Low Weight Molecules Research Articles

PEDOT:PSS Nanoparticle Membranes for Organic Solvent Nanofiltration.

Recycling of valuable solutes and recovery of organic solvents via organic solvent nanofiltration (OSN) are important for sustainable development. However, the trade-off between solvent permeability and solute rejection hampers the application of OSN membranes. To address this issue, the poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) nanoparticle membrane with hierarchical pores is constructed for OSN via vacuum filtration. The small pores (the free volume of the polymer chain) charge for the solute rejection (high rejection efficiency for low molecule weight solute) and allow solvent passing while the large pores (the void between two PEDOT:PSS nanoparticles) promote the solvent transport. Owing to the lack of connectivity among the large pores, the fabricated PEDOT:PSS nanoparticle membrane enhanced solvent permeance while maintaining a high solute rejection efficiency. The optimized PEDOT:PSS membrane affords a MeOH permeance of 7.2 L m-2 h-1 bar-1 with over 90% rejection of organic dyes, food additives, and photocatalysts. Moreover, the rigidity of PEDOT endows the membrane with distinctive stability under high-pressure conditions. The membrane is used to recycle the valuable catalysts in a methanol solution for 150h, maintaining good separation performance. Considering its high separation performance and stability, the proposed PEDOT:PSS membrane has great potential for industrial applications.

Impact of Hydroxy-Aluminum and Extracellular polymeric substances interactions on waste activated sludge Dewatering: A molecular perspective

Al13 and Al30 are the dominant aluminum (Al) species in polyaluminium chloride commonly used for sludge dewatering. However, the presence of extracellular polymeric substances (EPS) in the waste activated sludge hinders the coagulation effectiveness of Al-based coagulants. This study focused on the effects and mechanisms of Al13 and Al30 on treating sludge EPS. From a bulk perspective, the dosing of two coagulants significantly reduced the dissolved organic carbon and various organic compounds, reflecting their efficacy in removing organic substances in EPS. Further molecular characterization was revealed by FT-ICR MS. Al13 was more effective in removing lipids, lignins, and sulfur-containing compounds compared to Al30. Al13 also demonstrated a pronounced removal in components enriched in oxygen atoms (10–20) and KMD(COO) (0.5–0.7), suggesting its ability to remove molecules across a broader range of unsaturation. After coagulation with Al13, the areas corresponding to Al2p1/2 and Al2p2/3 in the Al2p spectra were more prominent compared to those in the Al30-coagulated EPS. Therefore, Al13 can both remove complex and low molecule weight compounds through abound forms of adsorption sites, making it more efficient in releasing bound water compared to Al30.

Structural characterization and immunoregulatory mechanism of a low-molecular-weight polysaccharide from lotus root

The extraction of polysaccharide from lotus root was highly homogenized, and the structure of the polysaccharide was not clear. Herein, we report a hot water method combined with α-amylase that was applied to extract lotus root polysaccharide. After purified, a lotus root polysaccharide fraction LP60-a with high purity and low molecule weight was obtained. Systematic characterization of the structure of LP60-a was achieved by monosaccharide composition, methylation and NMR analysis, showing that LP60-a was composed of α-1,6-glucan linked with a small amount of arabinogalactan. Conformational determination showed that LP60-a was a three-helix polysaccharide with random coil conformation. Furtherly, the immunomodulatory activities of LP60-a were investigated in RAW264.7 macrophages. The data indicated that LP60-a could enhance the proliferation and phagocytosis of macrophages significantly, and induce the expression of NO and TNF-α in macrophages without causing inflammation. Moreover, LP60-a promoted the phosphorylation of MAPK p38 and JNK, as well as NF-κB p65, indicating that LP60-a could activate RAW264.7 cells through MAPK and NF-κB signaling pathways. In conclusion, the results imply that LP60-a could enhance the immune function of macrophages, presenting a possibility to play a role as an immunomodulatory agent in dietary supplements.

Hair treatment products containing pigeon pea oil as chemical properties and anti-oxidant activity

The comparing small type (T9) and big type (ICP 7035), which were extracted by hexane maceration, this study looks at the properties of pigeon pea oil in hair treatment products. It finds that the percentage yield of big seed (ICP 7035) oil is higher than that of small seed (T9) oil, at 9.64 ± 0.10 and 9.32 ± 0.08, respectively. A study on the chemical properties of the oil revealed values for saponification, acidity, iodine, and peroxide. In all trials, T9 outperformed ICP 7035 in terms of test results, demonstrating the presence of fatty acids in the molecular components of triglycerides. Compared to ICP 7035, T9 had a lower molecule weight and a lower saturation level, making it less susceptible to oxidative lipid disorder and the tendency to deplete oil. The flavonoid content of T9 is higher than that of ICP 7035, equal to 27.76 ± 0.65 mg GAE g-1 extract and 25.90 ± 0.69 mg GAE g-1 extract, respectively. The flavonoid content of T9 is higher than that of ICP 7035, equal to 20.67 ± 0.58 mg QE g-1 extract and 18.76 ± 0.65 mg QE g-1 extract, respectively. The DPPH test showed that T9 was a stronger antioxidant than ICP 7035, with amounts of 0.26 ± 0.04 mg g-1 of extract and 0.35 ± 0.05 mg g-1, respectively. The development of hair care products revealed that a mixture containing the optimal dosage of T9 effectively ensured smooth hair lines and prevented microorganism contamination in all recipes. GRAPHICAL ABSTRACT HIGHLIGHTS Pigeon Pea Oil in Hair Care Products Comparison of T9 and ICP 7035 oil properties. ICP 7035 yield was higher than T9 yield. Chemical properties of oil included saponification, acidity, iodine, and peroxide. T9 oil had better phenolics, flavonoids, and DPPH values than ICP 7035. T9-rich mixtures in hair care products ensure smooth hair lines and prevent microorganism contamination.

Insights into the photodegradation of decamethylammonium bromide (DDAB) under UV/H2O2 system: Photodegradation kinetic modeling, degradation mechanism and toxicity evaluation

Decamethonium bromide (DDAB), as a class of quaternary ammonium-based disinfectants (QACs), was widely used during the COVID-19 outbreak. The abuse of DDAB is harmful to the health of aquatic organisms. The UV/H2O2 process is popularly utilized for the removal of trace contaminants from aqueous environments. Thus, in this paper, DDAB was selected as the model of QACs, and the degradation kinetics were simulated by Kintecus software. It was indicated that the effect of the degradation efficiency of DDAB was dominated by [·OH]ss. The degradation efficiency of DDAB was greater than 95 % when [·OH]ss was higher than 1.04×10−12 M. The high dosages of H2O2 (>100 μM) and the less concentration of pollutants (<10 μM) were more beneficial to the degradation of DDAB. The high dosages of NOM and CO32- in the system scavenged ·OH and thereby inhibited the degradation of DDAB. The interference of Cl- on the degradation efficiency was negligible. Additionally, the optimal pH value for removing DDAB was between 4 and 7. Besides, the degradation pathway of DDAB was inferred by Density Functional Theory (DFT) and Ultra-high Performance Liquid Chromatography-tandem Mass Spectrometry (UPLC-MS/MS). The results showed that the degradation of DDAB began with C-N bond breaking, then generated aldehydes, underwent demethylation reaction, and finally converted to low molecule weight molecules. The results of Ecological Structure Activity Relationships (ECOSAR) toxicity assessment demonstrated that the toxicity of all the degradation products was significantly low. Overall, this study provides theoretical basis for the removal of QACs in the aqueous environment.

Deciphering the degradation mechanism of thick graphite anodes in high-energy-density Li-ion batteries by electrochemical impedance spectroscopy

The utilization of thick electrodes represents a promising strategy for high energy density batteries, but practical application is hindered by the observed challenges of low cyclic stability and rate performance. To address these issues, we employed electrochemical impedance spectroscopy (EIS) as a non-destructive method to establish a diagnostic model capable of identifying the causes of the instability of thick electrodes. While EIS models for thick electrodes have previously been discussed, the connection between these models and the degradation mechanism has yet to be fully understood. Our investigation revealed that resistances of the current collector, solid electrolyte interphase, or electrolyte, increase with the increment of electrode thickness and further increases following the cycling test with a similar degree, indicating that the degradation of thick electrodes is not governed by those resistances. Rather, a new resistance component emerged in the thick electrode after the cycling test, indicating the emerged resistance plays as the predominant factor driving degradation. The new resistance component on the impedance spectra is linked to Li dendrite formation, due to impeded Li-ion transfer. The hindered Li-ion movement is probably due to the migration of low-weight molecules in the drying process and/or the extended distance Li-ions must transverse.

Metallophore Activity toward the Rare Earth Elements by Bacteria Isolated from Acid Mine Drainage Due to Coal Mining.

The field of microbe-metal interactions has been gaining significant attention. While the direct impact of metal oxyanions on bacteria has been investigated, significantly less attention has been placed on the ability of certain microbes to 'collect' such metal ions via secreted proteins. Many bacteria possess low-weight molecules called siderophores, which collect Fe from the environment to be brought back to the cell. However, some appear to have additional roles, including binding other metals, termed 'metallophores'. Microbes can remove/sequester these from their surroundings, but the breadth of those that can be removed is still unknown. Using the Chromeazurol S assay, we identified eight isolates, most belonging to the genus Pseudomonas, possessing siderophore activity, mainly from sites impacted by coal mine drainage, also possessing a metallophore activity toward the rare earth elements that does not appear to be related to ionic radii or previously reported EC50 concentrations for E. coli. We found the strength of metallophore activity towards these elements was as follows: Pr > Sc > Eu > Tm > Tb > Er > Yb > Ce > Lu > Sm > Ho > La > Nd > Dy > Gd > Y. This is the first study to investigate such activity and indicates bacteria may provide a means of removal/recovery of these critical elements.

Benzophenanthridine Alkaloid Chelerythrine Elicits Necroptosis of Gastric Cancer Cells via Selective Conjugation at the Redox Hyperreactive C-Terminal Sec498 Residue of Cytosolic Selenoprotein Thioredoxin Reductase.

Targeting thioredoxin reductase (TXNRD) with low-weight molecules is emerging as a high-efficacy anti-cancer strategy in chemotherapy. Sanguinarine has been reported to inhibit the activity of TXNRD1, indicating that benzophenanthridine alkaloid is a fascinating chemical entity in the field of TXNRD1 inhibitors. In this study, the inhibition of three benzophenanthridine alkaloids, including chelerythrine, sanguinarine, and nitidine, on recombinant TXNRD1 was investigated, and their anti-cancer mechanisms were revealed using three gastric cancer cell lines. Chelerythrine and sanguinarine are more potent inhibitors of TXNRD1 than nitidine, and the inhibitory effects take place in a dose- and time-dependent manner. Site-directed mutagenesis of TXNRD1 and in vitro inhibition analysis proved that chelerythrine or sanguinarine is primarily bound to the Sec498 residue of the enzyme, but the neighboring Cys497 and remaining N-terminal redox-active cysteines could also be modified after the conjugation of Sec498. With high similarity to sanguinarine, chelerythrine exhibited cytotoxic effects on multiple gastric cancer cell lines and suppressed the proliferation of tumor spheroids derived from NCI-N87 cells. Chelerythrine elevated cellular levels of reactive oxygen species (ROS) and induced endoplasmic reticulum (ER) stress. Moreover, the ROS induced by chelerythrine could be completely suppressed by the addition of N-acetyl-L-cysteine (NAC), and the same is true for sanguinarine. Notably, Nec-1, an RIPK1 inhibitor, rescued the chelerythrine-induced rapid cell death, indicating that chelerythrine triggers necroptosis in gastric cancer cells. Taken together, this study demonstrates that chelerythrine is a novel inhibitor of TXNRD1 by targeting Sec498 and possessing high anti-tumor properties on multiple gastric cancer cell lines by eliciting necroptosis.

Immunohistochemical Identification and Assessment of the Location of Immunoproteasome Subunits LMP2 and LMP7 in Acquired Cholesteatoma.

Cholesteatoma, accompanied by chronic inflammatory response, is characterized by invasive growth and osteolytic activity. As specific proteasome isoforms, the immunoproteasomes serve as an important modulator of inflammatory responses. The aim of the present study was to determine the biological activity of cholesteatoma through the analysis of the expression and localization of immunoproteasome subunits of low molecule weight protein (LMP) 2 and LMP7. Cholesteatoma specimens were obtained from 15 adults who underwent ear surgery due to acquired attic cholesteatoma. Normal skin specimens were taken from retro-auricular skin incisions from the same patients. The specimens were stained with anti-LMP7 antibody, using immunohistochemistry techniques based on the binding of biotinylated secondary antibody with the enzyme-labeled streptavidin and the Envision FLEX system. In all specimens of cholesteatoma, the immunohistochemical reaction with the antibody against the LMP2 was positive, in both the cytoplasm of the cholesteatoma matrix and the perimatrix. A negative reaction with anti-LMP2 was observed in the cytoplasm and nuclei of control skin cells. A positive nuclear and cytoplasmic immunohistochemical reaction with anti-LMP7 has been demonstrated in numerous cells, in both the matrix and perimatrix of cholesteatoma. We present evidence of the presence of expressions of LMP2 and LMP7 within cholesteatoma tissue. Our results might bring new information concerning immunoproteasome-dependent pathophysiologic mechanisms in cholesteatoma.

Occurrence and concentrations of organic micropollutants (OMPs) in highway stormwater: a comparative field study in Sweden

This study details the occurrence and concentrations of organic micropollutants (OMPs) in stormwater collected from a highway bridge catchment in Sweden. The prioritized OMPs were bisphenol-A (BPA), eight alkylphenols, sixteen polycyclic aromatic hydrocarbons (PAHs), and four fractions of petroleum hydrocarbons (PHCs), along with other global parameters, namely, total organic carbon (TOC), total suspended solids (TSS), turbidity, and conductivity (EC). A Monte Carlo (MC) simulation was applied to estimate the event mean concentrations (EMC) of OMPs based on intra-event subsamples during eight rain events, and analyze the associated uncertainties. Assessing the occurrence of all OMPs in the catchment and comparing the EMC values with corresponding environmental quality standards (EQSs) revealed that BPA, octylphenol (OP), nonylphenol (NP), five carcinogenic and four non-carcinogenic PAHs, and C16-C40 fractions of PHCs can be problematic for freshwater. On the other hand, alkylphenol ethoxylates (OPnEO and NPnEO), six low molecule weight PAHs, and lighter fractions of PHCs (C10-C16) do not occur at levels that are expected to pose an environmental risk. Our data analysis revealed that turbidity has a strong correlation with PAHs, PHCs, and TSS; and TOC and EC highly associated with BPA concentrations. Furthermore, the EMC error analysis showed that high uncertainty in OMP data can influence the final interpretation of EMC values. As such, some of the challenges that were experienced in the presented research yielded suggestions for future monitoring programs to obtain more reliable data acquisition and analysis.

Beyond Sol-Gel: Molecular Gels with Different Transitions.

The existence of sol-gel transitions is one of the most manifest properties of molecular gels. These transitions reflect their nature since they correspond to the association or dissociation of low weight molecules through non-covalent interactions to form the network constitutive of the gel. Most described molecular gels undergo only one gel-to-sol transition upon heating, and the reverse sol-to-gel transition upon cooling. It has been long observed that different conditions of formation could lead to gels with different morphologies, and that gels can undergo a transition from gel to crystals. However, more recent publications report molecular gels which exhibit additional transitions, for instance gel-to-gel transitions. This review surveys the molecular gels for which, in addition to sol-gel transitions, transitions of different nature have been reported: gel-to-gel transitions, gel-to-crystal transition, liquid-liquid phase separations, eutectic transformations, and synereses.

Depolymerization of robust polyetheretherketone to regenerate monomer units using sulfur reagents

Super engineering plastics, high-performance thermoplastic resins such as polyetheretherketone, and polyphenylene sulfide have been utilized in industries, owing to their high thermal stability and mechanical strength. However, their robustness hinders their depolymerization to produce monomers and low-weight molecules. Presently, chemical recycling for most super engineering plastics remains relatively unexplored. Herein, we report the depolymerization of insoluble polyetheretherketone using sulfur nucleophiles via carbon–oxygen bond cleavages to form benzophenone dithiolate and hydroquinone. Treatment with organic halides converted only the former products to afford various dithiofunctionalized benzophenones. The depolymerization proceeded as a solid–liquid reaction in the initial phase. Therefore, this method was not affected by the shape of polyetheretherketone, e.g., pellets or films. Moreover, this depolymerization method was applicable to carbon- or glass fiber-enforced polyetheretherketone material. The depolymerized product, dithiofunctionalized benzophenones, could be converted into diiodobenzophenone, which was applicable to the polymerization.

The anticoagulant treatment dilemma in pulmonary embolism associated to cancer

Abstract Pulmonary embolism (PE) is defined by the obstruction of pulmonary arteries by thrombi or emboli (malignant, grease, air). Most frequently, thrombi arise from deep veins of lower limbs. Pulmonary embolism is a medical emergency with a high death risk. Early mortality is high, sudden death occurs in about a quarter of the patients. On long term, it can lead to post-embolic pulmonary hypertension and recurrent pulmonary embolia. The high risk of death in acute phase and on long-term depends on the severity of the acute phase, on the recurrence, and on the co-morbidities. PE can be the first manifestation of on occult malignancy, or it may complicate an already diagnosed cancer. We present a retrospective analysis on PE associated to malignancy, on 106 patients, with classic anticoagulant treatment (low weight molecule heparin and/or antivitamin K agents) or novel oral anticoagulants (NOAC) and compare the early and late mortality associated to PE and anticoagulant treatment. Our observations note a higher percentage of recurrences but significantly lower mortality in patients treated with NOAC as compared to classic treatments.

Corrosion-resistant polyurethane coatings from structure-homogenized biorefinery lignin through fractionation and oxypropylation

Using lignin for polyurethane (PU) synthesis is challenging because of its heterogeneous structure, i.e., broad molecule weight (MW) distribution and diverse hydroxyl (OH) functionality. This complexity influences the crosslinking reaction between lignin and isocyanate and affects the quality of PU products. Here, we propose a two-step strategy for lignin structure homogenization by lowering its MW, while narrowing the MW distribution (step 1), and achieving uniform OH functionality (step 2). Step 1 involves a bioethanol fractionation process, yielding fractionated lignin with one order lower MW than the raw lignin while exhibiting better processability for the subsequent process. Step 2 is performed by an oxyalkylation process using fractionated lignin that converts phenolic and carboxylic OHs to aliphatic OHs. As a result, we obtained structure-homogenized lignin with good compatibility and crosslinking with hexamethylene diisocyanate for PU coating synthesis. Moreover, PU coatings prepared from structure-homogenized lignin display a defect-free microscopic structure and show better corrosion resistance than coatings fabricated from its raw lignin alternative. Overall, the structure homogenization process is a beneficial way of using lignin as biopolyol in PU synthesis toward the application-oriented design of corrosion-resistant lignin-based PU coatings.

Gold nanoparticles are capped under the IRMOF-3 platform for in-situ surface-enhanced Raman scattering technique and optic fiber sensor

Integrating noble-metal and organic-inorganic hybrid crystalline porous materials for Raman signal augmentation is crucial for surface-enhance Raman spectroscopy. This study effectively generated gold nanoparticles / metal-organic frameworks (Au NPs/IRMOF-3) hybrids. The activity of Au NPs/IRMOF-3 double component substrate was significantly enhanced under localized surface plasmon resonance (LSPR) because the hot electrons produced on Au NPs surface were incorporated with IRMOF-3 and utilized the porous structure to capture the analyte. Development much hot spots of great significance for surface-enhanced Raman scattering (SERS) technique, herein, we developed an Au NPs/IRMOF-3-based nanosensor for rhodamine B (RhB) sensing by using in-situ SERS technique. X-ray diffraction (XRD) spectrometry, surface morphology analysis, optical properties, and energy-dispersive X-ray (EDX) spectroscopy were used to examine the layer-by-layer deposited substrate. The Au NPs/IRMOF-3 multilayers generated chemical and electromagnetic amplification of Raman signals of Rhodamine B at a low concentration and high enhancement factor. In the presence of dopamine molecules, due to the strong specific affinity between the modified surface out-layer of fiber sensor and the target molecules, resulting in the obvious change of the optical power transmission signals, which can be used for dopamine sensing with high sensitivity and stability (limit of detection is 1.42 × 10 -18 M with a wide linear range from 10 -17 to 6 × 10 -8 M of dopamine). The Au NPs/IRMOF-3 nanosensor can be used as an ideal platform for real applications, especially for some gases or low-weight molecules in the future. • Using a traditional synthesis approach, low cost, and high synthesis efficiency. • This sensor has high homogeneity and a stable arrangement structure. • Determination of Rhodamine B at low detection limit of 10 -9 M along with an enhancement factor of 6.54 × 10 9 . • Limit of detection is 1.42 × 10 -18 M and measurement range with a linear response from 10 −17 to 10 −8 M.

Multicolor immunosensor for detection of zearalenone based on etching Au NBPs mediated by HRP

Zearalenone (ZEN) is a low-weight molecule toxin which can cause great damage to human health. A multicolor immunosensor for determination of ZEN was developed based on etching gold nanobipyramids (Au NBPs) mediated by horseradish peroxidase (HRP). In this new immunosensor, the anti-ZEN monoclonal antibody (McAb) induced the formation of ternary immunocomplex BSA-ZEN@McAb@HRP-IgG. Then, TMB was converted to TMB+ under the catalysis of HRP. Subsequently, TMB+ reacted with H+ to form TMB2+. Finally, the Au NBPs was etched by TMB2+ to produce blue shift of longitudinal absorption peaks of Local Surface Plasmon Resonance (LSPR). Meanwhile, the solution exhibited different multiple colors, which can be recognized by the naked eyes. Under the optimal conditions, the limit of detection of this new immunosensor was 0.011 ng/mL, whose linear range was 0.02 ~ 0.80 ng/mL. Besides, this new immunosensor had good sensitivity for ZEN and potential application prospect.

Postmortem metabolic fingerprinting in death investigations

Explore the possibility of using postmortem metabolic fingerprinting for determine cause of death. We have previously demonstrated that the low-weight molecules present in a biological system after death has the potential to reflect the events leading up to death. That molecular overview (i.e. the postmortem metabolome) could potentially be used as a fingerprint useful in determining the cause of death. In Sweden, approximately five thousand forensic autopsies are carried out each year where approximately fifteen hundred cases have died either from drug intoxication ( n ≈800), strangulations by hanging ( n ≈500), pneumonia ( n ≈150) or acidosis ( n ≈50). The aim of this study was to investigate if our toxicological screening could be used to generate a postmortem metabolic fingerprint of autopsy cases that died either from drug intoxication, strangulation by hanging, pneumonia or acidosis. All autopsy cases handled at the Swedish National Board of Forensic Medicine between June 2017 and October 2020, in which the cause of death was opioid and benzodiazepine intoxications, hanging, pneumonia or acidosis, with a toxicological screening in femoral blood, with a BMI between 18,5–30 kg/m 2 , with an age between 30–65 years, were considered for this study. From each of the four causes of death, twenty-nine autopsy cases were randomly selected ( n = 116). The ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF) data were processed using XCMS (R) and evaluated with principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA). Three quarters of the samples ( n = 88) were used for model building while the remaining quarter ( n = 28) were used for external model validation. A simplified model was built with the most pronounced and significant chromatographic peaks. The chromatographic peaks were identified using the online databases METLIN and HMDB. For the training set, with 1355 chromatographic peaks as x-variables a full group separation was observed and with a 100% correct classification of intoxication, hanging, pneumonia and acidosis cases. The model had a R2 and Q2 value of 0.88 and 0.49 respectively, indicating that the model described the data well and that the model was reproducible. For the validation set, 82% of the samples were correctly classified. In a simplified model, only based on 20 chromatographic peaks (e.g. acylcarnitines, aminoacids, ketonbodies, polyethyleneglycols, steroid hormones), 72% of the cases in the validation set were correctly classified. This study demonstates that postmortem metabolic fingerprinting could potentially be used as a quick screening approach in search of plausible cause of death which could be a vital addition in death investigations. Further, several of the identified chromatographic peaks seemed to be biologically relevant. For example, increased levels of cortisone and decreased levels of LysoPC observed in the pneumonia cases could reflect the severity of illness and the prolonged agonal period expected in pneumonia cases in comparison to the other cases. Furthermore, decreased levels of acylcarnitines were observed in the intoxication cases which could reflect the respiratory function and the mitochondrial activity, being an indicator for respiratory depression. Postmortem metabolic fingerprints is a promising tool in death investigations, but more studies are needed to fully explore its potential.

Studies on the Stability of Binding Media in Retouching Materials for Exterior Painted Wooden Decoration in Taiwan

The conservation of tradition polychrome in Taiwan adopted Western techniques from the beginning of twentieth century. However, the issue of whether such materials are suitable to the climate of Taiwan is a question that remains unanswered. The objective of this study was to assess the durability of three retouching binders under the external climate conditions of Taiwan. The binders that were tested included a watercolour coated with 5% acrylic resin Paraloid B72, an acrylic resin Paraloid B72 and a low molecule weight resin Laropal A81 using accelerated aging conditions that simulated the exterior climate of Taiwan. Alterations in colour, gloss, adhesion and solubility were measured to evaluate the stability and reversibility of the materials. The results showed that both watercolour coated with 5% Paraloid B72 and Laropal A81 had lower resistance to moisture, and thus are not recommended for use in exterior areas in Taiwan. Paraloid B72 remained more stable with good re-treatability after ageing, however it was still affected by UV/heat and condensation cycles. The observation of material behaviour in the study provides information for the selection of retouching materials for exterior Taiwanese traditional polychrome, and highlights the need for further systematic testing of suitable materials in the future.

Cloning and Expression of Heparinase Gene from a Novel Strain Raoultella NX-TZ-3-15.

Heparin is a class of highly sulfated, acidic, linear, and complex polysaccharide that belongs to the heparin/heparan sulfate (HS) glycosaminoglycans family. Enzymatic depolymerization of heparin by heparinases is a promising strategy for the production of ultra-low molecular weight heparins (ULMWHs) as anticoagulants. In the present study, a novel heparinase-producing strain Raoultella NX-TZ-3-15 was isolated and identified from soil samples. Herein, the heparinase gene MBP-H1 was cloned to the pBENT vector to enable expression in Escherichia coli. The optimized conditions made the activity of recombinant heparinase reach the highest level (2140 U/L). The overexpressed MBP-H1 was purified by affinity chromatography and a purity of more than 90% was obtained. The condition for biocatalysis was also optimized and three metal ions Ca2+, Co2+, and Mg2+ were utilized to activate the reaction. In addition, the kinetics regarding the new fusion heparinase was also determined with a Vm value of 11.29μmol/min and a Km value of 31.2μmol/L. In short, due to excellent Km and Vmax, the recombinant enzyme has great potential to be used in the clinic in medicine and industrial production of low or ultra-low molecule weight heparin.

Legumain/pH dual-responsive lytic peptide–paclitaxel conjugate for synergistic cancer therapy

After molecule targeted drug, monoclonal antibody and antibody–drug conjugates (ADCs), peptide–drug conjugates (PDCs) have become the next generation targeted anti-tumor drugs due to its properties of low molecule weight, efficient cell penetration, low immunogenicity, good pharmacokinetic and large-scale synthesis by solid phase synthesis. Herein, we present a lytic peptide PTP7-drug paclitaxel conjugate assembling nanoparticles (named PPP) that can sequentially respond to dual stimuli in the tumor microenvironment, which was designed for passive tumor-targeted delivery and on-demand release of a tumor lytic peptide (PTP-7) as well as a chemotherapeutic agent of paclitaxel (PTX). To achieve this, tumor lytic peptide PTP-7 was connected with polyethylene glycol by a peptide substrate of legumain to serve as hydrophobic segments of nanoparticles to protect the peptide from enzymatic degradation. After that, PTX was connected to the amino group of the polypeptide side chain through an acid-responsive chemical bond (2-propionic-3-methylmaleic anhydride, CDM). Therefore, the nanoparticle (PPP) collapsed when it encountered the weakly acidic tumor microenvironment where PTX molecules fell off, and further triggered the cleavage of the peptide substrate by legumain that is highly expressed in tumor stroma and tumor cell surface. Moreover, PPP presents improved stability, improved drug solubility, prolonged blood circulation and significant inhibition ability on tumor growth, which gives a reasonable strategy to accurately deliver small molecule drugs and active peptides simultaneously to tumor sites.