jejuni is

expressed from two separate promoters [47]. Our findings further indicate that transcription under iron-starvation can be controlled by Fur indirectly, as was observed for the dsbA1 gene. The sophisticated mechanism regulating dsb gene transcription in response to iron availability may be responsible for subtle changes in the abundance and/or activity of various Cabozantinib research buy substrates in the Dsb system. We demonstrated that activity of C. jejuni 81-176 AstA, which is a direct target of Dsb system, is dependent on iron level in the medium. However, as AstA level is dependent on the activities of both DsbA1 and DsbA2 (unpublished results), details of the process remain unclear. Recently performed comparative Helicobacter pylori and Neisseria gonorrhoeae transcriptomic analysis also indicated that genes included in the Fur regulon

can be positively or negatively regulated in response to iron availability [38, 48]. Like C. jejuni Fur, H. pylori Fur also binds to some promoters in its iron-free form to repress their expression [38, 49–51]. C. jejuni Fur reveals a relatively high degree of amino acid identity with H. pylori Fur. Nonetheless it is not able to complement apo-Fur regulation in an H. pylori fur mutant when delivered in trans [52]. Such unexpected results might be due to subtle differences in conformation of both proteins. Additional experiments, such as solving the three dimensional structure of C. jejuni Fur, are required to clarify https://www.selleckchem.com/products/MK-2206.html the functional differences between Fur proteins of these closely related species. Although both species have AT-rich genomes and some of their promoters have similar structure, it can not be excluded that the C. jejuni apo-Fur binding nucleotide sequences are not identical as those determined for H. pylori apo-Fur. ID-8 Also two H. pylori promoters, the pfr and sod gene promoters that are repressed by apo-Fur, exhibited low sequence similarity and revealed different affinities for apo-Fur [38, 50]. The second part of our research was aimed at understanding the relationship between dba and dsbI expression.

Experiments employing point mutated dba provided evidence for strong translational coupling of the dba and dsbI genes. Inhibition or premature termination of dba mRNA translation resulted in the lack of DsbI. This defect was not complemented by the intact chromosomal dba gene in C. jejuni 81-176 dsbI::cat. Translational coupling has already been described and is common among functionally related bacterial genes. It was documented that in many cases it involves operons containing overlapping genes as well as genes constituting an operon and divided by short intergenic region [53, 54]. C. jejuni 81-176 dba and dsbI do not overlap, but are separated by a relatively short intergenic region (11 bp). Experiments employing a recombinant plasmid that expressed only DsbI verified the importance of the dba-dsbI mRNA secondary structure for its translation.

The untreated and antibiotic-treated mice exhibited a 6–10 fold increase in spleen weights compared to healthy, uninfected animals. Bacterial loads in spleens were significantly reduced Enzalutamide cell line in antibiotic treated animals compared to untreated control but remained in the range of 1.6 × 104 CFU/g of spleen. The antibiotics administrated 24 hours post-infection for 10 days led to the development of a chronic, non-lethal abscess infection suggesting that B. mallei may have the propensity for latency, as does the very closely related organism

B. pseudomallei [25]. Efficacy of other antibiotics tested in hamsters revealed that time of administration of antimicrobials is the important factor affecting protection against B. mallei [24]. The experiments showed that administration of treatment less than 24 h post-exposure resulted in protection against the pathogen. A similar conclusion was obtained in antibiotics efficacy testing against B. pseudomallei infected mice [26]. Combined, this suggests that the infection could be contained or eliminated if very early antibiotic treatment was initiated to prevent the bacterial load from reaching JQ1 chemical structure a lethal dose in the host. The pharmacokinetics

of each antimicrobial, relative to the in vitro MIC and the ability of the bacteria to reside in privileged intracellular sites (not always easily accessible to the antimicrobials) should be considered as an important factor in effective treatment. For that reason, we tested levofloxacin in our study since fluoroquinolones are known to penetrate renal,

lung and bronchial track tissues achieving a high intracellular concentration exceeding levels of the drug in serum [23]. Both antimicrobials were very effective in intracellular bacterial killing reducing bacterial loads to practically undetectable levels, validating Methane monooxygenase their ability as cell-permeable antibiotics. Conclusion The current study showed that both ceftazidime and levofloxacin, despite good activity in vitro against B. mallei, failed to eradicate bacterium and resulted in development of a chronic, non-lethal form of glanders. Both antibiotics demonstrated some utility for treatment of glanders, including the ability for intracellular penetration and clearance of organisms in vitro, despite bacterial burdens recovered in vivo following i.p. antibiotic treatment. Methods Bacterial strain B. mallei strain ATCC 23344 (China 7) was cultured on Luria-Bertani supplemented with 4% glycerol (LBG) agar plates for 48 h at 37°C. Isolated colonies were sub-cultured to LBG broth, and cultures were incubated at 37°C until optical density readings at 600 nm (OD600) reached an exponential phase of growth. Bacteria were pelleted by centrifugation, washed and re-suspended in sterile 1× phosphate-buffered saline (PBS, pH 7.4) to obtain the desired CFU/ml. All procedures were performed in a biosafety level 3 laboratory.

The reaction between POD and ABTS was photometrically determined using a microplate reader at 405 nm. Statistical Analysis All data in the study were evaluated using SPSS11.5 (SPSS Inc., USA). Differences were considered significant at values of p < 0.05. Significant results were marked with ""*"".

Results Inflammation effect on the melanoma showed two phases: Inhibition and inhibition missing To determine if inflammation has an inhibitory effect on the melanoma cells, a wound mouse model was built. When the tumor grew to a specific size, we created a wound in the opposite side of the mouse’s body. The wound model was used to manufacture a full-body model of acute inflammation in order to investigate the macro effect between inflammation and tumors. The results show a gradual reduction of tumor volume when the Selleckchem RG7420 wound was building; the tumor volume reached the minimum at day 7. After day 7, the inhibitory effect of the wound (inflammation) https://www.selleckchem.com/products/BI-2536.html on the tumor down-regulated gradually. The tumor volume of the inflammatory group at day 11 was almost the same as the control group at day 13. This is even higher than the average tumor volume. The tumor growth curve showed two phases: the early phase (before day 7, the inhibition phase) and the latter phase (after day 7

and marked in day 11, the inhibition missing phase). The latter phase presented an increasing proliferation of tumors. (Figure 1A) Figure 1 A wound model was built in C57BL/B16 tumor-bearing mouse to determine the influence on melanoma by inflammation. When the tumor grew to 0.5 cm3, we created a wound beyond the tumor in the opposite site of the

mouse’s body. A.) The results show gradual reduction of the tumor volume when the wound was building; the tumor volume reached the minimum at day 7 (shown in black box, p < 0.01). After day 7, the tumor inhibitory effect of the wound (inflammation) weakened gradually. On about day 11 of the inflammatory group compared with the control group, tumor volume almost as same as the control group at day 13 (shown in black box, p > 0.05). B.) Megestrol Acetate The cross-section of the tumor showed that the tumor necrosis with hemorrhage occurred in different proportions of times and groups. On day 7, the group wound tumors were smaller than the control group, and the area with necrotic tissue is greater than the control group (p < 0.01). After 11 days, the tumor volume in the wound group was increased, but in the cross-section area of necrotic tissue rather than in the control group (p > 0.05). The necrotic percentage after day 11 showed the tumor through a mechanism to adapt the wounds caused by inflammation induced necrosis, promoted the emergence of proliferation. The cross-section of the tumor showed that the tumor necrosis with hemorrhage occurred at different times and groups.

Cho WK, Choi IS: Fabrication of hairy polymeric films inspired by geckos: wetting and high see more adhesion properties. Adv Funct Mater 2008, 18:1089–1096.CrossRef Competing interests The authors declare that they have no competing interests. Authors’ contributions CF designed the metallic interdigitated electrode structures, performed and analyzed the electrical measurements, and drafted the manuscript. NP designed the entire study, carried out the chemical bath deposition of ZnO rods, performed the optical measurements, and drafted the manuscript. ME performed the SEM measurements and made

the corrections of the manuscript. IZ mainly helped to carry out the CA and roll-off angle measurements. MS helped with the analysis of XRD data. IE supervised the research, giving valuable advices about the whole experiments and manuscript. All authors read and approved the final manuscript.”
“Background

Fully stretched DNA molecules are very important with regard to advancing the genomic sciences and analyses in order to understand the physical and biological properties of DNA, including the ability to directly manipulate and visualize single DNA molecules. In fact, engineering DNA stretching would be a key step in the development of the next generation of biological microfluidic devices [1, 2]. Microfluidics is the study of behavior manipulation and control of fluids confined to micrometer dimensions, typically 1 to 100 μm. Transport in the microchannels is the major phenomenon; it includes flow detections, liquid transport, control of molecular transport Alpelisib like DNA molecule

conformation dynamics, measurement of bulk-level rheological properties, and separation techniques with biophysical and genomic applications because they generate defined fluid flows that manipulate large DNA molecules [3]. In addition, understanding the complex behavior of DNA molecules flowing in microchannels is essential to the realization of lap-on-a-chip (LOC) and micro total analysis system (μTAS) intended to Fossariinae systematically manipulate, process, and analyze these molecules. The presence of DNA molecules gives the fluid viscoelastic behavior that may change the base flow pattern in curved channels [4]. Two general approaches to DNA stretching are in common use: DNA is stretched in a solution as it flows through a microchannel, or it is stretched on a solid surface. For the latter, the conditions required for significant DNA stretching include high shear rates and high pressure gradient operations with a pressure-driven flow, due to non-slip boundary conditions on the wall. The shear flow existing at the channel walls could stretch DNA molecules. The degree of stretching is correlated with the Weissenberg number of the flow, Wi = τ , where τ is a characteristic relaxation time for the molecule in the solution and is a characteristic shear rate based on the flow in the channel.

Moreover, this inhibition was titratable; addition of increasing concentrations of Na+ resulted in an increasing inhibition of EtBr efflux. Addition of choline chloride had no measurable effect on EtBr efflux (data not shown), thereby establishing that the inhibition of EtBr efflux by NaCl was due solely to Na+ ions. Together, the results of the whole cell transport assays suggest that EtBr and Na+ utilise the same binding site and/or translocation

pathway in MdtM. Indeed, in the closely related MdtM homolog MdfA, the multidrug and Na+ cation translocation pathways Akt inhibitor overlap [9]. Figure 5 Whole cell ethidium bromide transport assays performed in the presence of different concentrations of NaCl. Representative traces of the efflux of EtBr from cells expressing wild-type MdtM in the presence of 0 mM (A), 20 mM (B), 50 mM (C) and 100 mM (D) NaCl. EtBr efflux was monitored continuously by measuring fluorescence emission at 600 nm upon excitation at 545 nm. UTL2 cells that expressed the MdtM D22A mutant in the absence of added NaCl www.selleckchem.com/products/GDC-0449.html were used as a control (E). Cells loaded with EtBr were energised by addition of glucose (as indicated by the first arrow) and efflux of EtBr was monitored for 800 s. CCCP (100 μM) was added (as indicated by the second arrow) to abolish active transport. Fluorescence intensity was measured in counts per second (cps).

MdtM catalyses K+/H+ and Na+/H+ exchange activities The growth assay and whole cell EtBr efflux data implied that MdtM-catalysed K+/H+ and Na+/H+ antiport activities underpinned alkalitolerance. To examine if MdtM mediated the exchange of K+ and Na+ for protons, we measured the changes in

luminal pH of inverted membrane vesicles generated from antiporter-deficient TO114 cells [26] that overexpressed wild-type MdtM by monitoring the fluorescence dequenching of acridine orange upon addition of Na+ Cobimetinib mouse gluconate or K+ gluconate to the transport assay buffer at the indicated alkaline pH values (Figure 6). Inverted vesicles prepared from TO114 cells that overproduced dysfunctional MdtM D22A mutant were used as controls. Figure 6 Cation-driven proton translocation by MdtM. Cation-driven proton translocation by MdtM at alkaline pH was measured by the fluorescence dequenching of acridine orange upon addition of Na+ gluconate (A) or K+ gluconate (B) to inverted vesicles derived from antiporter-deficient E. coli TO114 cells that overexpressed recombinant wild-type MdtM (black traces) or the dysfunctional MdtM D22A mutant (grey traces). Respiration-dependent generation of ΔpH (acid inside) was established by addition of lactate as indicated and once the fluorescence quench of acridine orange reached a steady state, Na+ gluconate or K+ gluconate was added to a final concentration of 100 mM. Addition of 100 μM CCCP at the time indicated was used to completely dissipate ΔpH.

0E−06 39.7 0.011 rs2016266 0.003  12 SP1 7 52060245 52096493 64.8 8.0E−06 rs10876432 1.0E−06 26.0 0.011 rs2016266 0.003  12 AAAS 8 51987506 52001679 116.3 9.0E−06 rs10876432 1.0E−06 39.7 0.012 rs2016266 0.003  9 CDK5RAP2 16 122190967 122382258 99.0 9.0E−06 rs3780674 7.1E−06 41.2 0.016 rs3780674 0.001  12

PFDN5 8 51975501 51979501 116.3 1.5E−05 rs10876432 1.0E−06 MI-503 chemical structure 39.7 0.011 rs2016266 0.003  6 ESR1 61 152053323 152466101 234.0 2.7E−05 rs2504063 5.6E−08 176.9 6.0E−04 rs3020331 8.0E−06  12 MFSD5 11 51932146 51934455 73.1 8.8E−05 rs7314769 8.8E−05 26.6 0.046 rs2272313 0.030  12 RARG 12 51890619 51912303 71.7 1.2E−04 rs7314769 8.8E−05 30.6 0.031 rs2272300 0.014 Table 3 Genes associated at gene-based genome-wide significant and suggestive level with femoral neck BMD in dCG study (n = 5,858) Gene information Lumbar spine BMD Femoral neck BMD Chr Gene Number of SNPs Start position End position Test statistic Gene-based p Best SNP SNP p Test statistic Gene-based p Best SNP SNP p Significant gene  6 C6orf97 41 151856919 151984021 248.9 1.0E−06 rs4870044 4.0E−06 270.1 2.0E−06 rs7752591 2.2E−06  11 LRP4 12 46834993 46896652 32.7 0.040 rs7108147 0.004 126.5 4.0E−06 rs1007738 7.1E−06 Suggestive gene  11 CKAP5 12 46721659 46824419 28.2 0.079 rs7108147

0.004 144.9 1.1E−05 rs1007738 7.1E−06  20 ADRA1D 23 4149277 4177659 50.9 0.025 rs6076639 0.010 108.7 2.9E−05 rs4815683 1.6E−04  11 F2 7 46697318 46717632 8.8 0.282 rs4752926 0.063 80.7 3.4E−05 rs6485690 6.4E−05  1 KPRP 7 150997129 151001153 14.2 0.124 rs1332498 0.063 85.3 3.6E−05 rs1332498 3.3E−05

Tigecycline cell line Phosphoglycerate kinase  9 FOXE1 9 99655357 99658818 1.0 0.970 rs6586 0.529 84.7 6.5E−05 rs907580 4.6E−06  1 LCE4A 6 150948146 150948534 13.5 0.119 rs1332498 0.063 79.5 8.9E−05 rs1332498 3.3E−05  1 LCE2A 6 150937463 150938542 12.5 0.129 rs1332498 0.063 70.9 1.0E−04 rs1332498 3.3E−05  10 ERLIN1 6 101899836 101935804 32.3 0.002 rs10883447 2.3E−04 45.8 1.1E−04 rs10883447 1.7E−04  1 LCE2B 8 150925222 150926500 12.9 0.209 rs1332498 0.063 71.0 1.2E−04 rs1332498 3.3E−05 Meta-analysis of gene-based GWAS in southern Chinese and Europeans In the gene-based GWAS of spine BMD in Europeans, C6orf97 had an empirical p value of 0. If there were no simulated test statistics greater than the observed test statistics, the empirical p value would be 0. We replaced the “0” with 1 × 10−6 for the purpose of meta-analysis and applied weighted Z-transformed test to combine the p values of each gene with weighting of sample size of each study.

giardinii or R. gallicum[66]. In contrast we were unable to transfer R. grahamii ERs to other rhizobia. It is worth noting that tropici symbiotic plasmids are more conserved than phaseoli ones, and both are more conserved than the grahamii group pSyms. It is tempting to suggest that genome conservation among distinct species is related to transferability. On the other hand, transfer of plasmids to novel hosts can also detonate their evolution by picking up new genetic information (that would affect the genomic content) from other genomic backgrounds. We do not know if in natural habitats or in the presence of a microbial community, the lack

of transferability of R. grahamii ERs holds true. Besides, the limited conservation of pSyms among R. grahamii and R. mesoamericanum suggests that they are not frequently

interchanged among these species. Transfer of the R. grahamii symbiotic plasmid BYL719 to Agrobacterium was dependent on quorum sensing, a mechanism that regulates transfer of plasmids in rhizobia [25, 67] and agrobacteria [68, 69]. This lack of ER flow and existence of a genetic barrier could be due to different mechanisms, such as DNA restriction/methylation systems or to surface or entry exclusion systems. Surface exclusion at the level of formation of stable mating aggregates and entry exclusion seem to inhibit conjugation in a later step of the mating aggregate [70, 71]. Limited transfer may be due to a system similar to CRISPR/Cas, an adaptive immunity system found in Archaea and bacteria that eliminates virus or plasmids in a new host [72, 73]. These possibilities deserve further research. Putative chromids FDA approved Drug Library screening (megaplasmids) in the grahamii group have a lower percentage of gene content conservation than the chromosomes and symbiotic plasmids, in spite of their fairly high ANI values (Figure 1B and C). Considering the conserved genomic content in chromosomes, symbiotic MG-132 solubility dmso plasmids and putative chromids in the grahamii group, there clearly are three different degrees of conservation

(Figure 1C). We suggest a layout where the rhizobial genome is a 3 gear genome with different rates of change in each of the replicon types. In animals and plants, different regions of the genome exhibit variable levels of genetic divergence between populations (reviewed in Nosil et al.[74]). The extrachromosomal replicons of R. grahamii CCGE502 were related to those from R. mesoamericanum. An exception is the plasmid integrated in the R. grahamii chromosome for which no equivalent plasmid was found in R. mesoamericanum or in other rhizobia. However some common genes were found in the R. grahamii integrated replicon and in other Rhizobium species. ER organization plasticity was reported previously in rhizobia with the integration of plasmids or megaplasmids into the chromosome [75, 76]. This seems to have occurred in R. grahamii CCGE502 as we report here. It is noteworthy that some of the genes highly expressed in R.

Cryer B, Bauer DC (2002) Oral bisphosphonates and upper gastrointestinal tract

problems: what is the evidence? Mayo Clin Proc 77:1031–1043PubMedCrossRef 32. Shane E, Burr D, Ebeling PR et al (2010) Atypical subtrochanteric and diaphyseal femoral fractures: Selleck RAD001 report of a task force of the American society for bone and mineral research. J Bone Miner Res 25:2267–2294PubMedCrossRef 33. Cadarette SM, van Wijk BL, Patrick AR, Brookhart MA (2011) Adherence to pharmacotherapy for hypercholesterolemia, hypertension and osteoporosis: behavioral insights. Am J Pharm Ben, in press”
“Introduction Osteoporosis is defined as “a skeletal disease characterized by loss of bone strength susceptible to increased risk of fracture”, which is frequent in women and the elderly [1]. According to the current WHO diagnostic criteria [2], the number of osteoporosis patients in USA is estimated to be 5.3 million [3], while the 2006 Japanese guideline estimates the number of Japanese patients as 7.8 to 11 million [4]. The objective of treating osteoporosis is to prevent the occurrence of fracture. Among the fractures Pifithrin-�� attributable to osteoporosis, hip fracture has the most important influence on survival, quality of life,

and medical costs. The worldwide incidence of hip fracture is expected to increase from approximately 1.5 million in 1990 to 4.5–6.3 million in 2050 [5, 6]. The number of hip fractures in Japan was estimated to be 148,100 in 2007, and this has increased every 2-hydroxyphytanoyl-CoA lyase year since the start of

investigation in 1987 [7]. Prior fracture is a risk factor for new fractures in addition to sex, age, and low bone mineral density (BMD) [8]. In particular, patients with a history of hip fracture may have an increased risk of unaffected side hip fracture because of excessive weight bearing on the opposite side while walking due to anxiety about recurrence. Current drug treatment for osteoporosis has made considerable progress. Risedronate is a bisphosphonate that is employed in patients with osteoporosis, which reduces bone resorption and bone turnover by inhibiting osteoclast activity [9]. Risedronate has been shown to increase BMD [10, 11], and to inhibit the occurrence of vertebral compression fractures [12, 13] as well as hip fractures [14, 15]. Based on such evidence, it is considered that risedronate is one of the most effective treatments for osteoporosis currently available [16]. Only a few studies on the efficacy of risedronate for inhibiting hip fracture in specific Japanese patient group have been performed so far [17, 18]. In addition, although patients with a history of hip fracture have a higher risk of new hip fractures, a study has not been conducted in this patient population. Accordingly, we conducted a prospective matched cohort study in Japanese osteoporosis patients with a history of hip fracture.

​nih.​gov/​geo/​), accession number GPL13532 for the platform design and GSE29309 for the original dataset. b P-values of RT-qPCR results were caculated using Student’s t-test. c UD: under detection level in microarray analysis or by RT-qPCR. Discussion As Staphylococci biofilm formation is influenced by external factors such as glucose, NaCl, temperature,

aerobiosis-anaerobiosis, static-dynamic conditions, and pH [36–39], it suggests BVD-523 in vivo that there are mechanisms that can sense environmental signals and regulate bacterial biofilm formation. In S. epidermidis, the agrC/A TCS has been proven to negatively regulate biofilm formation [15, 16], while the lytS/R TCS has been shown to positively regulate bacterial autolysis [40]. In S. aureus, the saeRS TCS influences biofilm formation [17] and the expression of virulence-associated factors [18], whereas in S. epidermidis, a mutant with saeR deletion showed a slightly higher biofilm-forming ability compared to the parental strain [11]. In the present study, SE1457ΔsaeRS, a saeR and saeS deletion mutant from S. epidermidis 1457, was constructed by homologous recombination. Although saeRS in S. epidermidis ATCC 35984 and S. aureus Newman are similar both at nucleotide sequence level (75% for saeR and 67% for saeS) and at the amino acid level (84% for SaeR and 70% for SaeS), both biofilm formation

and autolysis were up-regulated in SE1457ΔsaeRS, suggesting that saeRS in S. epidermidis plays RXDX-106 cell line a different role from that in S. aureus. Additionally, when examined by SEM, increased quantities of extracellular polymeric substances (EPSs) were

observed in the SE1457ΔsaeRS biofilm compared to the SE1457 and SE1457saec biofilms (Figure 2A). Aap expression and PIA synthesis are important for biofilm formation. Therefore, we examined the contribution of Aap and PIA to SE1457ΔsaeRS biofilm formation. In S. epidermidis, Aap plays an important role in biofilm formation, and biofilm-positive strains that express aap show higher biofilm forming abilities than strains that lack the Aap protein [41]. In SE1457ΔsaeRS, Aap up-regulation was detected using 2-DE and confirmed by Western blot, suggesting that Aap is a factor Thalidomide associated with the enhanced biofilm formation capacity of SE1457ΔsaeRS. PIA plays a major role in intercellular adhesion in S. epidermidis biofilms [42]. However, no obvious differences in either PIA production or transcription of icaA, the gene that encodes an N-acetylglucosaminyl transferase enzyme critical for PIA synthesis, were observed between SE1457ΔsaeRS and SE1457 (Table 3). These results are consistent with the findings reported for a saeR deletion mutant by Handke et al. [11]. The enhanced S. epidermidis biofilm formation may be correlated with the increased amounts of eDNA released in the biofilm matrix [19, 25, 28]. Quantitative PCR revealed that eDNA release from S. epidermidis 1457ΔsaeRS was up-regulated (Figure 6).

A control sample without BLG was also fabricated as shown in Figure 1b. The thin layer of SiO2 was used to protect C60 film during subsequent metal evaporation step. Figure 1 Device schematics and characterization. (a) Molecular memory with

atomically smooth bilayer graphene sandwiched between 300 nm Ni and 100 nm C60 films. (b) Control device without MDV3100 supplier the bilayer graphene. (c) Raman spectrum of evaporated C60 film on the bilayer graphene is shown as well. A detailed characterization of the synthesized BLG has been reported earlier in [13]. Raman spectroscopy was used to confirm the quality of evaporated C60. A laser power of 2 mW with 5 s scan time and four scans per point is used to avoid sample heating. The Raman spectrum of evaporated C60 film on BLG is also shown in Figure 1c. The dominant peaks are at 491, 1,464, and 1,596 cm−1 wavenumbers, which confirm the coherence of C60 molecular structure even after thermal P450 inhibitor evaporation [14, 15]. Results and discussion In Figure 2, we report the transport characteristics in the first and second sweep cycles for the device with BLG contact. The device starts in the low-resistance state and the voltage is increased in the forward direction until it irreversibly switches to high-resistance state at

about 0.9 V, as shown in Figure 2a. After switching, the device withstands its high-resistance state, thus exhibiting hysteresis in the first cycle. We rule out the possibility of conductive filament formation (CFF) due to electromigration, since graphene

has a breaking strength value of approximately 42 N/m and is impermeable even to helium atoms [16, 17]. Moreover, in the CFF, current increases after switching, whereas an opposite trend is observed here. Apart from this, we find that the switching voltages for various devices lie in the 0.8 to 1.2 V bias range. This variation may be due to the amorphous and heterogeneous nature of the evaporated SiO2 film [18]. Figure Demeclocycline 2 Transport characteristics in the first and second sweep cycles. (a) During the first sweep cycle, the voltage is swept in the forward direction until the device switches to high-resistance state. During the reverse sweep, the device remains in the high-resistance and shows hysteresis. (b) The device remains in the high-resistance state during the second sweep cycle and no hysteresis or switching is observed. The switching behavior for the second sweep cycle is shown in Figure 2b. The device remains in the high-resistance state without hysteresis. In the subsequent sweep cycles, the device sustains its high-resistance state, thus making it a write-once read-many (WORM) memory device. Next, we report the retention characteristics in Figure 3, by using a read voltage pulse train of 0.4 V bias with 10 ms duration and 0.1% duty cycle. The mean value of current in the low-resistance state is 2.041 mA with a standard deviation of 0.973 × 10−3.