Structural and thermal investigation of lignocellulosic biomass conversion for enhancing sustainable imperative in progressive organic refinery paradigm for waste-to-energy applications

The depletion of finite fossil fuel reserves and the severe environmental degradation resulting from human activities have compelled the expeditious development and application of sustainable waste to energy technologies. To encapsulate energy and environment in sustainability paradigm, bio waste based energy production is need to be forged in organic bio refinery setup. According to world bioenergy association, biomass can cover 50 % of the primary energy demand of the world. Therefore, the present study focuses on reforming the energy mix for a clean energy generation, where, sample composition of cotton stalk was acidified in dilute (5% wt.) hydrochloric acid (HCL) for analyzing material burnout patterns in biomass conversion systems utilized in organic bio refinery sector. Advanced thermochemical burning technique, which includes pyrolysis and combustion was applied at four different leaching times from 0 to 180 min under nitrogen environment from 0 °C to 500 °C and air from 500 °C to 900 °C, respectively. Different analyses including proximate, ultimate, gross calorific value (GCV), thermos-gravimetric, kinetic, XRD, FTIR, SEM-EDS were used for analyzing the degradation of demineralized cotton stalk at different treatment rates. Proximate study demonstrated that cotton stalk leaching for 180 min has efficiently infused HCL, leading in a significant increase in fixed carbon and higher heating value of 20.23 % and 12.48%, respectively, as well as a reduction in carbon footprint of around 54.80%. The findings of proximate was validated by GCV analysis and CHNS analysis as value of carbon and hydrogen has shown increasing behavior with the time delay in demineralization Thermo-gravimetric and derivative thermo-gravimetric data analyses shows an increasing trend of conversion efficiency, with the maximum increase of 98 % reported for sample 3H.TT.DEM. XRD characterization has reported 23° to 25° angle for all the observed peaks. Sample 3H.TT.DEM has shown maximum angle inclination along with matured crystalline peak. The latter observations has been validated by FTIR spectroscopy as sample 3H.TT.DEM has reported maximum O-H group formation. Sample 3H.TT.DEM has reported lowest activation energy of 139.51 kJ*mole-1 and lowest reactivity of 0.000293649%*min 0C, due to moderate and stable reactiveness. In SEM examination, increment in pore size and number of pores within the structural matrix of cotton stalk was observed with the enhancement in acidulation process. Furthermore, in EDS analysis, 3H.TT.DEM has shown most balanced distribution of the elements. In this research, sustainable transformation of biomass is envisioned to improve the waste bio refinery system, significantly contributing to the achievement of Sustainable Development Goals 7, 12 and 13.

Core-shell nanostructured Cu-based bi-metallic electrocatalysts for co-production of ethylene and acetate

Direct electrocatalytic CCU routes to produce a myriad of valuable chemicals (e.g., methanol, acetic acid, ethylene, propanol, among others) will allow the chemical industry to shift away from the conventional fossil-based production. Electrofuels need to go beyond the current electroreduction of CO2 to CO, and we will here demonstrate the continuous flow electroreduction of syngas (i.e., CO and H2), which are the products from CO2-to-CO, with enhanced product selectivity (∼90% towards ethylene). To overcome current drawbacks, including bicarbonate formation that resulted in low CO2 utilisation and low C2+ product selectivity, the development of nanostructured core-shell bi-metallic electrocatalysts for direct electrochemical reduction of syngas to C2+ is proposed. Electrosynthesis of ethylene is performed in a state-of-the-art continuous flow three-compartment cell to produce ethylene (cathodic gas phase product) and acetate (cathodic liquid phase product), simultaneously.

A ruthenium cis-dihydride with 2-phosphinophosphinine ligands catalyses the acceptorless dehydrogenation of benzyl alcohol

The first ruthenium dihydride complex featuring a phosphinine ligand cis-[Ru(H)₂(2-PPh₂-3-Me-6-SiMe₃-PC₅H₂)₂] was synthesised exclusively as the cis-isomer. When formed in situ from the reaction of cis-[Ru(Cl)₂(2-PPh₂-3-Me-6-SiMe₃-PC₅H₂)₂] with two equivalents of Na[BHEt₃], as demonstrated by ³¹P and ¹H NMR spectroscopy, the catalysed acceptorless dehydrogenation of benzyl alcohol was observed leading to benzyl benzoate in up to 70% yield.

CO2 capture through electro-conductive adsorbent using physical adsorption system for sustainable development

The most critical energy and environmental challenge that our planet is facing today is to minimize the dependence on fossil fuels. Carbon dioxide may be of utmost significance as a solution of this issue through realization of carbon neutral energy cycle. Potentially, this could be achieved through the carbon dioxide capture as the urgent response to ongoing climate change. Activated carbon (AC) adsorption is one the most effective, environment friendly and techno-economic process for the carbon capture. In the current research, an electro-conductive-activated carbon was prepared by mixing powdered activated carbon (PAC) with an electro-conductive polymer (ECP). Different ratios of 0, 25, 50, 75 and 100 wt% of ECP with PAC were used for the different analyses of activated carbons in a gas mixture of CO₂/N₂ using a physical adsorption system. Adsorption and desorption analyses, capacities of the process and desorption effects were examined. Electro-conductive polymers (ECP) were mixed with AC samples, where breakthrough time was increased up to 400% when mixed with the PAC for CO₂ adsorption. Following adsorption analysis, desorption of activated carbons was conducted with different potentials. It was revealed that mixing could help the PAC sample to overcome the packing issue to increase the breakthrough capacity and the volumes before and after the breakthrough adsorption in the packed bed systems. The desorption rates of the PAC sample were also enhanced, and fast desorption was observed when mixed with ECP. It is envisioned that this method is very much promising carbon capture method for the techno-economic feasibility and sustainable development of the environment.

Modification of acidic and textural properties of a sulphated zirconia catalyst for efficient conversion of high-density polyethylene into liquid fuel

Consumption of plastic has a rapid increase of about 8% per annum and reached to 400 million per tonnes approximately, where about 50% of plastic was disposed after using only once. Different techniques for treating this increased waste faced a number of issues related to cost and environmental and sustainable development. Catalytic conversion has been found as one of the most viable solutions to solve this problem. Sulphated zirconia (SZ) catalyst modified with calcium carbide (CC) was found to improve high-density polyethylene (HDPE) conversion into liquid fuel. The liquid content was improved from 39.0wt% to 66.0wt% at 410 °C. HDPE was converted 100% by weight using, SZ/CC with 66wt% liquid yield as compared to the conversion of approximately 98wt% with about 40wt% only liquid yield for the pure SZ. The composition of hydrocarbon liquid product was significantly changed from paraffin (16%) and aromatic (58%) to olefin (74%) and naphthenic (23%) compounds. This significant increase in liquid was related to changes in the acidic and textural characteristics of the new hybrid catalyst, SZ/CC where the total ammonia desorption of 337.0 μm NH₃/g for the SZ was modified to 23.4 μm NH₃/g for the SZ/CC. Both SZ and SZ/CC catalysts showed characteristics of mesoporous material, where the internal pore volume of SZ had reduced from 0.21 mL/g for SZ to 0.04 mL/g for SZ/CC. Furthermore, XRD analysis indicated the presence of a new compound, CaZrO₃ in the SZ/CC, which confirmed a chemical interaction between the SZ and CC through sintering of ZrO₂ and CaO. Therefore, the SZ/CC catalyst improves the liquid yield significantly and the selectivity towards olefinic and naphthenic compounds.

In-situ regeneration of activated carbon with electric potential swing desorption (EPSD) for the H2S removal from biogas

In-situ regeneration of a granular activated carbon was conducted for the first time using electric potential swing desorption (EPSD) with potentials up to 30 V. The EPSD system was compared against a standard non-potential system using a fixed-bed reactor with a bed of 10 g of activated carbon treating a gas mixture with 10,000 ppm H₂S. Breakthrough times, adsorption desorption volume, capacities, effect of regeneration and desorption kinetics were investigated. The analysis showed that desorption of H₂S using the new EPSD system was 3 times quicker compared with the no potential system. Hence, physical adsorption using EPSD over activated carbon is efficient, safe and environmental friendly and could be used for the in-situ regeneration of granular activated carbon without using a PSA and/or TSA system. Additionally, adsorption and desorption cycles can be obtained with a classical two column system, which could lead towards a more efficient and economic biogas to biomethane process.

Sorption and phase distribution of ethanol and butanol blended gasoline vapours in the vadose zone after release

The sorption and phase distribution of 20% ethanol and butanol blended gasoline (E20 and B20) vapours have been examined in soils with varying soil organic matter (SOM) and water contents via laboratory microcosm experiments. The presence of 20% alcohol reduced the sorption of gasoline compounds by soil as well as the mass distribution of the compounds to soil solids. This effect was greater for ethanol than butanol. Compared with the sorption coefficient (Kd) of unblended gasoline compounds, the Kd of E20 gasoline compounds decreased by 54% for pentane, 54% for methylcyclopentane (MCP) and 63% for benzene, while the Kd of B20 gasoline compounds decreased by 39% for pentane, 38% for MCP and 49% for benzene. The retardation factor (R) of E20 gasoline compounds decreased by 53% for pentane, 53% for MCP and 48% for benzene, while the R of B20 gasoline compounds decreased by 39% for pentane, 37% for MCP and 38% for benzene. For all SOM and water contents tested, the Kd and R of all gasoline compounds were in the order of unblended gasoline > B20 > E20, indicating that the use of high ethanol volume in gasoline to combat climate change could put the groundwater at greater risk of contamination.

Replication of twelve association studies for Huntington's disease residual age of onset in large Venezuelan kindreds

BACKGROUND

The major determinant of age of onset in Huntington's disease is the length of the causative triplet CAG repeat. Significant variance remains, however, in residual age of onset even after repeat length is factored out. Many genetic polymorphisms have previously shown evidence of association with age of onset of Huntington's disease in several different populations.

OBJECTIVE

To replicate these genetic association tests in 443 affected people from a large set of kindreds from Venezuela.

METHODS

Previously tested polymorphisms were analysed in the HD gene itself (HD), the GluR6 kainate glutamate receptor (GRIK2), apolipoprotein E (APOE), the transcriptional coactivator CA150 (TCERG1), the ubiquitin carboxy-terminal hydrolase L1 (UCHL1), p53 (TP53), caspase-activated DNase (DFFB), and the NR2A and NR2B glutamate receptor subunits (GRIN2A, GRIN2B).

RESULTS

The GRIN2A single-nucleotide polymorphism explains a small but considerable amount of additional variance in residual age of onset in our sample. The TCERG1 microsatellite shows a trend towards association but does not reach statistical significance, perhaps because of the uninformative nature of the polymorphism caused by extreme allele frequencies. We did not replicate the genetic association of any of the other genes.

CONCLUSIONS

GRIN2A and TCERG1 may show true association with residual age of onset for Huntington's disease. The most surprising negative result is for the GRIK2 (TAA)(n) polymorphism, which has previously shown association with age of onset in four independent populations with Huntington's disease. The lack of association in the Venezuelan kindreds may be due to the extremely low frequency of the key (TAA)(16) allele in this population.

Biosynthesis and secretion of pituitary hormones: dynamics and regulation

Production and secretion of hormones by the pituitary involve highly orchestrated intracellular transport and sorting steps. Hormone precursors are routed through a series of compartments before being packaged in secretory granules. These highly dynamic carriers play crucial roles in both prohormone processing and peptide exocytosis. We have employed the ACTH-secreting AtT-20 cell line to study the membrane sorting events that confer functionality (prohormone activation and regulated exocytosis) to these secretory carriers. The unique ability of granules to promote prohormone processing is attributed to their acidic interior. Using a novel avidin-targeted fluorescence ratio imaging technique, we have found that the trans-Golgi of live AtT-20 cells maintains a mildly acidic (approximately pH 6.2) interior. Budding of secretory granules causes the lumen to acidify to <pH 6.0, which is both necessary and sufficient to trigger SPC3-mediated proteolytic conversion of proopiomelanocortin to ACTH. Investigation of the pH regulatory mechanism indicates that the trans-Golgi and secretory granules maintain different pH values by distinct sorting of key membrane transporters. Mathematical modeling of our data suggests that the decreasing pH values of organelles of the regulated secretory pathway is established by gradually increasing the density of active H+ pumps from the ER to Golgi while concomitantly decreasing the H+ permeability from ER to Golgi to secretory granules. An in vitro assay was developed to study the formation of processing-competent secretory granules from their processing-incompetent precursor trans-Golgi compartment. Our data suggest that ARF1-mediated sorting of proton pumps and leaks during early stages of granule formation confers processing competency to the resulting organelle. Once formed, these young granules continue to undergo membrane remodeling which results in dynamic changes in their exocytotic behavior. Two SNAREs, VAMP4 and synaptotagmin IV, enter newly formed granules but are removed from the maturing granule membrane by vesicle budding. Sorting of these proteins is correlated with the acquisition of Ca2+-triggered exocytosis and a decrease in unregulated exocytotic rate. Thus, biosynthesis and secretion of pituitary hormones are dynamically regulated by intracellular sorting events that govern the functions of their secretory carriers.

Biogenesis of processing-competent secretory organelles in vitro

Propeptide processing occurs in specific compartments of the secretory pathway, but how these processing-competent organelles are generated from their processing-incompetent precursor compartments is unknown. To dissect the process biochemically, we have developed a novel cell-free system reconstituting the production of processing-competent secretory granules in AtT-20 cells. Using donor membranes containing [(35)S]sulfate labeled pro-opiomelanocortin (POMC)(5) in the trans-Golgi, we can reconstitute cytosol- and ATP-dependent prohormone processing as well as incorporation of processed ACTH into immature secretory granules (ISGs). Under limiting cytosol conditions, both reactions are greatly stimulated by ADP-ribosylation factor 1 (ARF1) but not by the GDP-bound ARF1 T31N mutant. pH studies show that lumenal acidification, most likely due to ARF-mediated sorting of proton pumps and leaks during budding, confers processing competency to the resulting organelle. Surprisingly, comparison of onset of processing and ISG release reveals that they are distinct biochemical processes with different kinetics and separate cytosolic requirements. Moreover, ARF regulates the onset of prohormone processing but not ISG release. Our data suggest a two-step mechanism (onset of processing followed by ISG release) for the production of processing-competent organelles from the trans-Golgi and provide the first system with which these two steps may be individually dissected.

SREBP transcriptional activity is mediated through an interaction with the CREB-binding protein

The sterol regulatory element binding proteins (SREBP-1 and -2) activate transcription of genes whose products are involved in the cellular uptake and synthesis of cholesterol. Although considerable effort has been exerted to define the events regulating the levels of active SREBP, little is known about the transcriptional cofactors mediating SREBP function. In an unbiased search for potential coactivators of SREBP, we isolated a protein of 265 kD from HeLa cells that directly bound SREBP-1 and SREBP-2. Peptide sequencing and Western blot analysis established that the 265-kD protein was CBP (CREB-binding protein), a recently identified transcriptional coactivator. The putative activation domain of SREBP was shown to bind specifically to amino-terminal domains of recombinant CBP and p300 (a CBP-related protein). Moreover, transfection studies demonstrated that CBP enhances the ability of SREBP to activate transcription of reporter genes in HeLa cells. Together, these data suggest that CBP mediates SREBP transcriptional activity, thus revealing a new step in the biochemical pathway regulating cholesterol metabolism.

The gene for schnyder's crystalline corneal dystrophy maps to human chromosome 1p34.1-p36

Schnyder's crystalline corneal dystrophy (SCCD) is an autosomal dominant eye disease characterized by a bilateral clouding of the central cornea, arcus lipoides and/or visible crystalline deposits of cholesterol in the stroma. There is accumulation of phospholipid, unesterified cholesterol and cholesterol ester in the corneal stroma; this is believed to be due to an imbalance in the local factors affecting lipid/cholesterol transport or metabolism. The cellular mechanism of abnormal lipid transport and metabolism in SCCD is of interest due to its potential involvement in atherosclerosis, and its implications for the pathogenesis of cerebrovascular, coronary and peripheral vascular disease as well as corneal opacification. To determine the chromosomal location of the SCCD locus, genome-wide linkage analysis has been performed in two large Swede-Finn kindreds recently identified in central Massachusetts. After analysing 300 microsatellite markers > 90% of the genome was excluded from linkage to the SCCD locus. We now report the chromosomal assignment of the gene for SCCD in both families to be 1p34.1-p36; the maximum multipoint lod-score was 8.48 in the interval between D1S214 and D1S503. From haplotype analysis, the SCCD locus lies in the 16 cM interval between markers D1S2663 and D1S228. Several candidate genes for SCCD have been localized to the 1p34.1-p36 interval.

The translocation t(8;16)(p11;p13) of acute myeloid leukaemia fuses a putative acetyltransferase to the CREB-binding protein

The recurrent translocation t(8;16)(p11;p13) is a cytogenetic hallmark for the M4/M5 subtype of acute myeloid leukaemia. Here we identify the breakpoint-associated genes. Positional cloning on chromosome 16 implicates the CREB-binding protein (CBP), a transcriptional adaptor/coactivator protein. At the chromosome 8 breakpoint we identify a novel gene, MOZ, which encodes a 2,004-amino-acid protein characterized by two C4HC3 zinc fingers and a single C2HC zinc finger in conjunction with a putative acetyltransferase signature. In-frame MOZ-CBP fusion transcripts combine the MOZ finger motifs and putative acetyltransferase domain with a largely intact CBP. We suggest that MOZ may represent a chromatin-associated acetyltransferase, and raise the possibility that a dominant MOZ-CBP fusion protein could mediate leukaemogenesis via aberrant chromatin acetylation.

Targeted gene walking by low stringency polymerase chain reaction: assignment of a putative human brain sodium channel gene (SCN3A) to chromosome 2q24-31

We have developed a low stringency polymerase chain reaction (LSPCR) to isolate the unknown neighboring region around a known DNA sequence, thus allowing efficient targeted gene walking. The method involves the polymerase chain reaction (PCR) with a single primer under conditions of low stringency for primer annealing (40 degrees C) for the first few cycles followed by more cycles at high stringency (55 degrees C). This enables the amplification of a targeted DNA fragment along with other nontargeted fragments. High stringency (55 degrees C) nested PCRs with end-labeled primers are then used to generate a ladder of radioactive bands, which accurately identifies the targeted fragment(s). We performed LSPCR on human placental DNA using a highly conserved sodium channel-specific primer for 5 cycles at 40 degrees C followed by 27 cycles at 55 degrees C for primer annealing. Subsequently, using higher stringency (55 degrees C) PCR with radiolabeled nested primers for 8 cycles, we have isolated a 0.66-kb fragment of a putative human sodium channel gene. Partial sequence (325 bp) of this fragment revealed a 270-bp region (exon) with homology to the rat brain sodium channel III alpha (RBIII) gene at the nucleotide (87%) and amino acid (92%) levels. Therefore, we putatively assign this sequence as a part of a gene coding the alpha-subunit of a human brain type III sodium channel (SCN3A). Using PCR on two human/rodent somatic cell hybrid panels with primers specific to this putative SCN3A gene, we have localized this gene to chromosome 2. Fluorescence in situ hybridization to human metaphase chromosomes was used to sublocalize the SCN3A gene to chromosome at 2q24-31. In conclusion, LSPCR is an efficient and sensitive method for targeted gene walking and is also useful for the isolation of homologous genes in related species.

Localization of a putative human brain sodium channel gene (SCN1A) to chromosome band 2q24

We have identified four putative human sodium channel gene sequences, 55 bp each, using the polymerase chain reaction (PCR) on total human placental DNA with primers specific for the cDNA sequence of the rat brain sodium channel I alpha (Scn1a) gene. One of these sequences was extended bidirectionally by genomic inverse-PCR to obtain a 1.6-kb fragment. Sequencing of this 1,556-bp fragment showed a 282-bp complete exon, which has 95% and 94% homology at the nucleotide and amino acid levels, respectively, with the rat Scn1a gene. We putatively assign this sequence as belonging to the gene coding the alpha-subunit of a human brain type I sodium channel (SCN1A). PCR on human x rodent somatic cell hybrids with primers derived from SCN1A localized this gene to chromosome 2. Fluorescence in situ hybridization to human metaphase chromosomes sublocalized the gene to chromosome band 2q24.

Aortic baroreflex control of heart rate during hypertensive stimuli: effect of fitness

We examined the aortic baroreflex control of heart rate (HR) in seven healthy young men of average fitness (AF) and seven of high fitness (HF). The fitness level was determined by maximal oxygen uptake (AF = 42.9 +/- 1.1, HF = 62.3 +/- 1.8 ml.kg-1.min-1). Aortic baroreflex control of HR was determined during a steady-state increase of mean arterial pressure (MAP; AF, +15.0 +/- 2.1 and HF, +18.3 +/- 0.8 mmHg) with phenylephrine (PE) infusion combined with positive neck pressure (NP; AF, 18 +/- 2.0 and HF, 20 +/- 0.8 mmHg) to counteract the increased carotid sinus pressure and with low levels of lower body negative pressure to counteract the increased central venous pressure. There was no group difference in the increased MAP or NP, nor was there stage difference in MAP within either group during PE infusion. However, the isolated cardiac-aortic baroreflex gains (i.e., delta HR/delta MAP) were significantly less in the HF (0.16 +/- 0.02 and 0.14 +/- 0.03 beats.min-1.mmHg-1) than in the AF (0.52 +/- 0.08 and 0.59 +/- 0.07 beats.min-1.mmHg-1) subjects at PE + NP and PE + NP + lower body negative pressure. We concluded that during steady-state increases in MAP, the sensitivity of aortic baroreflex control of HR was significantly less in the HF than in the AF subjects.

Somatostatin and epinephrine decrease insulin messenger ribonucleic acid in HIT cells through a pertussis toxin-sensitive mechanism

The sites of action for somatostatin and epinephrine to inhibit insulin secretion have been reported to be exclusively in the exocytotic pathway. We used HIT cells, a clonal line of beta-cells, to examine whether these hormones might have as yet undescribed, nonexocytotic effects on insulin messenger RNA levels. We observed that both somatostatin and epinephrine not only inhibit insulin secretion (53 +/- 2% and 50 +/- 2% of control, respectively) but also decrease insulin mRNA levels (54 +/- 5% and 66 +/- 5% of control, respectively) and insulin content in HIT cells (61 +/- 2% and 51 +/- 1% of control, respectively). The latter two effects are discernible by 24 h, maximal by 48 h, and are prevented by preincubation of HIT cells with pertussis toxin. These new observations suggest that somatostatin and epinephrine negatively modulate insulin availability through a guanine nucleotide binding protein-mediated step in insulin synthesis before the exocytotic pathway. This general mechanism may allow these two hormones to serve as more long-term regulators of insulin availability in distinction to their shorter term and more readily reversible inhibitory effects on the exocytotic pathway.