Assessing activated sludge morphology by laser and image analysis

An excess of filamentous bacteria is a common settlement problem affecting the activated sludge process. In this study activated sludge morphology was monitored by image analysis and laser scattering. These were compared with the conventional sludge volume index. Good correlations between the two optical techniques for floc size were found when the small and interfering particles (< 50 m) were removed from the analysis (activated sludge size 100–500 m). A simpler image analysis procedure was developed using common software and equipment available in most laboratories. This should enable reproducible microbial morphology measurements to be used more widely routinely to predict the onset of poor settlement. The image analysis was used to determine the standard index of filamentinduced poor settlement, namely the total extended filament length. The results in common with some previously noted work did not show a simple link between either floc size or total extended filament length and sludge volume index. A new indicator of excess filaments is suggested, based on the frequency of occurrence of just the long extended filaments (> 100 m) which was shown to give better prediction of poor settlement (bulking)

Gender Gaps in the Measurement of Public Opinion About Homosexuality in Cross-national Surveys: A Question-Wording Experiment

Measures of attitudes towards homosexuality in cross-national studies have received criticism for not being ‘gender-sensitive’. The current study used a split-ballot design allowing for separate analyses of the attitudes towards ‘gay men and lesbian women’, ‘gay men’, and ‘lesbian women’ in a pooled sample of 3,381 participants from Great Britain, Hungary, and Portugal. Analyses controlling for sociodemographics showed that differences in attitudes towards male and female targets were generally small and did not interact with the gender of the rater. In addition, results showed that men’s attitudes towards homosexuality were more strongly related to their gender ideology than women’s attitudes. Implications of these findings for cross-national studies measuring attitudes towards homosexuality are discussed

Penggunaan Metode Eksperimen Pada Pembelajaran Materi Sifat Bahan Dan Kegunaannya Terhadap Hasil Dan Respon Belajar Siswa Kelas IV Min Tungkob Aceh Besar

The research on the use of experimental methods in learning characteristics of material and its usefulness toward students\u27 achievements and learning responses of Level 4 primary school students of MIN Tungkob Aceh Besar aims to determine students\u27 learning outcomes and responses toward the use of the method. This study uses experimental research. The data collection techniques were using test and distributing questionnaire to the students. The samples in this experimental study were students of class IV3 totaling 34 people as the experimental class and the class IV4 totaling 31 people as the control class. The data, which is the students\u27 learning outcomes collected from pretest and posttest, were analyzed using t-test formula. The data from the students\u27 questionnaire responses were analyzed using percentage formula.The result was that the students\u27 learning outcomes from the experimental class and the control class showed significant differences. Students\u27 responses toward the use of experimental methods in learning material characteristics and its usefulness were also very positive, where the students are very excited and interested in learning to use the experimental method in the study of material characteristics and its usefulness

Characterization of activated sludge processes by particle and floc analysis

Monitoring and control of activated sludge mostly use non-microbial specific parameters (e.g. SS, COD, BOD etc.). This thesis suggests they are no longer precise enough to give adequate reliability of the removal of N and P to meet the new standards. Basic theory points to the importance of mass transfer, diffusion and biochemical reaction rates in determining microbial morphology and therefore settlement. These phenomena are influenced by particle characteristics both of the feed and the floc itself. The thesis researches particle and floc characteristics and correlates their variability with the changes in waste characteristics, biodegradability, settleability, plant design (nitrifying, non-nitrifying, biological phosphorus removal and MBR) and effluent quality. [Continues.

Proton Diffusion across Membranes of Vesicles of Poly(styrene-<i>b</i>-acrylic Acid) Diblock Copolymers

A study of proton diffusion across membranes of block copolymer vesicles in dilute solution is described. The vesicles were formed by the self-assembly of a diblock copolymer of poly(styrene-b-acrylic acid) (PS310-b-PAA36, where the numbers represent the degree of polymerization for individual blocks). A pH gradient was created across the vesicle membrane with the interior pH (pHin) of ca. 2.9 and the exterior pH (pHout) of ca. 8.5. The permeability of the polystyrene (PS) membrane was tuned by the addition of different amounts of dioxane (0−40 wt %) to the external aqueous solution. Proton concentrations in the solution outside of the vesicles were followed by monitoring the spectrum of a pH-sensitive fluorescent dye, namely 8-hydroxypyrene-1,3,6-trisulfonate. After the start of the experiment, the proton concentrations increase linearly with the square root of time, while the slopes of the lines increase with dioxane content. To calculate the diffusion coefficients of the protons across the vesicular membrane, the concentration data were fitted using a model, which describes the diffusion of species across the membrane of a reservoir. The apparent diffusion coefficient (D*, which equals the true diffusion coefficient multiplied by the partition coefficient of protons between PS and water) increases from 1.1 × 10-18 cm2/s at 7 wt % dioxane in the external solution to 1.2 × 10-14 cm2/s at 40 wt %. The increase of D* with dioxane content is related to its plasticization of the PS membrane, which can be used as a gating mechanism

One-Step and Facile Synthesis of Poly(phenylalanine) as a Robust Drug Carrier for Enhanced Cancer Therapy

In recent decades, many poly­(amino acid)­s have been successfully prepared for various biomedical applications. To date, the synthesis and purification procedures used to generate these poly­(amino acid)­s have generally been complicated and costly. Here, a one-step synthesis strategy was developed and optimized via direct polymerization using thionyl chloride to easily and economically obtain poly­(amino acid)­s. Phenylalanine (Phe) was selected as a model amino acid to construct a family of biodegradable and biocompatible poly­(phenylalanine) (PPhe) molecules with a tunable molecular weight. The prepared PPhe can self-assemble into nanoparticles (PP-NPs) through nanoprecipitation with a particle size of approximately 100 nm. PP-NPs exhibit a high drug-loading capacity (>12 wt %) of paclitaxel (PTX, a commercial antitumor drug) and good therapeutic effects in CT26 cells. The in vivo evaluation of PTX@PP-NPs indicates that it has a prolonged blood circulation time and high tumor aggregation after intravenous injection, resulting in significant antitumor effects in CT26 tumor-bearing mice with minimal toxicity to normal organs. Overall, this study provides a facile and simple strategy for synthesizing poly­(amino acids) and a PPhe-based nanoparticle platform for effectively delivering various small-molecule drugs

Development of a Lysine-Based Poly(ester amide) Library with High Biosafety and a Finely Tunable Structure for Spatiotemporal-Controlled Protein Delivery

With the fast growth of protein therapeutics, efficient, precise, and universal delivery platforms are highly required. However, very few reports have discussed the progress of precisely spatiotemporal-controlled protein delivery. Therefore, a mini library of well-designed amino acid-based poly(ester amide)s derived from lysine (Lys-aaPEAs) has been developed. Lys-aaPEAs can interact with and encapsulate proteins into nanocomplexes via electrostatic interactions. The chemical structure of Lys-aaPEAs can be finely tuned by changing the type and molar ratio of the monomers. Studies of structure–function relationships reveal that the carbon chain length of diacid/diol segments, hydrophilicity, and electrical properties affect the polymer–protein interaction, cell–material interaction, and, therefore, the outcome of protein delivery. By modulating the structures of Lys-aaPEAs, the delivery systems could present customized physiochemical and biological properties and perform time- and space-specific protein release and delivery without causing any systematic toxicity. The screened systems exhibited prolonged hypoglycemic activity and superior biosafety in vivo, using insulin as a model protein and a mouse model bearing type 1 diabetes mellitus (T1DM). This work establishes a novel lysine-based polymer platform for spatiotemporal-controlled protein delivery and offers a paradigm of precise structure–function controllability for designing the next generation of polymers

In Situ Preparation of Stabilized Iron Sulfide Nanoparticle-Impregnated Alginate Composite for Selenite Remediation

Iron sulfide (FeS) nanoparticles have been applied for selenite (Se­(IV)) remediation in recent decades. However, the easy aggregation and oxidization of FeS hamper their reactivity. In this study, in situ immobilization technology was applied to prepare FeS nanoparticle-impregnated alginate composite (FeS-SA) for Se­(IV) remediation. FeS-SA removed 100% of the Se­(IV) (0.13 mM), whereas pure nonstabilized FeS and sodium alginate (SA) beads eliminated only 27 and 20% of the Se­(IV), respectively. The removal efficiency increased to 73% when pure stabilized FeS was used. Therefore, FeS-SA showed superior removal efficiency that was comparable with the joint effect of pure stabilized FeS and SA beads due to the homogeneous distribution of FeS in SA matrix. Furthermore, minor differences were established in the oxidation retardation effect of FeS exerted by SA beads under anoxic and oxic conditions. The biogenic regenerated FeS-SA still showed 40% removal efficiency for Se­(IV) after five cycles due to the Fe leaching. XPS technique combined with the reference compounds and electron balance revealed that FeSe and metal selenium were the main selenium species after treatment. This in situ preparation of stabilized FeS-SA exhibited an excellent application prospect in the remediation of Se­(IV)

Biomimetic Regulation of Microbially Induced Calcium Carbonate Precipitation Involving Immobilization of <i>Sporasarcina pasteurii</i> by Sodium Alginate

Many researchers in the past decade have explored the controlled synthesis of calcium carbonate with specific size, morphology, and polymorphism. This study explored the biomimetic regulation of microbially induced calcium carbonate precipitation (MICP) via employing immobilization technology. Calcium alginate gel was used to immobilize <i>Sporosarcina pasteurii</i>, a urea-positive microorganism. CO₃^2– was generated driven by ureolysis and reacted directly with Ca²⁺ that was cross-linked in sodium alginate to produce CaCO₃ precipitation. Based on SEM, TEM, XRD, HRTEM, and SAED results, amorphous calcium carbonate, vaterite, and calcite appeared in order. This evolution of CaCO₃ morphology and polymorphism apparently conforms to Ostwald’s rule. Various concentrations (1–3%) of sodium alginate caused different alginate molecules to form due to the collapse of calcium alginate gel carrying negative charges and exerting a significant influence on the morphology of CaCO₃ from hexagonal vaterite to capsule-shaped vaterite. The techniques discussed here can also be applied to other polysaccharides on CaCO₃, which implies that they are valuable with regard to polymorphic regulation because abundant polysaccharide apparently favors the vaterite polymorph

Association between single nucleotide polymorphism of BRCA1-interacting protein C-terminal helicase 1 and early-onset breast cancer in Uygur and Han women in Xinjiang of China

The study investigated the association between single nucleotide polymorphisms (SNPs) of BRCA1-interacting protein C-terminal helicase 1 (BACH1) gene and early-onset breast cancer in Uygur and Han women in Xinjiang. SNPs of BACH1 gene exons were detected by direct sequencing and snapshot technique in 80 Uygur and 80 Han patients with breast cancer and 240 healthy Uygur and 240 healthy Han women (all younger than 40 years old). In Uygur and Han breast cancer patients, the variant C allele of rs4986764 SNP can reduce the risk of breast cancer. The protective effect of this locus is more obvious in Han breast cancer patients without tumor family history (P = 0.001, OR = 0.079). In Uygur breast cancer patients, the GG genotype of rs4986765 (OR = 5.617) and the G genotypes (AG + GG) in the dominant model (OR = 4.254) and the AG of c.587A > G SNP (OR = 7.590) and G genotypes (AG + GG) in the dominant model (OR = 7.590) significantly increased the risk of breast cancer. However, they did not significantly increase the risk of breast cancer in Han population. The present study demonstrates that the rs4986764 mutation of BACH1 gene may reduce the risk of early-onset breast cancer in Uygur and Han populations in Xinjiang. The protective effect was more obvious in Han population without family history of cancer. The change of rs4986765 and c.587A > G sites both increased the risk of breast cancer for Uygur. However, there was no significant correlation with early-onset breast cancer in Han population.</p