Subsequent Neutralization Research Articles

Identification of broadly neutralizing monoclonal antibodies against Crimean-Congo hemorrhagic fever virus

Despite the serious public health impact of Crimean-Congo hemorrhagic fever (CCHF), the efficacy of antivirals targeting the causative agent, CCHF virus (CCHFV), remains debatable. Neutralizing monoclonal antibodies (MAbs) targeting the CCHFV glycoprotein Gc have been reported to protect mice against challenge with the prototype CCHFV strain, IbAr10200. However, due to extensive sequence diversity of CCHFV glycoproteins, it is unknown whether these MAbs neutralize other CCHFV strains. We initially used a CCHF virus-like particle (VLP) system to generate 11 VLP moieties, each possessing a glycoprotein from a genetically diverse CCHFV strain isolated in either Africa, Asia, the Middle East, or southeastern Europe. We used these VLPs in biosafety level 2 conditions to efficiently screen MAb cross-neutralization potency. Of the 16 MAbs tested, 3 (8A1, 11E7, and 30F7) demonstrated cross-neutralization activity with most CCHF VLPs, with 8A1 neutralizing all VLPs tested. Although binding studies suggest that none of the MAbs compete for the same epitope, combining 11E7, 30F7, or both 11E7 and 30F7 with 8A1 had no additive effect on increasing neutralization in this system. To confirm our findings from the VLP system, the 3 MAbs capable of strain cross-neutralization were confirmed to effectively neutralize 5 diverse CCHFV strains in vitro. Passaging CCHFV strains in the presence of sub-neutralizing concentrations of MAbs did not generate escape mutants resistant to subsequent neutralization. This study demonstrates the utility of the VLP system for screening neutralizing MAbs against multiple CCHFV strains, and provides the first evidence that a single MAb can effectively neutralize a number of diverse CCHFV strains in vitro, which may lead to development of future CCHF therapeutics.

Copper, nickel, and zinc cations biosorption properties of Gram-positive and Gram-negative MerP mercury-resistance proteins

ABSTRACT The mercury resistance (mer) operon is present in a wide range of bacteria but relevant research has been conducted mainly on Gram-negative bacteria. We compared the heavy metal biosorption properties of Gram-positive and Gram-negative MerP, a key metal-binding transporter of the mer operon that scavenges heavy metal ions in the periplasm for subsequent neutralization in the cytoplasm by other Mer proteins. The MerP proteins of the Gram-positive Bacillus cereus RC607 and Gram-negative Pseudomonas aeruginosa K-62 strains in Escherichia coli strain BL21 were expressed to derive the recombinant strains BL21+MerPBc and BL21+MerPPa, respectively. The BL21+MerPBc having a higher affinity for Ni2+ and Cu2+ ions than that of Zn2+ ions was found, whereas BL21+MerPPa preferentially adsorbed Zn2+ ions over Ni2+ and Cu2+ ions. Furthermore, X-ray photoelectron spectroscopy revealed that regardless of the initial ion concentration, Zn, Ni, and Cu were mainly present as oxides in BL21+MerPBc but were mainly present as sulfides at low ion concentrations in BL21+MerPPa, with oxides primarily detected only when the initial ion concentrations were high. These findings were confirmed through X-ray absorption near edge structure and extended X-ray absorption fine structure analyses. These results have revealed that the heavy metal biosorption properties differ between Gram-positive and Gram-negative MerP proteins.

Kinetics study on the leaching of rare earth and aluminum from FCC catalyst waste slag using hydrochloric acid

During the industrial production of FCC catalyst, a large amount of FCC catalyst waste slag (FCC waste slag) containing rare earths and aluminum was generated. Landfill was commonly used to deal with the slag, which may cause serious environmental degradation and resources depletion. A novel hydrometallurgical process consisting of hydrochloric acid leaching and subsequent neutralization is proposed to recover rare earths and aluminum from the FCC waste slag. The effect of leaching temperature, hydrochloric acid concentration and leaching time on the metal extraction are studied. The leaching kinetics of aluminum and rare earths are also investigated. It is shown that 91.0% of La, 92.2% of Ce, and 94.2% of Al are extracted under optimum leaching conditions of hydrochloric acid concentration 9.00mol/L, solid to liquid ratio (S/L ratio) 0.05g/mL, leaching temperature 293K and leaching time 30min. The leaching behaviors of aluminum and rare earths follow a shrinking core model which can be expressed as 1−1−x13=kapt, and the overall leaching process is controlled by the surface chemical reaction. The activation energies for the leaching of Al, La, and Ce are 6.24, 9.71, and 9.10kJ/mol, respectively. Zeolite Na-Y and FCC catalyst presented in the FCC waste slag is leached with HCl individually. Only the FCC catalyst has a negative effect on the leaching of rare earths and aluminum. Finally, selective precipitation is employed to produce Al(OH)3 and RE(OH)3, which can be reused for the industrial production of FCC catalyst.

Influence of acid hydrolysis and dialysis of κ-carrageenan on its ice recrystallization inhibition activity

The objective of this study was to investigate the influence of molecular weight of κ-carrageenan on its ice recrystallization inhibition (IRI) activity. To reduce the molecular weight, acid hydrolysis with 0.1 M trifluoroacetic acid (TFA) at 80 °C or 0.1 M hydrochloric acid (HCl) at 60 °C was performed. In addition, molecular weight was reduced by dialyzing κ-carrageenan against demineralized water. It was demonstrated that IRI activity of κ-carrageenan decreases with decreasing molecular weight, which is contrary to previous studies. It was shown in our study that the different results may be attributed to an aggregation of κ-carrageenan molecules due to high NaCl concentration, originated from HCl and subsequent neutralization with NaOH. This aggregation causes a decrease in IRI activity. Furthermore, it was shown that the addition of a small amount of NaCl can lead to an increase in IRI activity of κ-carrageenan.

Sensitivity of transatlantic dust transport to chemical aging and related atmospheric processes

Abstract. We present a sensitivity study on transatlantic dust transport, a process which has many implications for the atmosphere, the ocean and the climate. We investigate the impact of key processes that control the dust outflow, i.e., the emission flux, convection schemes and the chemical aging of mineral dust, by using the EMAC model following Abdelkader et al. (2015). To characterize the dust outflow over the Atlantic Ocean, we distinguish two geographic zones: (i) dust interactions within the Intertropical Convergence Zone (ITCZ), or the dust–ITCZ interaction zone (DIZ), and (ii) the adjacent dust transport over the Atlantic Ocean (DTA) zone. In the latter zone, the dust loading shows a steep and linear gradient westward over the Atlantic Ocean since particle sedimentation is the dominant removal process, whereas in the DIZ zone aerosol–cloud interactions, wet deposition and scavenging processes determine the extent of the dust outflow. Generally, the EMAC simulated dust compares well with CALIPSO observations; however, our reference model configuration tends to overestimate the dust extinction at a lower elevation and underestimates it at a higher elevation. The aerosol optical depth (AOD) over the Caribbean responds to the dust emission flux only when the emitted dust mass is significantly increased over the source region in Africa by a factor of 10. These findings point to the dominant role of dust removal (especially wet deposition) in transatlantic dust transport. Experiments with different convection schemes have indeed revealed that the transatlantic dust transport is more sensitive to the convection scheme than to the dust emission flux parameterization. To study the impact of dust chemical aging, we focus on a major dust outflow in July 2009. We use the calcium cation as a proxy for the overall chemical reactive dust fraction and consider the uptake of major inorganic acids (i.e., H2SO4, HNO3 and HCl) and their anions, i.e., sulfate (SO42−), bisulfate (HSO4−), nitrate (NO3−) and chloride (Cl−), on the surface of mineral particles. The subsequent neutralization reactions with the calcium cation form various salt compounds that cause the uptake of water vapor from the atmosphere, i.e., through the chemical aging of dust particles leading to an increase of 0.15 in the AOD under subsaturated conditions (July 2009 monthly mean). As a result of the radiative feedback on surface winds, dust emissions increased regionally. On the other hand, the aged dust particles, compared to the non-aged particles, are more efficiently removed by both wet and dry deposition due to the increased hygroscopicity and particle size (mainly due to water uptake). The enhanced removal of aged particles decreases the dust burden and lifetime, which indirectly reduces the dust AOD by 0.05 (monthly mean). Both processes can be significant (major dust outflow, July 2009), but the net effect depends on the region and level of dust chemical aging.

Plant-expressed Hepatitis B core antigen virus-like particles: Characterization and investigation of their stability in simulated and pig gastro-intestinal fluids

Virus-like particles (VLPs) are potential oral vaccine candidates, as their highly compact structure may allow them to withstand the harsh conditions of the gastro-intestinal (GI) environment. Hepatitis B core antigen (HBcAg) is an immunogenic protein that assembles into 30 or 34nm diameter VLPs. Here, the stabilities of both the HBcAg polypeptide itself and the three-dimensional structure of the VLPs upon exposure to in vitro and ex vivo simulated gastric and intestinal fluids were investigated. Plant-expressed HBcAg VLPs were efficiently purified by sucrose density gradient and characterized. The purified VLPs did not show major chemical or physical instability upon exposure to the low pH conditions typically found in the stomach; however, they completely agglomerated upon acidification and subsequent pH neutralization. The HBcAg polypeptide was highly digested upon exposure to pepsin in simulated gastric fluids. HBcAg appeared more stable in both simulated and ex vivo intestinal fluids, where despite a partial digestion of the HBcAg polypeptide, the VLPs maintained their most immunogenic epitopes and their particulate conformation. These results suggest that HBcAg VLPs are likely to be unstable in gastric fluids, yet if the gastric instability could be bypassed, they could maintain their particulate structure and immunogenicity in intestinal fluids.

Effect of developed acidity and neutralization of milk on sensory, microstructural and textural changes in khoa prepared from cow and buffalo milk.

Khoa is a heat desiccated milk product which serves as base material for traditional dairy based Indian sweets. Sensory, textural and microstructural changes in khoa were studied to assess the effect of developed acidity and neutralization of milk. Noticeable changes were observed in sensory, textural and micro structural quality of khoa as affected by quality of milk. Lower hardness, springiness, cohesiveness and accordingly, gumminess and chewiness were observed in khoa manufactured using neutralized milk due to higher moisture retention as compared to control and acidic milk khoa. It was also evident from the Scanning Electron Microscopy that higher moisture retention in neutralized milk khoa resulted in elongation of native microstructure of khoa by suppressing the grain formation leading to smooth and plain surface while, developed acidity in milk resulted in greater granule formation in the resulting khoa causing shrinkage of native microstructure and acidic flavour in khoa. Similarly, acidification and subsequent neutralization of milk adversely affected sensory attributes of resulting khoa.

Hydrodechlorination of Tetrachloromethane over Palladium Catalysts Supported on Mixed MgF₂-MgO Carriers.

Pd/MgO, Pd/MgF2 and Pd/MgO-MgF2 catalysts were investigated in the reaction of CCl4 hydrodechlorination. All the catalysts deactivated in time on stream, but the degree of deactivation varied from catalyst to catalyst. The MgF2-supported palladium with relatively large metal particles appeared the best catalyst, characterized by good activity and selectivity to C2-C5 hydrocarbons. Investigation of post-reaction catalyst samples allowed to find several details associated with the working state of hydrodechlorination catalysts. The role of support acidity was quite complex. On the one hand, a definite, although not very high Lewis acidity of MgF2 is beneficial for shaping high activity of palladium catalysts. The MgO-MgF2 support characterized by stronger Lewis acidity than MgF2 contributes to very good catalytic activity for a relatively long reaction period (~5 h) but subsequent neutralization of stronger acid centers (by coking) eliminates them from the catalyst. On the other hand, the role of acidity evolution, which takes place when basic supports (like MgO) are chlorided during HdCl reactions, is difficult to assess because different events associated with distribution of chlorided support species, leading to partial or even full blocking of the surface of palladium, which plays the role of active component in HdCl reactions.

Synthesis and investigation of the physical-chemical properties of 2-(5-((theophylline-7'-yl)methyl)-4-methyl-4H-1,2,4-triazole-3-ylthio)acetic acid salts

At this stage of modern science development scientists get a lot of questions in the field of medicine and pharmacy. The study and search of new ways for synthesis of high-performance and low-toxic substances is one of the most important questions among them. Special attention is paid to 1,2,4-triazole and xanthine. On their basis some medical drugs have been previously made and are widely used in nowadays medicine. The aim of this work was the synthesis of salts of 2-(5-((theophylline-7'-yl)methyl)-4-methyl-4 H -1,2,4-triazole-3-ylthio)acetic acid and the study of their properties. Methods and results . Theophylline has been selected as starting material. Through a number of stages 7'-((3-thio-4-methyl-4 H -1,2,4-triazole-5-yl)methyl)theophylline has been obtained. Salts with organic and inorganic bases have been obtained by the neutralization reaction in aqueous medium. The structure of the compounds has been confirmed with elemental analysis on Elemental Vario EL cube (Elementar Analysensysteme, Germany), IR spectra (4000–400 cm -1 ) have been taken off the module ALPHA-T of Bruker ALPHA FT-IR spectrometer (Bruker optics, Germany). Gear Liquid Chromatography System with Mass spectrometric detector (Agilent Technologies, USA): Agilent 1260 Infinity HPLC System; single quadrupole mass spectrometer Agilent 6120 with electrospray ionization (ESI); Open LAB CDS Software. The formation of salts has been confirmed by the signals corresponding to protonated amines. Conclusions. The optimal conditions of obtaining salts of 2-(5-((theophylline-7'-yl)methyl)-4-methyl-4 H -1,2,4-triazole-3-ylthio)acetic acid with inorganic and organic bases have been determined. Corresponding carboxylic acid has been obtained by interaction of the resulting thiol with monochloroacetic acid in aqueous solution with double quantity of alkali and subsequent neutralization by hydrochloric acid. It has been confirmed that the greatest outputs of the reaction products were observed while using water as the solvent and its further replacement of propan-1-ol or acetone. The general physical-chemical properties of the obtained compounds have been studied and a preliminary study of biological activity has been done.

Roles of iron species and pH optimization on sewage sludge conditioning with Fenton's reagent and lime

Conditioning sewage sludge with Fenton's reagent could effectively improve its dewaterability. However, drawbacks of conditioning with Fenton's reagent are requirement of acidic conditions to prevent iron precipitation and subsequent neutralization with alkaline additive to obtain the pH of the filtrate close to neutrality. In this study, roles of pH were thoroughly investigated in the acidification pretreatment, Fenton reaction, and the final filtrate after conditioning. Through the response surface methodology (RSM), the optimal dosages of H2SO4, Fe2+, H2O2, and lime acted as a neutralizer were found to be 0 (no acidification), 47.9, 34.3 and 43.2 mg/g DS (dry solids). With those optimal doses, water content of the dewatered sludge cakes could be reduced to 55.8 ± 0.6 wt%, and pH of the final filtrate was 6.6 ± 0.2. Fenton conditioning without initial acidification can simplify the conditioning process and reduce the usage of lime. The Fe3+ content in the sludge cakes showed a close correlation with the dewaterability of conditioned sludge, i.e., the water content of sludge cakes, SRF (specific resistance to filtration), CST (capillary suction time), bound water content, and specific surface area. It indicated that the coagulation by Fe3+ species in Fenton reaction could play an important role, compared to traditional Fenton oxidation effect on sludge conditioning. Thus, a two-step mechanism of Fenton oxidation and Fe(III) coagulation was proposed in sewage sludge conditioning. The mechanisms include the following: (1) extracellular polymeric substances (EPS) were firstly degraded into dissolved organics by Fenton oxidation; (2) bound water was converted to free water due to degradation of EPS; (3) the sludge particles were disintegrated into small ones by oxidation; (4) Fe3+ generated from Fenton reaction acted as a coagulant to agglomerate smaller sludge particles into larger dense particles with less bond water; (5) finally, the dewatered sludge cakes were obtained, with less small pores (1–10 nm) that contributed to water affinity, but with more large pores (>10 nm) that contributed to a permeable, rigid lattice structure. Morphology of the Fenton-conditioned sludge cake exhibited a porous structure. The estimated cost of the composite conditioner, Fenton's reagent and lime, is USD$ 43.8/t DS, which is less than that of ferric chloride and lime (USD$ 54/t DS). Furthermore, pH of the final filtrate using this composite conditioner is about 6.6. Comparatively, that using ferric chloride and lime is as high as 12.4.

Experimental Model System to Study pH Shift-Induced Aggregation of Monoclonal Antibodies Under Controlled Conditions.

To present a convenient screening method for evaluating additive effects on the renaturation of an acid-exposed monoclonal antibody (mAb). The assay involves brief incubation of a mAb at acidic pH and subsequent neutralization in the absence or presence of additive to induce mainly aggregation. An increase in absorbance depicted aggregation. The recorded aggregation data traces were fitted with a nucleation-autocatalytic growth model for the extraction of kinetic parameters. All kinetic data traces were fitted successfully with the selected model and the adjusted R square values were greater than 0.99. Trehalose had strongly stabilizing, proline mildly stabilizing and trimethylamine oxide had destabilizing effects on both the nucleation and growth phase of the reaction. Histidine was strongly stabilizing but was limited by its poor solubility. The results demonstrate the suitability of the experimental mAb aggregation system and the nucleation-autocatalytic growth fit in the screening and quantification of additive effects on the renaturation of an acid-exposed mAb respectively. This will aid the investigation and derivation of quantitative structure-activity relationships of additive effects on mAb solubility.

Separation of hemicellulose-derived saccharides from wood hydrolysate by lime and ion exchange resin

A combined process of lime treatment and mixed bed ion exchange was proposed to separate hemicellulose-derived saccharides (HDS) from prehydrolysis liquor (PHL) of lignocellulose as value added products. The optimization of lime treatment achieved up to 44.2% removal of non-saccharide organic compounds (NSOC), mainly colloidal substances, with negligible HDS degradation at 0.5% lime level and subsequent neutralization by phosphoric acid. The residual NSOC and calcium ions in lime-treated PHL were eliminated by mixed bed ion exchange. The breakthrough curves of HDS and NSOC showed selective retention toward NSOC, leading to 75% HDS recovery with 95% purity at 17 bed volumes of exchange capacity. In addition, macroporous resin showed higher exchange capacity than gel resin as indicated by the triple processing volume. The remarkable selectivity of the combined process suggested the feasibility for HDS separation from PHL.

Evaluation of Two Sets of Sorghum Bagasse Samples as the Feedstock for Fermentable Sugar Recovery via the Calcium Capturing by Carbonation (CaCCO) Process.

: Sorghum bagasse samples from two sets (n6 and bmr6; n18 and bmr18) of wild-type and corresponding “brown midrib” (bmr) mutant strains of sweet sorghum were evaluated as the feedstock for fermentable sugar recovery via the calcium capturing by carbonation (CaCCO) process, which involves Ca(OH)2 pretreatment of bagasse with subsequent neutralization with CO2 for enzymatic saccharification. Saccharification tests under various pretreatment conditions of the CaCCO process at different Ca(OH)2 concentrations, temperatures or residence periods indicated that bmr strains are more sensitive to the pretreatment than their counterparts are. It is expected that variant bmr6 is more suitable for glucose recovery than its wild-type counterpart because of the higher glucan content and better glucose recovery with less severe pretreatment. Meanwhile, bmr18showed higher scores of glucose recovery than its counterpart did, only at low pretreatment severity, and did not yield higher sugar recovery under the more severe conditions. The trend was similar to that of xylose recovery data from the two bmr strains. The advantages of bmr strains were also proven by means of simultaneous saccharification and fermentation of CaCCO-pretreated bagasse samples by pentose-fermenting yeast strain Candida shehatae Cs 4R. The amounts needed for production of 1 L of ethanol from n6, bmr6, n18, and bmr18samples were estimated as 4.11, 3.46, 4.03, and 3.95 kg, respectively. The bmr strains seem to have excellent compatibility with the CaCCO process for ethanol production, and it is expected that integrated research from the feedstock to bioprocess may result in breakthroughs for commercialization.

Monoclonal Antibodies Follow Distinct Aggregation Pathways During Production-Relevant Acidic Incubation and Neutralization.

Aggregation aspects of therapeutic monoclonal antibodies (mAbs) are of common concern to the pharmaceutical industry. Low pH treatment is applied during affinity purification and to inactivate endogenous retroviruses, directing interest to the mechanisms of acid-induced antibody aggregation. We characterized the oligomerization kinetics at pH 3.3, as well as the reversibility upon neutralization, of three model mAbs with identical variable regions, representative of IgG1, IgG2 and IgG4 respectively. We applied size-exclusion high performance liquid chromatography and orthogonal analytical methods, including small-angle X-ray scattering and dynamic light scattering and supplemented the experimental data with crystal structure-based spatial aggregation propensity (SAP) calculations. We revealed distinct solution behaviors between the three mAb models: At acidic pH IgG1 retained monomeric, whereas IgG2 and IgG4 exhibited two-phase oligomerization processes. After neutralization, IgG2 oligomers partially reverted to the monomeric state, while on the contrary, IgG4 oligomers tended to aggregate. Subclass-specific aggregation-prone motifs on the Fc fragments were identified, which may lead to two distinct pathways of reversible and irreversible aggregation, respectively. We conclude that subtle variations in mAb sequence greatly affect responses towards low-pH incubation and subsequent neutralization, and demonstrate how orthogonal biophysical methods distinguish between reversible and irreversible mAb aggregation pathways at early stages of acidic treatment.

Synthesis of δ-Bi2O3 microflowers and nanosheets using CH3COO(BiO) self-sacrifice precursor

Bismuthyl acetate (CH3COO(BiO); BiOAc) dispersed nanosheets and flower-like hierarchical architectures were easily prepared from the reaction between Bi2O3 and glacial acetic acid (HAc) or Bi(NO3)3·5H2O and HAc and subsequent neutralization by Na2CO3 under ambient condition. The BiOAc could be completely soluble in HAc-water (0.04–250v/v) mixture but insoluble in pure HAc or water, and thus could be collected as a novel photocatalyst candidate because of its availability, non-toxicity and cheapness. Rhodamine B (RhB) could be completely degraded over BiOAc nanosheets within 4min of UV light irradiation. Especially, BiOAc nanosheets and microflowers could be converted to δ-Bi2O3 by thermal treatment, while the morphology remained unchanged. The as-prepared δ-Bi2O3 exhibited enhanced photocatalytic activity for RhB degradation under simulated sunlight illumination owing to its suitable band gap energy.

Determination of Free and Total Carnitine and Choline in Infant Formulas and Adult Nutritional Products by UPLC/MS/MS: Single-Laboratory Validation, First Action 2014.04.

A single-laboratory validation (SLV) has been performed for a method that simultaneously determines choline and carnitine in nutritional products by ultra performance LC (UPLC)/MS/MS. All 11 matrixes from the AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) were tested. Depending on the sample preparation, either the added (free, with a water dilution and filtering) or total (after microwave digestion at 120°C in nitric acid and subsequent neutralization with ammonia) species can be detected. For nonmilk containing products, the total carnitine is almost always equal to the free carnitine. A substantial difference was noted between free and total choline in all products. All Standard Method Performance Requirements for carnitine and choline have been met. This report summarizes the material sent to the AOAC Expert Review Panel for SPIFAN nutrient methods for the review of this method, as well as some additional data from an internal validation. The method was granted AOAC First Action status for carnitine in 2014 (2014.04), but the choline data are also being presented. A comparison of choline results to those from other AOAC methods is given.

Low energy, organic solvent-free co-assembly of zein and caseinate to prepare stable dispersions

Water-insoluble zein (corn prolamins) has great potential for use as delivery systems. In this study, stable zein nanoparticle dispersions were produced using a pH-cycle method to form complexes with sodium caseinate (NaCas) without using an organic solvent. NaCas was mixed with zein at pH 11.5 and the subsequent neutralization to pH 7.0 enabled the co-assembly of zein and NaCas. The mean hydrodynamic diameter of spherical nanoparticles was smaller than 100 nm based on dynamic light scattering, scanning electron microscopy, and atomic force microscopy. The nanodispersions were stable during 30-day storage at 4 °C. The freeze-dried sample showed excellent re-dispersibility. The current study showed the promise of this novel method to prepare zein nanoparticles for applications such as delivery systems.

Quality Improvement of Sugar by Two Factor Factorial Experimentation in Optimization of Quantity of Lime and Sulphur Added in the Juice Sulphitation Process of a Sugar Plant

Sugar industry is one of the vital sectors in improving the economy of any country. But, sugar industries are striving hard to increase their profitability due to high cost of sugar production accompanied with low selling price. Without resorting to radical restructuring of sugar plant, but through proper planning, annual savings can be improved. One of the artifices to address this issue is through improving the quality of sugar so that selling price can be increased which in turn generates more revenue to the plant. The Juice Sulphitation process, as applied in the manufacturing of sugar, is a subject of such wide-spread interest. The mixed juice from the mills contains soluble and non-soluble suspended non-sugars. These impurities are to be precipitated by the judicious and controlled addition of Milk of Lime (CaO) and subsequent neutralization by Sulphur Dioxide (SO2) gas. This paper attempts to improve the quality of sugar by optimizing the quantity of lime (in the form of milk of lime) and sulphur (in the form of SO2 gas) added in the juice sulphitation process of a sugar plant. Two factor factorial experimentation was adopted to obtain an optimal combination of lime and sulphur quantities. Data of Transmittancy test on sugar juice was collected by varying the quantities of lime and sulphur. Analysis of Variance (ANOVA) table was plotted which explored the significant effects of individual treatments and interaction effects. Further to this, comparison of treatment means was carried out to find out the best treatment combination values for achieving the optimal quality of sugar from sugarcane.

Development of natural fibre reinforced flame retarded epoxy resin composites

Natural hemp fabric reinforced epoxy resin composites were prepared in flame retarded form. Fabrics were treated in three ways: the first method involved the immersion of preheated fabric into cold phosphoric acid solution (allowing penetration into the capillaries of the fibres) and subsequent neutralization, the second way was a reactive modification carried out with an aminosilane-type coupling agent, while the third treatment combined the sol–gel surface coating with the first method. The introduction of phosphorus into the reinforcing fibres decreased the flammability not only of the hemp fabrics, but also of the epoxy composites made thereof. By applying amine-type phosphorus-containing curing agent (TEDAP) in combination with the treated fabrics, V-0 UL-94 rating was achieved. Composites of unexpectedly improved static and dynamic mechanical properties could be prepared only when the simple phosphorous fibre treatment and reactive flame retardancy was combined.

HdeB Functions as an Acid-protective Chaperone in Bacteria

Enteric bacteria such as Escherichia coli utilize various acid response systems to counteract the acidic environment of the mammalian stomach. To protect their periplasmic proteome against rapid acid-mediated damage, bacteria contain the acid-activated periplasmic chaperones HdeA and HdeB. Activation of HdeA at pH 2 was shown to correlate with its acid-induced dissociation into partially unfolded monomers. In contrast, HdeB, which has high structural similarities to HdeA, shows negligible chaperone activity at pH 2 and only modest chaperone activity at pH 3. These results raised intriguing questions concerning the physiological role of HdeB in bacteria, its activation mechanism, and the structural requirements for its function as a molecular chaperone. In this study, we conducted structural and biochemical studies that revealed that HdeB indeed works as an effective molecular chaperone. However, in contrast to HdeA, whose chaperone function is optimal at pH 2, the chaperone function of HdeB is optimal at pH 4, at which HdeB is still fully dimeric and largely folded. NMR, analytical ultracentrifugation, and fluorescence studies suggest that the highly dynamic nature of HdeB at pH 4 alleviates the need for monomerization and partial unfolding. Once activated, HdeB binds various unfolding client proteins, prevents their aggregation, and supports their refolding upon subsequent neutralization. Overexpression of HdeA promotes bacterial survival at pH 2 and 3, whereas overexpression of HdeB positively affects bacterial growth at pH 4. These studies demonstrate how two structurally homologous proteins with seemingly identical in vivo functions have evolved to provide bacteria with the means for surviving a range of acidic protein-unfolding conditions.