Activated carbons derived from polyethylene terephthalate for coin-cell supercapacitor electrodes.

We successfully prepared activated carbon derived from polyethylene terephthalate (PET) via carbonization and subsequent activation under various conditions and applied it as active material for supercapacitors. In the activation, we used CO2 for physical activation or KOH for chemical activation and varied the activation temperature from 600 °C to 1,000 °C. We found that CO2 activation is unsuitable because of insufficient pore formation or low activation yield. Interestingly, PET-derived activated carbon obtained using KOH (PETK) at 700 °C-900 °C exhibited higher specific surface areas than YP50f, which is a commercial activated carbon. Furthermore, some PETKs even displayed a dramatic increase in crystallinity. In particular, the PET-derived activated carbon prepared at 900 °C with KOH (PETK900) had the highest retention rate at a high charge-discharge rate and better durability after 2500 cycles than YP50f. Furthermore, employing the same process that we used with the PET chips, we successfully converted waste PET bottles into activated carbon materials. Waste PET-derived activated carbons exhibited good electrochemical performance as active material for supercapacitors. We thus found chemical activation with KOH to be an appropriate method for manufacturing PET-derived activated carbon and PETKs derived both from PET chips and waste PET have considerable potential for commercial use as active materials for supercapacitors. Electronic Supplementary Material: Supplementary material is available for this article at 10.1007/s11814-023-1466-3 and is accessible for authorized users.

Risk factors for residual popliteal cyst after arthroscopic decompression and cystectomy: Associated with degenerative cartilage lesions.

BACKGROUND: In previous studies, good results have been reported after arthroscopic treatment of popliteal cysts and concomitant intra-articular pathology. However, only a few studies have reported the associated factors with residual popliteal cysts. The aim of this study was to examine the clinical and radiographic outcomes and investigate the factors associated with the recurrence of popliteal cyst after arthroscopic cyst decompression and cyst wall resection. HYPOTHESIS: The authors hypothesized that residual popliteal cyst after arthroscopic decompression and cystectomy would be associated with degenerative cartilage lesions. PATIENTS AND METHODS: From December 2010 to December 2018, 54 patients with popliteal cysts were treated with arthroscopic decompression and cyst wall resection through an additional posteromedial cystic portal. Magnetic resonance imaging (MRI) or ultrasonography was used to observe whether the popliteal cyst had disappeared or decreased. The maximum diameter of the popliteal cyst was measured after surgery. The patients were classified into the disappeared and reduced groups according to the treatment outcome. Age, sex, symptom duration, preoperative degenerative changes based on the Kellgren-Lawrence (K-L) grade, cartilage lesions according to the International Cartilage Repair Society (ICRS) grades, synovitis, functional outcomes, and associated intra-articular lesions were compared between the two groups. The functional outcome was evaluated on the basis of the Rauschning and Lindgren knee score. The study included 22 men and 32 women, with mean age of 49.6 years (range, 5-82 years). According to the ICRS grade system, 28 (51.8%) patients had grade 0 to II, 26 (48.2%) patients had grade III to IV. RESULTS: Follow-up radiographic evaluation revealed that the cyst had completely disappeared in 20 patients (37%) and reduced in size in 34 (63%). The mean cyst size was decreased significantly from 5.7cm (range, 1.7-15cm) to 1.7cm (range, 0-6.4cm), and the Rauschning and Lindgren knee score showed improved clinical features in all the patients. Between the disappeared and reduced groups, the presence of degenerative cartilage lesions (p=0.022, odds ratio 8.702, 95% confidence interval: 1.368-55.362) showed statistically significant differences. DISCUSSION: Through the posteromedial cystic portal, cysts were completely removed in approximately 40% of patients, and the size was reduced in 60% of patients. Presence of degenerative cartilage lesion represents an associated risk factor for residual popliteal cyst. These findings could be helpful in ensuring explaining poor prognostic factors. LEVEL OF EVIDENCE: IIIb; retrospective cohort study.

Radiologic findings associated with mucoid degeneration of the anterior cruciate ligament.

INTRODUCTION: Mucoid degeneration (MD) of the anterior cruciate ligament (ACL) is a well-recognized pathology characterized by the degradation of collagen fibers and infiltration of a mucoid-like substance. This study is to determine the anatomical associated factors for MD-ACL using radiographic and magnetic resonance imaging (MRI). MATERIALS AND METHODS: This was a retrospective study on patients who had undergone knee arthroscopy between 2011 and 2020. The patients with MD-ACL were defined and enrolled by the MRI and arthroscopy. Eventually, 52 patients in the MD-ACL group (group 1) and 52 patients in the control group (group 2) were enrolled, following sex and age matching. Radiologic evaluation included the assessment of Kellgren-Lawrence (K-L) grade, mechanical hip-knee-ankle (HKA) angle, posterior tibial slope (PTS) angle, and Insall-Salvati ratio. The notch width index and transverse notch angle were measured on MRI, and the grade of trochlear dysplasia was defined. Logistic regression analysis, receiver operating characteristic (ROC) curves, and area under curve (AUC) were performed. RESULTS: The ROM was significantly decreased in group 1, whereas the PTS angle was significantly larger in group 1. Combined ganglion cysts of ACL were found in 42/52 patients (80.7%) in group 1. The risk of MD-ACL was associated with a steeper PTS angle, increased Insall-Salvati ratio, male sex, higher K-L grade, and decreased transverse notch angle and notch width index. The cutoff values in ROC analysis were found to be ≤ 28.27% for the notch width index (AUC, 0.849; p < 0.001), > 12.2° for the PTS angle (AUC, 0.765; p < 0.001), and ≤ 47.4° for the transverse notch angle (AUC, 0.711; p < 0.001), but not significant for Insall-salvati ratio. CONCLUSION: A steeper PTS angle, decreased notch width index, and transverse notch angle are significantly associated with the presence of MD-ACL. These factors should be considered during diagnosis or when determining the treatment strategy for symptomatic MD-ACL patients. LEVEL OF EVIDENCE: Level IIIb.

Steep posterior lateral tibial slope, bone contusion on lateral compartments and combined medial collateral ligament injury are associated with the increased risk of lateral meniscal tear.

PURPOSE: To determine the risk factors for lateral meniscus and root tears in patients with acute anterior cruciate ligament (ACL) injuries. METHODS: A total of 226 patients undergoing acute ACL reconstruction were included in the study sample. Exclusion criteria were revisions, fractures, chronic cases, and multiple ligament injuries, with the exception of medial collateral ligament (MCL) injuries. The patients were divided into groups based on the presence of lateral meniscus and root tears by arthroscopy. Binary logistic regression was used to analyze risk factors including age, sex, body mass index (BMI), injury mechanism (contact/non-contact), Segond fracture, side-to-side laxity, location of bone contusion, medial and lateral tibial and meniscal slope, mechanical axis angle, and grade of pivot shift. RESULTS: Overall lateral meniscus (LM) tears were identified in 97 patients (42.9%), and LM root tears were found in 22 patients (9.7%). The risk of an LM tear in ACL-injured knees increased with bone contusion on LTP (odds ratio [OR], 3.5; 95% confidence interval [CI] 1.419-8.634; P = 0.007), steeper lateral tibial slope (OR, 1.133; 95% CI 1.003-1.28; P = 0.045), MCL injury (OR, 2.618; 95% CI 1.444-4.746; P = 0.002), and non-contact injury mechanism (OR, 3.132; 95% CI 1.446-6.785; P = 0.004) in logistic regression analysis. The risk of LM root tear in ACL-injured knees increased with high-grade pivot shift (OR, 9.127; 95% CI 2.821-29.525; P = 0.000) and steeper lateral tibial slope (OR, 1.293; 95% CI 1.061-1.576; P = 0.011). CONCLUSION: The increased risk of LM lesions in acute ACL-injured knees should be considered if significant risk factors including bone contusion on lateral compartments, MCL injury, and a steeper lateral tibial slope are present. Moreover, high-grade rotational injury with steeper lateral tibial slope are also significant risk factors for LM root tears, and therefore care should be taken by clinicians not to miss such lesions. LEVEL OF EVIDENCE: III.

Radiographic findings for surgery-related complications after pedicle subtraction osteotomy for thoracolumbar kyphosis in 230 patients with ankylosing spondylitis.

OBJECTIVE: The purpose of this study was to investigate the rate of and the risk factors for surgery-related complications demonstrated on radiography after pedicle subtraction osteotomy (PSO) for thoracolumbar kyphosis in patients with ankylosing spondylitis (AS). METHODS: The authors retrospectively reviewed the medical records of 230 consecutive patients with thoracolumbar kyphosis due to AS who had undergone 1-level PSO at a single institution in the period from 2010 to 2017. The causes of surgery-related complications were divided into two types: surgical/technical failure and mechanical failure. RESULTS: The patients consisted of 20 women and 210 men, with an average age of 43.4 years. The average follow-up period was 39.0 months. The preoperative sagittal vertical axis was 18.5 ± 69.3 cm, which improved to 4.9 ± 4.6 cm after PSO. Of the 77 patients (33.5%) who experienced minor or major surgery-related complications, 56 had complications related to surgical/technical failure (overall incidence 24.3%) and 21 had complications related to mechanical failure (overall incidence 9.1%). Fourteen patients (6.1%) underwent reoperation. However, among the 77 patients with complications, the rate of revision surgery was 18.2%. The most common radiological complications were as follows: sagittal translation in 24 patients, coronal imbalance in 20, under-correction in 8, delayed union in 8, and distal junctional failure and kyphosis in 8. The most common causes of reoperation were coronal imbalance in 4 patients, symptomatic malposition of pedicle screws in 3, and distal junctional failure in 3. Delayed union was statistically correlated with posterior sagittal translation (p = 0.007). CONCLUSIONS: PSO can provide acceptable radiographic outcomes for the correction of thoracolumbar kyphosis in patients with AS. However, a high incidence of surgery-related complications related to mechanical failure and surgical technique can develop. Thorough radiographic investigation before and during surgery is needed to determine whether complete ossification occurs along the anterior and posterior longitudinal ligaments of the spine.

Staged Revision of Infected-hip Arthroplasty Using an Antibiotics-loaded Intra-articular Cement Spacer: Impact on Cemented and Cementless Stem Retention.

PURPOSE: Currently, standard management of a peri-prosthetic infection is a two-stage revision precedure. However, removal of well-fixed cement is technically demanding and associated with numerous potential complications. For theses reasons, two-stage revision with preservation of the original femoral stem can be considered and several previous studies have achieved successful results. While most prior studies used cemented stems, the use of cementless stems during arthroplasty has been gradually increasing; this study aims to assess the comparative effectiveness of a two-stage revision of infected hip arthroplasties at preserving cemented and cementless stems. MATERIALS AND METHODS: Between December 2001 and February 2017, Inje University Sanggye Paik Hospital treated 45 cases of deep infections following hip arthroplasty with a two stage revisional arthroplasty using antibiotics-loaded cement spacers. This approach was applied in an effort to preserve the previously implanted femoral stem. Of these 45 cases, 20 were followed-up for at least two years and included in this analysis. Perioperative clinical symptoms, radiological findings, function and complications during insertion of an antibiotics-loaded cement spacer were analyzed in this study. RESULTS: Peri-prothetic infections were controlled in 19 of the 20 included cases. Clinical outcomes, as assessed using the Harris hip score, Western Ontario and McMaster University score, also improved. Importantly, similarly improved outcomes were achieved for both cemented and cementless femoral stems. CONCLUSION: In cases of deep infection following hip arthroplasty, two-stage revision arthroplasty to preserve the previously implanted femoral stem (cemented or cementless) effectively controls infections and preserves joint function.

How to Avoid Distal Adding-on Phenomenon for Rigid Curves in Major Thoracolumbar and Lumbar Adolescent Idiopathic Scoliosis? Identifying the Incidence of Distal Adding-on by Selection of Lowest Instrumented Vertebra.

OBJECTIVE: We sought to compare the radiologic outcomes for different distal fusion levels in a rigid curve with major thoracolumbar and lumbar (TL/L) adolescent idiopathic scoliosis (AIS) using rod derotation (RD) with direct vertebral rotation (DVR) after pedicle screw instrumentation (PSI). METHODS: This study finally enrolled 28 patients who were diagnosed with AIS in rigid curve with major TL/L curves, treated by PSI with RD and DVR and with a minimum 2-year follow-up. Patients were divided into 2 groups, L3 and L4, on the basis of the distal fusion level at the lowest instrumented vertebra (LIV) of L3 or L4. RESULTS: There was no significant difference in TL/L curve, thoracic (minor), and compensatory (caudal) curves between the L3 and L4 groups either postoperatively (P = 0.162, 0.426, and 0.762, respectively) or at the last follow-up (P = 0.952, 0.620, and 0.562, respectively). The overall prevalence of unsatisfactory results was 42.9% (12/28 patients). The prevalence of unsatisfactory results was 61.1% (11/18) in the L3 group and 10% (1/10) in the L4 group, which was significantly different (P < 0.05). CONCLUSIONS: Unsatisfactory results occurred more often in the L3 group than in the L4 group, and unsatisfactory results had significant influence on progression of TL/L and distal compensatory curves. Such progression was closely correlated with deteriorating LIV disk angle in the L3 group. Therefore if the curve is rigid, LIV should be extended to L4 to avoid the adding-on phenomenon in the treatment of major TL/L AIS using RD with DVR after PSI.

Structure and function of the yeast listerin (Ltn1) conserved N-terminal domain in binding to stalled 60S ribosomal subunits.

The Ltn1 E3 ligase (listerin in mammals) has emerged as a paradigm for understanding ribosome-associated ubiquitylation. Ltn1 binds to 60S ribosomal subunits to ubiquitylate nascent polypeptides that become stalled during synthesis; among Ltn1's substrates are aberrant products of mRNA lacking stop codons [nonstop translation products (NSPs)]. Here, we report the reconstitution of NSP ubiquitylation in Neurospora crassa cell extracts. Upon translation in vitro, ribosome-stalled NSPs were ubiquitylated in an Ltn1-dependent manner, while still ribosome-associated. Furthermore, we provide biochemical evidence that the conserved N-terminal domain (NTD) plays a significant role in the binding of Ltn1 to 60S ribosomal subunits and that NTD mutations causing defective 60S binding also lead to defective NSP ubiquitylation, without affecting Ltn1's intrinsic E3 ligase activity. Finally, we report the crystal structure of the Ltn1 NTD at 2.4-Å resolution. The structure, combined with additional mutational studies, provides insight to NTD's role in binding stalled 60S subunits. Our findings show that Neurospora extracts can be used as a tool to dissect mechanisms underlying ribosome-associated protein quality control and are consistent with a model in which Ltn1 uses 60S subunits as adapters, at least in part via its NTD, to target stalled NSPs for ubiquitylation.

Evaluating the effect of ambient particulate pollution on DNA methylation in Alaskan sled dogs: potential applications for a sentinel model of human health.

BACKGROUND: Exposure to ambient particulate matter (PM) is known to be associated with increased morbidity and mortality in human populations. During the winter months in Fairbanks, Alaska, severe temperature inversions lead to elevated concentrations of ambient PM smaller than 2.5 µm (PM2.5). Sled dogs represent an easily accessible environmentally exposed population that may yield findings informative for human health risk assessment. OBJECTIVES: In this pilot study, we evaluated whether ambient PM was associated with markers of global methylation in sled dogs. METHODS: Kennels were strategically recruited to provide a wide PM2.5 exposure gradient for the Fairbanks area. Continuous monitoring of ambient PM2.5 was conducted at each kennel during the winter of 2012/13 using a DustTrak 8530. Dogs received a physical examination and assessment of standard hematology and clinical chemistries. Global methylation was determined using the LUminometric Methylation Assay (LUMA) and 5-Methycytosine (5-mC) quantification. RESULTS: Three sled dog kennels (n~30 dogs/kennel) were evaluated and sampled. The average PM2.5 concentrations measured for kennels A, B, and C were 90 µg/m(3), 48 µg/m(3), 16 µg/m(3) (p<0.0001), respectively. The average (standard deviation) global methylation percentage for each kennel measured by LUMA was 76.22 (1.85), 76.52 (1.82), and 76.72 (2.26), respectively. The average (standard deviation) global methylation percentage for each kennel measured by 5-mC was 0.16 (0.04), 0.15 (0.04), and 0.15 (0.05), respectively. There was no statistically significant difference between the three kennels and their average global methylation percentage either by LUMA or 5-mC. CONCLUSIONS: In this study we evaluated global methylation using LUMA and 5-mC and found no differences between kennels, though exposure to ambient PM2.5 was significantly different between kennels. As more information becomes available regarding immunologically-related canine genes and functionally active promoter subunits, the utility of this surrogate could increase.

Production of Light Olefins Through Catalytic Cracking of C5 Raffinate Over Surface-Modified ZSM-5 Catalyst.

Surface modification of phosphorous-containing porous ZSM-5 catalyst (P/C-ZSM5-Sil.(X)) was carried out by a chemical liquid deposition (CLD) method using tetraethyl orthosilicate (TEOS) as a silylation agent. Different amount of TEOS (X = 5, 10, 20, and 30 wt%) was introduced into P/C-ZSM5il.(X) catalysts for surface modification. The catalysts were used for the production of light olefins (ethylene and propylene) through catalytic cracking of C5 raffinate. It was found that external surface acidity of P/C-ZSM5-Sil.(X) catalysts significantly decreased with increasing TEOS content. In the catalytic reaction, both conversion of C5 raffinate and yield for light olefins showed volcano-shaped curves with respect to TEOS content. Among the catalysts tested, P/C-ZSM5-Sil.(20) catalyst exhibited the best catalytic performance in terms of conversion of C5 raffinate and yield for light olefins. Thus, an optimal TEOS content was required for CLD treatment to maximize light olefin production in the catalytic cracking of C5 raffinate over P/C-ZSM5-Sil.(X) catalysts.

Synthesis of Dimethyl Carbonate from Ethylene Carbonate and Methanol Over Nano-Catalysts Supported on CeO2-MgO.

A series of CeO2(X)-MgO(1-X) (X = 0, 0.25, 0.5, 0.75, and 1.0) nano-catalysts were prepared by a co-precipitation method for use in the synthesis of dimethyl carbonate from ethylene carbonate and methanol. Among the CeO2(X)-MgO(1-X) catalysts, CeO2(0.25)-MgO(0.75) nano-catalyst showed the best catalytic performance. Alkali and alkaline earth metal oxides (MO = Li2O, K2O, Cs2O, SrO, and BaO) were then supported on CeO2(0.25)-MgO(0.75) by an incipient wetness impregnation method with an aim of improving the catalytic performance of CeO2(0.25)-MgO(0.75). Basicity of the catalysts was determined by CO2-TPD experiments in order to elucidate the effect of basicity on the catalytic performance. The correlation between catalytic performance and basicity showed that basicity played an important role in the reaction. Yield for dimethyl carbonate increased with increasing basicity of the catalysts. Among the catalysts tested, Li2O/CeO2(0.25)-MgO(0.75) nano-catalyst with the largest basicity showed the best catalytic performance in the synthesis of dimethyl carbonate.

Ubiquitylation by the Ltn1 E3 ligase protects 60S ribosomes from starvation-induced selective autophagy.

Autophagy, the process by which proteins or organelles are engulfed by autophagosomes and delivered for vacuolar/lysosomal degradation, is induced to ensure survival under starvation and other stresses. A selective autophagic pathway for 60S ribosomal subunits elicited by nitrogen starvation in yeast-ribophagy-was recently described and requires the Ubp3-Bre5 deubiquitylating enzyme. This discovery implied that an E3 ligases act upstream, whether inhibiting the process or providing an initial required signal. In this paper, we show that Ltn1/Rkr1, a 60S ribosome-associated E3 implicated in translational surveillance, acts as an inhibitor of 60S ribosomal subunit ribophagy and is antagonized by Ubp3. The ribosomal protein Rpl25 is a relevant target. Its ubiquitylation is Ltn1 dependent and Ubp3 reversed, and mutation of its ubiquitylation site rendered ribophagy less dependent on Ubp3. Consistently, the expression of Ltn1-but not Ubp3-rapidly decreased after starvation, presumably to allow ribophagy to proceed. Thus, Ltn1 and Ubp3-Bre5 likely contribute to adapt ribophagy activity to both nutrient supply and protein translation.

Graphene-containing carbon aerogel prepared using polyethyleneimine (PEl)-modified graphene oxide (GO) for supercapacitor: effect of polyethyleneimine-modified GO content.

Graphene-containing carbon aerogel was prepared by a sol-gel polymerization of resorcinol-formaldehyde (RF) method using polyethyleneimine (PEL)-modified chemically exfoliated graphene oxide (GO), and its electrochemical performance as an electrode for supercapacitor was examined. The effect of PEI-modified GO content on the physicochemical and electrochemical properties of graphene-containing carbon aerogel was investigated. For comparison, graphene-free carbon aerogel was also prepared. Among the samples, graphene-containing carbon aerogel prepared using 45 wt% PEI-modified GO solution (CA(45PG)) showed the highest BET surface area (784 m2/g) and the largest pore volume (1.71 cm3/g) with well-developed porous structure. Electrochemical properties of graphene-containing carbon aerogel and graphene-free carbon aerogel electrodes were measured by cyclic voltammetry, charge/discharge test, and electrochemical impedance spectroscopy in 6 M KOH electrolyte. Various electrochemical measurements revealed that CA(45PG) showed the highest specific capacitance (261 F/g), the lowest equivalent series resistance (0.16 Ω), and superior capacitive behavior. It is concluded that PEI-modified GO content served as an important factor determining the physicochemical properties and supercapacitive electrochemical performance of graphene-containing carbon aerogel.

Microporous and mesoporous ZSM-5 catalyst for catalytic cracking of C5 raffinate to light olefins.

ZSM5 catalysts (PAM(X)-ZSM5) with micropores and mesopores were prepared using polyacrylamide (PAM) as a soft template at different PAM content (X = 0, 0.12, 0.25, 0.53, 0.64, and 0.78 wt%), and they were applied to the production of light olefins (ethylene and propylene) through catalytic cracking of C5 raffinate. The effect of PAM content of PAM(X)-ZSM5 catalysts on the physicochemical properties and catalytic activities was investigated. N2 adsorption-desorption isotherms of PAM(X)-ZSM5 catalysts exhibited a broad hysteresis loop at high relative pressure, indicating the existence of mesopores in the catalysts. It was found that the catalytic performance of PAM(X)-ZSM5 catalysts was closely related to the mesoporosity of the catalysts. Conversion of C5 raffinate and yield for light olefins showed volcano-shaped trends with respect to mesopore/micropore volume ratio of the catalysts. Thus, an optimal PAM content was required to achieve maximum production of light olefins through catalytic cracking of C5 raffinate over microporous and mesoporous PAM(X)-ZSM5 catalysts.

Conversion of succinic acid to 1,4-butanediol via dimethyl succinate over rhenium nano-catalyst supported on copper-containing mesoporous carbon.

Copper-containing mesoporous carbons (XCu-MC) with different copper content (X = 8.0, 12.7, 15.9, 23.3, and 26.8 wt%) were prepared by a single-step surfactant-templating method. Rhenium nano-catalysts supported on copper-containing mesoporous carbons (Re/XCu-MC) were then prepared by an incipient wetness method. Re/XCu-MC (X = 8.0, 12.7, 15.9, 23.3, and 26.8 wt%) catalysts were characterized by nitrogen adsorption-desorption isotherm, HR-TEM, FT-IR, and H2- TPR analyses. Liquid-phase hydrogenation of succinic acid to 1,4-butanediol (BDO) via dimethyl succinate (DMS) was carried out over Re/XCu-MC catalysts in a batch reactor. The effect of copper content on the physicochemical properties and catalytic activities of Re/XCu-MC catalysts in the hydrogenation of succinic acid to BDO was investigated. Re/XCu-MC catalysts retained different physicochemical properties depending on copper content. In the hydrogenation of succinic acid to BDO, yield for BDO showed a volcano-shaped trend with respect to copper content. Thus, an optimal copper content was required to achieve maximum catalytic performance of Re/XCu-MC. It was also observed that yield for BDO increased with increasing the amount of hydrogen consumption by copper in the Re/XCu-MC catalysts.

Hydrogenation of succinic acid to 1,4-butanediol over rhenium catalyst supported on copper-containing mesoporous carbon.

Copper-containing mesoporous carbon (Cu-MC) was prepared by a single-step surfactant-templating method. For comparison, copper-impregnated mesoporous carbon (Cu/MC) was also prepared by a surfactant-templating method and a subsequent impregnation method. Rhenium catalysts supported on copper-containing mesoporous carbon and copper-impregnated mesoporous carbon (Re/Cu-MC and Re/Cu/MC, respectively) were then prepared by an incipient wetness method, and they were applied to the liquid-phase hydrogenation of succinic acid to 1,4-butanediol (BDO). It was observed that copper in the Re/Cu-MC catalyst was well incorporated into carbon framework, resulting in higher surface area and larger pore volume than those of Re/Cu/MC catalyst. Therefore, Re/Cu-MC catalyst showed higher copper dispersion than Re/Cu/MC catalyst, although both catalysts retained the same amounts of copper and rhenium. In the liquid-phase hydrogenation of succinic acid to BDO, Re/Cu-MC catalyst showed a better catalytic activity than Re/Cu/MC catalyst. Fine dispersion of copper in the Re/Cu-MC catalyst was responsible for its enhanced catalytic activity.

Catalytic cracking of C5 raffinate to light olefins over phosphorous-modified microporous and mesoporous ZSM-5.

Phosphorous-modified microporous and mesoporous ZSM-5 catalysts (XP/C-ZSM5) were prepared with a variation of phosphorous content (X = 0.17, 0.3, 0.7, 1.4, and 2.7 wt%), and they were applied to the production of light olefins (ethylene and propylene) through catalytic cracking of C5 raffinate. The effect of phosphorous content on the physicochemical properties and catalytic activities of XP/C-ZSM5 catalysts was investigated. It was revealed that physicochemical properties of XP/C-ZSM5 catalysts were strongly influenced by phosphorous content. Strong acidity of XP/C-ZSM5 catalysts decreased with increasing phosphorous content. In the catalytic cracking of C5 raffinate, both conversion of C5 raffinate and yield for light olefins (ethylene and propylene) showed volcano-shaped curves with respect to strong acidity. This result indicates that strong acidity of XP/C-ZSM5 catalysts played an important role in determining the catalytic performance in the catalytic cracking of C5 raffinate. Among the catalysts tested, 0.3P/C-ZSM5 catalyst with moderate strong acidity showed the best catalytic performance.

Single-particle EM reveals extensive conformational variability of the Ltn1 E3 ligase.

Ltn1 is a 180-kDa E3 ubiquitin ligase that associates with ribosomes and marks certain aberrant, translationally arrested nascent polypeptide chains for proteasomal degradation. In addition to its evolutionarily conserved large size, Ltn1 is characterized by the presence of a conserved N terminus, HEAT/ARM repeats predicted to comprise the majority of the protein, and a C-terminal catalytic RING domain, although the protein's exact structure is unknown. We used numerous single-particle EM strategies to characterize Ltn1's structure based on negative stain and vitreous ice data. Two-dimensional classifications and subsequent 3D reconstructions of electron density maps show that Ltn1 has an elongated form and presents a continuum of conformational states about two flexible hinge regions, whereas its overall architecture is reminiscent of multisubunit cullin-RING ubiquitin ligase complexes. We propose a model of Ltn1 function based on its conformational variability and flexibility that describes how these features may play a role in cotranslational protein quality control.

Hydrogenation of CO to methane over mesoporous nickel-iron-alumina xerogel nano-catalysts.

Mesoporous nickel-iron-alumina xerogel ((40-x)Ni(x)FeAX) nano-catalysts with different iron content (x = 0, 2.5, 5, 7.5, and 10) were prepared by a single-step sol-gel method for use in the methane production from carbon monoxide and hydrogen. The effect of iron content on the catalytic performance of (40-x)Ni(x)FeAX catalysts was investigated. In the methanation reaction, yield for CH4 decreased in the order of 35Ni5FeAX > 32.5Ni7.5FeAX > 30Ni10FeAX > 37.5Ni2.5FeAX > 40Ni0FeAX. This indicated that optimal iron content of mesoporous nickel-iron-alumina xerogel nano-catalyst was required for maximum production of CH4 in the methanation reaction. Experimental results revealed that optimal CO dissociation energy and large H2 adsorption ability of the catalyst were favorable for methane production. Among the catalysts tested, 35Ni5FeAX catalyst, which retained the most optimal CO dissociation energy and the largest H2 adsorption ability, exhibited the best catalytic performance in terms of conversion of CO and yield for CH4 in the methanation reaction. CO dissociation energy and H2 adsorption ability of the catalyst played a key role in determining the catalytic performance of (40-x)Ni(x)FeAX in the methanation reaction.

Online nonlinear sequential Bayesian estimation of a biological wastewater treatment process.

Online estimation of unknown state variables is a key component in the accurate modelling of biological wastewater treatment processes due to a lack of reliable online measurement systems. The extended Kalman filter (EKF) algorithm has been widely applied for wastewater treatment processes. However, the series approximations in the EKF algorithm are not valid, because biological wastewater treatment processes are highly nonlinear with a time-varying characteristic. This work proposes an alternative online estimation approach using the sequential Monte Carlo (SMC) methods for recursive online state estimation of a biological sequencing batch reactor for wastewater treatment. SMC is an algorithm that makes it possible to recursively construct the posterior probability density of the state variables, with respect to all available measurements, through a random exploration of the states by entities called 'particle'. In this work, the simplified and modified Activated Sludge Model No. 3 with nonlinear biological kinetic models is used as a process model and formulated in a dynamic state-space model applied to the SMC method. The performance of the SMC method for online state estimation applied to a biological sequencing batch reactor with online and offline measured data is encouraging. The results indicate that the SMC method could emerge as a powerful tool for solving online state and parameter estimation problems without any model linearization or restrictive assumptions pertaining to the type of nonlinear models for biological wastewater treatment processes.