Salicornia dolichostachya organosolv fractionation: towards establishing a halophyte biorefinery

Halophytes are a potential source of lignocellulosic material for biorefinery, as they can be grown in areas unsuitable for the cultivation of crops aimed at food production. To enable the viable use of halophytes in biorefineries, the present study investigated how different organosolv process parameters affected the fractionation of green pressed fibers of Salicornia dolichostachya. We produced pretreated solids characterized by up to 51.3% ± 1.7% cellulose, a significant increase from 25.6% ± 1.3% in untreated fibers. A delignification yield of as high as 60.7%, and hemicellulose removal of as high as 86.1% were also achieved in the current study. The obtained cellulose could be completely converted to glucose via enzymatic hydrolysis within 24 h. The lignin fractions obtained were of high purity, with sugar contamination of only 1.22% w/w and ashes below 1% w/w in most samples. Finally, up to 29.1% ± 0.4% hemicellulose was recovered as a separate product, whose proportion of oligomers to total sugars was 69.9% ± 3.0%. To the best of our knowledge, this is the first report in which Salicornia fibers are shown to be a suitable feedstock for organosolv biomass fractionation. These results expand the portfolio of biomass sources for biorefinery applications.

An organosolv method was developed for the fractionation of fibers of a halophyte plant in a biorefinery approach. Salicornia dolichostachya was used as raw material allowing the production of cellulose, hemicellulose, and lignin fractions.     

Dilute acid catalyzed fractionation and sugar production from bamboo shoot shell in γ-valerolactone/water medium

Overcoming the recalcitrance barrier of cellulosic biomass for efficient production of fermentable sugars at low cost is the current limitation for the industrialization of lignocellulosic biorefineries. In the present work, a two-step non-enzymatic strategy was developed for the fractionation of the main components in bamboo shoot shell (BSS) and conversion of polysaccharides into fermentable sugars by dilute acid in a γ-valerolactone (GVL)/H₂O solvent system. About 86.0% of lignin and 87.4% of hemicelluloses were removed in the first step by 0.6% H₂SO₄ under 140 °C for 1 h with the addition of 60% GVL. The residue solids enriched with cellulose were then subjected to acid hydrolysis employing 0.05% H₂SO₄ as the catalyst in 80% GVL at 180 °C for 20 min. The maximum total soluble sugar yield achieved in the acid hydrolysate was 70.7%. This research could provide valuable insights into the valorization of lignocellulosic biomass and become a promising alternative to the biomass-derived carbohydrate production scheme.

A non-enzymatic method is reported for the production of fermentable sugars from lignocellulose with a high total sugar recovery.     

Eucalyptus red grandis pretreatment with protic ionic liquids: effect of severity and influence of sub/super-critical CO2 atmosphere on pretreatment performance

Deconstruction of lignocellulosic biomass with low-cost ionic liquids (ILs) has proven to be a promising technology that could be implemented in a biorefinery to obtain renewable materials, fuels and chemicals. This study investigates the pretreatment efficacy of the ionoSolv pretreatment of Eucalyptus red grandis using the low-cost ionic liquid triethylammonium hydrogen sulfate ([N₂₂₂₀][HSO₄]) in the presence of 20 wt% water at 10% solids loading. The temperatures investigated were 120 °C and 150 °C. Also, the influence of performing the pretreatment under sub-critical and supercritical CO₂ was investigated. The IL used is very effective in deconstructing eucalyptus, producing cellulose-rich pulps resulting in enzymatic saccharification yields of 86% for some pretreatment conditions. It has been found that under a CO₂ atmosphere, the ionoSolv process is pressure independent. The good performance of this IL in the pretreatment of eucalyptus is promising for the development of a large-scale ionoSolv pretreatment processes.

Deconstruction of lignocellulosic biomass with low-cost ionic liquids (ILs) has proven to be a promising technology that could be implemented in a biorefinery to obtain renewable materials, fuels and chemicals.     

Fractionation and characterization of lignin from sugarcane bagasse using a sulfuric acid catalyzed solvothermal process

Conversion of lignocellulosic residue to bioenergy and biofuel is a promising platform for global sustainability. Fractionation is an initial step for isolating lignocellulosic components for subsequent valorization. The aim of this research is to develop the solvothermal fractionation of sugarcane bagasse to produce high purity lignin. The physio-chemical structure of isolated lignin from this process was determined. In this study, a central composite design-based response surface methodology (RSM) was used to optimize an acid promoter for isolating lignin from sugarcane bagasse using a solvothermal fractionation process. The reaction was carried out with sulfuric acid, at a concentration of 0.01–0.02 M and a reaction temperature of 180–200 °C for 30–90 min. The optimal conditions for the experiment were obtained at the acid concentration of 0.02 M with a temperature of 200 °C for 90 min in methyl isobutyl ketone (MIBK)/methanol/water (35% : 25% : 40% v/v%). The results showed that 88% of lignin removal was done in the solid phase, while 87% of lignin recovery was conducted in the organic phase. Furthermore, the changes in the physico-chemical characteristics of solid residue and lignin recovery were analyzed using various techniques. GPC analysis of recovered lignin from the organic fraction showed a lower M_w (1374 g mol⁻¹) and polydispersity index (1.75) compared to commercial organosolv lignin. The major lignin degradation temperature of commercial organosolv lignin was estimated to be 410 °C, whereas BGL showed two main degradations at 291 °C and 437 °C, which could point to potential relationships with the degradation of β-O-4 cross-links. The results indicated that recovered lignin was mostly cross-linked by β-O-4 cross-links. In addition, Py-GC/MS and 2D HSQC NMR gave more information regarding the compositional and structural features of recovered lignin. The development of the sulfuric acid catalyzed solvothermal process in this study provides efficient extraction of high-value organosolv lignin from sugarcane bagasse and the production of recovered lignin in the organic phase with low contamination from other contents. The lignin characteristic data can contribute to the development of lignin valorization in value-added applications.

Conversion of lignocellulosic residue to bioenergy and biofuel is a promising platform for global sustainability.     

Evaluation of xylooligosaccharide production from residual hemicelluloses of dissolving pulp by acid and enzymatic hydrolysis

Xylooligosaccharides (XOS) are useful food and pharmaceutical additives, which can be produced from various xylans. However, the XOS prepared from lignocellulosic materials are difficult to purify due to the complexity of the degradation products. Thus, hemicelluloses with a high-purity will be the preferred feedstock for XOS production. In this work, acid hydrolysis and enzymatic hydrolysis were applied to prepare XOS from the residual hemicelluloses of the dissolving pulp. The results showed that the highest XOS yield (45.18%) obtained from the acid hydrolysis was achieved with 1% sulfuric acid at 120 °C for 60 min, and xylohexaose accounted for 47% of the XOS. For enzymatic hydrolysis, under optimal conditions, the highest XOS yield of 42.96% was observed, and xylobiose and xylotriose comprised 90.5% of the XOS. It is suggested that the distribution of the XOS could be controlled significantly according to the enzymatic or acid hydrolysis conditions used.

The hemicelluloses extracted from dissolving pulp were applied to produce xylooligosaccharides (XOS) by acid and enzymatic hydrolysis.     

Rhododendron and Japanese Knotweed: invasive species as innovative crops for second generation biofuels for the ionoSolv process

We investigated the potential of two terrestrial biomass invasive species in the United-Kingdom as lignocellulosic biofuel feedstocks: Japanese Knotweed (Fallopia japonica) and Rhododendron (Rhododendron ponticum). We demonstrate that a pretreatment technique using a low-cost protic ionic liquid, the ionoSolv process, can be used for such types of plant species considered as waste, to allow their integration into a biorefinery. N,N,N-Dimethylbutylammonium hydrogen sulfate ([DMBA][HSO₄]) was able to fractionate the biomass into a cellulose-rich pulp and a lignin stream at high temperatures (150–170 °C) and short reaction times (15–60 minutes). More than 70–80% of the subsequent cellulose was hydrolysed into fermentable sugars, which were fermented into the renewable energy vector bioethanol.

Japanese Knotweed (Fallopia japonica) and Rhododendron (Rhododendron ponticum), two invasive species in the UK that are an environmental threat and economic burden, can be integrated into a flexible ionic liquid based biorefinery process to produce bioenergy and chemicals.     

Evaluation of Rodent Cage Processing Using Reduced Water Temperatures

Studies published in 1994 and 2000 established a temperature range of 143–180 °F for effective cage sanitization in animal facilities. These 2 studies were, respectively, theoretical and based on experiments using hot water to sanitize bacteria-coated test tubes. However, such experimental methods may not capture the practical advantages of modern washing technology or account for the routine use of detergent in cage wash. Moreover, these methods may not translate to the challenges of removing adhered debris and animal waste from the surfaces being sanitized. A sample of highly soiled cage bottoms, half of which were autoclaved with bedding to create challenging cleaning conditions, were processed at 6 combinations of wash and rinse cycles with 125 °F, 140 °F, and 180 °F water with detergent. All cycles were equipped with a data logging device to independently verify temperatures. After washing, cages underwent visual inspection and microbial sampling consisting of organic material detection using ATP detection and Replicate Organism Detection and Counting (RODAC) plates. Cages with any amount of visible debris failed inspection, as did cages that exceeded institutional sanitization thresholds. Results indicate that wash and rinse temperatures of 140 °F for a programmed wash duration of 450 s and rinse of 50 s effectively clean and disinfect both highly soiled and autoclaved cages. Accounting for both steam and electrical energy, these parameters result in an annual savings of $21,867.08 per washer on an equivalent run basis using the current institutional standard of 180 °F.

The Guide for the Care and Use of Laboratory Animals states that “effective disinfection can be achieved with wash and rinse water at 143–180°F or more.”¹³ Disinfection is defined as the reduction or elimination of microorganisms, whereas sanitization is the combined effect of cleaning, or removal of gross debris, with disinfection.¹³ In pursuing regulatory compliance and biosecurity, institutions commonly operate at the higher end of this range for both the wash and rinse stages, resulting in high utility usage and high-cost operation. Early research underlying recommendations for disinfection with water alone used a theoretical approach to establish time-heat combinations, known as cumulative heat factors.²⁶ Disinfection combinations are 1800 s at 143 °F (61.7 °C), 15 s at 161 °F (71.7 °C), and 0.1 s at 180 °F (82.2 °C).²⁶ Subsequent research has shown that contact times ranging from 2 to 5 s at 168 °F to 180 °F (75.6 to 82.2 °C) are sufficient to kill Pseudomonas aeruginosa, Salmonella cholerasuis, and Staphylococcus aureus,²⁷ and contact times of 2 min or more at 140 °F (60 °C) will kill Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Providencia rettgeri, and Staphylococcus epidermidis.²¹ When accounting for chemical and mechanical factors in tunnel washers, washing at the domestic hot water temperature (110 °F [43.3 °C]), followed by a rinse at 180 °F, can adequately prevent transmission of mouse parvovirus, Helicobacter spp., Mycoplasma pulmonis, Syphacia obvelata, and Myocoptes musculinus.⁶ The current study used performance standards in a practical study design to build on these disinfection principles and inform sanitization parameters for modern cage washing. Modern washers not only operate longer than the times required in the described cumulative heat factors, but they also use sophisticated mechanical delivery of water via high-pressure jets, dispense detergent, and allow programming of different temperatures at the wash and rinse stages. Test tube models and organism-directed research previously used to determine cage wash efficacy may not capture the challenges of debris removal encountered in day-to-day operation in an animal facility. Assessment of visible debris is recommended by cage processing working groups,¹² and should be included as a practical metric when establishing performance-based standards.The purpose of this study was to compare sanitization performance of reduced-temperature wash conditions to the standard wash cycle temperature of 180 °F. Experimental conditions combined wash and rinse temperatures of 125 °F, 140 °F, and 180 °F. Water sourced to the wash room in our facility is 125 °F (51.7 °C) and was therefore the minimal testable parameter. 140 °F (60 °C) is both commonly used in European facilities¹² and falls in the midrange of temperatures recommend for use with cage wash detergent (120 to 160 °F [48.9 to 71.1 °C]).²³ Highly soiled cages, half of which were autoclaved with bedding to represent the most challenging subset of cages to clean, were evaluated for disinfection and cleanliness. We hypothesized that cages washed and rinsed at 125 °F for 120 s would pass institutional sanitization standards, as assessed with visual inspection, ATP monitoring, and replicate organism detection and counting (RODAC). Given the energy usage, time, and utility costs necessary to reach temperatures of 180 °F, study aims were to verify sanitization performance at reduced temperatures, estimate time savings of operating at these various temperature parameters, and quantify cost and utility savings factoring in both electrical and steam-boosted heating.     

Time dependence of domain structures in potassium sodium niobate-based piezoelectric ceramics

Piezoelectric materials, which can convert energy between electrical and mechanical forms, are widely used in modern industry. (K,Na)NbO₃-based ceramics have attracted extensive attention due to their excellent performance characteristics among the lead-free materials. Piezoelectric properties are closely related to ferroelectric domain structures including the domain morphology and domain wall motion. However, time dependence of ferroelectric domains in (K,Na)NbO₃-based ceramics has barely been studied. Here, we synthesized Li-doped KNN ceramics. The morphologies and crystallographic parameters of the domain structures were characterized. Two ferroelectric domains, the 60°/120° and 180° domains, were identified in the ceramic. Surprisingly, the domain structure changed naturally as time passed, and most of the change occurred in the 180° domain wall, while the 60°/120° domains remained nearly unchanged. Our results are different from those of previous studies, which showed that the non-180° domain wall was more prone to movement than the 180° domain wall.

The ferroelectric domain structure of Li-doped (K,Na)NbO₃ changed naturally as time passed, and most of the change occurred in the 180° domain wall, while the 60°/120° domains remained nearly unchanged.     

Feasibility of polyethylene composites reinforced by distillers dried fibers with solubles (DDFS) after different generations of ethanol fermentation

In order to effectively evaluate the distillers dried fibers with solubles (DDFS) obtained from biorefinery processes, sorghum distiller (SD), cassava distiller (CD) and corn cob distiller (CCD) residuals from different generation bioethanol plants were used as the reinforcing phase for polyethylene composites. The mechanical performances and the physical properties of the polyethylene/DDFS composites were evaluated. The results showed that the CCD reinforced specimen offered the best mechanical performances, with a flexural strength of 21.8 ± 2.2 MPa and a tensile strength of 39.7 ± 3.2 MPa. After multigelation, the retention ratios of the rupture modulus and the elasticity modulus of the CCD reinforced specimen reached 88.7 ± 6.7% and 84.1 ± 2.7%, while after 2000 h of xenon lamp weathering they reached 96.2 ± 4.7% and 82 ± 1.8%, respectively. Hybridizing the biorefinery process with the process of composites production was feasible.

Flowchart of the process for prepares polyethylene/DDFS composites. Solid residuals after 1 G, 1.5 G and 2 G SSF bioethanol plants were used as the reinforcement.     

The growth behavior of brain-like SnO2 microspheres under a solvothermal reaction with tetrahydrofuran as a solvent and their gas sensitivity

In this paper, the growth behavior of brain-like SnO₂ microspheres synthesized by a tetrahydrofuran (THF) solvothermal method was studied. Unlike water or ethanol as the solvent, THF is a medium polar and aprotic solvent. Compared with other common polar solvents, the THF has no strong irregular effects on the growth process of SnO₂. In addition, the viscosity of THF also helps the SnO₂ to form a regular microstructure. The growth behavior of the brain-like SnO₂ microspheres is controlled by changing the synthesis temperature of the reaction. The SEM and TEM results reveal that the SnO₂ forms particles first (125 °C/3 h), and then these nanoparticles connect to each other forming nanowires and microspheres (diameter ≈ 1–2 μm) at 135 °C for 3 h; finally the microspheres further aggregate to form double or multi-sphere structures at 180 °C for 3 h. In this paper, the brain-like SnO₂ microspheres obtained at 125 °C for 3 h were selected as sensitive materials to test their gas sensing performance at different operating temperature (50 °C and 350 °C). The H₂S was tested at 50 °C which is the lowest operating temperature for the sensor. The combustible gas (H₂/CH₄/CO) was measured at 350 °C which is the highest temperature for the sensor. They all have extremely high sensitivity, but only H₂S has excellent selectivity.

A highly-sensitive MEMS sensor is fabricated based on brain-like SnO₂ microspheres under a solvothermal reaction with tetrahydrofuran as a solvent.     

Preparation and investigation of highly selective solid acid catalysts with sodium lignosulfonate for hydrolysis of hemicellulose in corncob

Saccharification of lignocellulose is a necessary procedure for deconstructing the complex structure for building a sugar platform that can be used for producing biofuel and high-value chemicals. In this study, a carbon-based solid acid catalyst derived from sodium lignosulfonate, a waste by-product from the paper industry, was successfully prepared and used for the hydrolysis of hemicellulose in corncob. The optimum preparation conditions for the catalyst were determined to be carbonization at 250 °C for 6 h, followed by sulfonation with concentrated H₂SO₄ (98%) and oxidation with 10% H₂O₂ (solid–liquid ratio of 1 : 75 g mL⁻¹) at 50 °C for 90 min. SEM, XRD, FT-IR, elemental analysis and acid–base titration were used for the characterization of the catalysts. It was found that 0.68 mmol g⁻¹ SO₃H and 4.78 mmol g⁻¹ total acid were loaded onto the catalyst. When corncob was hydrolyzed by this catalyst at 130 °C for 12 h, the catalyst exhibited high selectivity and produced a relatively high xylose yield of up to 84.2% (w/w) with a few by-products. Under these conditions, the retention rate of cellulose was 82.5%, and the selectivity reached 86.75%. After 5 cycles of reuse, the catalyst still showed high catalytic activity, with slightly decreased yields of xylose from 84.2% to 70.7%.

A novel carbon-based catalyst with high catalytic ability and xylose selectivity was prepared from sodium lignosulfonate.     

Pathological changes in the lung and brain of mice during heat stress and cooling treatment

BACKGROUND:

Heatstroke often leads to multiple organ dysfunction syndrome (MODS) with a death rate of 40% or a neurological morbidity of 30%. These high rates in patients with heatstroke are largely due to the progression of heat stress to MODS, resulting in no specific treatment available. This study aimed to develop a mouse model of heat stress and determine the pathological changes in the lung and brain during heat stress and cooling treatment.

METHODS:

A mouse model of heat stress was established in a pre-warmed incubator set at 35.5 ± 0.5°C and with a relative humidity of 60% ± 5%. Rectal temperature was monitored, and at a temperature of 39 °C, 40 °C, 41 °C, or 42 °C, the mice were sacrificed. The remaining animals were removed from the incubator and cooled at an ambient temperature of 25 ± 0.5 °C and a humidity of 35% ± 5% for 12 or 24 hours at a temperature of 41 °C or for 6 hours at a temperature of 42 °C. The control mice were sham-heated at a temperature of 25 ± 0.5 °C and a humidity of 35% ± 5%. The lungs and brains of all animals were isolated. Hematoxylin and eosin staining and light microscopy were performed to detect pathological changes.

RESULTS:

All mice demonstrated a uniform response to heat stress. A low degree of heat stress induced marked pathological changes of the lungs. With the rise of the temperature to 42°C, progressively greater damage to the lungs with further congestion of the lung matrix, asystematic hemorrhage of alveolar space, abscission of alveolar epithelial cells, and disappearance of pulmonary alveolus tissue structure were detected. However, absorption of congestion and hemorrhage as well as recovery of pulmonary alveolus tissue structure was observed following cooling treatment at an ambient temperature. With a low degree of heat stress, the brain only showed moderate edema. Neuronal denaturation and necrosis were detected at a temperature of 42°C. Interestingly, the lesions in the brain were further aggravated at 42 °C regardless of cooling treatment, but recovery was observed after cooling treatment at 41 °C.

CONCLUSIONS:

The pathological changes of the lungs and brain of mice showed distinctive lesions following heat stress and cooling treatment, and they were correlated with the time and duration of cooling treatment. The results of this study are helpful for further study of the mechanisms linking heatstroke.     

Equivalence of difluorodichloromethane (CFC-12) hydrolysis catalyzed by solid acid(base) MoO3(MgO)/ZrO2

In this paper, a solid acid(base) MoO₃(MgO)/ZrO₂ was prepared for the catalytic hydrolysis of difluorodichloromethane (CFC-12). The effects of the catalyst preparation method, calcination temperature, and hydrolysis temperature on the conversion rate of CFC-12 were studied. The catalysts were characterized by XRD, N₂ isotherm adsorption desorption, NH₃-TPD, and CO₂-TPD. Meanwhile, the equivalence of the catalytic activity of MoO₃(MgO)/ZrO₂ for CFC-12 was studied. Research shows that the solid acid MoO₃/ZrO₂ and solid base MgO/ZrO₂ catalyzed hydrolysis of CFC-12 is equivalent; the solid acid MoO₃/ZrO₂ is calcined at 600 °C for 3 h and the solid base MgO/ZrO₂ is calcined at 600 °C for 6 h (co-precipitation) and 700 °C for 6 h (impregnated) at a catalytic hydrolysis temperature of 300–400 °C and CFC-12 concentration of 4%. The catalytic hydrolysis products obtained were CO, HCl, and HF, and the CFC-12 conversion rate almost reached 100%.

In this paper, a solid acid(base) MoO₃(MgO)/ZrO₂ was prepared for the catalytic hydrolysis of difluorodichloromethane (CFC-12).     

Insight into biomass feedstock on formation of biochar-bound environmentally persistent free radicals under different pyrolysis temperatures

Environmentally persistent free radicals (EPFRs) in biochars have the ability of catalytic formation of reactive oxygen species, which may pose potential oxidative stresses to eco-environment and human health. Therefore, comprehending the formation and characteristics of EPFRs in biochars is important for their further applications. In this study, the woody lignocellulosic biomass (wood chips, pine needle and barks), non-woody lignocellulosic biomass (rice husk, corn stover, and duckweed), and non-lignocellulosic biomass (anaerobically digested sludge) were selected as biomass feedstock to prepare biochars under different pyrolysis temperatures (200–700 °C). The impact of biomass feedstock on formation of biochar-bound EPFRs was systematically compared. Elemental compositions and atomic ratios of H/C and O/C varied greatly among different biomass feedstocks and the subsequently resulting biochars. EPFRs in biochars derived from the studied lignocellulosic biomass have similar levels of spin concentrations (10¹⁸–10¹⁹ spins per g) except for lower EPFRs in biochars under 200 and 700 °C; however, sludge-based biochars, a typical non-lignocellulosic-biomass-based biochar, have much lower EPFRs (10¹⁶ spins per g) than lignocellulosic-biomass-based biochars under all the studied pyrolysis temperatures. Values of g factors ranged from 2.0025 to 2.0042 and line width was in the range of 2.15–11.3 for EPFRs in the resulting biochars. Spin concentrations of biochar-bound EPFRs increased with the increasing pyrolysis temperatures from 200 to 500 °C, and then decreased rapidly from 500 to 700 °C and oxygen-centered radicals shifted to carbon-centered radicals with the increasing pyrolysis temperatures from 200 to 700 °C for all the studied biomass feedstock. 300–500 °C was the appropriate pyrolysis temperature range for higher levels of spin concentrations of biochar-bound EPFRs. Moreover, EPFRs'' concentrations had significantly positive correlation with C contents and weak or none correlation with contents of transition metals. Overall, different types of biomass feedstock have significant impact on the formation of EPFRs in the resulting biochars.

Environmentally persistent free radicals (EPFRs) in biochars have the ability of catalytic formation of reactive oxygen species, which may pose potential oxidative stresses to eco-environment and human health.     

About the transformation of low Tm into high Tm poly(l-lactide)s by annealing under the influence of transesterification catalysts

Cyclic polylactides were prepared in bulk at 170 °C, crystallized at 120 °C and then annealed at temperatures between 130 and 170 °C with variation of catalyst, catalyst concentration and annealing time. The transformation of the initially formed low melting (LT_m) crystallites, having melting temperatures (T_m) < 180 °C into high melting (HT_m) crystallites having T_m values > 189 °C was monitored by means of DSC measurements and characterized in selected cases by SAXS measurements. It was confirmed that the formation of HT_m crystallites involves a significant growth of the thickness of the lamellar crystallites along with smoothing of their surface. Annealing at 170 °C for 1 d or longer causes thermal degradation with lowering of the molecular weights, a gradual transition of cyclic into linear chains and a moderate decrease of lamellar thickness. An unexpected result revealed by MALDI TOF mass spectrometry is a partial reorganization of the molecular weight distribution driven by a gain of crystallization enthalpy.

Cyclic polylactides were prepared in bulk at 170 °C, crystallized at 120 °C and then annealed at temperatures between 130 and 170 °C with variation of catalyst, catalyst concentration and annealing time.     

Screening ionic liquids for dissolving hemicellulose by COSMO-RS based on the selective model

The utilization of biomass resources has attracted more and more attention due to the consumption of non-renewable resources. Compared with cellulose and lignin, hemicellulose has been less studied. Some ionic liquids (ILs) have been proved to be excellent solvents for lignocellulosic pretreatment. However, screening of more efficient ILs is difficult due to numerous possible ILs. Computational chemistry has been proved effective in solvent screening, but a precise model is indispensable. In this work, we focused on building several appropriate models and selected the most suitable one. According to the structure of hemicellulose, six hemicellulose models were constructed and the mid-dimer of the xylan chain hemicellulose (MDXC) model was proved to be the best compared with the reported experimental results. Based on the MDXC model, 1368 ILs were screened to evaluate their ability to dissolve hemicellulose by Conductor-like Screening Model for Real Solvents (COSMO-RS). The activity coefficient (γ), excess enthalpy (H^E), and σ-profile indicated that the hydrogen-bond (H-bond) played a vital role in the dissolution of hemicellulose. Anions played a more critical role than cations, where small anions with H-bond acceptor groups could enhance the molecular interactions with hemicellulose. This work provided a thermodynamic understanding of hemicellulose and IL solvent systems. It highlights the importance of building appropriate solute models, which may be necessary to predict of the other thermodynamic properties in the future.

Thousands of ILs with the potential to efficiently dissolve hemicellulose were screened by COSMO-RS, and the best model of hemicellulose was constructed and verified. This screening method will play an important role in sustainable development.     

Effects of 4 weeks preoperative exercise on knee extensor strength after anterior cruciate ligament reconstruction

[Purpose] After an anterior cruciate ligament injury and subsequent reconstruction, quadriceps muscle weakness and disruption of proprioceptive function are common. The purpose of this study was to examine the effects of a 4 weeks preoperative exercise intervention on knee strength power and function post-surgery. [Subjects and Methods] Eighty male patients (27.8±5.7 age), scheduled for reconstruction surgery, were randomly assigned to two groups, the preoperative exercise group (n=40) and a no preoperative exercise group (n=40). The preoperative exercise group participated in a 4-week preoperative and 12-week post-operative programs, while the no preoperative exercise group participated only in the 12-week postoperative exercise program. Isokinetic measured of quadriceps strength were obtained at 4 weeks before and 3 months after surgery. [Results] The knee extensor strength deficits measured at 60°/s and 180°/s was significantly lower in the preoperative exercise group compared with the no preoperative exercise group. At 3 months after surgery, the extensor strength deficit was 28.5±9.0% at 60°/sec and 23.3±9.0% at 180°/sec in the preoperative exercise group, whereas the no preoperative exercise group showed extensor strength deficits of 36.5±10.7% and 27.9±12.6% at 60°/sec and 180°/sec, respectively. The preoperative exercise group demonstrated significant improvement the single-leg hop distance. [Conclusion] Four week preoperative exercise may produce many positive effects post reconstruction surgery, including faster recovery of knee extensor strength and function, as measured by single-leg hop ability.Key words: Anterior cruciate ligament, Preoperative exercise, Knee extensor strength     

Comparison of trunk and hip muscle activity during different degrees of lumbar and hip extension

[Purpose] This study compared the activity of trunk and hip muscles during different degrees of lumbar and hip extension. [Subjects] The study enrolled 18 participants. [Methods] Two exercises (hip and lumbar extension) and two ranges (180° and <180°) were studied. [Results] Differences in degree of extension affected the percentage maximal voluntary isometric contraction of the lumbar erector spinae and biceps femoris muscles, with significantly higher average values at >180° than at 180° lumbar extension. No significant differences were found in gluteus maximus activity according to exercise type or range. [Conclusion] Hip extension may be more effective and safer for lumbar rehabilitation than lumbar extension.Key words: EMG, Hip extension, Lumbar extension     

Changes in falling risk depending on induced axis directions of astigmatism on static posture

[Purpose] To assess the changes in falling risk depending on the induced axis direction of astigmatism using cylindrical lenses in a static posture. [Subjects and Methods] Twenty subjects (10 males, 10 females; mean age, 23.4 ± 2.70 years) fully corrected by subjective refraction participated. To induce myopic simple astigmatism conditions, cylindrical lenses of +0.50, +1.00, +1.50, +2.00, +3.00, +4.00, and +5.00 D were used. The direction of astigmatic axes were induced under five conditions with increased cylindrical powers:, 180°, 90°, and 45° on both eyes; 180°/90° right/left eye, and 45°/135° right/left eye. Changes in the fall risk index were analyzed using the TETRAX biofeedback system. Measurements were performed for 32 seconds for each condition. [Results] The fall risk index increased significantly from C+4.00 D in 180°/90° right/left eye, C+3.00 D in 45°/135° right/left eye, and C+3.00 D in 45° on both eyes versus corrected emmetropia. Among the five axis conditions with the same cylindrical power lenses, the increase in the fall risk index was highest at 45° in both eyes. [Conclusion] Uncorrected oblique astigmatism may increase falling risk compared to with-the-rule and against-the-rule astigmatism. Clinical specialists should consider appropriate correction of astigmatism for preventing falls, especially for uncorrected oblique astigmatism.Key words: Fall risk index, Astigmatism, Axis directions     

Effect of ultrasonic application during KOH pretreatment and anaerobic process on digestion performance of wheat straw

The digester performance was enhanced by ultrasonic application during pretreatment and the anaerobic digestion (AD) process. Two setups (with and without ultrasonic application) were applied during pretreatment and AD, to untreated and potassium hydroxide (KOH) pretreated wheat straw. The results confirmed that the ultrasonic application enhanced the hydrolysis process during pretreatment. The highest total volatile fatty acid (TVFA) (3012 ± 18 mg L⁻¹) production and overall lignin, hemicellulose, and cellulose (LHC) reductions (22.4 ± 0.5%) were obtained from ultrasonic assisted KOH pretreated (KOH_U) samples, after 36 hours of pretreatment. Similarly, the SEM analysis showed obvious disruption in the outer structure of KOH_U samples. However, the ultrasonic application during AD showed significant improvement in biodegradation rate, biogas and biomethane production. Obvious reduction in sonication time (76%) along with enhanced biogas (570 ± 9 mL gm⁻¹ VS) and biomethane (306 ± 12 mL gm⁻¹ VS) production were observed from KOH pretreated digesters, when ultrasonication was applied during AD. Moreover, the biodegradation rate reached up to 76% along with highest total solid (TS) and volatile solid (VS) reductions from digesters with single KOH pretreatment and ultrasonic influence during AD. Finally, the digester effluent ranged in between the stable values, confirming the completion of the AD process. These results suggested that ultrasonic application was more effective when applied during AD due to the higher liquid to solid ratio. The reduction in energy input can be beneficial for commercial applications and to recognize the better stage for ultrasonic application for enhanced biomethane yield.

The effect of ultrasonic application during KOH pretreatment and anaerobic digestion of wheat straw.