitals with deeper insights about depressive behavioral patterns, thereby improving diagnostic process. In this paper, we propose a big data analytics framework to detect depression for users of social networks. In addition to syntactic and syntax features, it focuses on pragmatic features toward modeling the intention of users. User intention represents the true motivation behind social network behaviors. Moreover, since the behaviors of user's friends in the network are believed to have an influence on the user, the framework also models the influence of friends on the user's mental states. We evaluate the performance of the proposed framework on a massive real dataset obtained from Facebook and show that the framework outperforms existing methods for diagnosing user-level depression in social networks.

Fast pyrolysis is a promising method for the production of liquid fuels and chemicals from lignocellulosic biomass. However, the catalytic effects of inherent alkali and alkaline earth metals and the high temperature used for the fast pyrolysis of biomass can drastically promote uncontrolled C-C/C-O bond cleavages and polycondensation reactions, resulting in the formation of considerable amounts of undesired light oxygenated organic compounds, permanent gases and char. Here, we demonstrate that H2SO4 loading can lower the pyrolysis temperature of biomass from 500 to 300 °C with higher yield of platform chemicals. The pyrolysis of H2SO4-loaded biomass at 300 °C is capable of selectively breaking C-O bonds in polysaccharides and effectively suppressing the formation of light oxygenated organic compounds, permanent gases and char. Approximately 50–60 wt% biomass feedstocks are primarily converted into anhydrosugars (mainly levoglucosan and xylosan) and their dehydrated products (mainly levoglucosenone and furfural). It is inferred that H2SO4 combined with the inherent alkali and alkaline earth metals (AAEM) in raw biomass can simultaneously inhibits the catalytic functions of AAEM and H2SO4 for achieving oriented conversion of hemicellulose and cellulose at low temperature. This study provides a very simple, atom-economical and energy-efficient pyrolytic strategy for enhancing the production of platform chemicals from biomass.

Hemicellulose is the most reactive component of biomass during torrefaction. Torrefied hemicellulose will be one of the most significant factors determining the reactivity of torrefied biomass during subsequent pyrolysis and CO2 gasification. Xylan, as the representative for hemicellulose, was torrefied in a bench scale tubular reactor with varying torrefaction temperature and residence time. The results demonstrated that the pyrolysis and CO2 gasification reactivity of xylan and its derived char was evidently reduced by torrefaction. As torrefaction temperature increased from 200 to 280 °C, the comprehensive pyrolysis index (CPI) of xylan decreased evidently from 16.14 to 2.72 10-4%/(min·°C2), while the average CO2 gasification reactivity of biochar derived from xylan decreased from 9.11 to 7.33 min−1. These results could be attributed to that xylan proceeded devolatilization, polycondensation and carbonization reactions during torrefaction to form torrefied xylan with a condensed aromatic structure. The H/C or O/C ratio of torrefied xylan can be used as a structural indicator for quantitative evaluation of its torrefaction severity and resulting reactivity during pyrolysis and CO2 gasification. These findings can provide useful information for identifying the effect of torrefaction on structure alterations of hemicellulose and resulting reactivity during pyrolysis and CO2 gasification.

The steroid 11α-hydroxylase encoded by CYP68J5 in Aspergillus ochraceus TCCC41060 is involved in the 11α-hydroxylation of 16,17α-epoxyprogesterone. To increase the steroid 11α-hydroxylation efficiency of the production strain Aspergillus ochraceus TCCC41060, recombinant strains of A. ochraceus over-expressing CYP68J5 were constructed. Using 16,17α-epoxyprogesterone as substrate (20 g/l) under optimized conditions, recombinant strain CYP68J5-TrpC-2 exhibited conversion rates of 92% compared with 80% for the control strain TCCC41060. Moreover, the time required for the recombinant strain CYP68J5-TrpC-2 to achieve the highest conversion rates (92%) was reduced by 12 h compared with that of the control strain to achieve 80% conversion. It is concluded that recombinant A. ochraceus strains over-expressing the CYP68J5 gene significantly increased conversion rates and dramatically shortened the transformation time, thus improving process efficiency of 11α-hydroxylation of 16,17α-epoxyprogesterone.