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In this paper, we consider a free boundary problem modeling tumor growth in the presence of drugs with high molecular mass. This model is an improvement of a similar model proposed by Byrne and Chaplain ((1995) [1] ). The novelty in our model is to better account for the fast diffusion coefficient of nutrients and the slow diffusion coefficient of drugs with high molecular mass, which is more realistic. The introduction of these terms, however, makes the analysis of linear stability more challenging in the spectral analysis of the linearized operator. A significant challenge is the lack of explicit expressions for their locations. We shall give a complete classification of parameters λ σ , λ β , τ, σ ‾ , β ‾ and σ ˜ under which either (i) there exist exact one radially symmetric stationary solution ( σ S , β S , p S ) with the boundary r = R 2 , or (ii) exact two solutions ( σ S , β S , p S ) with the boundary r = R 1 or r = R 2 ( R 1 R 2 ), or (iii) no solutions. We further show that for all γ μ > 0 , ( σ S , β S , p S , R 1 ) is linearly unstable under non-radially symmetric perturbations, while there exists a threshold value c ⁎ ⩾ 0 such that ( σ S , β S , p S , R 2 ) is linearly stable for γ μ > c ⁎ and linearly unstable for γ μ ∈ ( 0 , c ⁎ ) . As a biological implication, we discuss the positive and negative effects of drugs with high molecular mass on tumor growth and get a high risk region for drugs. Our results provide a strategy for tumor treatment.

Although there is increasing awareness of the potential role of organic N compounds (ON) in plant nutrition, its implications for soil organic matter (SOM) stabilization have hardly been discussed yet. The aim of this paper is therefore to gather the newest insights into plant use of high molecular mass organic N, its effect on root growth and anatomy, and finally, to discuss the implications of plant use of organic N for SOM stabilization. I propose that modified root growth due to the uptake of ON provides greater root and root-associated microbe input, leading to enhanced SOM stabilization. Finally, I discuss the role of the proposed framework in different ecosystems, and I encourage future studies combining plant N nutrition and SOM stabilization.

Models capturing the growth of polycyclic aromatic compounds (PACs) and nanoparticles in combustion have always faced a large degree of uncertainty due to the paucity of detailed direct experimental validation. In particular, data on molecular structures, chemical composition, size, cross-linking, and aliphatic chains is still very limited. In the past few years, we have developed an atomistic code, SNapS2, that models the formation of PACs in combustion conditions, providing information on the chemical and structural evolution of these compounds. In this paper, we present a detailed analysis of the compounds formed in a premixed ethylene-air flame that was previously characterized experimentally by AFM (Commodo et al. 2019). The comparison is based on molecular structures and extends to other properties of PACs. The results demonstrate that SNapS2 is able to capture the vast array of PACs in terms of a large variety of functional groups. The simulations, confirmed to a large extent by the experimental data, show the presence of different types of oxygenated (e.g., phenol, ketone) and cyclic (acenaphthylene-type, acenaphthene-type, and fluorene-type five-membered rings) functional groups. Moreover, the structures that were not observed in the simulations (indane-type five-membered rings or six-membered rings containing oxygen) are missing due to the lack of formation pathways, highlighting the fact that important kinetic mechanisms are still missing in the literature. Finally, we observed that a preponderant number of high molecular mass PACs are curved, which may have an impact on their aggregation and sampling. Overall, while some discrepancies remain due to the inherent limitation of the model and the AFM techniques, this work demonstrates the unique capabilities of the SNapS2 code to provide insights on the structures and chemical pathways of PACs.

New aspects of human mucosal cavity protection systems are under consideration. On the basis of own data it was suggested that mucosal cavities function as mucosal organs. New players of mucosal organ were proposed. They included system probiotic lectins and probiotic microorganisms, and system synthetic polymeric multivalence pattern glycoconjugates. Lectins and glycoconjugates (mucin-like or imitating, antigens, polysaccharides and other high molecular mass metabolites and postbiotics) were suggested to communicate to other glycoconjugates-recognizing molecules and receptors of the human higher hierarchic protection systems. Concept of functioning mucosal organs is supported by own proposals, strategies, approaches, methods and algorithms. The data are useful for constructing biotope ordered pro/synbiotic microbiocenoses for application in medical biotechnology.

Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic compounds which are emitted through incomplete combustion of organic materials, fossil fuels, consumption of processed meat, smoked food, and from various industrial activities. High molecular mass and mobility make PAHs widespread and lethal for human health. A cellular system in human detoxifies these toxicants through specialized enzymatic machinery called xenobiotic-metabolizing (CYP450) and phase-II (GSTs) enzymes (XMEs). These metabolizing enzymes include cytochromes P450 family (CYP1, CYP2), glutathione s-transferases, and ALDHs. Gene polymorphisms in XMEs encoding genes can compromise their metabolizing capacity to detoxify ingested carcinogens (PAHs etc.) that may lead to prolong and elevated exposure to ingested toxicants and may consequently lead to cancer. Moreover, PAHs can induce cancer through reprograming XMEs' gene functions by altering their epigenetic markers. This review article discusses possible interplay between individual's gene polymorphism in XMEs' genes, their altered epigenetic markers, and exposure to PAHs in cancer susceptibility in Pakistan.

Naked mole-rat (NMR), the longest-living rodent, produces very-high-molecular-mass hyaluronan (vHMM-HA), compared to other mammalian species. However, it is unclear if exceptional polymer length of vHMM-HA is important for longevity. Here, we show that vHMM-HA (>6.1 MDa) has superior cytoprotective properties compared to the shorter HMM-HA. It protects not only NMR cells, but also mouse and human cells from stress-induced cell-cycle arrest and cell death in a polymer length-dependent manner. The cytoprotective effect is dependent on the major HA-receptor, CD44. We find that vHMM-HA suppresses CD44 protein-protein interactions, whereas HMM-HA promotes them. As a result, vHMM-HA and HMM-HA induce opposing effects on the expression of CD44-dependent genes, which are associated with the p53 pathway. Concomitantly, vHMM-HA partially attenuates p53 and protects cells from stress in a p53-dependent manner. Our results implicate vHMM-HA in anti-aging mechanisms and suggest the potential applications of vHMM-HA for enhancing cellular stress resistance., Naked mole rats are the longest-lived rodents and produce very-high-molecular-mass hyaluronan (vHMM-HA). Here the authors show that naked mole rat vHMM-HA is better at protecting mouse and human cells from cell cycle arrest and cell death, compared to the high-molecular-mass hyaluronan produced by these species.

The review initially provides a short introduction to prostate cancer (PCa) incidence, mortality, and diagnostics. Next, the need for novel biomarkers for PCa diagnostics is briefly discussed. The core of the review provides details about PCa aetiology, alternative biomarkers available for PCa diagnostics besides prostate specific antigen and their biosensing. In particular, low molecular mass biomolecules (ions and metabolites) and high molecular mass biomolecules (proteins, RNA, DNA, glycoproteins, enzymes) are discussed, along with clinical performance parameters.

The preparation of antibody drug conjugates (ADCs), particularly those containing hydrophobic payloads, may promote aggregate formation. The aggregate (high molecular mass species, HMMS) is an impurity that must be controlled in the final drug substance and drug product formulation to meet product safety and efficacy. Although there are numerous methods designed to mitigate protein aggregation, some of the reasons for the formation of aggregates in ADCs are unique and specific to the synthetic preparation and structure of each conjugate. Proper structural characterization and identification of causes of aggregation are key to improving the process for preparation of ADCs for minimizing aggregate formation. In this article, we have characterized aggregates generated during the preparation of a lysine conjugate, gemtuzumab ozogamicin, prepared from an IgG4 antibody (hP67.6) and a calicheamicin-based linker-payload. Using analytical and biophysical techniques, structural details of the aggregates formed in t...

International audience; A low-cost synthetic 2-cyano-3-(2-thienyl)acrylic acid (CTA) is developed as a new MALDI matrix for the analysis of various classes of compounds such as lipids (e.g., fatty acids), peptides, proteins, saccharides, natural products (i.e., iridoids), PEGs, and organometallics in the positive-ion mode. The difficulty in the analysis of high molecular mass PEGs was overcome by using CTA as matrix even at low concentrations. Both high molecular mass proteins and peptides were successfully analyzed using CTA. The mass spectra of all of the studied analytes with CTA showed high signal-to-noise (S/N) ratios and spectral resolutions when compared to other conventional matrices such as SA, DHB, DT, and HCCA. However, in the case of peptide analysis with CTA, the resulting mass spectra are found to be similar to that of the well-established HCCA matrix. On the basis of the physicochemical properties of the analytes, the CTA works as a proton/cation or electron-transfer matrix. It proves that the CTA can be used as a common matrix for the analysis of majority classes of analytes instead of using a specific matrix for the particular class of analytes. Further, the CTA provides an advantage in the analysis of unknown samples as it rules out ambiguity in the selection of particular matrix and it may also offer a complete profile of the tissue surface in the MALDI-imaging experiments.

Complex (hetero)polysaccharides, glycosaminoglycans (GAGs), are fundamental biomacromolecules for all living organisms having important biological and pathophysiological roles. Moreover, in the form of native or depolymerized biomolecules, they are active pharmaceutical and nutraceutical agents after extraction and purification from animal sources. Capillary electrophoresis (CE) is applied in many different biological, pharmacological, and nutraceutical fields, clearly showing evidence of the importance of this analytical method in glycosciences. Thanks to its versatility in separation and detection modes, CE may be applied for the analysis and quantification of intact high molecular mass heteropolysaccharides as well as their low molecular weight derivatives up to derived oligosaccharides, disaccharides, and monosaccharides, as single species but also in mixtures. As discussed in the present review and largely illustrated in the current scientific literature, CE may be one of the analytical techniques most useful in quality control laboratories of pharmaceutical and nutraceutical companies for the determination of GAGs’ purity and quality in raw material and finished products.

Plastics are mixtures of organic polymers of high molecular mass and other additives. The etymology of the word “Polymer” derives from two Greek words, ‘Poly’, which means many (numerous), and ‘Meros’ which means units (parts). Monomers are the chemical building blocks of polymers. This chapter deals with the synthesis of the most interesting thermoplastic and thermosetting biopolymers using food waste as a low-cost feedstock. The properties and commercial importance of various bioplastics are described. Copolymerization and blending will be shortly presented. The mechanical and physico-chemical characterization of bioplastics will be dealt with in Chaps. 8 and 9.

Using TiOiPr4 with a pyrazole ligand for one-pot LA polymerization improved catalytic activity compared with using TiOiPr4 only. At 60 °C, TiOiPr4 with furPz exhibited a higher catalytic activity (approximately 3-fold) than TiOiPr4. At room temperature, TiOiPr4 with BuPz exhibited a higher catalytic activity (approximately 17-fold) than TiOiPr4. High molecular mass PLA (MnGPC = 51 100, and Đ = 1.10) could be produced by using TiOiPr4 with furPz in melt polymerization ([TiOiPr4] : [furPz] = 1000 : 1 : 1 at 100 °C, 240 min). The crystal structure of MePz2Ti2OiPr7 revealed the cooperative activation between two Ti atoms during LA polymerization.

Hypnale hypnale (hump-nosed pit viper) is a venomous pit viper species found in the Western Ghats of India and Sri Lanka. Due to the severe life-threatening envenomation effects induced by its venom components, Hypnale hypnale has been classified under ‘category 1’ of medically important snake species by the World Health Organization. Since there are no specific antivenoms available to combat its envenomation in India, the only option available is to administer Indian polyvalent antivenoms. However, the cross-neutralization potential of the commercially available polyvalent antivenoms on Indian Hypnale hypnale venom has not been explored so far. In the current study, in vitro immunological cross-reactivity of Hypnale hypnale venom towards various Indian polyvalent antivenoms were assessed using end point titration ELISA and Western blotting. A three to four-fold increase in EC50 values were obtained for Hypnale hypnale venom towards all the antivenoms tested. Observation of minimal binding specificities towards low and high molecular mass venom proteins are suggestive of the fact that commercially available polyvalent antivenoms failed to detect and bind to the antigenic epitopes of considerable number of proteins present in Hypnale hypnale venom. This highlights the importance of including Hypnale hypnale venom in the immunization mixture while raising antivenoms.

Thermophoresis is the migration of dispersed molecules or particles in an inhomogeneous temperature field. It has been associated with various nonequilibrium phenomena ranging from stratified oil reservoirs to prebiotic evolution and the origin of life. The thermophoretic velocity is difficult to predict and appears almost random. We show that, in the case of strongly asymmetric mixtures with high molecular mass ratios of the solute to the solvent, it unexpectedly assumes a universal value once the trivial influence of the viscosity has been factored out. This asymptotic behavior is surprisingly universal and a general property of many highly asymmetric molecular mixtures ranging from organic molecules in n-alkanes to dilute solutions of high polymers. A quantitative explanation is provided on the basis of the asymmetric limit of the pseudoisotopic Soret effect.

Marine organisms have been proven to be a valuable source of bioactive compounds. Among them, we highlight the sulfated galactans (SGs) from seaweeds, which besides being massively exploited as industrial thickening and gelling agents (agarans and carrageenans), have also shown promising pharmacological properties. Investigations on the non-agaran/-carrageenan SG from the red algae Bothryocladia occidentalis (SGBo) have demonstrated clear correlations between physical-chemical features and biological activities. SGBo is composed of 2,3-disulfated (~33%) or 2-sulfated (33%) α-D-galactose linked to non- or 2-sulfated β-D-galactose repetitive disaccharide units. The notable serpin-dependent/-independent anticoagulant activity of SGBo (~130 international units [IU]/mg) is higher than those of other SGs containing less 2,3-disulfated α-D-galactose units and their low-molecular-weight derivatives, and thus is directly correlated to its high molecular mass (>200 kDa) and sulfation pattern. Although SGBo has antithrombotic efficacy equivalent to heparin and decreased bleeding potential at low-doses, high-doses substantially increase thrombus formation in animal models. Such an odd dose-dependent dual antithrombotic/prothrombotic activity has been attributed to the ability of SGBo to activate factor XII. In addition to anticoagulant properties, SGBo also exerts antimalarial, antileishmanial and antiophidic activities, and, therefore, has a remarkable potential for the research and development of novel drugs.

The solventless reaction of diisopropylaminoborane with n-butylamine, at room temperature, leads to a mixture of B(sp2) H-, B(sp3) H2 -, and B(sp3) H3 -containing species. At low temperature, the reaction outcome is completely modified, thus leading selectively to the formation of high-mass polybutylaminoborane. When extended to a variety of primary amines, under solventless conditions and at low temperature, this reaction provides a new, efficient, and direct metal-free access to high-molecular-mass polyaminoboranes in good to high yields under mild reaction conditions.

The variations of extraction characteristics towards plutonium of “30% TBP – Isopar-M – HNO 3 ” system under irradiation with accelerated electrons in cyclic mode of extractant use were investigated. It was found that the residual concentration of plutonium in the extractant after stripping over 15 cycles (520 kGy dose) increases twice, and during the regeneration step increases by 4–6 times. At the same time, the Pu distribution coefficient varies only slightly in cyclic mode. The formation of products with high molecular mass during hydrolysis leads to an increase in viscosity of the organic phase and hindering of the phase separation.

Soybean is considered an important source of human food and animal feed. Okara and tofu whey are the main by-products of soymilk and tofu production. The distribution of enzymes β-amylase and lipoxygenase (Lox) from six soybean genotypes in protein extracts of okara and tofu as well as in soymilk and tofu whey was assessed. SDS-electrophoretic results showed that production process significantly affected high molecular mass protein fractions of soybean by-products. Low amounts of Lox in soymilk were registered, while in okara protein extracts and tofu whey this enzyme was present in trace. In tofu protein extracts, Lox was registered in higher quantity that might be the result of the aggregation process during formation of the tofu gel. Content of β-amylase in all soy protein products was high and similar to the content in soybean genotype. Content of β-amylase in okara depended on respective soybean genotype. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR 31022 and the EU FP7 project Grant Agreement No.316004 (REGPOT-AREA]

We present and analyse 12CO, 13CO and C18O(2-1) ALMA observations of the C1 globule inside the Helix nebula in order to determine its physical properties. Our findings confirm the molecular nature of the globule with a multi-peak structure. The 12CO line has a high optical depth of about 10. The derived 12C/13C ratio of 10 and 16O/18O ratio of 115 are not in agreement with the expected isotopic ratios of carbon-rich AGB stars. Assuming that the 12CO optical depth has been underestimated, we can find a consistent fit for an initial mass of 2 Msol. We obtain a molecular mass of 2x10-4 Msol for the C1 globule, which is much higher than its mass in the literature. Clumping could play a role in the high molecular mass of the knot. The origin of the tail is discussed. Our findings show that the most probable model appears to be shadowing. The kinematics and molecular morphology of the knot are not consistent with a wind-swept model and the photoevaporation model alone is not enough to explain the nature of the globule. We propose an integrated model where the effects of the photoevaporation, the stream and shadowing models are all considered in the tail shaping process., 17 pages, 12 figures, accepted for publication in MNRAS

Plastic is made of synthetic organic polymers of high molecular mass, which are usually produced through the polymerization of monomers derived from oil, gas or coal. In the second half of the 20th Century, its production expanded, which resulted in the elaboration of various products such as lightweight, versatile, durable, formable and corrosion- and flameresistant plastic types. Today, plastic products can be found in diverse fields, such as healthcare, energy generation and automotive industries, construction, electronics, packaging and textiles, as well as at the household level. In the last few decades, global production of plastic has increased by 500% (more than 322 million tons in 2016) and almost 10% of the annual production has ended up into the. Plastic waste is transported to landfills, and a part of it is carried away by winds. Together with carelessly discharged plastic (e.g. packaging and construction materials), plastic waste enters the environment continuously. Historically, floating plastic has been reported in the Northern Hemisphere subtropical gyres since the early 1970s in the North Atlantic, North Pacific and in the Southern Hemisphere. These gyres are formed by circular surface currents created by Ekman currents, driven by local wind, and the Coriolis force (spinning of the Earth). Across the globe, several monitoring campaigns are operating, such as the Tara expedition, which observed that 88% of surface waters presented microplastics even in the most remote places.

The segmental interactions derived from the application of the model to all of the blends described above are positive and therefore may be termed “repulsive.” The commercial availability of the aromatic polyester polyarylate, polyarylate, has created considerable interest involving blends with polycarbonate. The latter simplification has proven to be more than adequate in describing phase behavior of blends of semiaromatic polyamides and aliphatic polyamides. The confounding effects of cyclohexyl groups in some polyester blends has been observed on several occasions and is almost certainly caused by sensitivity of the overall interaction to the simplification of alicyclic structures as a polymethylene sequence. The interaction in polymer mixtures is usually positive or unfavorable for miscibility. This turns out to be true for many blends involving polyesters, however, polyesters of very high molecular mass are difficult to obtain.

Our experiment was to study the effect of high molecular mass ferulic acid sugar ester (HFASE) from corn bran on proliferation of intestinal bifidobacteria in aged mice induced by D-galactose. The number of bifidobacteria in the intestine of D-galactose-induced aging mice was lower than that of normal mice. After the intragastric administration of different doses of HFASE (100, 200, and 300 mg kg-1 day-1 body weight) in experimental groups, the number of bifidobacteria was also higher than the aging group. The proliferation rate of bifidobacteria in the intestine of the experimental groups was fast in the first 24 days of feeding and then tended to be gentle. The H-l experimental group (100 mg/kg body weight) had the most obvious effect of the proliferation of bifidobacteria. PRACTICAL APPLICATIONS: As the by-product of corn starch processing, corn bran was usually processed into animal feed and sold at a low price. The results of this study indicated that high molecular mass corn bran ferulic acid sugar ester had the effect of promoting the proliferation of bifidobacteria in aging mice, which provided ideas for the development and application of corn bran in the food industries. It could be added as a raw material for functional foods to common foods such as yogurt, baked bread, cereals, and porridge.

Background. Many biological processes are performed by different protein complexes. During the association of proteins and enzymes forming specific complexes, the latter can include ions of various metal ions, which may be important for their formation and biological function. Objective of the Studies. However, to date in the literature there are no data on metal ions that are part of any protein complexes. Methods. A very stable multiprotein complex (~1000±100 kDa) was separated from other proteins of nine samples of female milk by gel filtration on Sepharose 4B. The content of microelements in the stable multiprotein complex and milk was analyzed using two-jet plasma atomic emission spectrometry. Results. The content of different elements in milk on average decreased in the order: Ca>P>Mg>Al≥Zn≥Fe>Cu >B (0.76–3500 μg/g of dry milk powder), while the content of some elements was very low (Sr>Mn>Cr>Ba>Pb>Ag>Ni>Cd, μg/g). The content of eight elements in stable multiprotein complex was 1.2-9.6-fold higher than in milk and increased in the order: Ca≈MgB (19.7)>Ag (28.7)>Ni (38)≥Sr (110). Conclusions. The analysis of the relative content of sixteen elements in human milk and oligomeric complexes of proteins was performed for the first time. Data on the content of metals indicate that during the formation of protein which associates the increase in the content of metal ions bound with proteins of the complex can occur. Such metal ions can be important for the formation and biological function of protein complexes.

The overall goal of the present study was to identify the high molecular weight species formed during the synthesis and processing of polymeric methylene diphenyl diisocyanate (PMDI) and determine the root cause of the viscosity buildup in these materials. Initial studies focused on the use of MALDI-TOF mass spectrometry to examine the PMDI mixture and MALDI-TOF/TOF CID fragmentation for elucidating the degradation mechanisms of the identified compounds. The low molecular mass portion of the MALDI spectrum was observed to contain the expected PMDI and small quantities of carbodiimides (CDIs). The high molecular mass portion of the spectrum primarily contained 1,3-diazetidine branched carbodiimide dimers, uretonimine branched CDIs, and imino-s-triazine along with low levels of guanidine branched CDIs. The results of this study indicate that the root cause of the observed CDI defects was extensive branch formation through unexpected side reactions catalyzed by iron(III). These reactions lead to a buildup of...

Prior to 2012 street sediment from the Greater Toronto Area was being managed by a local authority and provided to rural landowners under the assumption it was clean fill. The aim of this study was to characterise the chemical and physical composition of that street sediment applied to an agricultural field in southwestern Ontario, Canada and determine if contaminants had migrated to native soil. Soil was sampled from an impact and a background location during the fall of 2016 at four soil depths (0–10, 10–20, 20–30 and 30–40 cm below the surface) to characterise texture, pH, organic content, recoverable metals and total polycyclic aromatic hydrocarbons (PAHs). Textural analysis revealed street sediment was dominated by very coarse and coarse sand which differed from the native silty clay loam and extended to 30 cm below the surface. Some PAHs, including benzo(a)pyrene (1.29 μg g−1) exceeded the typical regional background concentrations. A distinct pattern of high molecular mass PAHs in the native soil below street sediments suggests that PAHs have migrated to native soil. To our knowledge this is the first study to report PAH concentrations in street sediment in Ontario and to show their potential movement and introduction to native soil. Future studies should focus on transport mechanisms and understanding movement of PAHs in native coarse textured soil.

Since the installation of anti-doping rules and regulations and their international enforcement in the mid-1960s, mass spectrometry has been an integral part of doping control procedures. Although its utility was limited in the first decade, instrumental improvements and method optimizations have made mass spectrometry, in all its facets, an indispensable tool in modern sports drug testing. In this review, milestones in doping control analysis accomplished in Germany and reaching from the early developments to the current use of hyphenated mass spectrometric techniques concerning low- and high molecular mass analytes are presented. The considered drug classes include anabolic agents, peptidic drugs, nucleotide-derived therapeutics, approved and non-approved organic as well as inorganic analytes, and particular focus is put on drug class- and instrument-driven strategies. © 2015 Wiley Periodicals, Inc. Mass Spec Rev 36:16-46, 2017.

The group contribution method proposed by Valderrama and Robles in 2007 and updated by Valderrama and co-workers in 2012 to estimate the critical properties of ionic liquids is extended to evaluate these properties for ionic liquids of higher molecular mass. The modifications are done to follow the behavior that these properties have for other type of substances, such as the asymptotic tendency of the normal boiling temperature as the molecular mass M increases. The magnitudes of the modifications are found so that the pressure test and the density test previously defined by the authors are fulfilled for most substances. The proposed extension does not change anything of the original method already in use which is valid for ILs with M 500 g/mol are considered in this work. Of these, 310 passed the pressure test. Also, 111 of these ILs have experimental density values and 103 pass the density test, with absolute average deviation of 4.1 %. A spreadsheet fo...

The penicillin-binding proteins (PBPs) are well known targets for the β-lactam antibiotics. They continue to be a focus of interest for pharmaceutical design, as exemplified by the number of new agents under clinical investigation as well as novel experimental molecules. Considerable advances have been made in understanding the structure and function of this family of enzymes, through high-resolution structural studies and mechanistic studies in solution. These studies have thrown light on role of the high molecular mass PBPs in mediating β-lactam resistance, although much work remains to be done to enable a full description of the mechanisms by which these proteins modulate their sensitivity towards β-lactams while retaining their essential activity in cell wall biosynthesis.

The amylose and amylopectin of starch separated from four different D. opposita Thunb. were investigated by capillary electrophoresis. Nowadays, much research was focused on the utilization of plant starch as an industrial raw material which can effectively reduce the dependence on non-renewable resource. Then, the content of amylose in the starch will largely influence the availability of starches. Most detect methods were not suitable for this detection because of the high molecular mass of starch. This paper described the application of capillary electrophoresis to separate the amylose and amylopectin in four different D. opposita Thunb. and made a differentiation between them based on the well-known affinity of these compounds to iodine. The paper also improved the method of detecting yam starch because the method applying in other starches might appear somewhat different.

In this experimental study we focused our interest on comparing the effect of lower and higher molecular mass alcohol–gasoline-blended fuels on the regulated emissions emitted by a small non-road spark-ignition engine. Twenty-one test fuels were used in this experimental study that included gasoline as a reference as well as low and high molecular mass alcohol–gasoline blends containing 5%, 10%, 20% and 40% v/v. In exhaust gases that originated from alcohol gasoline test fuels, low CO/HC and high CO2/NOx emissions were observed as the total percentage of alcohol in the blend increased. Methanol–gasoline blends seemed to achieve good combustion efficiency, but the engine will require a catalytic converter against high NOx emissions. Butanol–gasoline blends in several cases gave lower emissions in comparison with the ethanol and propanol–gasoline blends. Finally, the pentanol–gasoline blends showed exactly the same emission patterns as those of neat gasoline.

Microbial degradation of resins and asphaltenes by indigenous soil microflora has been studied under laboratory conditions on model soil systems. It has been shown that high-molecular-mass heteroatomic components of oil are available for the oxidation by soil microorganisms; within 180 days of the experiment the utilization of resins and asphaltenes was 41.5 and 35.0 wt %, respectively. Analysis of the residual products of biodegradation showed a marked change in the composition of high-molecular-mass heteroatomic components. Biodegradation of resins and asphaltenes occurs predominantly with the “detachment” of peripheral paraffin structures, the aromatic ring is converted substantially less.

Plastics are synthetic polymer compound mostly made from petrochemical sources, such compound has high molecular mass and plasticity and certain chemicals are added to increase the performance and efficiency of the products. Plastics size less than 5 mm are categorized as Microplastics and it is one of the greatest potential threat to marine environment for the whole world. There are two types of micro-plastics i.e. primary micro-plastics and secondary micro-plastics. Primary microplastics are the by-products of particulate emissions released from industrial production, the release of plastics dust from plastics products. Secondary microplastics are larger plastic particulate material. These micro-plastics eventually end up in water bodies travelling all the way from rivers to seas or oceans. Microplastic can also act as a pollutant transport medium for other toxic elements such as DDT and hexachlorobenzene and eventually end up within the body of a living organism who consume it. The Government Agencies and Non-government organization of different nations have adopted many policies and laws to curb the harmful effects of plastics and microplastics. A concrete and comprehensive plan should be adopted for zero tolerance against plastics waste and peoples participation is a must to achieve the full success.

The targets of β-lactam antibiotics are bacterial DD-peptidases (penicillin-binding proteins). β-Lactam SAR studies over many years have demonstrated the importance of a specifically placed negative charge, usually carboxylate, on these molecules. We show here that neutral analogues of classical β-lactam antibiotics are of comparable activity to the originals against β-lactam-resistant high molecular mass DD-peptidases of the B1 class, a group that includes PBP2a of methicillin-resistant Staphylococcus aureus. These neutral β-lactams may direct new development of antibiotics against certain penicillin-resistant bacteria. These molecules do have antibiotic activity against Gram-positive bacteria.

A "virtual two-dimensional (2D)-like" approach based on pH 2.5-6.0 gel isoelectrofocusing coupled to MALDI-TOF mass spectrometry (MS) was addressed for challenging the ovine casein heterogeneity due to polymorphism and post-translational modifications. The procedure enabled the identification of the main casein components including i) the four casein families at different degrees of phosphorylation, ii) nonallelic variants of either alpha(s1)- or alpha(s2)-CN, iii) differently glycosylated kappa-CN, and iv) high molecular mass proteolytic peptides. Protein assignment was confirmed by MALDI-TOF (MS) mass mapping of the tryptic digests, while phosphorylation sites were localized by tandem mass spectrometry. A straightforward identification was hindered by unexpected molecular mass shifts due to the oxidization of alpha(s1)- and the beta-CN. Indeed, using nano-ESI-MS, the casein sub-types were proved to contain a variable number of oxidized methionine residues. Data were additionally substantiated using polyclonal antibodies raised against the single casein families for immunolabelling purposes. The outcomes herein demonstrate the potentiality of the "virtual 2D-like" approach and provide indications useful for the inter-laboratory discrepancies in casein identification. They also greatly facilitate the comparison of data and the establishment of multi-user image-based isoelectrofocusing gels. (C) 2012 Elsevier Ltd. All rights reserved.

Herein, we report a fast (15 min) and solvent-free mechanochemical approach to construct polymers of intrinsic microporosity (PIMs) with high molecular mass and low polydispersity by solid grinding. The enhanced reaction efficiency results from the instantaneous frictional heating and continuous exposure of active sites within those solid reactants.