Increase In C2 Research Articles

Selective electroreduction of CO2 to C2+ products on cobalt decorated copper catalysts

Cu-catalyzed electrochemical CO2 reduction reaction (CO2RR) to multi-carbon (C2+) products is often plagued by low selectivity because the adsorption energies of different reaction intermediates are in a linear scaling relationship. Development of Cu-based bimetallic catalysts has been considered as an attractive strategy to address this issue; however, conventional bimetallic catalysts often avoid metals with strong CO adsorption energies to prevent surface poisoning. Herein, we demonstrated that limiting the amount of Co in CuCo bimetallic catalysts can enhance C2+ product selectivity. Specifically, we synthesized a series of CuCox catalysts with trace amounts of Co (0.07-1.8 at%) decorated on the surface of Cu nanowires using a simple dip coating method. Our results revealed a volcano-shaped correlation between Co loading and C2+ selectivity, with the CuCo0.4% catalyst exhibiting a 2-fold increase in C2+ selectivity compared to the Cu nanowire sample. In situ Raman and Infrared spectroscopies suggested that an optimal amount of Co could stabilize the Cu oxide/hydroxide species under the CO2RR condition and promote the adsorption of CO, thus enhancing the C2+ selectivity. This work expands the potential for developing Cu-based bimetallic catalysts for CO2RR.

Role of Copeptin in Predicting Postoperative Hyponatremia and Hypernatremia in Patients Undergoing Endoscopic Pituitary Adenoma Surgery.

Arginine vasopressin (AVP) is an important hormone responsible for maintaining sodium homeostasis after pituitary surgery. The measurement of AVP levels is difficult because of its short half-life (t 1/2 ). Copeptin is a preprohormone of AVP, and it is a more stable peptide, which can be used as surrogate marker for AVP. This study aims to assess the role of copeptin as a predictor of postoperative hyponatremia and hypernatremia in patients undergoing endoscopic pituitary adenoma surgery. This prospective study included 50 patients who underwent endoscopic pituitary adenoma surgery. Serum copeptin levels of these patients were assessed (1) preoperatively (C1), (2) at extubation (C2), and (3) postoperative day 4 (C3). Perioperative data regarding fluid and sodium balance were collected from patients. Statistical analysis was done using the above data. The copeptin values were assessed against the sodium disturbances. 100% of patients who developed transient diabetes insipidus had a relative decrease in C2 from C1 ( P - .0002). 88% of patients who developed early hyponatremia had a relative increase in C2 as compared with C1 ( P < .01). 75% of patients who developed delayed hyponatremia had a relative increase in C3 as compared with C1 ( P = .003). A relative increase or decrease in early change in copeptin (C2-C1) can predict development of early hyponatremia or transient central diabetes insipidus, respectively. A relative increase in delayed change in copeptin (C3-C1) can predict development of delayed hyponatremia.

UV irradiation behavior of Salix psammophila sand barriers in the process of desertification control.

Salix psammophila sand barriers degrade under sunlight exposure, resulting in diminished protective performance and shortened service life in desertification control. To address the unresolved issue of photoinduced damage and degradation in sand barriers, we conducted simulations to assess the accelerated damage effect of ultraviolet (UV) rays during solar exposure of S. psammophila sand barriers. Our analysis focused on elucidating the mechanism of UV irradiation in sand barriers by examining the structural and material property changes that occur during the degradation process. The results indicated the following: (1) The discoloration of sand barriers resulting from UV irradiation was primarily ascribed to the modification in lignin content. (2) The morphology and protective performance of S. psammophila sand barriers underwent significant changes following exposure to UV irradiation. The 96-day and 144-day time points of UV exposure are crucial for evaluating the extent of UV degradation in sand barriers. After 192 days of UV irradiation, there was a decrease in mass loss percentage by 3.62%, modulus of elasticity by 8.63%, and modulus of rupture by 6.74%. (3) The lignin, hemicellulose, and cellulose content decreased by 23.12%, 14.30%, and 6.96%, respectively. The impact of UV irradiation on the polysaccharide (cellulose and hemicellulose) in S. psammophila sand barriers was relatively minimal. (4) The carbon binding form in S. psammophila sand barriers underwent a transformation, characterized by a significant decrease in C1 content and an increase in C2 and C3 content. This resulted in a gradual enhancement of the oxidation state and binding energy of carbon. Therefore, to prolong the utilization lifespan of S. psammophila sand barriers, it is essential to address the UV irradiation behavior from the perspective of inhibiting lignin reactions.

Cu+-Mediated CO Coordination for Promoting C–C Coupling for CO2 and CO Electroreduction

Selective electrochemical upgrading of CO2 to multicarbon (C2+) products requires a C-C coupling process, yet the underlying promoting mechanism of widely involved Cu oxidation states remains largely unclear, hindering the subtle design of efficient catalysts. Herein, we unveil the critical role of Cu+ in promoting C-C coupling via coordination with a CO intermediate during electrochemical CO2 reduction. We find that, relative to other halogen anions, iodide (I-) in HCO3- electrolytes accelerates the generation of strongly oxidative hydroxyl radicals that accounts for the formation of Cu+, which can be dynamically stabilized by I- via the formation of CuI. The in situ generated CO intermediate strongly binds to CuI sites, forming nonclassical Cu(CO)n+ complexes, leading to an approximately 3.0-fold increase of C2+ Faradaic efficiency at -0.9 VRHE relative to that of I--free Cu surfaces. Accordingly, a deliberate introduction of CuI into I--containing HCO3- electrolytes for direct CO electroreduction brings about a 4.3-fold higher C2+ selectivity. This work provides insights into the role of Cu+ in C-C coupling and the enhanced C2+ selectivity for CO2 and CO electrochemical reduction.

Crossing the cervicothoracic junction: an evaluation of radiographic alignment, functional outcomes, and patient-reported outcomes.

There is currently no consensus regarding the appropriate lower instrumented vertebra (LIV) for multilevel posterior cervical fusion (PCF) constructs between C7 and crossing the cervicothoracic junction (CTJ). The goal of the present study was to compare postoperative sagittal alignment and functional outcomes among adult patients presenting with cervical myelopathy undergoing multilevel PCF terminating at C7 versus spanning the CTJ. A single-institution retrospective analysis (January 2017-December 2018) was performed of patients undergoing multilevel PCF for cervical myelopathy that involved the C6-7 vertebrae. Pre- and postoperative cervical spine radiographs were analyzed for cervical lordosis, cervical sagittal vertical axis (cSVA), and first thoracic (T1) vertebral slope (T1S) in two randomized independent trials. Modified Japanese Orthopaedic Association (mJOA) and Patient-Reported Outcomes Measurement Information System (PROMIS) scores were used to compare functional and patient-reported outcomes at the 12-month postoperative follow-up. Sixty-six consecutive patients undergoing PCF and 53 age-matched controls were included in the study. There were 36 patients in the C7 LIV cohort and 30 patients in the LIV spanning the CTJ cohort. Despite significant correction, patients undergoing fusion remained less lordotic than asymptomatic controls, with a C2-7 Cobb angle of 17.7° versus 25.5° (p < 0.001) and a T1S of 25.6° versus 36.3° (p < 0.001). The CTJ cohort had superior alignment corrections in all radiographic parameters at the 12-month postoperative follow-up compared with the C7 cohort: increase in T1S (ΔT1S 14.1° vs 2.0°, p < 0.001), increase in C2-7 lordosis (ΔC2-7 lordosis 11.7° vs 1.5°, p < 0.001), and decrease in cSVA (ΔcSVA 8.9 vs 5.0 mm, p < 0.001). There were no differences in the mJOA motor and sensory scores between cohorts pre- and postoperatively. The C7 cohort reported significantly better PROMIS scores at 6 months (22.0 ± 3.2 vs 11.5 ± 0.5, p = 0.04) and 12 months (27.0 ± 5.2 vs 13.5 ± 0.9, p = 0.01) postoperatively. Crossing the CTJ may provide a greater cervical sagittal alignment correction in multilevel PCF surgeries. However, the improved alignment may not be associated with improved functional outcomes as measured by the mJOA scale. A new finding is that crossing the CTJ may be associated with worse patient-reported outcomes at 6 and 12 months of postoperative follow-up as measured by the PROMIS, which should be considered in surgical decision-making. Future prospective studies evaluating long-term radiographic, patient-reported, and functional outcomes are warranted.

Genetic parameters of immune traits for Landrace and Large White pig breeds.

Improving the immunocompetence towards pathogens represents a desirable objective of breeding strategies to increase resilience. However, the immune system is complex and the genetic foundation of the underlying components is not yet clarified. In the present study, we focused on 22 blood parameters of 1,144 Landrace (LR) and Large White (LW) piglets at the age of 6-7 weeks. The immune profiles covered immune cells, red blood cell characteristics and cytokines. Genetic parameters based on pedigree information along with possible environmental effects were estimated. Litter effects play an important role in the expression of immune parameters of their young progenies. Hence, litter impacts on the piglet's immune profile including the immune parameters of the dam itself were investigated by different models. To incorporate the complexity of the immune network, the data were further investigated with a principal component analysis. Immune traits showed low to high breed-specific heritabilities (h2 ). Strong positive rg were estimated among red blood cell characteristics (0.77-0.99) and among cytokines (0.48-0.99). Neutrophils and lymphocytes illustrated a high negative rg (-0.96 to -0.98). The litter impact on piglet's immunity was examined and strengthened already observed breed differences. In LR, h2 (0.22-0.15) and litter effect (c2 ) (0.52-0.44) for IFN-γ decreased after statistical consideration of maternal impact. In LW, a decrease in h2 (0.32-0.18) for IFN-γ and an increase in c2 (0.54-0.56) were observed. Here, sufficient correlations were detected within various immune traits and functional biological networks of principal components. Most immune traits are heritable and are promising to cover global breed-specific immunocompetence in pigs. The analysis of immune traits has to be extended in order to find an optimal range and to characterize relationships between immunity and performance to gain an improved immune system without accidental losses in productivity.

Variations in molecular and isotopes composition of seepage gases in the north-western and south-eastern parts of Lake Baikal

The paper presents results of gas-geochemical studies of bottom sediments and petroleum potential assessment of Baikal Rift Basin. During the expeditions of the Class@Baikal project in 2014–2019, gases from the Lake Baikal bottom sediments were analyzed. The results showed a clear difference in chemical and isotopic composition of the seeping gases collected in the northwestern and southeastern parts of the lake. The seepage released from northwest part were relatively enriched by methane and had a low concentration of C2+ compounds. The seepage gases had relatively lighter carbon isotopes composition of CH4 (from -72,7 to -50,1 ‰ VPDB) and the high variability of δ13C in C2H6 (from -65 to -22 ‰ VPDB). The gases released from southeastern part of the lake had an increase in C2+ compounds and had relatively lighter carbon isotopes composition of methane (from –57,2 to –41,0 ‰ VPDB). The carbon isotopes composition of ethane varies from -32 to -25 ‰ VPDB. Asymmetric structure of the Baikal rift basin and various processes of gas migration within it might cause the variations. Diffusive process led to the lighter carbon isotopes composition of the seepage gases from the northwestern part of lake and the gas molecular composition enrichment by methane. Such molecular and isotopic fractionations caused by geochemical processes helps to understand the migration of gas from source rocks to the earth’s surface. Similar geochemical indicators of fractionation should be taken into consideration when assessing oil and gas source rocks and basin potential from gas geochemical studies data.

Characterization of dicarboxylic acids, oxoacids, and α-dicarbonyls in PM2.5 within the urban boundary layer in southern China: Sources and formation pathways

Low-molecular-weight dicarboxylic acids, which are important components of secondary organic aerosols, have been extensively studied in recent years. Many studies have focused on ground-level observations and literature reports on the vertical distribution of the organic aerosols within the urban boundary layer are limited. In this study, the vertical profiles of dicarboxylic acids and related organic compounds (DCRCs) in PM2.5 were investigated at altitudinal levels (ground level and 488 m above the ground level) at the Canton Tower in Guangzhou, southern China, to elucidate their primary sources and secondary formation processes. The concentrations of DCRCs at ground level were generally higher than those at 488 m. Oxalic acid (C2) was the most abundant species, followed by succinic acid (C4) and malonic acid (C3) at both heights. The higher ratio of DCRCs-bound carbon to organic carbon (i.e., DCRCs-C/OC) at 488 m (4.8 ± 1.2%) relative to that at ground level (2.7 ± 0.5%) indicated a higher degree of aerosol aging at 488 m. The abundance of C2 was increased and the conversion of C4 to C3 was enhanced due to the photochemical oxidation of its homologues during long-range transport periods. The increase in C2 was associated with in-cloud processes during pollution periods. Principal component analysis showed that DCRCs were mainly derived from atmospheric secondary processing and biomass burning was also an important source of long-chain carboxylic acids during autumn in Guangzhou. Our results illustrate that secondary processing and biomass burning play prominent roles in controlling the abundance of DCRCs. Furthermore, DCRCs are affected by air masses from regional areas, oxidation of their precursors via vertical transport and in-cloud processes.

Effect of reducibility on the performance of Co-based catalysts for the production of high-calorie synthetic natural gas

Co-based catalysts were developed for the production of high-calorie synthetic natural gas. The Co reduction in Al2O3- and SiO2-supported catalysts prepared with different Co loading, and their catalytic properties for high-calorie methanation were investigated. The CO conversion of the Co/SiO2 catalysts was superior to that of the Co/ Al2O3 with the same Co loading, due to their better reducibility at 400°C. The activities of both the Al2O3 and SiO2-supported catalysts increased with Co loading, while the growth of hydrocarbon chains decreased as the Co loading increased. As the reduction temperature increased, crystallite size of Co increased in 10Co/SiO2, resulting in decrease of CO conversion and increase of C2+ selectivity. The highest CO conversion (98.7%) was obtained over 10Co/SiO2 reduced at 400 °C. Moreover, the heating value of the product gas (10,405 kcal/Nm3) exceeded the standard heating value without requiring a high reduction temperature (700 °C) or a noble metal (Ru).

Densely packed-matrices of heat moisture treated-starch determine the digestion rate constant as revealed by logarithm of slope plots.

Factors affecting the extent and rate constant of starch digestion have been determined by applying logarithm of slope (LOS) plot approach to banana starch modified by heat moisture treatment (HMT) at different temperatures (100, 110 and 120°C) and time (4 and 8h). LOS plot result showed that native and HMT-starches exhibited two separate digestion rate constants (k 1 in rapid and k 2 in slower phase). The digestibility increased with the increase in temperature and time of HMT in which the amount of digestible starch at slower phase (C 2∞ ) predominantly contributed to the increase in total digestible starch (total C ∞ ). Small change of the digestible starch in rapid phase (C 1∞ ) might be attributed to the comparatively intact granule surfaces and the relatively small change in ratio of ordered to disordered α-glucan chains at the granule surface as observed by FTIR-ATR. Meanwhile the increase in C 2∞ might be linked to the decrease in crystallinity as observed by XRD. Compared to the native starch, denser packed-structure characterising an A-type crystalline structure in HMT-starches is a key factor determining the lower k 2 in HMT-starches. The densely packed-matrices might slow down the amylase diffusion through the granule to reach digestible α-glucan chains.

Nutrient Content, in Vitro Ruminal Fermentation Characteristics and Antimethanogenic Potential of Three Algerian Asteraceae Species

The in vitro rumen fermentation parameters and the antimethanogenic potential of three Asteraceae species: Chamaemelum nobile, Centaurea pulata and Chrysanthemum segetum were determined. Serum bottles containing 200 mg of each plant and 30 ml of the culture medium (artificial saliva plus rumen juice) were incubated for 24 h. After incubation, pH, volatile fatty acid (VFA), ammonia (NH3) and methane (CH4) productions were recorded. Methanogens and protozoa were quantified using a Real Time PCR technique (qPCR). Cumulative gas productions, in vitro organic matter digestibility and VFA were not significantly affected by the added species when compared to the control (P &gt; 0.05). The effects of Chamaemelum nobile and Chrysanthemum segetum on methane production, NH3 and acetate to propionate ratio (C2:C3) were similar. The two species were able to modulate rumen fermentation to produce significantly lower CH4 concentrations (-24.3% and -27.1%, respectively) compared to the control. C.pulata produced the highest cumulative gas and stimulated the microbial metabolism with an increase in C2:C3 ratio, NH3 and methane production (P &lt; 0.05). No significant effect of the three species on methanogenic Archaea and protozoa was registered (P &gt; 0.05). The three species studied herein show a good potential for mitigating ruminal methane production without any undesirable effects on the main fermentation parameters.

Effect of cut on secondary metabolite profile in hydroponically-grown Rumex acetosa L. seedlings: a metabolomic approach

Seedlings of Rumex acetosa L. (sorrel) were grown in floating system and two consecutive cuts took place: 15 (C1) and 30 (C2) days after sowing. An untargeted metabolomics approach was utilised to fingerprint phenolics and other health-related compounds in sorrel leaves, as well as to unveil differences between the two cuts. The untargeted approach allowed to putatively identify 458 metabolites considering both the cuts. Three new terpenoids and two new phenylpropanoid glycosides (dihydrosyringin and dihydroconiferin) with antifungal and anti-inflammatory activity were annotated. Overall, leaves from C2 had lower level of secondary metabolites (44 were down-accumulated), especially sesquiterpenes and stilbenes. Conversely, anthocyanins showed a relevant increase in C2 than in C1 leaves. The dataset suggests that sorrel leaves represent a good source of nutraceutical compounds and unveils the pivotal effect of pre-harvest factor in secondary metabolite profile.

Light Absorption and Fluorescence Characteristics of Atmospheric Water-soluble Organic Compounds and Humic-like Substances During the Winter Season in Guangzhou

The light absorption and fluorescence characteristics of atmospheric water-soluble organic compounds (WSOC) and humic-like substances (HULIS) during the winter season in Guangzhou were examined using UV-vis spectroscopy and excitation-emission matrix spectroscopy combined with parallel factor analysis (EEM-PARAFAC). The results showed that the SUVA254, HIX, and MAE365 values of HULIS were higher than those of WSOC, suggesting that the former had higher aromaticity, humification, and light-absorption capacity in winter atmospheric PM2.5 in Guangzhou. EEM-PARAFAC analysis identified three fluorescence components, including fulvic-like acid (C1), humic-like acid (C2), and protein-like (C3) components. The total humic-like components (C1+C2) accounted for 78% and 85% for WSOC and HULIS, respectively, which indicated that humic-like fluorescence components were the major components for both WSOC and HULIS and that HULIS were enriched with the dominant humic-like fluorophores. In addition, the aromaticity, humification, light-absorbing capacity, and C2 levels of WSOC and HULIS during the haze episode were significantly higher than those in the non-haze episode. This suggested that the water-soluble organics with higher molecular weights and stronger light-absorption capacities tended to form during the haze episode. The correlations analysis revealed strong negative correlations between C1 levels of WSOC and HULIS and HIX, MAE365, OCsec, K+, SO42-, and NH4+. Additionally, strong positive correlations were observed between C2 levels and the same factors. These results implied that the decrease in C1 and increase in C2 might lead to increased humification and light-absorption in WSOC and HULIS, and biomass burning and secondary organic aerosols might contribute to the C2 component.

Molecular distribution and stable carbon isotopic compositions of dicarboxylic acids and related SOA from biogenic sources in the summertime atmosphere of Mt. Tai in the North China Plain

Abstract. Molecular distributions and stable carbon isotopic (δ13C values) compositions of dicarboxylic acids and related secondary organic aerosols (SOA) in PM2.5 aerosols collected on a day/night basis at the summit of Mt. Tai (1534 m a.s.l.) in the summer of 2016 were analyzed to investigate the sources and photochemical aging process of organic aerosols in the forested highland region of the North China Plain. The molecular distributions of dicarboxylic acids and related SOA are characterized by the dominance of oxalic acid (C2), followed by malonic (C3), succinic (C4) and azelaic (C9) acids. The concentration ratios of C2 ∕ C4, diacid-C ∕ OC and C2 ∕ total diacids are larger in the daytime than in the nighttime, suggesting that the daytime aerosols are more photochemically aged than those in the nighttime due to the higher temperature and stronger solar radiation. Both ratios of C2 ∕ C4 (R2&gt;0.5) and C3 ∕ C4 (R2&gt;0.5) correlated strongly with the ambient temperatures, indicating that SOA in the mountaintop atmosphere are mainly derived from the photochemical oxidation of local emissions rather than long-range transport. The mass ratios of azelaic acid to adipic acid (C9 ∕ C6), azelaic acid to phthalic aid (C9 ∕ Ph) and glyoxal to methylglyoxal (Gly ∕ mGly) and the strong linear correlations of major dicarboxylic acids and related SOA (i.e., C2, C3, C4, ωC2, Pyr, Gly and mGly) with biogenic precursors (SOA tracers derived from isoprene, α/β-pinene and β-caryophyllene) further suggest that aerosols in this region are mainly originated from biogenic sources (i.e., tree emissions). C2 concentrations correlated well with aerosol pH, indicating that particle acidity favors the organic acid formation. The stable carbon isotopic compositions (δ13C) of the dicarboxylic acids are higher in the daytime than in the nighttime, with the highest value (-16.5±1.9 ‰) found for C2 and the lowest value (-25.2±2.7 ‰) found for C9. An increase in δ13C values of C2 along with increases in C2 ∕ Gly and C2 ∕ mGly ratios was observed, largely due to the isotopic fractionation effect during the precursor oxidation process.

Evaluation ofserum free carnitine/acylcarnitine levels and left ventricular systolic functions in children with idiopathic epilepsy receiving valproic acid

ObjectivesIn the study, the effect of valproic acid on serum free/acylcarnitine levels and left ventricular systolic function in pediatric patients with idiopathic epilepsy receiving valproic acid was investigated. Patients and MethodsPatients receiving valproic acid treatment for six months between January 2012 and December 2012 were evaluated. Blood samples were obtained from the participants twice (pretreatment and the sixth month of treatment) and serum-free and acylcarnitine levels (from C2 to C18:1-OH) were measured using tandem mass spectrometry. Cardiac functions (ejection fraction, shortening fraction, cardiac output, left ventricular systolic and diastolic diameters, left atrial diameter, aortic diameter, cardiac output, and myocardial performance index) were evaluated by echocardiography simultaneously. ResultsA total of fourty patients, 23 female (57.5%) and 17 male (42.5%), with the diagnosis of idiopathic epilepsy and receiving valproic acid monotherapy were studied. Comparison of serum-free and acylcarnitine levels measured pretreatment and sixth month of treatment revealed a decrease in average C0 and C5:1 (respectively p < 0.001, p = 0.013) and an increase in C2, C3, C5-OH, C8:1 and C4-DC levels (respectively p < 0.001, p < 0.001, p = 0.019, p = 0.013, p < 0.001). Other serum acylcarnitine levels did not change significantly (p > 0.05). No difference was observed in concurrent echocardiographic measurements of left ventricular systolic function (p > 0.05). ConclusionThe study demonstrated that valproic acid treatment results in low levels of free carnitine and changes in some acylcarnitine subgroups but has no influence on left ventricular systolic function.

Complement C3 Expression Is Decreased in Autism Spectrum Disorder Subjects and Contributes to Behavioral Deficits in Rodents

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with hallmark symptoms including social deficits, communication deficits and repetitive behaviors. Accumulating evidence suggests a potential role of the immune system in the pathophysiology of ASD. The complement system represents one of the major effector mechanisms of the innate immune system, and regulates inflammation, and orchestrates defense against pathogens. However, the role of CNS complement system in ASD is not well understood. In the present study, we found a significant increase in C2, C5, and MASP1, but a decrease in C1q, C3, and C4 mRNA levels in the middle frontal gyrus of ASD subjects compared to controls. Significant decreases in the mRNA levels of 2 key proinflammatory cytokines, IL-17 and IL-23 were observed in ASD subjects. Our study further demonstrated a strong association of complement genes with IL-17 and IL-23, suggesting a possible role of the complement system in immune dysregulation in ASD. We observed significant associations between complement components and abnormality of development scores in subjects with ASD. In rodents, C3 knockdown in the prefrontal cortex induced social interaction deficits and repetitive behavior in mice. Together, these studies suggest a potential role of C3 in the pathophysiology of ASD.

Hydrothermal degradation of hemicelluloses from triploid poplar in hot compressed water at 180–340 °C

Hemicelluloses isolated from triploid poplar were subjected to hydrothermal degradation at 180–340 °C. The detailed physicochemical characteristics of hydrothermal degradation products including monosaccharide and XOS, molecular weight, inhibitory and organic compounds were detected by HPAEC, GPC, HPLC, and GC–MS, respectively. An increase in temperature led to a significant decrease in molecular weight and an increase in C2–C5 organic alcohols and acids. More importantly, besides two well-known routes that hemicelluloses are hydrolyzed to monosaccharide, followed by further degraded to furfural, a series of reaction routes was proposed to clarify and explain the mechanisms of the hydrothermal degradation of hemicelluloses from triploid poplar, which involved: (i) a predominant route of fragmentation; (ii) side reactions such as oxidation, dehydration, isomerization/rearrangement, and self-lactonization; (iii) larger molecular fragments from sugars by deoxydation or/and oxidation, followed by self-lactonization; and (iv) very few extensive re-polymerization including esterification and condensation among hemicelluloses and lignin fragments.

Exergy Analysis of Waste Heat Recovery Section in Steam-Natural Gas Reforming Process

In this work, an exergy analysis is performed for the waste heat recovery section (WHRS) of the steam-natural gas reforming (SNGR) process as a major energy intensive process. Two alternate conditions are investigated to evaluate the required thermodynamic parameters: normal operating condition and increase of C2+ components in the process feed stream. At normal operating condition, the exergy efficiency of WHRS amounts to 0.58 while some 17.2 kJ energy is destructed for each mole of H2 produced. If heavier than methane components are increased in the feed up to 8.5 mole %, despite the increase of H2 production, the exergy efficiency decreases down to 0.54 and exergy destruction is reduced to 13.8 kJ for each mole of H2 produced. It is concluded that waste heat recovery has an important role on the exergy parameters of steam reforming processes, and an efficient heat exchange mechanism should be designed for this purpose. In addition, a change of reforming feed composition has a significant effect on the ...

Study on Application of Vinyl Methyl Ether in MTO Reaction

MTO is the core technology of the coal-to-olefins process. Vinyl methyl ether was added to the reaction feed to investigate the infulence of methoxy group concentration in MTO reaction. Several series of metal-modified ZSM-5 were synthesized to investigate the effect of metal element in the progress methoxy group involved. The reaction results indicated that both the addition of vinyl methyl ether and the metal modification on catalyst led to an increase in C2~C3 olefins yield. The highest C2~C3 olefins yield was obtained using methanol with 5wt% vinyl methyl ether as feed and ZSM-5 with 3wt% Ba modified as catalyst.

239: Effects of a rehabilitation program on large and small artery elasticity, in cardiac patients. Comparison between diabetics and non diabetics patients

Impairment in arterial compliance is associated with diabetes. Arterial stiffness is related to the cardiovascular disease risk. Treatments allowing arterial compliance increase should be relevant to improve prognosis. Previous studies have demonstrated that rehabilitation programs were able to improve arterial compliance in cardiac patients. In the present study, we have assessed the effect of a 6-week rehabilitation program on arterial compliance in diabetic patients (DP) in comparison with non-diabetic patients (NDP) with heart disease. 134 type2 DP and 160 NDP engaged in aerobic training and multidisciplinary educational interventions five days per week. DP and NDP were matched appropriately for age (respectively 57.5 vs 56.5 years), sex ratio (29% vs 25% women) and type of heart disease. Sixty one percent of DP was treated by insulin. Baseline HbA (1c) was greater than 6.6% in 64% of cases. Retinopathy and microalbuminuria were detected in respectively 31% and 36% of subjects. Large (C1) and small artery (C2) elasticity indices were measured using the HDI/PulseWaveTM CR-2000 Research CardioVascular Profiling System (Hypertension Diagnostics TM, Inc) before and after rehabilitation. Before exercise training C2 was lower in DP in comparison with NDP (3.3 vs 3.6 - p<0.02) whereas C1 was similar (15.7 vs 15.3 - p=0.6). After training, significant increases in C1 and C2 were found in the two groups. In diabetic patient a +9% increase in C1 (16.6 - p=0.01) and a 21% increase in C2 (4.2 - p<0.001) were found. This increase was assessed to +7% for C1 (16.7 - p=0.002) and to +18% for C2 (4.3 - p<0.001) in NDP. The percentage of increase in C1 and C2 was not statistically significant between DP and NDP. Small artery elasticity is lower in diabetics compared with non diabetics. A 6-week aerobic training and multidisciplinary educational program improves both large and small artery elasticity in DP and NDP.