Palladium (II), platinum (II) and silver (I) complexes with oxazolines: Their synthesis, characterization, DFT calculation, molecular docking and antitumour effects.

Six new Pd(II), Pt(II) and Ag(I) complexes, (1);{Pd (L1)]2C6H4}2Cl4} (2); Pt(L2)(DMSO)Cl; 3; {PtL5]2C6H4}2·PhCOO-⋅11NO3-; 4; {[Pt(L4)]2C6H4}; the binuclear cyclometalated complex the polymer chain (5); {[PtL5]C6H4}·NO3-}; and the polymeric silver species (6); Zn(L6)2·AgNO3·CHCl3 were synthesized and thoroughly characterized using X-ray diffraction and spectroscopic techniques (L1=(S,S)-1,4-i-PrOx]2C6H4}2Cl4, L2=Di(2,2-bis(4R-isopropyl-4,5-dihydro-oxazol-2-yl)acetonitrile) zinc (II) (BR1);L3= 1,4-bis(4R-benzyl-4,5-dihydro-oxazol-2-yl)benzene (AR2); L4= 1,4-bis(4R-benzyl-4,5-dihydro-oxazol-2-yl)benzene，L5=1,4-bis(4R-benzyl-4,5-dihydro-oxazol-2-yl)-benzene，L6=Di(2,2-bis(4S-isopropyl-4,5-dihydrooxazol-2-yl)acetonitrile) zinc (II). Complexes 1-6 showed cytotoxic effects against human tumour cell lines, including a multidrug-resistant subline. Oxazoline and Pd complex 1 induced apoptosis in A549 cells. DFT calculations were also performed to exhibit the excellent bioactivity of complex 1 against A549, MDA-MB-231, and KB cells. Complex 1, with the best docking score and a stable interaction network within the binding site of the G-quadruplex, could stably interact with the G-quadruplex. Additionally, complex 1 was further used in the animal experiment of human lung adenocarcinoma cells in nude mice. By comparing with the model control group, the tumour volume, relative tumour volume and relative tumour proliferation rate T/C decreased significantly in the cisplatin group and compound 1 (complex 1) group.

A successful case of electrical storm rescue after acute myocardial infarction.

BACKGROUND: Electrical storm (ES) is a heterogeneous clinical emergency that can present with malignant ventricular arrhythmias such as ventricular fibrillation (VF), ventricular tachycardia (VT), requiring the need for cardiac defibrillation. ES is a life-threatening condition with a high mortality rate. Successfully managing ES in the setting of acute myocardial infarction (MI) is expected to be known by physicians on call to reduce in-hospital mortality. CASE PRESENTATION: A 57-year-old man presenting with acute onset chest pain was found to have an infero-posterior ST-segment elevation myocardial infarction (STEMI) complicated by acute right ventricular MI secondary to total occlusion of the proximal right coronary artery (RCA). The patient developed ES in the form of recurrent VF that was managed successfully with electrical defibrillation, antiarrhythmic therapy with amiodarone and esmolol, endotracheal intubation, sedation, electrolyte replacement, volume resuscitation, comfort care, psychological intervention, and percutaneous coronary intervention (PCI) of the occluded epicardial artery. With these interventions used in quick succession and with the aspiration of a massive RCA thrombus, the patient was reversed to hemodynamic stability, did not have further episodes of VF, and survived the index hospitalization. CONCLUSION: ES is a rare but fatal complication of acute MI. Residents on night shifts should be better prepared and equipped to deal with this rare condition. We hope our successful experience can benefit physicians on call who take care of acute MI patients that deteriorate with ES.

Synthesis and biological evaluation of mixed-ligand cyclometalated iridium(III)-quinoline complexes.

With the aim of gaining new insight into the underlying apoptosis mechanisms and in vivo efficacy of cyclometalated Ir(III) complexes as metalodrugs, six new cyclometalated Ir(III)-quinoline complexes, [Ir(1a)(2pq)2] (2a), [Ir(1b)(2pq)2] (2b), [Ir(1c)(2pq)2] (2c), [Ir(1d)(2pq)2] (2d), [Ir(1e)(2pq)2] (2e), and [Ir(1f)(2pq)2] (2f) (2pq = 2-phenylisoquinoline), have been synthesized using 5,7-dihalo-8-hydroxylquinoline ligands (1a-1f) and [Ir(2pq)2Cl]2 precursors and characterized. Complexes 2a-2f have shown potent anticancer activity against cisplatin-resistant SK-OV-3/DDP and A549/DDP cells (IC50 = 0.11-1.83 µM), following the order 2e > 2f > 2b > 2c > 2d > 2a. Confocal microscopy images suggest that 2e and 2b could act as red-color probes for specific cell imaging and efficiently initiate apoptosis and autophagy in the mitochondria, cell cytosol, and nucleus. Overexpression of beclin1, caspase-9, cytochrome c, LC3II, and apaf-1; inhibition of p62, cyclin D1, cyclin A2, and CDK2; and a substantial rapid accumulation suggest a paraptotic mode of cell death induced by autophagy, DNA damage, and mitochondrial stress. In addition, the inhibitory rate of 2e on A549/DDP tumor growth was 64.1% at a concentration of 10.0 mg kg-1, which is clearly higher than that of cisplatin. According to the biological assay, the cyclometalated Ir(III)-quinoline complex 2e exhibited a higher anticancer effect than 2b, which may be associated with the electronic effect of the methyl group of the 1e ligand of 2e playing a key role in the mechanism.

An Efficient Turing-Type Ag2 Se-CoSe2 Multi-Interfacial Oxygen-Evolving Electrocatalyst*.

Although the Turing structures, or stationary reaction-diffusion patterns, have received increasing attention in biology and chemistry, making such unusual patterns on inorganic solids is fundamentally challenging. We report a simple cation exchange approach to produce Turing-type Ag2 Se on CoSe2 nanobelts relied on diffusion-driven instability. The resultant Turing-type Ag2 Se-CoSe2 material is highly effective to catalyze the oxygen evolution reaction (OER) in alkaline electrolytes with an 84.5 % anodic energy efficiency. Electrochemical measurements show that the intrinsic OER activity correlates linearly with the length of Ag2 Se-CoSe2 interfaces, determining that such Turing-type interfaces are more active sites for OER. Combing X-ray absorption and computational simulations, we ascribe the excellent OER performance to the optimized adsorption energies for critical oxygen-containing intermediates at the unconventional interfaces.

[Effect of electroacupuncture on expression of stromal cell derived factor-1α in focal ischemic cerebral tissue of rats with cerebral ischemia/ reperfusion injury].

OBJECTIVE: To observe the effect of electroacupuncture (EA) of "Baihui" (GV20) and "Zusanli" (ST36) on the expression of stromal cell derived factor-1α (SDF-1α) and CD34 in ischemic cortex tissue of cerebral ische-mia /reperfusion injury (CI/RI) rats, so as to study its mechanisms underlying improving CI/RI. METHODS: Thirty male SD rats were equally and randomly divided into sham operation, model and EA groups (n=10 rats in each group). The CI/RI model was established by occlusion of the middle cerebral artery for 120 min, followed by reperfusion. EA (40 Hz, 1-2 mA) was applied to GV20 and left ST36 for 20 min, once daily for successive 14 days. The neurological deficit severity was assessed by using Longa's and colleagues' methods. The histopathological changes of the ischemic tissues were observed after H.E. staining and the expression of SDF-1α and CD34 in the ischemic cortex tissues was detected by immunohistochemistry. RESULTS: After modeling, the neurological deficit score, and the numbers of SDF-1α and CD34-positive cells in the ischemic cerebral cortex tissue were significantly increased in the model group (P<0.05). Following EA intervention, the increased neurological deficit score was reversed at the 3rd, 7th and 14th day, and the increased SDF-1α and CD34-positive cells were significantly further up-regulated in the EA group (P<0.05). H.E. staining showed tissue edema, widening of the intercellular space, cavitation-like changes, neuronal shrinkage, nuclear pyknosis with hyperchroma or even disappearance, and aggregation of inflammatory and neurogliocytes in the model group. These situations were relatively milder in the EA group. CONCLUSION: EA of GV20 and ST36 can improve neurological function of CI/RI rats, which may be associated with its effect in up-regulating the expression of SDF-1α and CD34 proteins in the ischemic cerebral cortex tissues.

One-step templated synthesis of chiral organometallic salicyloxazoline complexes.

BACKGROUND: The general approach to the synthesis of metal complexes begins with ligand synthesis, followed by ligand reaction with metal salts to afford organometallic complexes. Our research group first reported a one-pot multicomponent synthesis of chiral oxazolinyl-zinc complexes, in the presence of a large amount of ZnCl2 (0.4-2.6 equiv.), with the yields of some products reaching 90%. RESULTS: Our prior strategy was extended to use copper, cobalt, nickel, manganese, palladium or platinum salts as the third component. The one-step method used 1.0 equivalent of a metal salt, such as M(OAc)2·nH2O or MCl2·nH2O (M: Cu, Co, Ni, Pd or Pt, n = 1, 2 or 4), as a reagent to generate chiral salicyloxazoline complexes 1-8 in the reaction of 2-cyanophenol with different d- and l-amino alcohols. CONCLUSION: Complexes 1-8 were obtained using a one-pot method with a sequential strategy. The reaction outcome was demonstrated for three-component reactions between metal salts, amino alcohols and 2-hydroxybenzonitrile to afford organometallic complexes in good yields (65-95%).

Correction to: One-step templated synthesis of chiral organometallic salicyloxazoline complexes.

[This corrects the article DOI: 10.1186/s13065-019-0565-z.].

An electrochemical biosensor based on the enhanced quasi-reversible redox signal of prussian blue generated by self-sacrificial label of iron metal-organic framework.

We develop for the first time a new electrochemical biosensor for signal-on detection of T4 polynucleotide kinase (PNK) based on the enhanced quasi-reversible redox signal of prussian blue generated by self-sacrificial label of iron metal-organic framework (FeMOF). The DNA hairpin probe modified with FeMOF@AuNPs at the 3'-thiol end acts as the substrate of PNK. The presence of PNK enables the 5'-phosphorylation of hairpin probe, which may subsequently function as the substrate of lambda exonuclease. Lambda exonuclease removes the 5' mononucleotides from the stem, unfolding the hairpin structure and releasing the single-stranded DNA (ssDNA). The resultant FeMOF@AuNP-modified ssDNA may specifically hybridize with the capture probe to form the double-strand DNA (dsDNA) duplex, enabling the immobilization of FeMOF on the electrode surface. The reaction of Fe3+ in the MOF with K4Fe(CN)6 leads to the formation of prussian blue on the electrode surface and consequently the generation of a high electrochemical signal. This assay is very simple without the involvement of the pre-synthesized prussian blue which is unstable in neutral buffer, and the self-sacrificial label of FeMOF can achieve great signal amplification without the involvement of any extra functional materials. Due to the introduction of self-sacrificial label of FeMOF and the formation of prussian blue nanolayers with good quasi-reversible cyclic voltammetric electrochemical activity, this biosensor exhibits high sensitivity and a large dynamic range. Moreover, this biosensor can be used to screen the PNK inhibitors, holding great potential in disease diagnosis and drug discovery.

Electrogenerated chemiluminescence of ZnO nanorods and its sensitive detection of cytochrome C.

Various kinds of ZnO nanoparticles have been successfully used in gas sensing applications, however, these nanomaterials have been rarely investigated in electrogenerated chemiluminescence (ECL). In the present work, ZnO nanorods (ZnONRs) were synthesized by hydrothermal method, and characterized by field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). ECL behaviors of ZnONRs were investigated in neutral aqueous condition in the presence of K2S2O8. Cyclic voltammetry (CV) results revealed that ZnONRs can react with K2S2O8 to generate strong light emission, revealing that K2S2O8 can act as coreactant of ZnONRs ECL. ZnONRs synthesized under different pH conditions exhibited different ECL intensities, and the most intense ECL signal was obtained at pH 7.0. Cytochrome C could compete with ZnONRs to react with K2S2O8, and exhibited apparent inhibiting effect on ZnONRs ECL, which can be sensitively detected in the range of 1.0 × 10-11-5.0 × 10-9molL-1, with a detection limit of 4.7 × 10-12molL-1 (3σ). The present ECL system exhibited high sensitivity and good stability, which is suitable for the fabrication of novel ECL sensors.

Tuning the Color Temperature of White-Light-Emitting Electrochemical Cells by Laser-Scanning Perovskite-Nanocrystal Color Conversion Layers.

The development of white-light-emitting electrochemical cells (LECs) has attracted great attention owing to their numerous advantages. Recently, perovskite materials have also shown many outstanding optoelectronic properties in light absorption and emission, and hence they are suitable for serving as the color conversion layers (CCLs) in solid-state white-light-emitting diodes (LEDs). Here, white LECs were fabricated by integrating non-doped blue-green LECs with CCLs made of a single composition of perovskite nanocrystal (NCs). Moreover, the correlated color temperatures (CCTs) of the white LECs can be tuned by modifying the optical properties of the perovskite NCs, in the same way as so as the color conversion properties of CCLs are tuned, through laser scan. By controlling the laser power, scanning number, and duty cycle of the scanned grating patterns on perovskite-NC CCLs, the CCTs of the white LECs can be tuned from 2502 K to nearly 4300 K. Since this method is much different from that used with conventional CCLs, which use multiple compositions of perovskite NCs to produce white light, the inherent anion-exchange issue of perovskite NCs can be avoided.

[Optimal Design of Light Folding Imaging Spectrometer Based on Dyson Concentric System].

Concave grating spectrometer based on Dyson concentric optical system has advantages of low aberration, large aperture and compact structure. The object plane and image plane of concentric spectrometer subsystem must be reunited into one plane while the distance between the object point and image point is relatively small. Thus it is difficult to satisfy this requirement for the existing focal plane of detection technology and assembly technology. In order to solve the assembly problem of the object and detector, the traditional Dyson concentric spectrometer was improved by introducing the off-axis mirror to shift the image light beam. The results show that the object plane and image plane of the improved system are separated successfully by the beam folding, and the aberration at all wavelengths is more rational distribution.

Rapid Fabrication of Gold Nanoflowers Tuned by pH: Insights Into the Growth Mechanism.

We reported a one-pot, no added seeding and green method to synthesize gold nanoflowers, in which HAuC4 and H2O2 were added one by one into the alkaline protocatechuic aldehyde solution at room temperature. Au(III) was partially reduced by protocatechuic aldehyde to produce primary Au nanocrystals, and then Au nanocrystals agglomerated into loose flower-like nanoparticles as seeds, which catalyzed H2O2 reduction of the residual Au(III), thus accelerating the formation of compact 3D gold nanoflowers. The key synthesis strategy was to use protocatechuic aldehyde as a structure-induced agent to influence the growth of gold nanoflowers. The pH value of growth solution could tune the size and/or morphology of gold nanoflowers through its influence on the adhesion force of protocatechuic aldehyde on gold surfaces and the species type of Au(III) complexes. When the pH value of growth solution was above 7.26 (the pKa of protocatechuic aldehyde), the flower-like of gold nanostructural architectures with different sizes could be fabricated. The obtained gold nanoflowers had a large dimension of 198 and 157 nm at the pH of 7.6 and 8, respectively. Size control of gold nanoflowers can be accomplished in the growth solutions of pH 9.4-12.0 with a similar diameter around 60 nm. The as-synthesized gold nanoflowers exhibited good stability and have the prospects for surface-enhanced Raman scattering enhancement.

Enantioselective Functionalization of Inactive sp(3) C-H Bonds Remote to Functional Group by Metal/Organo Cooperative Catalysis.

A metal/organo cooperative catalysis to enable the enantioselective functionalization of inactive C-H bonds γ to the formyl group in aliphatic aldehydes has been established. Instead of using enals as substrates in traditional organocatalytic cyclization reactions, the aliphatic aldehydes directly participated in [4 + 2] cyclization with quinone derivatives exploiting molecular oxygen as oxidants to afford optically active cyclic molecules with excellent levels of enantioselectivity. This method features a combination of pot, step, and atom economy.

Investigation of carbon dioxide emission in China by primary component analysis.

Principal component analysis (PCA) is employed to investigate the relationship between CO2 emissions (COEs) stemming from fossil fuel burning and cement manufacturing and their affecting factors. Eight affecting factors, namely, Population (P), Urban Population (UP); the Output Values of Primary Industry (PIOV), Secondary Industry (SIOV), and Tertiary Industry (TIOV); and the Proportions of Primary Industry's Output Value (PPIOV), Secondary Industry's Output Value (PSIOV), and Tertiary Industry's Output Value (PTIOV), are chosen. PCA is employed to eliminate the multicollinearity of the affecting factors. Two principal components, which can explain 92.86% of the variance of the eight affecting factors, are chosen as variables in the regression analysis. Ordinary least square regression is used to estimate multiple linear regression models, in which COEs and the principal components serve as dependent and independent variables, respectively. The results are given in the following. (1) Theoretically, the carbon intensities of PIOV, SIOV, and TIOV are 2573.4693, 552.7036, and 606.0791 kt per one billion $, respectively. The incomplete statistical data, the different statistical standards, and the ideology of self sufficiency and peasantry appear to show that the carbon intensity of PIOV is higher than those of SIOV and TIOV in China. (2) PPIOV, PSIOV, and PTIOV influence the fluctuations of COE. The parameters of PPIOV, PSIOV, and PTIOV are -2706946.7564, 2557300.5450, and 3924767.9807 kt, respectively. As the economic structure of China is strongly tied to technology level, the period when PIOV plays the leading position is characterized by lagging technology and economic developing. Thus, the influence of PPIOV has a negative value. As the increase of PSIOV and PTIOV is always followed by technological innovation and economic development, PSIOV and PTIOV have the opposite influence. (3) The carbon intensities of P and UP are 1.1029 and 1.7862 kt per thousand people, respectively. The carbon intensity of the rural population can be inferred to be lower than 1.1029 kt per thousand people. The characteristics of poverty and the use of bio-energy in rural areas result in a carbon intensity of the rural population that is lower than that of P.

Solid-phase microfibers based on polyethylene glycol modified single-walled carbon nanotubes for the determination of chlorinated organic carriers in textiles.

Based on polyethylene glycol modified single-walled carbon nanotubes, a novel sol-gel fiber coating was prepared and applied to the headspace microextraction of chlorinated organic carriers (COCs) in textiles by gas chromatography-electron capture detection. The preparation of polyethylene glycol modified single-walled carbon nanotubes and the sol-gel fiber coating process was stated and confirmed by infrared spectra, Raman spectroscopy, and scanning electron microscopy. Several parameters affecting headspace microextraction, including extraction temperature, extraction time, salting-out effect, and desorption time, were optimized by detecting 11 COCs in simulative sweat samples. Compared with the commercial solid-phase microextraction fibers, the sol-gel polyethylene glycol modified single-walled carbon nanotubes fiber showed higher extraction efficiency, better thermal stability, and longer life span. The method detection limits for COCs were in the range from 0.02 to 7.5 ng L(-1) (S/N = 3). The linearity of the developed method varied from 0.001 to 50 µg L(-1) for all analytes, with coefficients of correlation greater than 0.974. The developed method was successfully applied to the analysis of trace COCs in textiles, the recoveries of the analytes indicated that the developed method was considerably useful for the determination of COCs in ecological textile samples.

Exacerbation of chronic inflammatory diseases by infectious agents: Fact or fiction?

Chronic inflammatory diseases caused by obesity represent critical public health concerns worldwide. In these diseases such as metabolic syndrome, diabetes and atherosclerosis, adipose tissue acts as an endocrine organ that releases large quantities of inflammatory mediators into circulation. Besides classically recognized effectors on the development of obesity and resultant conditions, infection has attracted attention as an enhancer of chronic inflammatory diseases. Infectious diseases have long been associated with obesity, metabolic syndrome, diabetes and atherosclerosis. However, the infectious hypothesis for chronic inflammatory diseases has been challenged by inconclusive clinical trials. Nevertheless, the large body of evidence accumulated over decades on the association of infectious diseases with obesity, diabetes and cardiovascular disease should not be disregarded. Instead, re-formulation of hypotheses of the mechanisms by which microbes affect obesity-associated diseases may be required with an emphasis on the early events in the progression of such diseases and the multifactorial nature of pathogen-host interactions. This review focuses on pathogens that directly promote obesity and on pathogens that cause chronic infections and thereby enhance metabolic diseases in obese patients. A new perspective on the interaction between infections and obesity-related diseases may improve management of chronic inflammatory diseases that rank high among global threats to human health.

Electrogenerated chemiluminescence of luminol in neutral and alkaline aqueous solutions on a silver nanoparticle self-assembled gold electrode.

The electrochemiluminescence (ECL) behaviour of luminol on a silver nanoparticle self-assembled gold electrode in neutral and alkaline solutions was investigated using conventional cyclic voltammetry (CV). The silver nanoparticle self-assembled gold electrode exhibited excellent ECL properties for the luminol ECL system. In neutral solutions, four ECL peaks (ECL-1-ECL-4) were observed at 0.73, 1.15, -0.46 and -1.35 V (vs. SCE), respectively. The intensities of these peaks were enhanced significantly compared with those on a bulk gold electrode and a gold nanoparticle self-assembled gold electrode. It was found that ECL-1 and ECL-2 on a silver nanoparticle-modified electrode were about 1000 and 1770 times stronger than those on a bare Au electrode and were about 17 and 15 times stronger than those on a gold nanoparticle-modified electrode, respectively. In alkaline solutions, four ECL peaks were also observed that were much stronger than those in neutral solutions, and ECL-1 and ECL-2 were enhanced by about three orders and one order of magnitude compared with those on a bare Au electrode and on a gold nanoparticle self-assembled electrode, respectively. Moreover, the silver nanoparticle-modified electrode exhibited good stability and reproducibility for luminol ECL. These peaks were found to depend on a number of factors, including silver nanoparticles on the surface of the modified electrode, potential scan direction, scan rate, scan range, the presence of O2 or N2, pH values, the concentrations of NaBr and luminol, and buffer solutions. The emitter of the ECL was confirmed as 3-aminophthalate by analysing the CL spectra. The surface state of the silver nanoparticle self-assembled electrode was characterized by scanning electron microscopy (SEM) and the interface property of the electrode was studied by electrochemical impedance spectroscopy (EIS). A mechanism for the formation of these ECL peaks is proposed. The results demonstrate that luminol has excellent ECL properties, such as strong ECL intensity and good reproducibility on a silver nanoparticle-modified gold electrode, in both neutral and alkaline solutions, which is of great potential in analytical applications.

Electrogenerated chemiluminescence of luminol on a gold-nanorod-modified gold electrode.

Electrogenerated chemiluminescence (ECL) of luminol on a gold-nanorod-modified gold electrode was studied, and five ECL peaks were obtained under conventional cyclic voltammetry in both neutral and alkaline solutions. Among them, four ECL peaks (ECL-1-4) were also observed on a gold-nanosphere-modified gold electrode, but the intensities of these ECL peaks were enhanced about 2-10-fold on a gold-nanorod-modified gold electrode in neutral solution. One new strong ECL peak (ECL-5) was obtained at -0.28 V (vs SCE) on a gold-nanorod-modified gold electrode in both neutral and alkaline solutions and enhanced with an increase in pH. In strong alkaline solutions, ECL-1 and ECL-2 on a gold-nanosphere-modified electrode were much stronger than those on a gold-nanorod-modified gold electrode, while ECL-3-5 appeared to only happen on a gold-nanorod-modified gold electrode. The emitter of all the ECL peaks was identified as 3-aminophthalate. The ECL peaks were found to depend on the scan direction, the electrolytes, the pH, and the presence of O(2) and N(2). The reaction pathways for ECL-4 have been further elucidated, and the mechanism of the new ECL peak (ECL-5) has been proposed. The results indicate that a gold-nanorod-modified gold electrode has a catalytic effect on luminol ECL different from that of a gold-nanosphere-modified gold electrode, revealing that the shape of the metal nanoparticles has an important effect on the luminol ECL behavior. The strong ECL of luminol in neutral solution obtained on a gold-nanorod-modified electrode may be used for the sensitive detection of biologically important compounds in physiological conditions.

FTIR-spectral analysis of two photosynthetic hydrogen-producing [corrected] strains and their extracellular polymeric substances.

The Fourier transform infrared (FTIR) spectra of the cells of two photosynthetic H(2)-producing strains, Rhodoblastus acidophilus and Rhodobacter capsulatus, as well as their extracellular polymeric substances (EPS), were evaluated. The FTIR spectra of R. capsulatus and its EPS during its cultivation were also recorded. The main peaks in the spectra, including 1,080 cm(-1) (carbohydrates), 1,250 cm(-1) (nucleic acids), 2,830-2,930 cm(-1) (lipids), 1,660-1,535 cm(-1) (Amide I and II of proteins), were observed. The relative heights of these peaks in the spectra of the two strains were different, showing the difference in contents of various components in the cells or EPS. The ratios among the main components in the EPS obtained from the FTIR spectra were in good agreement with those from a conventional quantitative chemical analysis. As an easy, rapid, and direct technique, the FTIR spectroscopy could be used to characterize the components and their relative contents of EPS of photosynthetic bacteria.

Interaction of an organic selenium compound with human serum albumin: a spectroscopic study.

The interaction between 4,4'-diselenadibenzoic acid and human serum albumin (HSA) was investigated by fluorescence and absorption spectroscopy. The quenching mechanism of fluorescence of HSA by 4,4'-diselenadibenzoic acid was discussed. It is proved that the fluorescence quenching of HSA by 4,4'-diselenadibenzoic acid is a result of the formation of the HSA-4,4'-diselenadibenzoic acid complex. The binding sites number n, apparent corporation constant K, and corresponding thermodynamic parameters, deltaH(theta), deltaG(theta), and deltaS(theta) were calculated. Results indicate that the electrostatic interactions forces played major role in the reaction.