Decomposition Behavior and Decomposition Products of Epoxy Resin Cured with MeHHPA in Near-critical Water

A kind of chemical method that used water as the liquid reaction medium to decompose epoxy resin was studied. The thermosetting epoxy resin was decomposed successfully under the condition of near-critical water. The decomposition rate of epoxy resin raised rapidly as the reaction time and reaction temperature increased. The decomposition reaction products were characterized by infra-red spectra and gas chromatography-mass spectrometry. The phenol, isopropylphenol, 4, 4＇-（1-methylethylidene） bis-phenol were found as the main compounds in liquid products, which were common monomers from epoxy resin. When reaction was carried out at the temperature of 260℃ -300 ℃, the decomposition mechanism of epoxy resin was envisaged as the ether and ester bonds cracking.

二甲双胍与吡格列酮两种2型糖尿病药物在亲水作用色谱上的保留机理研究（英文）

二甲双胍和吡格列酮是治疗2型糖尿病的常见药物,经常用于同一复方制剂。制药和临床领域常要求同时测定这两种药物。亲水作用色谱近来在医药分析领域展现出良好的前景。本文通过研究流动相的有机溶剂含量、pH值和缓冲盐浓度等参数对色谱保留的影响,从而尝试揭示两种药物在亲水性硅胶柱上的分离机理。流动相中甲醇的增加会导致二甲双胍的保留因子的增加。流动相pH值比较低时,二甲双胍的保留因子会随着pH值升高而增加,而当pH值>6.09,其反而会随着pH值的升高而下降。吡格列酮的保留因子几乎不受甲醇比例和pH值的影响。缓冲盐浓度对两种药物的保留因子几乎都没有影响。因此,对于二甲双胍,亲水作用是主要的保留机理,静电作用和氢键也起到了重要作用。对于吡格列酮,亲水作用是支配性的。经过优化的亲水作用色谱方法可成功地应用到分离测定两种药物在2型糖尿病复方药物中的含量。

Reduced-particle size wheat bran and endoxylanase supplementation in broiler feed affect arabinoxylan hydrolysis and fermentation with broiler age differently

Since the caecal microbiota of young broilers are not yet able to ferment the dietary fibre(DF)fraction of the feed to a large extent,increasing the accessibility of DF substrates along the gastrointestinal tract is crucial to benefit from the health stimulating metabolic end-products(e.g.butyric acid)generated upon microbial DF fermentation.Therefore,the present study aimed to evaluate the potential of reduced-particle size wheat bran(RPS-WB)and endoxylanases as feed additives to stimulate arabinoxylan(AX)hydrolysis and fermentation along the hindgut of young broilers.To this end,RPS-WB and endoxylanase supplementation were evaluated in a 2×2 factorial design using a total of 256 male 1-d-old chicks(Ross 308).Broilers were assigned to 4 dietary treatments:a basal wheat-based diet with(1)no feed additives(control,CTRL),(2)an endoxylanase(XYL;Econase XT 25 at 0.10 g/kg diet),(3)1%wheat bran with an average reduced particle size of 297μm(RPS-WB)and(4)an endoxylanase and 1%RPS-WB(RPS-WB+XYL).Each dietary treatment was replicated 8 times and on d 10 and 28,respectively,24 and 16 broilers per treatment group were euthanised to analyse AX degradation,short-chain fatty acid production and digesta viscosity in the ileum and caecum.Broilers receiving XYL in their diet showed increased AX solubilisation and fermentation at both d 10 and 28 compared to the CTRL group(P<0.05).Adding RPS-WB to the diet stimulated wheat AX utilisation by the primary AX degraders in the caecum at 10 d of age compared to the CTRL group,as observed by the high AX digestibility coefficient for the RPS-WB supplemented group at this young age(P<0.05).At 28 d,RPS-WB supplementation lowered body-weight gains but increased butyric acid concentrations compared to the XYL and CTRL group(P<0.05).Although no synergistic effect for RPS-WB+XYL broilers was observed for AX hydrolysis and fermentation,these findings suggest that both additives can raise a dual benefit to the broiler as a butyrogenic effect and improved AX fermentation along the ileum and caecum were observed throughout the broiler's life.

Microbial Changes in the Fluorescence Character of Natural Organic Matter from a Wastewater Source

Natural Organic Matter (NOM) is a mixture of aromatic and aliphatic organic compounds of natural origin in any type of aquatic system. Human activities impact the constituents of NOM, from its production to its fate, particularly in the treatment of domestic waste waters. In this work, the impact of microorganisms isolated from a Waste Water Treatment Plant (WWTP) was investigated to determine the fate of NOM fractions in raw sewage, using fluorescence spectroscopy. Wastewater samples were taken at three different times from a WWTP, and incubated for 4 days under two treatments: 1) “raw sewage”, and 2) “spiked”, i.e., the same raw sewage, spiked with bacteria previously isolated from the WWTP. The incubated waters were analyzed by fluorescence spectroscopy, digitally resolved into NOM components: humic- and fulvic-like, and two types of protein-like, i.e., tryptophan- and tyrosine-like, using a Parallel Factor Analysis routine (PARAFAC). The results demonstrate that the “spiked” samples showed the largest changes with incubation time. The signals of the tryptophan- and tyrosine-like components decreased, suggesting a net microbial digestion of proteinaceous material. In contrast, the fulvic-like signals, and to some extent, the humic-like signals increased, suggesting the production of the associated molecular materials during the incubation period. This study provides direct evidence of human impact on the make-up of NOM: the cultures of microbes found at a WWTP consume the proteinaceous material, whereas humic-like and fulvic-like materials are produced.

Graphene Sheets with Modified Surface by Sodium Lauryl Sulfate Surfactant for Biomedical Applications

This work describes synthesis of graphene sheets with modified surface by sodium lauryl sulfate (SLS) surfactant using one-pot solvothermal reaction method. Effect of sodium lauryl sulfate surfactant amount on surface modification level of graphene sheets was investigated. Ether (-S-OR- at 762 cm-1 - 863 cm-1), thiocarbonyl (=C=S at 1050 cm-1 - 1176 cm-1) and sulfoxide (S-O, Vs and Vas at 1030 cm-1 - 1450 cm-1) functional groups released from sodium lauryl sulfate (SLS) surfactant during solvothermal reaction and attached on the surface of graphene sheets were detected by (attenuated total reflectance-fast Fourier infrared) ATR-FTIR spectroscopy. (Atomic force microscope) AFM observations revealed apparent surface of graphene sheets modified by surfactant molecules with an average multiple profile of graphene nanosheets ≈ 4.8 nm high. This synthesis way of surface modified graphene sheets can be considered as easy, one-step and cheap method for manufacturing of novel biosurface with graphene, as reinforcement for biopolymer coatings such as ultra-high molecular weight polypropylene (UHMWPE), metallic biomaterials (Ti and Ti alloys) and bioceramics as hydroxyapatite (HA).

Feed endoxylanase type and dose affect arabinoxylan hydrolysis and fermentation in ageing broilers☆

Despite the general use of endoxylanases in poultry feed to improve broiler performance,the abundance of different endoxylanase products and the variable response to their application in the field prevent a clear understanding of endoxylanase functionality in vivo.To gain insight into this functionality,we investigated the impact of endoxylanase type(Belfeed from Bacillus subtilis versus Econase XT from Nonomuraea flexuosa)and dose(10,100,1,000 mg/kg)in combination with broiler age on arabinoxylan(AX)hydrolysis and fermentation in broilers(Ross 308)fed a wheat-soy based diet.In a digestibility trial and a performance trial,a total of 1,057 one-day-old chicks received the control diet or 1 of the 6 endoxylanase supplemented wheat-soy based diets with,respectively,5 replicate cages and 8 replicate pens per dietary treatment per trial.The AX content and structure,the AX digestibility values and the short-chain fatty acids produced were analysed at the level of the ileum,caeca and excreta at d 11 and 36.Endoxylanase supplementation resulted in a more extensive solubilisation of wheat AX and a reduction in the intestinal viscosity compared to the control(P<0.05).A high endoxylanase dose was,however,required to obtain increased hydrolysis of the dietary AX along the gastrointestinal tract against the control(P<0.001).Depending on the type of endoxylanase,a pool of AX with distinct physicochemical properties was created.The B.subtilis endoxylanase created a large pool of soluble AX in the ileum,thereby increasing ileal viscosity compared to broilers fed an endoxylanase from N.flexuosa(P<0.001).The N.flexuosa endoxylanase mainly triggered caecal AX fermentation in young broilers,by delivering easily fermentable AX substrates with a low degree of polymerisation(P=0.03).The effects were particularly present in young broilers(d 11).From this study,it is clear that the type and dose of endoxylanase added to wheat-soy based diets determine the nature of AX substrates formed.These,in turn,affect the intestinal viscosity and the interplay between the dietary AX compounds and microbiota,hence dictating AX digestion at young broiler ages and performance outcomes towards slaughter age.

Concentration and Preservation of Very Low Abundance Biomarkers in Urine, such as Human Growth Hormone (hGH), by Cibacron Blue F3G-A Loaded Hydrogel Particles

Urine is a potential source of diagnostic biomarkers for detection of diseases,and is a very attractive means of non-invasive biospecimen collection.Nonetheless,proteomic measurement in urine is very challenging because diagnostic biomarkers exist in very low concentration(usually below the sensitivity of common immunoassays)and may be subject to rapid degradation.Hydrogel nanoparticles functionalized with Cibacron Blue F3G-A(CB)have been applied to address these challenges for urine biomarker measurement.We chose one of the most difficult low abundance,but medically relevant,hormones in the urine:human growth hormone(hGH).The normal range of hGH in serum is 1 to 10 ng/mL but the urine concentration is suspected to be a thousand times less,well below the detection limit(50 pg/mL)of sensitive clinical hGH immunoassays.We demonstrate that CB particles can capture,preserve and concentrate hGH in urine at physiological salt and urea concentrations,so that hGH can be measured in the linear range of a clinical immunometric assay.Recombinant and cadaveric hGH were captured from synthetic and human urine,concentrated and measured with an Immulite chemiluminescent immunoassay.Values of hGH less than 0.05 ng/mL(the Immulite detection limit)were concentrated to 2 ng/mL,with a urine volume of 1 mL.Dose response studies using 10 mL of urine demonstrated that the concentration of hGH in the particle eluate was linearly dependent on the concentration of hGH in the starting solution,and that all hGH was removed from solution.Thus if the starting urine volume is 100 mL,the detection limit will be 0.1 pg/mL.Urine from a healthy donor whose serum hGH concentration was 1.34 ng/mL was studied in order detect endogenous hGH.Starting from a volume of 33 mL,the particle eluate had an hGH concentration of 58 pg/mL,giving an estimated initial concentration of hGH in urine of 0.175 pg/mL.The nanotechnology described here appears to have the desired precision,accuracy and sensitivity to support large scale clinical studies of urine hGH levels.

The N-terminus of COX-1 and its effect on cyclooxygenase-1 catalytic activity

Cyclooxygenases are encoded by COX-1 and COX-2. They share over sixty percent sequence identity in human and are similar to each other in their crystallographic structures. One major difference in the primary structure of these two isozymes is the presence of eight amino acids in the amino-terminal region of COX-1 that are not present in COX-2. The function of this amino acid sequence is unknown. In this study, a human COX-1 mutant （Δ7aa） with this sequence removed was studied in parallel with COX-1. Signal peptide cleavage, N-linked glycosylation, protein expression, distribution and dimerization were not affected by the mutation. The mutant was enzymati-cally active and showed the same sensitivity toward aspirin. The KM for the enzyme remained the same as COX-1. However, the Vmax of the COX-1 mutant decreased by 3.3-fold. We conclude that the COX-1 specific amino-terminal sequence has a subtle but detectable effect on COX-1 catalysis.

Forensic isoscapes based on intra-individual temporal variation of δ^(18)O and ^(206)Pb/^(207)Pb in human teeth

Isotopic signatures used in the georeferencing of human remains are largely fixed by spatially distinct geologic and environmental processes.However,location-dependent temporal changes in these isotope ratios should also be considered when determining an individual’s provenance and/or trajectory.Distributions of the relevant isotopes can be impacted by predictable external factors such as climate change,delocalisation of food and water sources and changes in sources and uses of metals.Using Multi-Collector Inductively-Coupled Plasma Mass Spectrometer(MC-ICP-MS)analyses of ^(206)Pb/^(207)Pb in tooth enamel and dentin from a population of 21±1-year-old individuals born circa 1984 and isotope ratio mass spectrometry(IRMS)of δ^(18)O in their enamel,we examined the expected influence of some of these factors.The resulting adjustments to the geographic distribution of isotope ratios(isoscapes)found in tooth enamel and dentin may contain additional useful information for forensic identification,but the shifts in values can also impact the uncertainty and usefulness of identifications if they are not taken into account.

The Fold-Illuminator:A low-cost,portable,and disposable incubator-illuminator device

Fluorescent reporters have revolutionized modern applications in the fields of molecular and synthetic biology,enabling applications ranging from education to point-of-care diagnostics.Past advancements in these fields have primarily focused on improving reaction conditions,the development of new applications,and the broad dissemination of these technologies.However,field and classroom-based applications have remained limited in part due to the nature of fluorescent signal detection,which often requires the use of costly lab equipment to observe and quantify fluorescence readouts.Users without access to laboratory equipment rely on qualitative assessments of fluorescence,a process that remains highly variable from user-to-user even within the same classroom.To overcome this challenge,we have developed a foldable illuminator and incubator device to support field-applications of synthetic biology-based biosensors for education and diagnostics.The Fold-Illuminator is an affordable,portable,and recyclable device that allows for the visible detection of fluorescent biomolecules.The Fold-Illuminator’s design allows for assembly in under 10 min,a user can then utilize the optional heating element to incubate biochemical reactions and visualize fluorescence outputs in a defined and light-controlled environment.Interchangeable LED strips and light-filtering screens provide modularity to pair with the fluorescence wavelengths of interest.The user can then unfold the device for convenient storage,transport,or even recycling.The cost for the Fold-Illuminator is$5.58 USD and is compatible with an optional heating element for an additional$3.98 cost,with potential for further reductions in cost for larger quantities.Open-source templates for cutting device parts from paper stock are provided for both printing and cutting by hand;cutting can also be achieved with consumer-grade smart cutting machines such as the Cricut®.Combined with the broad applications of fluorescent reporters,the Fold-Illuminator has the potential to improve access to fluorescence visualization and quantification for new users as well as emerging field applications.

Label-free 3D computational imaging of spermatozoon locomotion, head spin and flagellum beating over a large volume

We report a high-throughput and label-free computational imaging technique that simultaneously measures in three-dimensional(3D)space the locomotion and angular spin of the freely moving heads of microswimmers and the beating patterns of their flagella over a sample volume more than two orders-of-magnitude larger compared to existing optical modalities.Using this platform,we quantified the 3D locomotion of 2133 bovine sperms and determined the spin axis and the angular velocity of the sperm head,providing the perspective of an observer seated at the moving and spinning sperm head.In this constantly transforming perspective,flagellum-beating patterns are decoupled from both the 3D translation and spin of the head,which provides the opportunity to truly investigate the 3D spatio-temporal kinematics of the flagellum.In addition to providing unprecedented information on the 3D locomotion of microswimmers,this computational imaging technique could also be instrumental for micro-robotics and sensing research,enabling the high-throughput quantification of the impact of various stimuli and chemicals on the 3D swimming patterns of sperms,motile bacteria and other micro-organisms,generating new insights into taxis behaviors and the underlying biophysics.

Integrins and focal adhesion kinase in the malignant behavior of gliomas

Glioblastoma multiforme(GBM)is the most common type of glioma and is associated with a very poor prognosis.The standard treatment includes radiotherapy concurrent with temozolomide,however recently the Food and Drug Administration approved bevacizumab for use in patients with progressive glioblastoma following prior therapy.The limited number of treatment options points to the need for novel effective therapeutic approaches.A promising approach is the use of tyrosine kinase inhibitors(TKIs)in GBM treatment.However,the results from the majority of clinical trials using TKIs are not very encouraging.One growing area is the development of tumor-homing peptides that resemble the integrin recognition sequence RGD.In this article,the role of integrins and focal adhesion kinase in malignant glioma is reviewed,and an experimental study is proposed that will apply a strategy for peptide-mediated delivery of compounds deep into tumor parenchyma using tumor-homing peptides.

Controlled Vertical Transfer of Individual Au Atoms Using a Surface Supported Carbon Radical for Atomically Precise Manufacturing

To explore a proof-of-concept for atomically precise manufacturing(APM)using scanning probe microscopy(SPM),first principle theoretical calculations of atom-by-atom transfer from the apex of an SPM tip to an individual radical on a surfacebound organic molecule have been performed.Atom transfer is achieved by spatially controlled motion of a gold terminated tip to the radical.Two molecular tools for SPM-based APM have been designed and investigated,each comprising an adamantane core,a radical end group,and trithiol linkers to enable strong chemisorption on the Au(111)surface:ethynyl-adamantanetrithiol and adamantyl-trithiol.We demonstrate the details of controlled Au atom abstraction during tip approach toward and retraction from the radical species.Upon approach of the tip,the apical Au atom undergoes a transfer toward the carbon radical at a clearly defined threshold separation.This atomic displacement is accompanied by a net energy gain of the system in the range−0.5 to−1.5 eV,depending on the radical structure.In the case of a triangular pyramidal apex model,two tip configurations are possible after the tip atom displacement:(1)an Au atom is abstracted from the tip and bound to the C radical,not bound to the tip base anymore,and(2)apical tip atoms rearrange to form a continuous neck between the tip and radical.In the second case,subsequent tip retraction leads to the same final configuration as the first,with the abstracted Au atom bound to radical carbon atom of the molecular tool.For the less reactive adamantyl-trithiol radical molecular tool,Au atom transfer is less energetically favored,but this has the advantage of avoiding other apex gold atoms from rearrangement.

Hardening Effects in Superhard Transition-Metal Borides

CONSPECTUS:Mechanical hardness is a physical property used to gauge the applications of materials in the manufacturing and machining industries.Because of their high hardness and wear resistance,superhard materials(Vickers hardness,Hv≥40 GPa)are commonly used as cutting tools and abrasives.Although diamond is the hardest known material used for industrial applications,its synthesis requires both high pressure and high temperature.Interest in the field of superhard materials research has led to the search for alternatives with high hardness and thermal stability at low cost.The discovery of novel ultraincompressible,superhard materials has largely developed through trial and error along two paths.In one approach,researchers combine light elements,such as boron,carbon,nitrogen,and oxygen,often at high pressure,to replicate the highly directional,dense,covalent bonds of diamond.In the second approach,these light elements(B,C,N,and O)are combined with highly incompressible,electron-rich transition metals to form dense covalently bonded networks at ambient pressure.