Enhanced thermoelectric performance in polymorphic heavily Co-doped Cu2SnS3 through carrier compensation by Sb substitution.

Heavily acceptor-doped Cu2SnS3 (CTS) shows promisingly large power factor (PF) due to its rather high electrical conductivity (σ) which causes a modest ZT with a high electronic thermal conductivity (κe ). In the present work, a strategy of carrier compensation through Sb-doping at the Sn site in Cu2Sn0.8Co0.2S3 was investigated, aiming at tailoring electrical and phonon transport properties simultaneously. Rietveld analysis suggested a complex polymorphic microstructure in which the cation-(semi)ordered tetragonal phase becomes dominant over the coherently bonded cation-disordered cubic phase, as is preliminarily revealed using TEM observation, upon Sb-doping and Sb would substitute Sn preferentially in the tetragonal structure. With increasing content of Sb, the σ was lowered and the Seebeck coefficient (S) was enhanced effectively, which gave rise to high PFs maintained at ~10.4 µWcm-1K-2 at 773 K together with an optimal reduction in κe by 60-70% in the whole temperature range. The lattice thermal conductivity was effectively suppressed from 1.75 Wm-1K-1 to ~1.2 Wm-1K-1 at 323 K while maintained very low at 0.3-0.4 Wm-1K-1 at 773 K. As a result, a peak ZT of ~0.88 at 773 K has been achieved for Cu2Sn0.74Sb0.06Co0.2S3, which stands among the tops so far of the CTS-based diamond-like ternary sulfides. These findings demonstrate that polymorphic microstructures with cation-disordered interfaces as an approach to achieve effective phonon-blocking and low lattice thermal conductivity, of which further crystal chemistry, microstructural and electrical tailoring are possible by appropriate doping.

A cold responsive ethylene responsive factor from Medicago falcata confers cold tolerance by up-regulation of polyamine turnover, antioxidant protection, and proline accumulation.

Ethylene responsive factor (ERF) subfamily transcription factors play an important role in plant abiotic and biotic stress tolerance. A cold responsive ERF, MfERF1, was isolated from Medicago falcata, an important forage legume that has great cold tolerance. Overexpression of MfERF1 resulted in an increased tolerance to freezing and chilling in transgenic tobacco plants, whereas down-regulation of the ortholog of MfERF1 in Medicago truncatula resulted in reduced freezing tolerance in RNAi plants. Higher transcript levels of some stress responsive genes (CHN50, OSM, ERD10C, and SAMS) and those involved in spermidine (Spd) and spermine (Spm) synthesis (SAMDC1, SAMDC2, SPDS1, SPDS2, and SPMS) and catabolism (PAO) were observed in transgenic plants than in wild type. However, neither Spd nor Spm level was accumulated in transgenic plants as a result of promoted polyamine oxidase activity. Transgenic plants had higher activities of antioxidants associated with the induced encoding genes including Cu, Zn-SOD, CAT1, CAT2, CAT3, and cpAPX and accumulated more proline associated with induced P5CS and reduced PROX2 transcription as compared with wild type. The results suggest that MfERF1 confers cold tolerance through promoted polyamine turnover, antioxidant protection, and proline accumulation.

Recent advances in microRNA detection.

The development of simple, robust, and reliable microRNA (miRNA) detection methods is of great significance in the studies of the biological function of miRNAs, molecular diagnostics, treatment of diseases, and targeted drugs. In recent years, with the increasing development of miRNA research, lots of novel approaches were developed for the detection of miRNA in terms of sensitivity, specificity, multiplicity, in situ imaging, etc. In particular, nucleic acid amplification-based methods and many detection techniques such as droplet digital PCR (ddPCR), electrochemiluminescence (ECL), surface-enhanced Raman spectroscopy (SERS), and mass spectrometry (MS) have been employed widely for the highly sensitive detection of miRNA. New progress in miRNA detection has accelerated miRNA functional research and clinical diagnostics. In this review, we summarize the recent progress in the development of miRNA detection methods and new applications. This review will provide guidelines for the development of more advanced miRNA detection methods with high sensitivity and specificity, and applicability to biochemical research, disease diagnosis and therapy.

Adsorbing low concentrations of Cr(VI) onto CeO2@ZSM-5 and the adsorption kinetics, isotherms and thermodynamics.

The CeO2@ZSM-5 was prepared by the dipping method. We used ZSM-5 and CeO2 as the carrier and load components, respectively. The aim was to reduce the low concentration of Cr(VI) in simulated wastewater (the concentration of Cr(VI) ranged from 0.2 to 1 mg/L). The characteristics of ZSM-5 and CeO2@ZSM-5 samples were determined by X-ray powder diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and Brunauer-Emmett-Teller (BET). Characterization results showed that the particle size, BET surface area and pore volume for CeO2@ZSM-5 was around 0.783 nm, 421.307 m2/g and 0.313 m3/g, respectively. In addition, the optimum conditions were obtained by the orthogonal test, and the details were as follows: optimal pH, adsorbent dose, initial concentration of Cr(VI) and equilibrium time were 3, 5 g/L, 0.6 mg/L and 70 min respectively. The removal of Cr(VI) was 99.56% in these conditions. The pseudo-second-order model best described the adsorption kinetics of Cr(VI) onto CeO2@ZSM-5. Isotherm data were treated according to Langmuir, Freundlich and Temkin isotherm models. The results showed that the Freundlich adsorption isotherm model fitted best in the temperature range studied. Adsorption capacity increased with temperature, showing the endothermic nature of Cr(VI) adsorption. The desorption results showed the best recovery of Cr(VI) using 0.1 M HCl.

Association Between Postoperative Decrease of Albumin and Outcomes in Patients Undergoing Craniotomy for Brain Tumors.

BACKGROUND: Serum albumin reflects nutritional status and is associated with postoperative complications and mortality. Delta albumin (ΔAlb), defined as the difference between preoperative and lowest postoperative levels, could predict complications and mortality, even with postoperative levels above 30 g/L prompting albumin infusions. This study aimed to assess how ΔAlb relates to outcomes in craniotomy patients with brain tumors. METHODS: This retrospective study screened patients diagnosed with a brain tumor who underwent cerebral surgery from a single Chinese hospital between December 2010 and April 2021. Patients were divided into 4 groups based on their ΔAlb levels: <5 g/L (normal), 5-9.9 g/L (mild ΔAlb), 10-14.9 g/L (moderate ΔAlb), and ≥15 g/L (severe ΔAlb). The primary outcome was postoperative 30-day mortality. RESULTS: Among the 9660 patients undergoing craniotomy for brain tumors, the median ΔAlb level after craniotomy was 7.3 g/L. ΔAlb was associated with increased postoperative 30-day mortality; odds ratios for mild, moderate, and severe ΔAlb were 1.93 (95% confidence interval [CI], 1.17-3.18, P = 0.01), 2.21 (95% CI, 1.28-3.79, P = 0.004), and 7.26 (95% CI, 4.19-12.58, P < 0.01), respectively. Significantly, ΔAlb >5 g/L was found to have a strong association with a higher risk of mortality, even when the nadir Alb remained greater than 30 g/L (odds ratio, 1.84; 95% CI, 1.13-3.00, P = 0.014). CONCLUSIONS: Among patients undergoing craniotomy for brain tumor resection, a mild degree of ΔAlb was associated with increased 30-day mortality, even if the nadir Alb remained greater than 30 g/L. Moreover, ΔAlb was associated with postoperative complications and longer lengths of stay.

A cold responsive galactinol synthase gene from Medicago falcata (MfGolS1) is induced by myo-inositol and confers multiple tolerances to abiotic stresses.

Galactinol synthase (GolS, EC 2.4.1.123) catalyzes formation of galactinol and the subsequent synthesis of raffinose family oligosaccharides. The relationship of GolS to drought and salt tolerance has been well documented, however, little information is available about the role of GolS gene in cold tolerance. A coding sequence of MfGolS1 cDNA was cloned from Medicago sativa spp falcata (i.e. M. falcata), a species that exhibits greater cold tolerance than alfalfa (M. sativa). MfGolS1 transcript was not detected in untreated vegetative tissues using RNA blot hybridization; however, it was greatly induced in leaves, but not in stem and petiole, after cold treatment. Higher levels of MfGolS1 transcript were induced and maintained in M. falcata than in M. sativa during cold acclimation. Accordingly, more sugars including sucrose, galactinol, raffinose and stachyose were accumulated in M. falcata than in M. sativa. The data indicated that MfGolS1 transcript and its resultant sugar accumulation were associated with the differential cold tolerance between M. falcata and M. sativa. MfGolS1 transcript was weakly induced by dehydration and salt stresses, but not responsive to abscisic acid. MfGolS1 could be induced by myo-inositol, which is proposed to participate in cold-induced MfGolS1 expression. Overexpression of MfGolS1 in tobacco resulted in elevated tolerance to freezing and chilling in transgenic plants as a result of enhanced levels of galactinol, raffinose and stachyose. Tolerance to drought and salt stresses was also increased in the transgenic tobacco plants. It is suggested that MfGolS1 plays an important role in plant tolerance to abiotic stresses.

18F-FAPI-04 PET/CT parameters predict PD-L1 expression in esophageal squamous cell carcinoma.

Purpose: This prospective study examined whether metabolism parameters obtained using the tracer 18F-AlFNOTA-fibroblast activation protein inhibitor (FAPI)-04 (denoted as 18F-FAPI-04) in positron emission tomography/computed tomography (PET/CT) can predict programmed death ligand-1 (PD-L1) expression in patients with locally advanced esophageal squamous cell carcinoma (LA-ESCC). Patients and methods: The 24 enrolled LA-ESCC patients underwent an 18F-FAPI-04 PET/CT scan. The maximum, mean, peak and standard deviation standard uptake values (SUVmax, SUVmean, SUVpeak and SUVsd), metabolic tumor volume (MTV), and total lesion FAP (TLF) expression of the primary tumor were collected. Additionally, we evaluated PD-L1 expression on cancer cells by immunohistochemistry and immunofluorescence methods. Patients were divided into negative and positive expressions according to the expression of PD-L1 (CPS < 10 and CPS ≥ 10), and the variables were compared between the two groups. Results: The SUVmax, SUVmean, SUVpeak and SUVsd were significantly higher in patients with positive expression than in negative expression (all p < 0.05). Receiver operating characteristic curve analysis identified SUVmean (area under the curve [AUC] = 0.882, p = 0.004), SUVsd (AUC = 0.874, p = 0.005), SUVpeak (AUC = 0.840, p = 0.010) and SUVmax (AUC = 0.765, p = 0.045) as significant predictors of the PD-L1 positive expression, with cutoff values of 9.67, 1.90, 9.67 and 13.71, respectively. On univariate logistic regression analysis, SUVmean (p = 0.045), SUVsd (p = 0.024), and SUVpeak (p = 0.031) were significantly correlated with the PD-L1 positive expression. On multivariable logistic regression analysis, SUVsd (p = 0.035) was an optimum predictor factor for PD-L1 positive expression. Conclusion: 18F-FAPI-04 PET/CT parameters, including SUVmean, SUVpeak, and SUVsd, correlated with PD-L1 expression in patients with LA-ESCC, and thus SUVsd was an optimum predictor for PD-L1 positive expression, which could help to explore the existence of immune checkpoints and select ESCC candidates for immunotherapy.

Clinical value of 18F-FDG PET/CT to predict MYCN gene, chromosome 1p36 and 11q status in pediatric neuroblastoma and ganglioneuroblastoma.

Objective: To explore the value of 18F-2-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET)/computed tomography(CT) in MYCN gene and chromosome 1p36 and 11 statuses in newly diagnosed pediatric NB(neuroblastoma) and GNB(ganglioneuroblastoma). Methods: We retrospectively analyzed newly diagnosed patients with 48 NB and 12 with GNB in our hospital. The data obtained from the clinical medical records included age, sex, pathologic type, and laboratory parameters such as lactate dehydrogenase (LDH), neuron-specific enolase (NSE) and the status of MYCN gene and chromosome 1p36 and 11q. The bone conditions were also obtained in the examination of bone marrow biopsy. Primary tumors were manually segmented to measure the maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), tumor volume(MTV) and total lesion glycolysis(TLG) and the maximal length of the lesion in the axial image(LEGmax). Results: The differences in bone marrow involvement and lymph node metastases in patients with chromosome 11q deletions were statistically significant (all p < 0.05). Chromosome 11q deletion was an independent factor affecting bone marrow involvement (OR=17.796, p=0.011). The levels of NSE, LDH, LEGmax and SUVmax, SUVmean, MTV, TLG all predicted MYCN gene amplification (all p < 0.05). The levels of LDH, LEGmax and MTV, TLG all predicted deletions in chromosomes 1p36 (all p < 0.05), while NSE, SUVmax and SUVmean did not (all p > 005). Conclusion: The LDH levels, LEGmax, MTV and TLG can effectively predict the status of the MYCN oncogene and chromosome 1p36 in pediatric neuroblastoma and ganglioneuroblastoma. Those patients with chromosome 11q deletions are more likely to develop bone marrow involvement and lymph node metastases, showing a worse progression-free survival.

Oral cavity-derived stem cells and preclinical models of jaw-bone defects for bone tissue engineering.

BACKGROUND: Jaw-bone defects caused by various diseases lead to aesthetic and functional complications, which can seriously affect the life quality of patients. Current treatments cannot fully meet the needs of reconstruction of jaw-bone defects. Thus, the research and application of bone tissue engineering are a "hot topic." As seed cells for engineering of jaw-bone tissue, oral cavity-derived stem cells have been explored and used widely. Models of jaw-bone defect are excellent tools for the study of bone defect repair in vivo. Different types of bone defect repair require different stem cells and bone defect models. This review aimed to better understand the research status of oral and maxillofacial bone regeneration. MAIN TEXT: Data were gathered from PubMed searches and references from relevant studies using the search phrases "bone" AND ("PDLSC" OR "DPSC" OR "SCAP" OR "GMSC" OR "SHED" OR "DFSC" OR "ABMSC" OR "TGPC"); ("jaw" OR "alveolar") AND "bone defect." We screened studies that focus on "bone formation of oral cavity-derived stem cells" and "jaw bone defect models," and reviewed the advantages and disadvantages of oral cavity-derived stem cells and preclinical model of jaw-bone defect models. CONCLUSION: The type of cell and animal model should be selected according to the specific research purpose and disease type. This review can provide a foundation for the selection of oral cavity-derived stem cells and defect models in tissue engineering of the jaw bone.

Case report: Imaging findings of true thymic hyperplasia at 18F-FDG PET/CT in an infant.

True thymic hyperplasia (TTH) in children is rare and difficult to distinguish from other thymic tumors such as thymoma and thymic carcinoma. A 3-year-old girl underwent an 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) scan (18F-FDG PET/CT) and a chest CT scan to evaluate an anterior mediastinal mass. 18F-FDG PET/CT revealed a mediastinal mass showing heterogeneously increased FDG uptake with a maximum standardized uptake value (SUVmax) of 7.1. Eventually, postoperative pathological diagnosis demonstrated TTH. So far, there are no reports of 18F-FDG PET/CT imaging of this disease.

Succinate/IL-1ß Signaling Axis Promotes the Inflammatory Progression of Endothelial and Exacerbates Atherosclerosis.

Inflammation is an important driver of atherosclerosis. Succinate is a new extracellular inflammatory alarm released by activated macrophages. Succinate is sensed by succinate receptor 1 (Sucnr1) and then transferred to effector cells. It is worth exploring whether succinate is capable of facilitating the inflammatory response in atherosclerosis. In this study, we firstly found that arterial serum of Coronary Heart Disease (CHD) patients contained significantly higher succinate and interleukin (IL)-1ß than Health control (HC) subjects, and succinate was positively correlated with IL-1ß. As demonstrated by the in vitro study, succinate/hypoxia-inducible factor 1α (Hif)-1α/IL-1ß signal axis existed and significantly facilitated the inflammatory program in human umbilical vein endothelial cells (HUVECs). Under the coculture, activated macrophages released succinate, which would be transferred to HUVECs via Sucnr1 and then activate Hif-1α to produce a greater amount of IL-1ß. Likewise, the aortic sinus's inflammatory phenotype was found to be more significant within Apoe-/- mice that were injected with succinate. Furthermore, Sucnr1 inhibitor (NF-56-EJ40) could significantly interrupt succinate/IL-1ß signal in HUVECs and macrophages. As revealed by this study, glycolytic metabolism following the release of succinate could be found in atherosclerotic pathology, and succinate would drive succinate/IL-1ß signal dependent on Sucnr1 and then exacerbate inflammatory responses. Sucnr1 might be a novel target for cutting off the transduction of succinate signal to prevent the inflammation of atherosclerosis.

[Separation of chemical compositions in root of Rumex patientia L. with off-line two-dimensional liquid chromatography].

An innovative analytical method based on the off-line two-dimensional reversed-phase/reversed-phase liquid chromatography (2D-RPLC/RPLC) was established to separate the components of root of Rumex patientia L. The chromatograms of ethyl acetate extract of root of Rumex patientia L. on a phenyl/tetrazolium column (250 mm×4.6 mm, 7 µm) and a Unitary C18 column (250 mm×4.6 mm, 7 µm) were compared, and they showed different separation abilities. A phenyl/tetrazolium column was used for the first dimensional separation with 0.1% (v/v) formic acid aqueous solution and methanol as mobile phases, and 18 fractions was collected. The second dimensional liquid chromatography analysis was carried out on a Unitary C18 column with 0.1% (v/v) formic acid aqueous solution and methanol as mobile phases. Based on the experiment setup and results, it was concluded that off-line 2D-LC can be an effective method for the separation of the trace components and the screening of active compounds of root of Rumex patientia L.

Strategy for the Realization of Highly Efficient Solution-Processed All-Fluorescence White OLEDs-Encapsulated Thermally Activated Delayed Fluorescent Yellow Emitters.

Fabrication of highly efficient all thermally activated delayed fluorescence (TADF) white organic light-emitting diodes (WOLEDs) through solution-process still remains a big challenge. Here, two encapsulated TADF molecules with a small singlet-triplet energy gap (Δ EST) and high photoluminescence quantum yield (PLQY) were designed and synthesized as yellow emitters for solution-processed WOLEDs. The high current, power, and external quantum efficiencies of 41.6 cd A-1, 30.4 lm W-1, and 17.3% were achieved for the solution-processed all-fluorescence WOLEDs with a single-emission layer. In contrast, even with the same Δ EST and PLQY, the corresponding unencapsulated parent emitters will account for nearly 50% loss of the potential device efficiency. This is for the first time that the small molecular TADF blue host and TADF yellow guest are used to construct solution-processed all-fluorescence WOLEDs, which exhibit high efficiency comparable with most of the vacuum-deposited all-fluorescence white devices. These results not only demonstrate the great potential of TADF emitters in achieving highly efficient solution-processed WOLEDs, but also testify the key role of molecular encapsulation in reducing polar-exciton quenching and enhancing electroluminescence performance.

A high-nuclearity isopolyoxotungstate based manganese cluster: one-pot synthesis and step-by-step assembly.

A manganese(iii,iv)-tungsten(vi) supercluster based on 72 manganese ions (48 MnIV and 24 MnIII) and 48 tungsten(vi) centers [{MnIV24MnIII12O28(H2O)23}2(W24O120)2]40- has been prepared from the carboxylic Mn12 cluster. Its structure comprises two unprecedented cage-like Mn36W24 cores linked via two Mn-O-W bonds, leading to a Mn72W48 assembly. The inorganic synthetic mechanism was investigated through different synthesis methods and comprehensive ESI-MS tests.

Facile Fabrication of Ordered Component-Tunable Heterobimetallic Self-Assembly Nanosheet for Catalyzing "Click" Reaction.

How to maximize the number of desirable active sites on the surface of the catalyst and minimize the number of sites promoting undesirable side reactions is currently an important research topic. In this study, a new way based on the synergism to achieve the successful fabrication of an ordered heterobimetallic self-assembled monolayer (denoted as BMSAM) with a controlled composition and an excellent orientation of metals in the monolayer was developed. BMSAM consisting of phenanthroline and Schiff-base groups was prepared, and its novel heterobimetallic (Cu and Pd) self-assembled monolayer anchored in silicon (denoted as Si-Fmp-Cu-Pd BMSAM) with a controlled composition and a fixed position was fabricated and characterized by UV, cyclic voltammetry, Raman, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), X-ray diffraction (XRD), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and water-drop contact angle (WDCA) analyses. The effects of Si-Fmp-Cu-Pd BMSAM on its catalytic properties were also systematically investigated using "click" reaction as a template by WDCA, XPS, SEM, XRD, ICP-AES and in situ Fourier transform infrared analyses in a heterogeneous system. The results showed that the excellent catalytic characteristic could be attributed to the partial (ordered or proper distance) isolation of active sites displaying high densities of specific atomic ensembles. The catalytic reaction mechanism of the click reaction interpreted that the catalytic process mainly occurred on the surface of the monolayer, internal active site (Pd) and rationalized that the Cu(I) species and Pd(0) reduced from the Cu(II) and Pd(II) catalyst were active species, which had a proper distance between two different metals. The cuprate-triazole intermediate and the palladium intermediate, whose production is the key step, should lie in a proper position between the copper and active palladium sites, with which the reaction rate of transmetalation would be improved to increase the amount of the undesired Sonogashira coupling product.

Phase I study of postoperative radiotherapy concurrent with S-1 in patients with gastric cancer.

Postoperative chemoradiotherapy (CRT) with concurrent 5-fluorouracil is the standard care for gastric cancer patients after curative surgery. The previous studies revealed that the subgroup of patients with high recurrence risk would benefit most from adjuvant CRT. S-1, a novel oral fluorouracil, has showed very effective in metastatic gastric cancer and became the standard option for gastric cancer with D2 dissection. The safety and dosage of S-1 combined with postoperative radiotherapy have not yet been evaluated. This study is to determine the maximum tolerate dose (MTD) and dose-limiting toxicity (DLT) of S-1 given concurrently with postoperative high-dose radiotherapy in gastric cancer. Patients with more advanced stage (pT4 and/or pN+) after R0 resection were recruited. Eligible patients received one cycle standard SOX (S-1 plus oxaliplatin) chemotherapy, then S-1 monotherapy with concurrent radiotherapy for 6 weeks, followed by additional three cycles of SOX. During the concurrent CRT, S-1 was administered on every radiotherapy treatment day according to a predefined dose-escalation schedule. Radiotherapy (3D-RT or IMRT) was given to a total dose of 50.4 Gy in 28 fractions. DLT was defined as grade 3 or 4 hematologic and non-hematologic toxicity. From March 2011 to October 2012, 21 patients were enrolled at five dose levels: 40 (n = 3), 50 (n = 3), 60 (n = 6), 70 (n = 6) and 80 mg/m(2)/day (n = 3). D2-dissection was performed in 18 patients (85.7 %) and 15 patients (71.4 %) had stage III disease. The most common dose-related toxicity was anorexia, nausea and vomiting, fatigue and leucopenia. DLT was occurred in one patient at 60 mg/m(2)/day (grade 3 fatigue), one patient at 70 mg/m(2)/day (grade 3 vomiting and anorexia), two patients at 80 mg/m(2)/day (one with grade 3 vomiting and anorexia; another with grade 3 febrile leucopenia). Four patients did not complete CRT as planned. Overall, this phase I study demonstrated that postoperative CRT with daily S-1 was feasible in gastric cancer and the MTD of S-1 concurrent with radiotherapy was 70 mg/m(2)/day. This S-1-based postoperative CRT will be investigated in a multicenter phase III study in West China.

Spectral studies on aluminum ion binding to the ligands with phenolic group(s): implications for the differences between N- and C-terminal binding sites of human serum apotransferrin.

Both the binding and releasing of ferric ions in C-, and N-terminal binding sites of human serum transferrin are different. To understand the difference here the interactions of aluminum with the ligands containing phenolic group(s), including 8-hydroxyquinoline, salicylic acid, N,N'-di(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid, N,N'-ethylenebis[2-(o-hydroxyphenolic)glycine], and human serum apotransferrin, respectively, are investigated by using UV difference and fluorescence spectra methods in 0.1 M N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid at pH 7.4. Aluminum binding produces a UV difference peak near 235 nm that is characteristic of phenolic groups binding to aluminum. The peak at 235 nm has been used to determine conditional binding constants of log K(Al-HBED)=8.88+/-0.74 and log K(Al-EHPG)=9.38+/-0.03. However, the effects of aluminum binding on the fluorescence intensity of N,N'-ethylenebis[2-(o-hydroxyphenolic)glycine], salicylic acid and N,N'-di(2-hydroxybenzyl) ethylenediamine-N,N'-diacetic acid, 8-hydroxyquinoline are disparate, the former showing a decrease and the latter an increase. At pH 7.4, there is N cdots, three dots, centered H-O type intramolecular hydrogen bond in 8-hydroxyquinoline, N,N'-di(2-hydroxybenzyl) ethylenediamine-N,N'-diacetic acid and O cdots, three dots, centered H-O type intramolecular hydrogen bond in salicylic acid, N,N'-ethylenebis[2-(o-hydroxyphenolic)glycine]. The effects of salts on the fluorescence intensity of the ligands containing phenolic group(s) show that fluorescence emission increases with the breaking of an N cdots, three dots, centered H-O type intramolecular hydrogen bond and fluorescence emission decreases with the breaking of an O cdots, three dots, centered H-O type intramolecular hydrogen bond. Fluorescence titrations of apotransferrin and both forms of monoferric transferrin with aluminum indicated that there is O cdots, three dots, centered H-O type intramolecular hydrogen bonds for the phenolic groups of Tyr426 and Tyr517 in the C-terminal binding site. While N cdots, three dots, centered H-O type intramolecular hydrogen bonds are found for the phenolic groups of Tyr95 and Tyr188 in the N-terminal binding site.

Change of handedness in cholesteric liquid crystalline phase for N-phthaloylchitosan solutions in organic solvents.

The influence of concentration on the helicoidal change of N-phthaloylchitosan (PhCh) solutions in Me2SO, DMAc and DMF was investigated by means of circular dichroism (CD). The critical concentrations to form liquid crystal phase in these three solvents were 43, 45 and 48 wt.%, respectively as measured with polarized optical microscope. There were two kinds of CD peaks, sharp peaks with absorption maximum at about 330 nm induced by the helical conformation of molecular chain, and very broad peaks covering almost whole visible region induced by the cholesteric helix of mesophase. The later only appeared in concentrated solutions with the concentration higher than the critical concentration. The handedness of both levels of helicoidal structures changed from left- to right-handed with the increase of concentration for PhCh/Me2SO solutions. The chirality transfer occurred between these two chiral levels. For PhCh/DMAc and PhCh/DMF systems, only the handedness of helical conformation reversed, but the cholesteric helix did not change. As a method to measure critical concentration, CD is more sensitive than polarized optical microscopy (POM).

Nitrate removal from aqueous solution by Arundo donax L. reed based anion exchange resin.

Arundo donax L. reed based anion exchange resin (ALR-AE resin) was prepared by the amination reaction for the adsorption of nitrate from aqueous solution. The physicochemical properties of the ALR-AE resin as well as its adsorption properties for nitrate were measured. Results indicated that large amounts of amine groups have been grafted onto the structure of the resin. The FTIR and Raman spectra validated the ion exchange mechanism for nitrate adsorption by ALR-AE resin. The adsorption data showed an exothermic nature for the adsorption of nitrate by ALR-AE resin, and the equilibrium time for the adsorption process was about 10 min. The maximum adsorption capacity (Q(max)) for nitrate was 44.61 mg/g. The saturated adsorption capacity of ALR-AE resin in column was about 38.9 mg/g, which accounted for about 87.2% of the resin's Q(max). The preferential adsorption capacity of the ALR-AE resin followed the order as: SO(4)(2-)>NO(3)(-) ≈ PO(4)(3-)>NO(2)(-). In addition, the utilization of the resin in actual water samples indicated that the ALR-AE resin could be used for the treatment of many ionic polluted wastewaters.