Additionally, it would explain why only a 3–30% of lactating women suffer from such infection when it is the predominant bacterial species found in breast milk of healthy women [29,30]. Conclusion Staphylococcus epidermidisis the most prevalent staphylococcal species isolated from breast milk of women suffering mastitis, where it is present at a concentration notably higher than that present in milk of healthy woman (≥ 4.0 versus ≤ 3.0 log10cfu mL-1, respectively). The percentage of strains showing biofilm production

ability and resitance to mupirocin, erythromycin, clindamicyn and/or methicillin was significantly Selleckchem PF01367338 higher among those obtained from women with lactational mastitis than among those isolated from healthy selleck products women. The random method used to select staphylococcal colonies from the samples could introduce a bias regarding the low number of samples from whichS. aureuswas isolated. Traditionally,S. aureushas been considered as the main etiological agent of mastitis. However, the results of this work suggest thatS. PCI-32765 mouse epidermidiscould be an additional and underrated cause of lactational mastitis; as a consequence, its presence should be also considered in bacteriological analyses of human milk when there is a suspicious

of a mastitis infection. Further studies involving a larger number of samples and staphylococcal isolates will be required to confirm the results obtained in this study. Methods Samples and isolation of staphylococcal isolates A total of 30 women aged 25–34 years with clinical symptoms of infectious mastitis participated in the study (Table1). They were diagnosed Erlotinib in vitro by the lactation consultants attending different primary health-care centers in Spain in a 2-months period (October-November 2007). The total staphylococcal count was higher ≥ 4 log10cfu mL-1in all their samples. Women with mammary abscesses or any kind of parallel diseases and patients treated with antibiotherapy during the previous two weeks of the study were excluded.

All volunteers gave written informed consent to the protocol, which was approved by the Ethical Committee of Hospital Clínico of Madrid (Spain). The milk samples were collected as described previously [31], and plated onto ready to use Baird Parker (BP) plates supplied by bioMérieux (Marcy l’Etoile, France). The plates were incubated in aerobiosis at 37°C for 48 h. Identification of staphylococci Initially, a total of 270 isolates (10 from each sample displaying bacterial growth on BP plates) were randomly selected and tested for catalase and coagulase activities and for their resistance to lysozyme and lysostaphin [32]. All of them were subjected to a novel multiplex PCR method designed to allow a rapid identification ofS. epidermidisandS. aureusisolates. The new primers (see below) were designed on the basis of the variable regions of thetufgene sequence ofStaphylococcususing the program Clone Manager Suite 7.0 (Sci Ed Central, USA).

J Biotechnol 2003, 106:135–146.PubMedCrossRef 61. Sinorhizobium meliloti 1021 Sm14kOLI [http://​www.​cebitec.​Batimastat molecular weight uni-bielefeld.​de/​transcriptomics/​transcriptomics-facility/​sm14koli.​html] 62. Sturn A, Quackenbush J, Trajanoski Z: Genesis: cluster analysis of microarray data. Bioinformatics 2002, 18:207–208.PubMedCrossRef 63. EMMA server [http://​www.​cebitec.​uni-bielefeld.​de/​groups/​brf/​software/​emma_​info/​] 64. Meade HM, Long SR,

Ruvkun GB, Brown SE, Ausubel FM: Physical and genetic characterization of symbiotic https://www.selleckchem.com/products/epz015666.html and auxotrophic mutants of Rhizobium meliloti induced by transposon Tn5 mutagenesis. J Bacteriol 1982, 149:114–122.PubMed 65. Grant SG, Jessee J, Bloom FR, Hanahan D: Differential plasmid rescue from transgenic mouse DNAs into Escherichia coli methylation-restriction mutants.

Proc Natl Acad Sci USA 1990, 87:4645–4649.PubMedCrossRef Authors’ contributions DKCL carried out the molecular genetic studies, the statistical analysis and wrote the manuscript. SW and AP participated in the design of the study, revised it critically for important intellectual content and have given final approval of the version to be published.”
“Background Fur (Ferric uptake regulator) is a global transcription factor that regulates a diversity of biological processes such as iron homeostasis, TCA cycle metabolism, acid resistance, oxidative stress response, chemotaxis and Autophagy inhibitor pathogenesis (reviewed in [1]). The active, DNA-binding form of this regulator is as a Fur homodimer complexed with ferrous iron. The DNA target recognized by Fe2+-Fur is a 19-bp inverted repeat sequence called a “”Fur box”" (GATAATGATAATCATTATC) [2]. The binding of Fe2+-Fur to a “”Fur box”" in the promoter regions of target genes effectively prevents the recruitment of the RNA polymerase holoenzyme, and thus represses

transcription [3, 4]. Although Fur typically acts as a transcriptional repressor, it also appears to positively regulate certain genes in E. coli [5, 6]. This paradox was understood only recently, with the discovery of a 90-nt small RNA named RyhB [7]. RyhB negatively regulates a number of target genes by base pairing with their mRNAs and recruiting before RNaseE, thus causing degradation of the mRNAs [7, 8]. The ryhB gene itself is repressed by Fur via a “”Fur box”" in its promoter; thus, Fur repression of the negative regulator RyhB manifests as indirect positive regulation by Fur. The targets of RyhB include genes encoding iron-storage protein (Bfr) and enzymes of the TCA cycle (SdhABCD and AcnA) and oxidative stress response (SodB) [7]. The RyhB-mediated regulation of TCA cycle genes explains the inability of E. coli fur mutants to grow on succinate or fumarate [9]. S. oneidensis is a γ-proteobacterium with a striking capacity to reduce organic compounds and heavy metals, making it a potential bioremediator of environmental contaminants. The S. oneidensis Fur exhibits clear homology to its E. coli ortholog (73% amino acid identity).

The phylogenetic tree was linearized assuming equal evolutionary rates in all lineages [37]. The evolutionary distances were computed using the Maximum Composite Likelihood method [34]. and are in the units of the number of base substitutions per site. It has been recently reported that strains 116 (ST9) and 3077 (ST17) specify an identical FnBPA A domain called isotype II [22]. In this study, these strains were found to specify different FnBPB A domains, isotypes II and VI respectively. This indicates that the phylogeny of fnbB alleles does not match that of fnbA alleles despite the two genes

being closely linked. FnBP isotypes encoded by bovine S. www.selleckchem.com/products/YM155.html aureus strains We expanded the investigation into FnBP variation to include FnBPs from a variety of bovine S. aureus strains. Nineteen bovine isolates representing genetically

unrelated strains were screened to determine if they Linsitinib nmr specified the same FnBP isotypes as human strains. This strain collection included strain RF122, the genome of which has been sequenced [25]. RF122 contains only one fnb gene encoding FnBPA. DNA encoding fnbA was amplified from the genomic DNA of each strain using generic A domain primers. PCR products hybridised to FnBPA probes specific for isotypes I, II, III or IV. Similarly fnbB DNA was amplified by PCR from the genomic DNA of all strains except RF122. These PCR products hybridised to FnBPB probes specific for isotype I, II, III, IV or XMU-MP-1 V. These results indicate that the FnBP isotypes which are expressed by human strains are also specified by bovine strains. Furthermore, the results of this study suggest that the nearly lack of fnbB in

the genome of strain RF122 is not characteristic of all bovine strains. None of the strains tested specify FnBPA or FnBPB isotypes V, VI or VII. Figure 4 shows a neighbour-joining phylogenetic tree which was constructed based on MLST data as described above. The FnBPA and FnBPB A domain isotypes specified by each genotype are included. The distribution of fnbB and fnbA variants does not correlate with the genetic relatedness of the strains as determined by MLST. The phylogeny of fnb alleles carried by bovine S. aureus isolates is therefore very similar to that of human strains. Figure 4 Neighbour-joining tree based upon concatenated sequences of MLST alleles from bovine S. aureus strains. MLST allele sequences representing each bovine-specific strain studied here were used to generate a neighbour joining tree using MEGA 4. The A domain isotypes carried by strains of each MLST genotype, as determined by hybridization analysis, are indicated. A gene encoding FnBPB is absent from the genome of strain RF122 (ST155). The percentage of replicate trees in which the associated taxa clustered together in the bootstrap test (500 replicates) are shown next to the branches [36].

As shown in Figure 3, the performance of a lipid bilayer-based sensor based on graphene nanostructure is assessed by the conductance characteristic. Before the electrolyte solution has been added, pure water as a water-gated ambipolar GFET was added into the membrane to measure the transfer curve. There is substantial STAT inhibitor this website agreement between the proposed model of the lipid bilayer-based biosensor and the experimental result which is extracted from the reference [10]. Figure 3 Comparison between bipolar transfer curve of conductance model (blue line) and experimental extracted data (red line) for neutral membrane. As depicted in Figure 4, by

applying the gate voltage to the biomimetic membrane, it is clearly seen that the conductance of GFET-based graphene shows ambipolar LY2874455 datasheet behavior. The doping states of graphene are monitored by the V g,min to measure the smallest conductance of the graphene layer, which is identified from the transfer characteristic curve. In total, the V g,min shift

(at the Dirac point) can be considered as a good indicator for lipid bilayer modulation and measurement. Nevertheless, the magnitude of the voltage shift from both positive and negative lipids is comparable when this shift is measured from the position of the minimum conductivity of bare graphene. As shown in Figure 4, the changes in the membrane’s electric charge can be detected electrically. The conductivity graph is changed when the electric charges are changing for biomimetic membrane-coated graphene biosensor. So, more electrically charged molecules will be adsorbed and the sensor will be capable of attracting more molecules, which leads to a change in the V g,min on the device, and the hole density value can be estimated as decreasing. A negatively exciting membrane demonstrates a very small enhancement in conductivity and a positive change in the Dirac point compared with that of exposed graphene.This is because of an enhancement in the remaining pollution charges caused by the negatively

charged membrane. A detection-charged lipid bilayer can be obtained based on a detectable Aurora Kinase Dirac point shift. In light of this fact, the main objective of the current paper is to present a new model for biomimetic membrane-coated graphene biosensors. In this model, the thickness and the type of coated charge as a function of gate voltage is simulated and control parameters are suggested. Subsequently, to obtain a greater insight into the role of both the thickness and the type of lipid bilayer, GFET modeling is employed to identify the relationship between the conductance and the voltage of the liquid gate, where two electrodes of the sensor, as shown in Figure 5, are considered as the source and drain contacts.

SOD eliminates the free radical superoxide by converting it to hydrogen peroxide, which, in turn, is cleared by CAT. Several pathways are involved in the production of superoxide in normal cells and tissues such as xanthine oxidase, the mitochondrial electron transport system enzymes, NAD(P)H oxidase, etc. [72]. The interaction of silicon QDs with these pathways after substantial tissue accumulation may account for the increased superoxide radical input a week after QDs

exposure. Our data show distinct changes in CAT activity, which is elevated at every time interval studied, with the most notable increase of 42% measured in the seventh day Figure 5 The effect of silicon-based QDs on the SOD and CAT activities in Carassius gibelio liver. Results are expressed as percent #Ganetespib nmr randurls[1|1|,|CHEM1|]# from controls ± RSD (n = 6); *** P ≤ 0.001. after Si-based SHP099 QDs administration. The progressive induction of CAT would indicate the emergence of an increasing source of hydrogen peroxide during a 7-day period after QDs IP injection. It is well established that H2O2 is produced through two-electron reduction of O2 by cytochrome P-450, D-amino acid oxidase, acetyl coenzyme A oxidase, or uric acid oxidase [73]. Additionally, Kupffer cells, which are fixed to the endothelial cells lining the hepatic sinusoids have a great capacity to endocytose exogenous

particles (including QDs) and secrete large amounts of ROS [74]. Since the amount of QDs in the liver accumulates gradually and is at a maximum after 7 days, we suggest that the substrate for CAT must be generated by the QDs directly or indirectly. It is possible Lepirudin that the early activation of CAT may be due to an increased production of H2O2 by a mechanism different from ·O2 – dismutation. Indeed, the fact that H2O2 generation may be central to silica nanoparticle toxicity has recently been deduced, since catalase treatment decreases the nanotoxic effects of SiO2 nanoparticles [75]. The activity of GPX increased after 1 day of exposure by 38% and remained approximately at this

level in the next days (Figure 4). GPX works in concert with CAT to scavenge the endogenous hydrogen peroxide, but GPX has much higher affinity for H2O2 than CAT suggesting that this enzyme acts in vivo at low H2O2 concentrations whereas CAT is activated at high substrate concentrations [76]. The early activation of liver GPX and the persistence of almost the same level of activity throughout the experiment may be due to other functions of the enzyme, like lipid radical detoxification. The GSTs are a group of multifunctional proteins, which play a central role in detoxification of hydroperoxides, by conjugation with GSH [35]. An accentuated decrease in the levels of GST activity was observed post-QDs treatment (Figure 4). At low GSH concentrations, cytosolic GST is inhibited by the binding of alpha, beta-unsaturated carbonyl derivatives to specific cysteine residues of the enzyme [77].

In fact, the current concept of geriatric fracture care should encompass the holistic management of these patients from surgical management of the fracture to rehabilitation and prevention of subsequent fragility fractures. We have also included reports on several successful models of comanaged care and geriatric fracture programs, and several review articles on how these programs Tipifarnib cell line affect the outcome of patients with fragility hip fractures. We hope it will serve as a basis for better understanding of the orthopedic challenge in the management of

such a major health problem. Conflicts of Interest Dr. Leung is the speaker for Synthes and has received research support from Synthes; Dr. Blauth performs consultant and teaching activities with Synthes; Dr. Bavonratanavech declares no conflicts of interest. Open Access This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original LXH254 author(s) and source are credited. References 1. United Nations, Department of Economic and Social Affairs, Population Division (2007) World population prospects: the 2006 revision, highlights, working paper no. ESA/P/WP.202 2. Cooper C, Campion

C, Melton LJIII (1992) Hip fractures in the elderly: a world-wide projection. Alisertib cost Osteoporosis Int 2:285–289CrossRef 3. Elliott J, Beringer T, Kee F, Marsh D, Willis C, Stevenson M (2003) Predicting survival after treatment for fracture of the proximal femur and the effect of delays to surgery. J Clin Epidemiol 56(8):788–795CrossRefPubMed 4. Sernbo I, Johnell O (1993) Consequences of a hip fracture: a prospective Orotic acid study over

1 year. Osteoporosis Int 3:148–153CrossRef 5. Schmidt AH, Leighton R, Parviz J, Sems A, Berry DJ (2009) Optimal arthroplasty for femoral neck fractures: is total hip arthroplasty the answer? J Orthop Trauma 23(6):428–433CrossRefPubMed 6. Adams CI, Robinson CM, Court-Brown CM, McQueen MM (2001) Prospective randomized controlled trial of an intramedullary nail versus dynamic screw and plate for intertrochanteric fractures of the femur. J Orthop Trauma 15(6):394–400CrossRefPubMed 7. Mereddy P, Kamath S, Ramakrishnan M, Malik H, Donnachie N (2009) The AO/ASIF proximal femoral nail antirotation (PFNA): a new design for the treatment of unstable proximal femoral fractures. Injury 40(4):428–432CrossRefPubMed 8. Baumgaertner MR, Curtin SL, Lindskog DM, Keggi JM (1995) The value of the tip-apex distance in predicting failure of fixation of peritrochanteric fractures of the hip. J Bone Joint Surg Am 77(7):1058–1064PubMed 9. Elder GM, Harvey EJ, Vaidya R, Guy P, Meek RN, Aebi M (2005) The effectiveness of orthopaedic trauma theatres in decreasing morbidity and mortality: a study of 701 displaced subcapital hip fractures in two trauma centres.

Mater Sci Eng C 2009, 29:1574–1583.CrossRef 46. Riva R, Ragelle H, Des Rieux A, Duhem N, Jérôme C, Préat V: selleck Chitosan and chitosan derivatives in drug delivery and tissue engineering. Adv Polym Sci 2011, 244:19–44.CrossRef 47. Varma AJ, Deshpande SV, Kennedy JF: Metal complexation by chitosan and its derivatives: a review. Carbohydr Polym 2004, 55:77–93.CrossRef

48. Rangel-Mendeza R, Monroy-Zepedab R, Leyva-Ramosb E, Diaz-Floresa PE, Shirai K: Chitosan selectivity for removing cadmium (II), copper (II), and lead (II) from aqueous phase: pH and organic matter effect. J Hazard Mater 2009, 162:503–511.CrossRef 49. Rivas JCM, Salvagni E, Parsons S: Investigating the effect of hydrogen bonding environments in amide cleavage reactions at zinc(II) complexes DMXAA purchase with intramolecular amide oxygen co-ordination. Dalton Trans https://www.selleckchem.com/products/Trichostatin-A.html 2004, 21:4185–4192.CrossRef 50. Wang XH, Du YM, Liu H: Preparation, characterization and antimicrobial activity of chitosan–Zn complex. Carbohydr Polym 2004, 56:21–26.CrossRef 51. Hasan S, Ghosh TK, Viswanath DS, Boddu VM: Dispersion of chitosan on perlite for enhancement of copper (II) adsorption capacity. J Hazard Mater 2008, 152:826–837.CrossRef

52. Wang M, Zhang Q, Hao W, Sun Z–X: Surface stoichiometry of zinc sulphide and its effect on the adsorption behaviors of xanthate. Chem Cent J 2011, 5:73.CrossRef 53. Sonia TA, Sharma CP: Chitosan and its derivatives for drug delivery perspective. Adv Polym Sci 2011, 243:23–54.CrossRef 54. Chenite A, Buschmann M, Wang D, Chaput C, Kandani N: Rheological characterization of thermogelling chitosan/glycerol-phosphate solutions. Carbohydr Polym 2001, 46:39–47.CrossRef 55. Claesson PM, Ninham BW: pH dependent interactions between adsorbed chitosan layers. Langmuir 1992, 8:1406–1412.CrossRef 56. Kalyuzhny G, Murray RW: Ligand effects on the optical properties of CdSe nanocrystals. GABA Receptor J Phys Chem B 2005, 109:7012–7021.CrossRef 57. Landes CF, Braun M, El-Sayed MA: On the nanoparticle to molecular size transition: fluorescence

quenching studies. J Phys Chem B 2011, 105:10554–10558.CrossRef 58. Baker DR, Kamat PV: Tuning the emission of CdSe quantum dots by controlled trap enhancement. Langmuir 2010, 26:11272–11276.CrossRef Competing interests The authors declare that they have no competing interests. Authors’ contributions HSM carried out the experimental design and analysis and drafted the manuscript. AAPM carried out the characterization and analysis and drafted the manuscript. FPR participated in the synthesis, characterization and analysis of quantum dots. All authors read and approved the final manuscript.”
“Background With the feature size of miniaturized mechanical components shrinking down to the nanometer regime, friction and wear, as the major causes of mechanical failures and dissipative energy losses, play pronounced and even dominant role in determining the functionality of nanoelectromechanical system (NEMS) devices [1–3].

BN and JB declare no conflict of interest. Open Access This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited. References 1. Williams I, Churchill D, Anderson J, Boffito M, Bower M, Cairns G, et al. British HIV Association guidelines for the treatment of HIV-1-positive adults with antiretroviral therapy 2012. GSK872 HIV Med. 2012;13(Suppl 2):1–85. 2. Cohen CJ, Molina JM, Cahn P, Clotet B, Fourie J,

Grinsztejn B, et al. Efficacy and safety of rilpivirine (TMC278) versus efavirenz at

48 weeks in treatment-naive HIV-1-infected patients: pooled results from the phase 3 double-blind randomized ECHO and THRIVE Trials. J Acquir Immune Defic Syndr. 2012;60(1):33–42.PubMedCrossRef 3. Nelson GSK126 cell line M, Girard PM, Demasi R, Chen L, Smets E, Sekar V, et al. Suboptimal adherence to darunavir/ritonavir has minimal effect on efficacy compared with lopinavir/ritonavir in treatment-naive, HIV-infected patients: 96 week ARTEMIS data. J Antimicrob Chemother. 2010;65(7):1505–9.PubMedCrossRef 4. Elzi L, Marzolini C, Furrer H, Ledergerber B, Cavassini M, Hirschel B, et al. Treatment modification in human immunodeficiency virus-infected individuals starting combination antiretroviral therapy between 2005 and 2008. Arch Selleck CB-839 Intern Med. 2010;170(1):57–65.PubMedCrossRef 5. Cooper V, Moyle GJ, Fisher M, Reilly G, Ewan J, Liu HC, et al. Beliefs about antiretroviral therapy, treatment adherence and quality of life in a 48-week randomised study of continuation of zidovudine/lamivudine or switch to Tolmetin tenofovir DF/emtricitabine, each with efavirenz. AIDS Care. 2011;23(6):705–13.PubMedCrossRef 6. Duran

S, Spire B, Raffi F, Walter V, Bouhour D, Journot V, et al. Self-reported symptoms after initiation of a protease inhibitor in HIV-infected patients and their impact on adherence to HAART. HIV Clin Trials. 2001;2(1):38–45. 7. Lennox JL, DeJesus E, Lazzarin A, Pollard RB, Madruga JV, Berger DS, et al. Safety and efficacy of raltegravir-based versus efavirenz-based combination. Lancet. 2009;374(9692):796–806.PubMedCrossRef 8. Li JZ, Paredes R, Ribaudo HJ, Svarovskaia ES, Metzner KJ, Kozal MJ, et al. Low-frequency HIV-1 drug resistance mutations and risk of NNRTI-based. JAMA. 2011;305(13):1327–35.PubMedCentralPubMedCrossRef 9. Gianotti N, Tiberi S, Menzo S, Danise A, Boeri E, Galli L, et al. HIV-1 replication capacity and genotype changes in patients undergoing treatment. J Med Virol. 2008;80(2):201–8.PubMedCrossRef 10. Mathias AA, Germa P, Lee M, et al.

Although MLSA can be used to infer phylogeny, this approach

suffers from arbitrariness in choice of in genes which varies from one taxon selleckchem to the next. Our proposed approach, core-genome phylogeny, can be considered an Wnt inhibitor extension of MLSA and rMLST. However, as it is based on all shared CDSs in a given genus, it makes use of all potentially informative sequence sites. ANI, like AAI, measures pair-wise similarities between genome sequences but provides better resolution of species and sub-species [58, 59]. Conclusions The aim of this study has been to determine, using the genus Acinetobacter as a test case, whether genome sequence data alone are sufficient for the delineation and even definition of bacterial species. To this end, we explored the applicability of two broad approaches: sequence-based phylogenies for single and multiple gene and distance-based methods that include gene content comparisons (K-string and genomic fluidity) and whole-genome sequence similarities (ANI). We have found that a phylogenetic analysis of the genus Acinetobacter based on 16S rRNA gene sequences provides unreliable and uninformative results. By contrast, a core genome phylogenetic tree provides robust,

informative results that are backwards compatible with the existing taxonomy. MK-8776 ic50 Among the distance metrics, we found that approaches using gene content (K-string and genomic fluidity) led to anomalous conclusions, e.g., placing the SDF strain outside of the A. baumannii cluster, presumably because they are affected by horizontal gene transfer. In contrast, the easy-to-compute ANI results are congruent with the core genome phylogeny and traditional Pyruvate dehydrogenase approaches. Using the core genome phylogeny and ANI approach, we found three misclassifications, one of which

represents new species. These findings illustrate the need to genome-sequence all strains archived in culture collections, which is likely to become technically and economically feasible in the near future. We believe a combination of core genome phylogenetic analysis and ANI provides a feasible method for bacterial species delineation, in which species are defined as monophyletic groups of isolates that exhibit at least 95% pair-wise ANI to each other. This approach combines a theoretically rigorous approach (sequence phylogeny) with a pragmatic metric (ANI) that provides a numerical cut-off that is backwards compatible and has been shown to be applicable to a diverse group of bacteria [10, 60]. Our sequence-based approach has several desirable characteristics. Firstly, it is capable of resolving the inconsistency in classification of genomospecies. For example, our results confirm the recent assignment of genomospecies 3 and 13TU to Latin binomials A. pittii and A. nosocomialis, respectively.

All of the peaks for various annealing temperatures were identified to be those of the cubic ZnS phase (JCPDS card no. buy MLN4924 79–0043) [14]. The

crystallinity of ZnS increased along with annealing temperature. When the temperature was increased to 250°C, the peaks of (111), (220), and (311) were obviously seen. In this experiment, as ZnSO4 was dissolved in water, Zn2+ ions could form a variety of complexes in the solution, and this was hydrolyzed to form Zn(OH)2. The possible chemical reactions for the synthesis of ZnS nanocrystals are as follows: (1) (2) (3) (4) check details Figure 1 XRD spectra of the ZnS films. Grown (spectrum a) without annealing and at annealing temperatures of (spectrum b) 150°C and (c) 250°C, selleck kinase inhibitor respectively. During the reaction processes, sulfide ions release slowly from CH3CSNH2 and react with zinc ions. Consequently, ZnS nanocrystals form via an in situ chemical reaction manner. Equation 4 indicates that ZnS is produced by the reaction of S2- and Zn2+. TEM analysis provides further insights into the structural properties of as-synthesized ZnS nanocrystals.

Figure 2a shows a low-magnification TEM image where the nanocrystals are clearly observed. The average grain size of the ZnS nanocrystal was about 16 nm. The crystalline ZnS were identified by the electron diffraction (ED) pattern in the inset of Figure 2b, which shows diffused rings indicating that the ZnS hollow spheres are constructed of polycrystalline ZnS nanocrystals. The concentric rings can be assigned

to diffractions from the (111), (220), and (311) planes of cubic ZnS, which coincides with the XRD pattern. A representative HRTEM image enlarging the round part of the structure in Figure 2b is given. The interplanar distances Reverse transcriptase of the crystal fringes are about 3.03 Å. The energy-dispersive X-ray spectroscopy (EDS) line profiles indicate that the nanocrystal consists of Zn and S, as shown in Figure 2c. In addition, the atomic concentrations of Zn = 56% and S = 44% were calculated from the EDS spectrum. Figure 2 Structural properties of as-synthesized ZnS nanocrystals. (a) TEM image of as-synthesized ZnS nanocrystals. (b) HRTEM image of the nanocrystal and the electron diffraction pattern. (c) EDS analysis of the ZnS nanocrystals. Figure 3a,b,c,d shows scanning electron microscopy (SEM) images of the ZnS film on Si plane annealed at temperatures of 100°C, 150°C, 200°C, and 250°C, respectively. It can be clearly seen that the dominant feature of the films is the appearance of small islands. The grain particles were condensed by assembled nanocrystals. It was conjectured that the assembly effect arising from nanocrystals are responsible for the decrease of surface energy. The particle size increased as the sintering temperature increased. It is believed that a higher temperature enhanced higher atomic mobility and caused faster grain growth.