Search

In treating anterior choroidal artery (AChA) aneurysms, preserving the AChA main trunk is of course necessary to prevent postoperative ischemic complications. However, in practice, complete occlusions are often limited by small branches. We aimed to demonstrate that even in cases where complete occlusion of the AChA aneurysm is complex due to small branches, complete occlusion can be safely achieved using indocyanine green video-angiography and intraoperative neurophysiological monitoring (IONM). We performed a retrospective review of all unruptured AChA aneurysms surgically treated at our institution from 2012 to 2021. All available surgical videos were reviewed to find AChA aneurysms clipped with small branches; clinical and radiological data were collected for these cases. Among 391 cases of unruptured AChA aneurysms treated surgically, 25 AChA aneurysms were clipped with small branches. AChA-related ischemic complications occurred in 2 cases (8%) without retrograde indocyanine green filling to the branches. These 2 cases had changes in IONM. There were no ischemic complications in the remaining cases with retrograde indocyanine green filling to the branches and no change in IONM. During an average follow-up of 47 months (12–111 months), a small residual neck was observed in 3 cases (12%) and recurrence or progression of the aneurysm was observed in only 1 case (4%). The surgical treatment of AChA aneurysms carries the risk of devastating ischemic complications. Even in cases where complete clip ligation seems impossible due to small branches associated with AChA aneurysms, complete occlusion can be safely achieved using indocyanine green video-angiography and IONM. [ABSTRACT FROM AUTHOR]

Dural arteriovenous fistulas at the craniocervical junction (CCJ DAVFs) are a rare vascular disease. Endovascular treatment (EVT) and microsurgery are the primary treatment modalities for CCJ DAVFs. However, incomplete treatment or complications may occur after treatment because of the anatomical complexity. We analyzed the neurosurgical treatment experiences of CCJ DAVFs to recommend suitable classification and treatment options. CCJ DAVFs were anatomically classified into three types according to the feeding arteries and their relationships with the anterior spinal (ASAs) and lateral spinal arteries (LSAs). Type 1 was fed by the radiculomeningeal artery from the vertebral artery and was not associated with the ASA or LSA. Type 2 was fed by the radiculomeningeal artery, and the radicular artery supplied the LSA near the fistula point. Type 3 had the characteristics of type 1 or type 2 CCJ DAVFs, except the ASA also contributed to the fistula. There were 5, 7, and 4 cases of type 1, type 2, and type 3 CCJ DAVFs, respectively. EVT was attempted in 12 patients, of whom only 1 (type 1) was completely cured without complications. Nine cases had residual lesions after EVT, and two had spinal cord infarction due to occlusion of the LSA. Fourteen patients underwent microsurgical treatment. In all 14 cases, CCJ DAVFs were completely obliterated after microsurgery. In cases of type 1 CCJ DAVF, both microsurgical treatment and EVT may be considered. However, for type 2 and 3 CCJ DAVFs, microsurgery may be a superior treatment modality. [ABSTRACT FROM AUTHOR]

Cerebral myxomatous aneurysms (CMA) are intracranial aneurysms caused by cardiac myxoma. The exact mechanism underlying their development has not yet been elucidated. And an optimal treatment method has not yet been established because of rarity of the disease. In addition, most existing reports have had a short follow-up period or lack of follow-up imaging test results. The aim of this study was to provide better insights into the course and treatment options of CMAs. We describe 4 CMA patients treated in our hospital and literature search was performed using PubMed and Embase databases. Keywords used were as follows: "cerebral myxomatous aneurysm", "myxomatous aneurysm", "cardiac myxoma", and "intracranial aneurysm". Only publications in English and related to this disorder with adequate follow-up periods and aneurysmal wall biopsy results were included. Clinical, radiological, pathological, and treatment characteristics were analyzed. A total of 149 CMA cases were managed conservatively that included 9 enlargements, 6 regressions, and 134 stable aneurysms, which were identified for a total of 453.33 aneurysm years (1.91% per aneurysm year, 1.27% per aneurysm year, and 28.76% per aneurysm year, respectively). Poor outcome rate was high in cases with hemorrhage (either parenchymal or subarachnoidal hemorrhage) due to rupture of the CMA (46.67%, 7 out of 15). Thirteen cases had aneurysm biopsy results of which 11 showed tumor invasion on the aneurysm wall. Even though the natural course of unruptured, benign-looking CMAs appears to be favorable, the presence or absence of viable tumor cells in the aneurysm may promote an unfavorable disease course. In the case of large, symptomatic, and enlarging CMAs, surgical, endovascular, or combined treatment should be considered as the mortality and morbidity due to rupture might be high. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the degradation characteristics of kraft lignin (KL) during peracetic acid (PAA) treatment, and to produce potentially valuable polymers of low molecular weight lignin by controlling the reaction conditions. For the peracetic acid treatment, acetic acid (AA) and hydrogen peroxide (HP) were directly mixed at ratios of 4:1, 1:1, and 1:4 (v/v) and employed as reaction media. After PAA treatment of kraft lignin at 80 °C, complete dissolution of the lignin and reduction in the molecular weight were observed. When the PAA reaction was performed at high HP concentration (1:4, v/v), the aromatic lignin skeleton opened and converted to a structure containing large amounts of carboxyl groups. On the other hand, the treatment at high AA concentration (4:1, v/v) decomposed lignin while maintaining its aromatic structure. Hence, we demonstrated that the selective production of lignin-derived polymers can be controlled depending on PAA and HP concentrations. Unlabelled Image [ABSTRACT FROM AUTHOR]

To understand the effects of the biomass constituents for enzymatic hydrolysis, a tropical hardwood, Eucalyptus pellita , was employed to change the content of chemical constituents and regression assessment was progressed. The liquid hot water and acid-chlorite pretreatment controlled hemicellulose and lignin removal rate from 3.1 to 91.7% and from 4.4 to 99.1%, respectively. Total lignin in E. pellita (34.8%) was obviously reduced up to 9.0% under 4 g of sodium chlorite and 0.8 mL of acetic acid with 3 times loading. In this case, acid-insoluble lignin (2.4%) was entirely eliminated compared with that of E. pellita (29.0%), whereas acid-soluble lignin (6.6%) was preferably increased compared with of E. pellita (2.3%). The maximum glucose yield (87.5%) after the combined pretreatment and enzymatic hydrolysis were dramatically improved compared with that of liquid hot water pretreatment alone (28.2%). Meanwhile, a high glucose yield (83.9%) could also be obtained by acid-chlorite pretreatment alone. The adjusted R-squared value of hemicellulose and lignin removal rate (0.9285) and lignin removal rate alone (0.9063) with glucose yield was determined by linear regression analysis. • Relationship between chemical constituents and glucose yield was evaluated. • 99.1% of lignin was selectively removed by acid-chlorite pretreatment. • High glucose yield over 85% was achieved after combined pretreatment. • Only hemicellulose removal had no significant effect on glucose production. • Hemicellulose and lignin had synergetic effect on glucose yield (R2 = 0.9285). [ABSTRACT FROM AUTHOR]

Abstract The main purpose of this study was simultaneous production of glucose, ethanol organosolv lignin (EOL), and furfural for total utilization of lignocellulosic biomass to improve economics of biorefinery. The glucose production (37.1 g, under conditions of 160 °C with 1% sulfuric acid) was significantly increased after organosolv pretreatment, dissolving 11.4 g of the initial hemicellulose-derived sugars and 22.6 g of the initial lignin. Progressively, organosolv lignin precipitation and furfural production processes were conducted using the liquid hydrolysates obtained after organosolv pretreatment. 12 g of EOL (at 160 °C, 1% sulfuric acid) was yielded with the remaining residues of soluble lignin-derived compounds in the liquid hydrolysates. Also, 7.9 g of furfural (at 160 °C, 1% sulfuric acid) was observed after additional acid-catalyzed treatment from the liquid hydrolysates. Consequently, a high yield of glucose, EOL and furfural can be obtained simultaneously using ethanol organosolv pretreatment. Highlights • Ethanol organosolv pretreatment was conducted for total utilization of biomass. • Biomass components were separated after ethanol organosolv pretreatment. • 37.1 g of glucose was produced after enzymatic hydrolysis. • 12.0 g of EOL and 7.9 g of furfural were obtained by additional process. • This concept of process was proposed for the competitiveness of biorefinery. [ABSTRACT FROM AUTHOR]

• Antioxidant activity of ethanol organosolv lignin and synergy were investigated. • Phenolic-OH content was predominant factor in the antioxidant activity of the lignin. • Lignin with a higher phenolic-OH and a lower IC50 value covered wide synergy ranges. • Synergy with myricetin was verified by comparing predicted and actual values. • Phenolic-OH ratio of myricetin and the lignin for the synergy was suggested. Lignin has potential as a substitute for natural antioxidants in cosmetics and food industries due to its radical scavenging ability and price competitiveness. The antioxidant activity of lignin depends on its structural properties, and they accordingly have synergy with natural antioxidants. Based on the structural characteristics, the antioxidant activity of ethanol organosolv lignin (EOL) and synergy with myricetin were investigated. The phenolic-OH content was a predominant factor in the antioxidant activity of EOL, and EOL-H with a higher phenolic-OH content and lower IC 50 value (0.17 mg/mL) covered a wide synergy range of 1:32–2:1 (EOL:myricetin). The synergistic effect was verified by comparing predicted and actual values based on ESR analysis, and the phenolic-OH ratio (>0.4) of myricetin and EOL for the synergy was suggested. In this respect, the results highlight the potential of lignin with high phenolic-OH content as a substitute for commercial antioxidants with superior activity and broad synergy ranges. [ABSTRACT FROM AUTHOR]

Lignin has different structural characteristics depending on the extraction conditions. In this study, three types of ethanol organosolv lignin (EOL) were produced under different extraction conditions involving the reaction temperature (140, 160, 180 °C), sulfuric acid concentration (0.5, 1, 1.5 %), and ethanol concentration (40, 60, 80 %) to compare the difference in properties when mixed with polylactic acid (PLA) matrix after atom transfer radical polymerization (ATRP). ATRP of EOL was conducted to improve its compatibility with PLA using methyl methacrylate (MMA) as a monomer. The molecular weight of each EOL increased significantly, and the glass transition temperature (T g) decreased from approximately 150 to 110 °C. The EOL- g -PMMA copolymer exhibited a melting point (T m), whereas EOL did not, implying that the thermoplasticity increased. The EOL- g -PMMA/PLA blend and film were prepared with 10 % of the copolymer in the PLA matrix. The tensile strength and strain of the blend were higher than those of unmodified organosolv lignin as the compatibility increased, and the UV transmittance was lower than that of neat PLA because of the UV protecting properties of EOL moiety. • The ATRP using three EOL types was successfully conducted. • The T m appeared after the ATRP. • Compared to the neat EOL/PLA blend, the EOL- g -PMMA/PLA blend showed similar mechanical strength to the neat PLA. • EOL- g -PMMA showed UV protection properties in the PLA matrix. [ABSTRACT FROM AUTHOR]

The main purpose of this study was to produce succinic acid from hemicellulose in lignocellulosic biomass by successive process without purification as a biorefinery concept. Liquid hot water (LHW) treatment was conducted to extract water soluble hemicelluloses from Quercus mongolica to produce furfural from lignocellulosic biomass. Additional acid catalyzed dehydration was conducted to liquid hydrolysate from LHW treatment for furfural production. At 170 °C of reaction temperature, 42% of furfural yield was achieved from pentose in liquid hydrolysate. This Acid treated liquor (ATL) was treated with hydrogen peroxide to oxidize furfural to C4 dicarboxylic acid such as succinic or maleic acid. Main product was succinic acid which is produced by oxidation of furfural, and minor amount of maleic acid was produced via oxidation. The xylose was degraded to furfural and then oxidized to succinic acid, while acid soluble lignin inhibited succinic acid production by reacting with intermediates of succinic acid. This results indicated that hemicellulose rich liquid hydrolysate has potential to source for succinic acid without further purification. • Liquid hot water treatment was conducted to extract hemicellulose from biomass. • Furfural was produced via acid catalyzed dehydration of hemicellulose. • Sequential addition of hydrogen peroxide oxidized furfural to succinic acid. • Xylose in liquid was oxidized to succinic acid. • Acid soluble lignin tended to react with intermediates of succinic acid. [ABSTRACT FROM AUTHOR]

In this study, the physicochemical properties of torrefied biomass (larch and yellow poplar) were investigated based on torrefaction temperature. The effect of torrefied biomass on the hydrophobicity and mechanical properties of a polylactic acid (PLA) composites was evaluated. Hemicellulose was removed from the biomass during torrefaction, whereas the cellulose and lignin contents increased slightly. The color of the biomass changed from brown to black. The grindability of the torrefied biomass improved as the torrefaction temperature increased, which contributed to the production of fine particles (>100 mesh). A PLA composite was prepared using torrefied biomass (10 %) and polylactic acid. At 280 °C, water contact angle was the highest, regardless of the particle size and biomass species. Tensile strength of the PLA composite was slightly lower than that of PLA alone, regardless of the particle size of torrefied biomass. Nevertheless, the strength increased with the torrefaction temperature, except for larch with a relatively large particle size (<100 mesh). The tensile strength of the control was 68.0 MPa, whereas that of the torrefied biomass ranged from 61.1 to 65.8 MPa. [ABSTRACT FROM AUTHOR]

• A sequential process was proposed for total utilization of woody biomass. • Hemicellulose was selectively decomposed with producing xylooligomers. • Lignin was degraded by 50% diluted PAA treatment with producing dicarboxylic acids. • Cellulose accessibility to the enzyme was improved by constituent deconstruction. For improving the economic efficiency of the biorefining concept, selective decomposition and separation of biomass components is indispensable. In this respect, a sequential pretreatment process consisting of liquid hot water treatment and diluted peracetic acid (PAA) treatment was proposed for total utilization of lignocellulosic woody biomass. During the liquid hot water treatment, hemicellulose can be decomposed efficiently without significant loss of cellulose and lignin, implying the possibility for xylooligomer production by thermochemical treatment. In the PAA treatment, lignin was successfully degraded and liquefied using a 50% diluted PAA solvent, suggesting the possibility of dicarboxylic acid production. After the sequential process proposed in this study, the cellulose accessibility to the enzyme could be maximized by inducing selective deconstruction of hemicellulose and lignin. [ABSTRACT FROM AUTHOR]

We propose a closed-loop pretreatment process, wherein volatiles produced during steam explosion pretreatment were recovered and reintroduced as acid catalysts into the pretreatment system. The volatiles were separated through a drastic decompression process followed by a steam explosion process and recovered as a liquified catalyst (LFC) through a heat exchanger. The LFC effectively served as an acid catalyst for hemicellulose hydrolysis, significantly decreasing residence time from 90 min to 30 min to achieve 80 % conversion yield at 170 °C. Hydrolysates with high content of lower molecular weight oligomeric sugars were obtained using LFC, and were considered advantageous for application as prebiotics. These results are attributed to the complementary features of acetic acid and furfural contained within the LFC. Computational simulation using Aspen Plus was used to investigate the effects of recycling on LFC, and it demonstrated the feasibility of the catalyst-recirculating system. A validation study was conducted based on simulation results to predict the actual performance of the proposed pretreatment system. Based on these results, the recirculating system was predicted to improve the conversion yield and low-molecular weight oligomers yield by 1.5-fold and 1.6-fold, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, alternative pathway using glucaric acid as precursor of 2,5-furandicarboxylic acid (FDCA) was proposed. The acid catalyzed cyclization and sequential dehydration of glucaric acid to FDCA was performed in gamma-valerolactone. The glucaric acid conversion to FDCA was promoted at reaction temperature over 140 °C, while FDCA production from glucaric acid was achieved within 1 h. 50.25% of FDCA was produced from glucaric acid at 200 °C of reaction temperature, 1 h of reaction time, 1.66% (w/v) of glucaric acid concentration (5% of sulfuric acid concentration). The acid catalyst catalyzed cyclization of glucaric acid and dehydration of intermediates, and gamma-valerolactone stabilized intermediates and FDCA from undesirable degradation. FDCA was further produced from EH-glucaric acid produced from enzymatic hydrolysate of Miscanthus, impurities in EH-glucaric acid decreased FDCA yield. Separation and purification of produced FDCA was achieved by simple precipitation followed by activated carbon treatment. Activated carbon treatment improved purity of FDCA up to 98%. [Display omitted] • Glucaric acid conversion to FDCA in gamma-valerolactone solvent with acid catalyst. • Effect of acid catalyst and solvent to FDCA production was analyzed. • FDCA was produced from enzymatic hydrolysate derived glucaric acid. • Separation and purification of FDCA by precipitation and activated carbon treatment. [ABSTRACT FROM AUTHOR]

A technology to extract lignin oil from pretreated biomass has been developed for a cosmetic additive application (i.e., UV protection) through isopropyl alcohol without any catalyst. It was used for co-product lignin oil with XOS from a biorefinery process in this study. One of the key factors impacting economic feasibility is extraction solvent recovery, and it is important to design the process details based on techno-economic analysis. Therefore, this study has integrated lab experiments, process designs with Aspen Plus process simulations, and Excel-based techno-economic analysis to investigate the effect of solvent recovery on overall economics. Three options for solvent recovery (e.g., distillation, salting-out, and molecular sieve) have been explored. The salting-out method showed the best economic performance with an IRR of 33.6%, while the distillation method was 21.7% and the molecular sieve method was 16.7%. Key parameters are also identified by sensitivity analyses, which indicate the improvement potential for each case. This study has laid a foundation for lignin oil production studies, but its concept and approach can be applied to any solvent recycling in a biorefinery process, which is often neglected in lab-scale biorefinery studies. [Display omitted] [ABSTRACT FROM AUTHOR]

The objective of this study was to prepare a feedstock, which xylose should be highly solubilized and most of the glucose remained in the solid fraction, for supercritical water hydrolysis (SCWH). Response surface methodology (RSM) with two independent variables (reaction time and sulfuric acid concentration) was adopted to find suitable conditions for pretreatment using a simple apparatus an autoclave for massive production. Based on the results of the RSM experiments, higher xylose contents were obtained in the liquid fraction after dilute acid pretreatment at 121 °C for 60 min with 6.82% H 2 SO 4 (condition #8 (18.0%)) and at 121 °C for 102.3 min with 4% H 2 SO 4 (condition #6 (16.0%)). To preventing corrosion of the apparatus, condition #6 was modified by prolonging the reaction time to 105 min, which led to a xylose content of 17.6% in the liquid fraction. Furthermore, structural degradation of the solid fraction was observed, indicating a positive effect for sugar production via SCWH. [ABSTRACT FROM AUTHOR]

The main purpose of this study was to investigate the glucan conversion rate after enzymatic hydrolysis depending on the treatment methods and conditions with changes in the chemical composition of treated solid fraction of Jabon Merah. The glucan conversion rate (17.4%) was not significantly improved after liquid hot water treatment (1st step) even though most of the hemicellulose was dissolved into liquid hydrolysate. Subsequently, dilute acid, organosolv, and peracetic acid treatment (2nd step) was conducted under various conditions to enhance glucan conversion. Among the 2nd step treatment, the glucan conversion rate of organosolv (max. 46.0%) and peracetic acid treatment (max. 65.9%) was increased remarkably through decomposition of acid-insoluble lignin (AIL). Finally, the glucan conversion rate and AIL content were highly correlated, which was revealed by the R-squared value (0.84), but inhibitory factors including cellulose crystallinity must be considered for advanced glucan conversion from highly recalcitrant biomasses, such as Jabon Merah. [ABSTRACT FROM AUTHOR]

Because nanocellulose has a large specific surface area and abundant hydroxyl functional groups due to its unique nanomorphology, interest increases as an eco-friendly water treatment material. However, the distinctive properties of nanocellulose, which exists in a dispersion state, strongly hamper its usage in practical water treatment processes. Additionally, nanocellulose shows low performance in removing anionic pollutants because of its anionic characteristics. In an effort to address this challenge, regenerated cellulose (RC) hydrogel was fabricated through cellulose's dissolution and regeneration process using an eco-friendly aqueous solvent system. Subsequently, a crosslinking process was carried out to introduce the cationic functional groups to the RC surface PEI coating (P/RC). As a result, the PEI surface cationization process improved the mechanical rigidity of RC and showed an excellent Cr(VI) removal capacity of 578 mg/g. In addition, the prepared P/RC maintained more than 90% removal efficiency even after seven reuses. [Display omitted] [ABSTRACT FROM AUTHOR]