Current control efforts are rather rare and rely primarily on ant

Current control efforts are rather rare and rely primarily on antibiotic applications (e.g., streptomycin or oxytetracycline) to protect flowers. However, the use of antibiotics for the management of fire blight is highly controversial due to the potential risk of promoting the emergence and spread of antibiotic resistance [5]. Gram-negative bacteria often possess multidrug efflux transporters within the cytoplasmic

membrane, which have been found to recognize and expel a broad range of structurally unrelated compounds from the cell [6, 7]. Among the multidrug efflux pumps, members of the resistance-nodulation-cell division (RND) family appear to be the most effective efflux systems in Gram-negative bacteria. RND transporters form a tripartite complex, consisting of an inner membrane pump that recognizes and captures the substrates, a periplasmic membrane Vorinostat molecular weight fusion protein (MFP) and an outer membrane channel [8, 9]. AcrAB is the major multidrug this website efflux pump in E. coli and shows high conservation among Gram-negative bacteria [8, 10–12]. AcrD, a close homolog of AcrB, is an RND-type efflux pump characterized as a transporter of aminoglycosides, a highly

hydrophilic class of molecules, and as a transporter of several amphiphilic compounds [13, 14]. Typically, the inner membrane pump and the periplasmic MFP are co-transcribed in tandem on polycistronic mRNA molecules [15]. Interestingly, this is

not the case for acrD, which appears as a single gene and seemingly functions in concert with AcrA, a MFP co-transcribed with AcrB [14]. Both AcrAB and AcrD efflux systems are also present in the plant pathogen E. amylovora. AcrAB has already been Buspirone HCl characterized as an efflux system required for virulence of E. amylovora in resistance towards apple phytoalexins and for successful colonization of the host plant [16]. AcrAB of E. amylovora showed a similar substrate spectrum as AcrAB of E. coli[17]. In this study, the substrate specificity of AcrD from E. amylovora was characterized and its contribution to virulence in apple and pear analyzed. As it was found that acrD is expressed only at low levels under in vitro conditions, we were interested in investigating whether the expression of the AcrD transporter in E. amylovora is induced in planta. Multidrug transporters are often expressed under control of local, as well as, global transcriptional regulators [18]. Current data show that expression of acrD in E. coli can be induced by the two-component regulatory system BaeSR [19]. Two-component systems (TCS) play an important role in the regulation of physiological processes in response to environmental or cellular parameters and enable bacterial cells to adapt to changing environmental conditions.

In this section, we will review the recent progress on the EPS in

In this section, we will review the recent progress on the EPS in low-dimensional perovskite manganite nanostructures. EPS in manganite nanoparticles EPS is an important phenomenon in CMR material, which leads to the new applications of Stattic datasheet spintronics. Along with the development of nanotechnology, the EPS phenomenon in CMR nanoparticles are received much attention. Recently, the evolution of the EPS with magnetic field in nanosized Nd0.5Ca0.5MnO3

[19], La0.25Ca0.75MnO3 [47], Pr0.5Ca0.5MnO3 [21], La0.2Ca0.8MnO3 [56], and Pr0.67Ca0.33MnO3 [57] particles has been reported. For example, in nanosized Pr0.67Ca0.33MnO3 particles with average diameter of 100 nm, it was found that a sharp transition from AFM to FM did not occur even up to 60 kOe, as demonstrated in Figure  1 [57]. The field dependence of the analyzed magnetization data for the

Pr0.67Ca0.33MnO3 nanoparticles is shown in Figure  2 [57]. As a comparison, the data for the bulk counterpart is also given out. It is clear that the evolution tend of ΔM is a little different from that of the bulk counterpart, i.e., first a sharp decrease and then an increase slowly up to 50 kOe. However, the irreversibility temperature (T irr) exhibits a very different change tend as compared with that of the bulk counterpart, which is sharply decreased from 100 to 5,000 Oe and then continually increased. The magnetization M ZFC and M FC are increased smoothly with increasing the magnetic field H up to 60 kOe but a step-like increase

of M ZFC and M FC like in bulk counterpart is not observed. For H below Vactosertib solubility dmso 5,000 Oe, the first sharp decrease of the ΔM T irr, and weak decline of ΔT is attributed to the gradual conquest of the anisotropy of frozen spin and alignment with field, since the magnetic field is not large enough to induce the growth of the FM cluster. Due to the surface effect, the FM-like surface spins contribute additional moment, which leads to a large magnetization for nanoparticles as compared with bulk counterpart. However, due to the strong coupling between the surface spins and interface spins (which also deviate from AFM arrangement), the exchange this website field required to force a transition of surface spins and interface spins to full FM is approximately 5 × 106 Oe [58]. As a consequence, even the field is increased up to 60 kOe, which can align the AFM core spins like for bulk, it is still not large enough to make the nanoparticles to be full FM configuration, thus leading to a slow increase of the ΔM and T irr [58]. The significant increase of the exchange bias field of the Pr0.67Ca0.33MnO3 nanoparticle as compared with the bulk counterpart can be attributed to the surface pressure and uncompensated surface spins. Figure 1 Field cooled and zero field cooled magnetization of Pr 0.67 Ca 0.33 MnO 3 nanoparticles. Field cooled (closed symbols) and zero field cooled (open symbols) magnetization of Pr0.67Ca0.

98 ±15% for mean power Participants practiced the anaerobic capa

98 ±15% for mean power. Participants practiced the anaerobic capacity test during the familiarization session to minimize learning effects. Side effect assessment Participants were given weekly questionnaires on how well they tolerated the supplement,

how well they followed the supplement protocol, and if they experienced any medical problems/symptoms during the study. Compliance to the supplementation protocol was monitored by turning in empty weekly supplement containers, supplement logs and verbal confirmation. After completing Emricasan research buy the compliance procedures, subjects were given the required supplements and dosages for the following supplementation period. Data analysis Participant baseline demographic data were analyzed by one-way Analysis of Variance (ANOVA). Study data were analyzed by Multivariate Selleckchem LY2090314 Analysis

of Variance (MANOVA) with repeated measures. Overall MANOVA effects were examined using the Wilks’ Lamda time and group x time p-levels as well as MANOVA univariate ANOVA group effects. Greenhouse-Geisser univariate tests of within-subjects time and group x time effects and between-subjects univariate group effects were reported for each variable analyzed within the MANOVA model. In some instances, repeated measures ANOVA was run on variables not included in a MANOVA design with univariate group, time, and group x time interaction effects reported. Data were considered statistically significant when the probability of type I error was 0.05 or less and statistical trends were considered when the probability Dolichyl-phosphate-mannose-protein mannosyltransferase of error ranged between p > 0.05 to p < 0.10. If a significant group, treatment and/or interaction alpha level was observed, Tukey’s least

significant differences (LSD) post-hoc analysis was performed to determine where significance was obtained. A priori power analysis of the design indicated that an n-size of 12 per group was sufficiently powered to identify previously reported changes in muscle creatine content and training adaptations in responses to creatine supplementation (>0.70). Results Subject demographics Forty-one participants were initially recruited for the study, completed consent forms and participated in the required familiarization session. Of the original 41 participants, 36 completed the 28-day research study. Three participants dropped out due to time constraints, one due to an unrelated illness, and one due to apprehension of the muscle biopsy procedure. None of the participants dropped out of the study due to side effects related to the study protocol. Table 3 shows the baseline demographics for the participants. Overall, participants were 20.2 ± 2 years, 181 ± 7 cm, 82.1 ± 12 kg, and 14.7 ± 5% fat with 3.8 ± 3 years of resistance training experience. One-way ANOVA revealed no significant differences among groups in baseline demographic variables.

0/7 8 1 6 0 021   Electron transport   1435 BRA0893 thioredoxin 3

0/7.8 1.6 0.021   Electron transport   1435 BRA0893 thioredoxin 34.7/4.8 −1.34 0.0045   Glycolysis/TCA cycle   1145 BR1132 enolase 45.4/5.0 1.43 0.0021   Amino acid metabolism     Biosynthesis   1915 BRA0883 3-isopropylmalate dehydratase, small subunit 22.5/5.0 −1.55 0.0013 221 BR1488 carbamoyl-phosphate BIBW2992 ic50 synthase, large subunit 126.9/5.0 −1.34 0.0098   Degradation

  278 BRA0725 glycine cleavage system P protein 99.9/5.8 1.51 0.00044   Transport   1219 BRA1193 amino acid ABC transporter 44.2/5.6 1.38 0,000015 1293 BRA0953 amino acid ABC transporter, periplasmic amino acid-binding protein, putative 43.3/5.3 1.36 0.0019 1549 BR0741 amino acid ABC transporter, periplasmic amino acid binding protein 37.2/5.3 1.31 0.00014   Protein metabolism     Biosynthesis   1783 BR0455 ribosomal protein S6 17.1/8.0 1.69 0.0069 1980 BR0452 ribosomal protein L9 21.0/4.8 1.59 0.00041   Secretion   313 BR1945 preprotein translocase, SecA subunit 103.0/5.1 −1.34 0.005   DNA/RNA metabolism     Biosynthesis   221 BR1488 carbamoyl-phosphate synthase, large subunit 126.9/5.0 −1.34 0.0098 454 BR0837 phosphoribosylformylglycinamidine synthase II 80.0/4.8 −1.31 0.01 456 BR0837 phosphoribosylformylglycinamidine synthase II 80.0/4.8 −1.31 0.015   Degradation   689 BR2169 polyribonucleotide nucleotidyltransferase 77.7/5.0 1.55 0.0029   Fatty acid metabolism

    Degradation   1881 BR1510 long-chain acyl-CoA thioester hydrolase, putative 14.25/6.6 1.67 *   Sugar metabolism     Transport   1642 BR0544 ribose ABC transporter, https://www.selleckchem.com/products/rocilinostat-acy-1215.html periplasmic D-ribose-binding 34.6/4.8 1.46 *   Regulation   1743 BR0569 transcriptional regulator, Ros/MucR family 16.10/7.8 1.73 0.021 1843 BR2159 transcriptional regulator, Cro/Cl family 15.1/9.0 1.6 * 1813 BR1502 leucine-responsive regulatory protein 17.8/6.7 1.5 0.049   Oxidoreduction

  1975 BRA0708 alkyl hydroperoxide reductase C 20.6/5.0 −1.39 0.005   Cofactor biosynthesis   826 BRA0491 8-amino-7-oxononanoate synthase 40.6/7.3 1.52 0.033   Unknown function   2190 BRA0336 conserved hypothetical protein 18.4/5.0 −1.42 0. 022 a The indicated number is an arbitrary designation of the annotated spots on the 2D proteome maps [see Additional files 1 and Mannose-binding protein-associated serine protease 2]. b Open reading frame number attributed by Paulsen et al. [20]. c As annotated by Paulsen et al. [20]. d Calculated from the amino acid sequence of the translated open reading frame. e Increase or decrease of protein concentrations after normalization of protein spot intensities from 2D-DIGE gels of B. suis recovered from a 6-weeks-starvation condition as compared to normalized protein spot intensities of corresponding spots from early stationary phase control of B. suis in TS broth. f Statistical significance of the ratio described in e .

bovis in M bovis BCG [5] Complementation experiments have demon

bovis in M. bovis BCG [5]. Complementation experiments have demonstrated that mutations that abolish production GDC-0994 cell line or secretion of RD1 ESAT-6 proteins confer an attenuated phenotype in various animal models, which in turn suggests that ESAT-6/CFP-10 play an important role in survival and multiplication of M.

tuberculosis within the host cell [20, 21]. Moreover, ESAT-6 proteins have been identified as strong targets for human B- and T-cell response, a finding which stimulates great interest in the potential of these antigens for vaccine use [22]. Besides EsxA and EsxB, EsxH (Rv0288), included in cluster 3, has also been identified as a strong antigen in TB patient and BCG vaccinated donor [23]. Two other ESAT proteins (Rv3017c, or EsxQ and Rv3019c, or EsxR), despite their high degree of identity with Rv0288, display a unique epitope pattern [24]. These observations strengthen the hypothesis that these genes could encode proteins whose functions are similar, but whose recognition by the immune system differs; differential Adriamycin mouse expression of individual genes could lead to antigenic variation, which would help mycobacteria to escape from the host defence. To better understand esx genes function it is

important to investigate their expression in varying conditions and in differing phases of the infective process. esx genes were also identified in other mycobacteria; in particular the fast growing M. smegmatis contains three ESAT-6 gene clusters, which correspond to the previously identified regions 1 (encompassing region between msmeg0057 and msmeg0083 genes), 3 (msmeg0615-msmeg0625) and 4 (msmeg1534-msmeg1538) of M. tuberculosis. The finding that bacteria ADAM7 carrying ESAT-6 genes live in varying environmental niches suggests that, besides virulence, these proteins could have a more general

role in mycobacterial physiology. To better define the putative role of cluster 3 in mycobacterial pathogenicity and physiology, we decided to study ESAT cluster 3 gene regulation in M. smegmatis and in M. tuberculosis. As the rv0282 promoter region had been previously characterized [16], we analysed msmeg0615 promoter region activity. Our results suggest that regulation differs in these organisms; while in M. tuberculosis gene cluster 3 is controlled by IdeR and Zur regulators in an iron- and zinc-dependent manner, in M. smegmatis only IdeR-dependent regulation is retained, while zinc has no effect on gene expression. Iron is a growth limiting factor both in the environment and during human infection. In mammalian hosts this metal is bound to high affinity iron-binding proteins, and abnormal high iron levels in serum are associated with exacerbation of the disease [25]. It is worth noting that the differences in ESAT-6 cluster expression 3 in M. tuberculosis and M. smegmatis could be due to differences in the life styles of these organisms. As a pulmonary pathogen, M.

The operating power was 100 W, and the typical etching time was 9

The operating power was 100 W, and the typical etching time was 90 min. Plasma treatment on the composite

membrane was performed at 100 Pa at room temperature. A 13.56-MHz RF power supply (CESAR 136, Advanced Energy Industries, Inc., CO, USA) was used to generate plasma. Ar (99.999%) and O2 (99.999%) were employed as feed gases, and the background vacuum of the equipment was 1 × 10-4 Pa. The composite membrane with opened CNT channels was then immersed in a 50% hydrogen fluoride acid solution for 24 h to remove the CNT/parylene membrane from the silicon substrate. The freestanding composite membrane [28] was washed with deionized water, followed by drying. The bottom or untreated surface of the membrane was also treated shortly by plasma etching to expose CNTs. Finally, a through-hole membrane was obtained. It is important to exclude the gas leakage HDAC cancer within the polymer matrix when the gas permeances through the CNTs in the composite membranes are measured. The gas leakage in the CNT/parylene composite membrane was characterized through H2 permeation measurement before it was treated by plasma etching. The freestanding CNT/parylene composite membrane was first sealed between two pieces of aluminum adhesive tapes with pre-punched holes (3 mm in diameter). Then, the membrane was mounted

in the gas line of a permeation testing apparatus, which was purged with the target gas Wnt tumor for several times to avoid any possible impurities. Finally, pure H2, He, N2, Ar, O2, and CO2 (99.999%) were introduced to the upstream side of the membrane [29] for permeation measurements. A pressure or flow controller (MKS 250E, MKS Instruments, MA, USA) was connected to the upstream

and downstream sides of the composite membrane to control the relative gas pressures by automatically tuning the gas feeding rates. The permeabilities at a variety of pressures (10 to 80 Torr) were measured using a mass flow meter connected at the downstream side. The measurements were carried out at different temperatures. The pore density and porosity of the membranes were measured using KCl diffusion through the membrane [30]. Results and discussion Figure 1a shows a scanning electron microscopy (SEM) image of Phosphoglycerate kinase a typical CNT forest grown by water-assisted CVD. The forest is about 10 μm in height, and the CNTs are highly aligned and continuous as shown in the inset of Figure 1a. Figure 1b presents a high-resolution transmission electron microscopy (HRTEM) image of a typical CNT in the forests. The diameter was around 7 nm, and the graphitic wall number was 3. Thermogravimetric analysis (TGA) at a heating rate of 5°C/min (Figure 1c) shows that there is no measurable residue in the sample heated over 750°C in air, suggesting a very high carbon purity of the CNTs.

NYC ributed conception, designed the study and wrote the manuscri

NYC ributed conception, designed the study and wrote the manuscript. HXG carriedouttheexperiments, collected and interpretated the data. XMW carriedouttheexperiments, collect ed and interpretated the data. FYX assisted with study implementation. QR and SHL assisted with study implementation and supervised laboratory procedures. BL carriedouttheexperiments, collected and interpretated the data. LZ supervised laboratory procedures. HZ contributed conception, analyzed the data, and wrote the manuscript. Allauthorsreadandapprovedthefinalmanuscript.”
“Background Pancreatic cancer is a devastating disease; it is the YM155 molecular weight eighth

most common cause of death (from cancer in both sexes combined) in the World, and is responsible for 227,000 deaths per year [1]. The median survival time after tumour detection is 3-6 months [2], with an all-stage 5-year survival rate of < 5% [3]. Surgery offers the best possibility for survival but at time of diagnosis, only 15% of patients are eligible for resection [4]. The poor outcome is mainly due to difficulties in early detection, lack of an effective treatment and limited understanding of the biological characteristics of this disease. Intrinsic resistance to chemotherapy and radiation

[5] coupled with its early systematic dissemination, local tumour progression and metastatic propensity are associated with pancreatic cancer [6]. The processes involved in tumour cell invasion and metastasis are complex. The ability of cancer cells to degrade NF-��B inhibitor and adhere to the basement membrane and metastasise to distant organs is one of the most critical aspects of cancer. Adhesion molecules, such as integrins mediate direct cell-cell recognition and cell-matrix interactions [7] are essential for tumour cell migration [8] and

for basement membrane penetration [9]. In pancreatic cancer, expression of integrins α6β1 Florfenicol [10–12] and αvβ3 [13] have previously been associated with invasion in cell lines and tissues. However, contrasting results with respect to tumour type and integrin expression patterns makes it difficult to draw general conclusions on the role of specific integrins. Tumour progression and metastasis are associated with changes in a multitude of integrin signalling cascades. Transformed cancer cells are often characterised by the loss/reduction of integrin expression [14, 15]. Extracellular matrix (ECM)-ligand binding to an integrin initiates signals, which are transmitted via different, yet interconnecting, pathways and elicit various cell functions, such as morphological changes, adhesion, migration and gene activation, all relevant to the metastatic cascade. The surrounding microenvironment and adhesion properties of pancreatic tumours and sub-populations within the tumour may determine which integrins increase or reduce metastasis in particular tumours [16].

Two additional anecdotes provide further credibility to our findi

Two additional anecdotes provide further credibility to our finding that HB 219 expression rate is a robust positive predictor of rosetting: First, we find that in all of the nine cases where there is rosettting data for an isolate that has HB 219 present in its most highly expressed sequence, considerable rosetting is observed

(defined as > 0.1). Secondly, we find that the DBLα domains of known rosetting var genes [30, 31] contain HB 219 (Additional file 1: Figure S2). Based on a comparison of the BIC scores of the models that result from the above variable selection procedures (Table  1), it seems that a more informative model for rosetting can be achieved when HB expression https://www.selleckchem.com/products/OSI-906.html rates are used as candidate independent variables in addition to classic var types. More

specifically, the most informative model is achieved when we consider the expression rates of several HBs in addition to the expression rates of one classic var type: BS1/CP6. This becomes even clearer when we perform a fourth variable selection procedure using the principal XMU-MP-1 components discussed below (row D in Table  1 and Additional file 3: Table S3). Principal components of HB expression rate profiles and variation in rosetting We perform a PCA on the HB expression rate profile, which we define as the set of expression rates for all 29 HBs. This deconstructs the HB expression rate profiles into orthogonal principal components (PCs) based on how they vary across different isolates. We then repeat the above network and variable selection analyses using PCs in place of individual HB expression rates (Additional file 1: Figures S11 and S12). We find that PC 1 is related to the cys2 versus non-cys2 distinction (Figure  5B), and that it captures the difference between HBs that are associated with severe versus mild spectrum phenotypes

(Figure  3; Additional file 1: Figure S4). PC 1 correlates with all of the severe spectrum phenotypes (Figure  5E) and the HB expression rates that contribute most to PC 1 are those with strong associations with disease phenotypes. PC 1 describes 8.15% of the variation among isolates with regard to their HB expression rates (Additional file 1: Figure S14). The HBs that have large nearly positive values in PC 1 define the core of the mild spectrum linkage/phenotype subnetwork (Figures  3, 5A and D; Additional file 1: Figures S4 and S13). Likewise, the HB that has the dominant negative value in PC 1, HB 60, defines the core of the severe spectrum linkage/phenotype subnetwork (Figures  3, 5A and C; Additional file 1: Figures S4 and S13). These observations about PC 1 are robust to the specific isolates used for the PCA. When non-overlapping subsets of isolates are analyzed separately, the relative contributions of the various HB expression rates that primarily contribute to PC 1 remain essentially the same (Additional file 1: Figure S15). Figure 5 Principal components of HB expression rate profiles.

The major consequence of core mutation is loss of sequence-specif

The major consequence of core mutation is loss of sequence-specific DNA binding to the canonical wtp53-binding site of target genes with loss of p53

oncosuppressor function. In some cases though, mtp53 proteins may acquire pro-oncogenic functions contributing to tumor progression [5]; moreover, loss of the ability of mtp53 to induce the expression of the E3-ubiquitin ligase MDM2 is thought to be responsible for the mtp53 enhanced stability [6]. These observations, and the finding that mtp53 protein is often expressed at high levels in tumors, make mtp53 reactivation an attractive strategy as anticancer therapy [7]. Many screening studies are underway to identify small molecules that reactivate mtp53 by acting on the equilibrium of native and denatured protein immediately OICR-9429 in vivo Target Selective Inhibitor Library concentration after translation, by acting on the misfolded states, or by alleviating the mtp53 pro-oncogenic affects (i.e., mutp53/p73 interaction) [5, 7, 8]. In previous studies we found that ZnCl2 treatment induced the transition of mutant p53 protein into a functional conformation [9–12]. Although we found that ZnCl2 treatment did not induce cell death by itself,

it restored mt-p53-carrying cell sensitivity to chemotherapy allowing tumor regression [9–12]. Here we aimed at examine the effect of a novel Zinc compound, a heteroleptic pentacoordinated (bpy-9)Zn(curc, Cl) complex (hereafter indicated as Zn-curc) containing a 4,4’-disubstituted-2,2′-bipyridine as main ligand and curcumin (curc) and chloride (Cl) as ancillary ligands Fossariinae [13, 14], in mutant p53-carrying cancer cells. The presence of the curcumin framework in the Zn-curc complex allows intrinsic fluorescence

activity, therefore we attempted to exploit this feature to evaluate the intratumoral distribution of Zn-curc in an ortothopic model of glioblastoma in mice. We choose to use glioblastoma because it is the most common and lethal primary central nervous system (CNS) where inactivation of the p53 gene and the presence of aberrant p53 expression are often reported [15]. Moreover, glioblastoma presents unique challenges to therapy due to its location, aggressive biological behaviour, angiogenesis and diffuse infiltrative growth. Thus, glioblastoma becomes easily chemoresistant, besides, the existence of blood-tumor barrier (BTB) represents an obstacle influencing the therapeutic efficacies via systemic administration [16]. In this study, we analyzed the biological effect of the novel Zn-curc complex in several cancer cell lines carrying different p53 mutations. Immunoprecipitation studies with conformation-specific antibodies were performed to evaluate p53 protein conformation after treatment. Finally, immunofluorescence analysis of glioblastoma tissues, of an ortothopic mice model treated with Zn-curc, was performed lo look for Zn-curc localization.

4 ± 0 7 nm Figure 1b shows the X-ray diffraction (XRD) patterns

4 ± 0.7 nm. Figure 1b shows the X-ray diffraction (XRD) patterns of the Ag2S nanocrystals, and all the diffraction

peaks can be indexed to the monoclinic Ag2S phase (JCPDS card: no. 14-0072). Figure 1 TEM image and XRD patterns and standard diffraction lines of Ag 2 S. TEM image of resultant Ag2S nanocrystals (a) and XRD patterns of Ag2S nanocrystals and standard diffraction lines of monoclinic Ag2S (b). The electrically bistable devices were fabricated on glass substrates pre-coated with an indium-tin-oxide (ITO) anode, which were alternately cleaned by deionized water, acetone, and ethanol in an ultrasonic environment. Afterwards, the poly(3,4-ethylenedioxythiophene)/poly-(styrene-sulfonate) (PEDOT/PSS) was spin-coated onto the substrate and was annealed ACP-196 datasheet at 150°C for 20 min, check details which could smooth the ITO surface and improved the device stability by hindering oxygen and indium diffusion through the anode. The PVK and Ag2S nanocrystals were mixed and dissolved in chlorobenzene solution with a mass ratio of 1:1. The solution would further form the active layer by the spin-coating method. Finally, a top Al electrode layer of 200 nm thickness was deposited onto the top surface by thermal evaporation under the vacuum of about 1 × 10−6 torr.

Results and discussion The I-V characteristics of the devices with a structure of ITO/PEDOT:PSS/Ag2S:PVK/Al under different sweeping voltages are shown FER in Figure 2. The voltage scan sweeps −5 to 5, −10 to 10, and −15 to 15 V, respectively. All the I-V curves of the devices under different sweeping voltages exhibit a typical electrical bistability. The magnitude of the I-V hysteresis increases

with increasing maximum sweeping voltages, and the ON/OFF current ratio of the device can approach 104. Herein, we take the I-V result under the sweeping voltage from −15 to 15 V as an example to describe the electrical hysteresis process. When the sweeping voltage exceeds a certain threshold, namely V on (about 8 V), the current increases rapidly, which indicates that the conducting state transforms from OFF to ON state. When the sweeping voltage scans from 0 to −15 V, the current reaches its maximum at a certain voltage (about −6 V), which is labeled as V off (the voltage region where the NDR effect takes place), and then decreases quickly with the increasing reverse voltage, which is a typical NDR behavior. As a result, the conducting state changes from ON to OFF state. Considering that there is no obvious hysteresis observed in the device using only PVK as active layer we suggest that the Ag2S nanocrystals play a significant role in the electrical bistability. Furthermore, it can be seen in Figure 2 that the absolute value of V off increases with the increasing magnitude of the sweeping voltage, indicating that there might be a certain connection between the NDR effect and the sweeping voltages.