This risk profile consists of the following nine items: two or more falls in the preceding year, regular dizziness, functional limitations, poor grip strength, low body weight, having a cat Belinostat clinical trial or dog in the household, fear of falling, high alcohol intake and a high level of education. After the first home visit, 36 participants did not meet the inclusion criteria and were excluded. Participants who scored 7 points or lower on the fall risk profile were considered at low risk of recurrent falling and were excluded from the

RCT and economic evaluation. Participants with a risk score of 8 or higher and participants living in a residential home were considered to be at high risk of recurrent falling. These high-risk participants were randomly allocated to the intervention and usual care groups. At the end of the home LDE225 ic50 visit, an appointment was made to visit the geriatric outpatient clinic for persons in the intervention group. No extra assessments or visits were done in the usual care group. Intervention

The multifactorial transmural intervention started with a visit to the geriatric outpatient clinic. A multifactorial fall risk assessment was conducted by the geriatrician to identify modifiable fall risk factors. The assessment of fall risk factors and the design of the treatment plan were based on the Dutch Institute for Healthcare Improvement (CBO) guideline “Prevention of fall incidents in older persons” [20]. The assessment consisted of a general medical history, a fall and mobility history, and physical examination

with special emphasis on signs of postural hypotension, neurological deficits, visual disturbances, gait and mobility disorders and medication. Additional diagnostic tests were performed if indicated (e.g. laboratory tests or imaging). Based on the assessment of fall risk factors, an individually tailored treatment regimen aimed at reduction of the fall risk was composed in collaboration with the general practitioner of the participant. The multifactorial treatment consisted of, for example, withdrawal of psychotropic drugs, balance and strength exercises by a physical therapist, Phosphoribosylglycinamide formyltransferase home hazard reduction by an occupational therapist or referral to an ophthalmologist or cardiologist. Usual care During the study period, usual care in The Netherlands after a fall mainly consisted of treatment of the consequences of the fall. Although a national guideline was released in 2004 [20], multifactorial fall risk prevention had not yet been implemented by general practitioners or at the A&E departments. Clinical outcome measures Clinical outcome measures of the economic evaluation were the prevalence of fallers and recurrent fallers and utility (quality of life). All participants reported falls during at least 1 year using a fall calendar [4]. The participants ticked per week whether they did or did not fall.

They could also correspond to transient species, which are accidentally passing,

although a recent metagenomic analysis found a very low rate of sequences from putative transient species [35]. We found that most OTUs have been observed once (Additional file 9, Table S4). We have deliberately omitted these OTUs from the analyses of cosmopolitanism and specificity, because their low abundance does not allow to extract conclusions about their environmental distributions. Nevertheless, their inclusion does not affect significantly the conclusions extracted for all taxonomic ranks, except that of species (Additional file 10, Figure S6). Further study is required to understand why the majority of OTUs are rare, and some work has already been done by Sogin and colleagues to address this point [31]. As commented above, selleck inhibitor they could correspond to specialist species with a very limited niche. But it is also likely that learn more the limited size of

samplings cannot recover low-abundance OTUs from the environments and samples where they actually exist. After all, it is virtually impossible to conclusively show that a microbial taxon is absent from a given location by the current sequencing methods [6]. Also the heterogeneous size of the samples can introduce a bias in the results, because big samples are likely to recover more species than small ones. Also rare OTUs are more likely to be detected in larger samples. Information about the abundance of each taxa in each sample could provide relevant information to correct this size effect. But unfortunately, this information is not present in the original source of data. Therefore, the patterns described here could be affected because samples of different size are being considered. To exclude this possibility, we created smaller datasets composed uniquely of samples of comparable size. The results of cosmopolitanism and ubiquity for two such datasets are shown in Additional file 2, Figure S1. It can be seen that the patterns are very similar to the ones obtained

with the full dataset. Also in the correspondence analysis we transformed the data dividing frequencies by the number of samples instead, as a proxy for the number of sequences, thus assuming that larger click here samples tend to have more sequences. Finally, in the Bayesian model of affinities, we included random effects to partially account for the variation of the unknown number of sequences. It is also necessary to consider that most data have been obtained by the standard sequencing procedures which involve PCR amplification steps using “”universal”" primers, a procedure that is known to be biased [36, 37]. Universal primers are designed according to current knowledge and could perform poorly or even miss species or taxa that remain unknown. Another source of potential biases is that in clone library sampling, often just some few clones of interest are sequenced or submitted, discarding the rest.

We thank Mari Nyyssönen for help with the microarray experiments, and thank Jizhong Zhou and Liyou Wu for providing the microarrays. The work was supported by a grant from U.S Department of Energy, Office of Science, DE-FG02-04ER63923 and by the WCU (World Class University) program through the National Research Foundation

of Korea funded by the Ministry of Education, Science and Technology (R33-10076). References 1. Villemur R, Lanthier M, Beaudet R, Lépine F: The Desulfitobacterium genus. FEMS Microbiology Reviews 2006, 30:706–733.PubMedCrossRef 2. Kunapuli U, Jahn MK, Lueders T, Geyer R, Heipieper HJ, Meckenstock RU: Desulfitobacterium aromaticivorans sp. nov. and Geobacter toluenoxydans sp. nov., iron-reducing bacteria capable of anaerobic degradation of monoaromatic hydrocarbons. JAK inhibitor Int J Syst Evol Microbiol 2010,60(3):686–695.PubMedCrossRef 3. Maymo-Gatell Tanespimycin mouse X, Chien Y, Gossett JM, Zinder SH: Isolation of a bacterium that reductively dechlorinates tetrachloroethene to ethene. Science 1997, 276:1568–1571.PubMedCrossRef 4. Madsen T, Licht D: Isolation and characterization of an

anaerobic chlorophenol-transforming bacterium. Appl Environ Microbiol 1992, 58:2874–2878.PubMed 5. Christiansen N, Ahring BK: Desulfitobacterium hafniense sp. nov., an anaerobic, reductively dechlorinating bacterium. Int J Syst Bacteriol 1996, 46:442–448.CrossRef 6. Niggemyer A, Spring S, Stackebrandt E, Rosenzweig RF: Isolation and characterization of a novel As(V)-reducing bacterium: implications for arsenic mobilization and the genus Desulfitobacterium . Appl Environ Microbiol 2001, 67:5568–5580.PubMedCrossRef 7. Lie TJ, Godchaux W, Leadbetter ER: Sulfonates as terminal electron acceptors for growth of sulfite-reducing bacteria ( Desulfitobacterium spp.) and sulfate-reducing bacteria: effects of inhibitors of sulfidogenesis. 17-DMAG (Alvespimycin) HCl Appl Environ Microbiol 1999,65(10):4611–4617.PubMed 8. Suyama A, Iwakiri R, Kai K, Tokunaga T, Sera

N, Furukawa K: Isolation and characterization of Desulfitobacterium sp. strain Y51 capable of efficient dechlorination of tetrachloroethene and polychloroethanes. Biosci Biotechnol Biochem 2001, 65:1474–1481.PubMedCrossRef 9. Nonaka H, Keresztes G, Shinoda Y, Ikenaga Y, Abe M, Naito K, Inatomi K, Furukawa K, Inui M, Yukawa H: Complete genome sequence of the dehalorespiring bacterium Desulfitobacterium hafniense Y51 and comparison with Dehalococcoides ethenogenes 195. J Bacteriol 2006,188(6):2262–2274.PubMedCrossRef 10. Suyama A, Yamashita M, Yoshino S, Furukawa K: Molecular characterization of the PceA reductive dehalogenase of Desulfitobacterium sp. Strain Y51. J Bacteriol 2002,184(13):3419–3425.PubMedCrossRef 11. Juhala RJ, Ford ME, Duda RL, Youlton A, Hatfull GF, Hendrix RW: Genomic sequences of bacteriophages HK97 and HK022: pervasive genetic mosaicism in the lambdoid bacteriophages. Journal of Molecular Biology 2000,299(1):27–51.PubMedCrossRef 12.

Toxicity profiles were reported according to the WHO’s criteria. QOL was reported in different criteria, which based on different QOL scale. Remission

Rate of Pain 2491 patients from 30 cohort studies, 1216 in the transdermal fentanyl group and 1275 in the sustained-release oral morphine group were included in the meta-analysis of clinical efficacy. Overall effect of remission rate of pain was analyzed by a fixed-effect model (fixed), because test for heterogeneity among the trials was not significant (p = 1.00). The remission rate in transdermal fentanyl group and sustained-release oral morphine group were 86.60% and 88.31% respectively, there was no significant difference [RR = 1.13, 95% CI (0.92, 1.38), P = 0.23]. More details were shown in Table 1 and the forest plot was shown in additional file Caspase inhibitor 2. Table 1 Comparisons between Transdermal Fentanyl and Sustained-release Ixazomib clinical trial Oral Morphine Endpoints No. of patients/studies RR (95% CI)a Pb Ph c Remission rate 2491/30 1.13 (0.92, 1.38) 0.23 1.00 Constipation 2593/31 0.35 (0.27, 0.45) < 0.00001 < 0.00001 Nausea/vomiting 2593/31 0.57 (0.49, 0.67) < 0.00001 0.009 Vertigo/somnolence 2300/28 0.59 (0.51, 0.68) < 0.00001 0.08 a RR, relative risk; 95% CI, 95% confidence interval

b p value of significance tests of RR = 1 c p value of heterogeneity tests Adverse Effects Data on main adverse effects was summarized in the additional file 1. Overall effect of constipation and nausea/vomiting were analyzed by a random-effect model (random), because test for heterogeneity among the trials

was significant (p < 0.05). Compared with sustained-release oral morphine, pooled RR of constipation was 0.35 [95%CI (0.27, 0.45), p < 0.00001]; pooled RR of nausea/vomiting was 0.57 [95%CI (0.49, 0.67), p < 0.00001]. Overall effect of vertigo/somnolence was analyzed by a fixed-effect model (fixed), because test for heterogeneity among the trials was not significant (p = 0.08). Pooled RR of vertigo/somnolence was 0.59 [95%CI (0.51, 0.68), p < 0.00001] in patients used transdermal fentanyl. In short, transdermal fentanyl caused less adverse effects in comparison of sustained-release oral morphine in patients with moderate-severe cancer pain. More details were showed in Table 1 and the forest plots were shown in additional file 2. Quality of Life Six of selected trials were included to systematic PLEK2 review of QOL [9, 14, 17, 32–34]. Primary endpoints of QOL were appetite, sleep, activity of daily living, mental states, emotion, communication and interest. QOL was not pooled for meta-analysis because different QOL evaluation criteria were used. After review of these six trials, all the data from each trial supported either transdermal fentanyl or sustained-release oral morphine improved QOL of cancer patients. In trial of Pang et al., more patients got better QOL after sustained-release oral morphine transferred to transdermal fentanyl [34].

In conclusion, it is favorable to fabricate high emission efficiency ZnO thin film on GaN/Si substrate rather than Si (111) substrate. The study provides an opportunity for constructing the nanopillar array ZnO/GaN heterostructure and deep UV emission LED devices. Acknowledgments The authors are grateful for the financial support by the Shandong Provincial Natural Science Foundation (Y2008A21, ZR2009FZ006, ZR2010EL017), the Encouragement Foundation for Excellent Middle-aged and

Young Scientist of Shandong Province (grant no. BS2012CL005), the Doctor Foundation of University of Jinan (XBS0833), the Shandong Provincial Science and Technology Project (2009GG20003028), and the Research Foundation of the University of Jinan (grant no. XKY1127). References 1. Peng W, Qu S, Cong G, Wang Z: Synthesis and structures of morphology-controlled ZnO selleck chemicals llc nano- and micro-crystals. Cryst Growth Des 2006, 6:1518–1522.CrossRef 2.

Ivill M, Pearton SJ, Norton DP, Kelly J, Hebard AF: Magnetization dependence on electron density in epitaxial ZnO thin films codoped with Mn and Sn. J Appl Phys 2005, 97:053904.CrossRef 3. Wang HQ, Koshizaki N, Li L, Jia LC, Kawaguchi K, Li XY, Pyatenko A, Swiatkowska-Warkocka Apoptosis inhibitor Z, Bando Y, Golberg D: Size-tailored ZnO submicrometer spheres: bottom-Up construction, size-related optical extinction, and selective aniline trapping. Adv Mater 2011, 23:1865.CrossRef 4. Wang HQ, Li GH, Jia LC, Wang GZ, Li L: General in situ chemical etching synthesis of ZnO nanotips array. Appl Phys

Lett 2008, 93:153110.CrossRef 5. Liu M, Wei XQ, Zhang ZG, Sun G, Chen CS, Xue CS, Zhuang HZ, Man BY: Effect of temperature on pulsed laser deposition of ZnO films. Appl Surf Sci 2006, 252:4321.CrossRef 6. Wang QP, Zhang DH, Ma HL, Zhang XH, Zhang XJ: Photoluminescence of ZnO films prepared by r.f. sputtering on different substrates. Appl Surf Sci 2003, 220:12.CrossRef 7. Wei XQ, Huang JZ, Zhang MY, Du Y, Man BY: Effects of substrate parameters on structure and optical properties of ZnO thin films fabricated by pulsed laser deposition. Materials Science and Engineering Nintedanib (BIBF 1120) B 2010, 166:141–146.CrossRef 8. Rastogi AC, Desu SB, Hattacharya PB, Katiyar RS: Effect of starin gradient on luminescence and electronic properties of pulsed laser deposited zinc oxide thin films. J Electronceram 2004, 13:345.CrossRef 9. Shan FK, Liu ZF: Studies of ZnO thin films on sapphire (0001) substrates deposited by pulsed laser deposition. J Electroceram 2004, 13:189.CrossRef 10. Aahas A, Kim HK, Blachere J: Epitaxial growth of ZnO films on Si substrates using an epitaxial GaN buffer. Appl Phys Lett 2001, 78:1511.CrossRef 11. Chen YF, Hong S, Ko H: Exciton spectra of ZnO epitaxial layers on lattice-matched substrates grown with laser-molecular-beam epitaxy. Appl Phys Lett 2000, 76:559.CrossRef 12.

Email addresses were obtained from published membership lists. The authors attempted to exclude email addresses that overlapped between organizations. This project was approved by the Institutional Review Board. Results were collected on a commercial survey website (http://​www.​surveymonkey.​com). Only a single mass emailing was completed, and the survey was closed after one

month. No follow-up emails or repeat email solicitations were used. All responses were kept completely confidential. Standard two-sided chi-square tests GSK126 were used to test for significant associations between specialty and survey responses. Because some expected cell counts were less than 5, results were confirmed using APO866 ic50 Monte-Carlo approximations of Fisher’s exact test with one

million repetitions. Testing was done using R version 2.10.1. Results A total of 785 responses were received, representing an overall response rate of 6.7%. Members of the American Association for the Surgery of Trauma had the highest response rate, at 15.7% (Table 1). Several emails were received from recipients of the survey, explaining that they were not clinicians, not physicians, or did not take care of patients with TCVI. Table 1 Responses according to professional society   Number of survey requests sent Number of responses American Association of Neurological Surgeons 5,481 335 (6.1%) American Association for the Surgery of Trauma 923 145 (15.7%) American Heart Association Stroke Council 4,638 263 (5.7%) Society for Clinical Vascular Surgery 742 42 (5.7%) Overall survey results The total responses to the survey questions are listed

in Table 2. The largest number of respondents were neurosurgeons (342, 45.2%) and the next largest responding specialty was neurology (205, 27.1%). Only 46 of the respondents (6.0%) reported seeing BIBF1120 no TCVI cases each year; the most common frequency was 1-5 per year, which was reported by 442 (57.4%) of the respondents. A conservative estimate of the total number of TCVI cases seen by the respondents can be estimated by multiplying number of respondents reporting each range of cases per year by the lowest number in each range. Thus, as a group, the respondents estimated that they see at least 2,680 TCVI cases each year. Table 2 Overall responses to the questionnaire 1. What is your specialty?   • Trauma surgeon = 137 (18.1%)   • General surgeon = 19 (2.5%)   • Neurosurgeon = 342 (45.2%)   • Vascular surgeon = 52 (6.9%)   • Neurologist = 205 (27.1%)   • Interventional radiologist = 30 (4.0%) 2. What is the approximate number of traumatic carotid or vertebral artery dissections or other injuries that you see per year?   • None = 46 (6.0%)   • 1-5 = 442 (57.4%)   • 5-10 = 144 (18.7%)   • > 10 = 138 (17.9%) 3. What is your preferred method of imaging?   • MRI/MRA = 175 (22.8%)   • CTA = 464 (60.5%)   • Doppler = 13 (1.7%)   • Catheter angiography = 115 (15.0%) 4.

To obtain the 5′ flanking region, the primers AP1/CasR20 and AP2/CasW-E70-R04 were used for

PCR1 and PCR2, respectively. To obtain the 3′ flanking region, the primers AP1/CasF9 and AP2/CasW-E70-F04 were used for PCR1 and PCR2, respectively. PCR reactions were performed in 1× buffer containing 1.5 mM of MgCl2, 200 μM of dNTPs, 200 nM of the www.selleckchem.com/products/AC-220.html adaptor, 0.2 μM of the Cas-specific primer and 0.5 U of Taq DNA polymerase (Eurobio, Courtaboeuf, France). All PCRs were conducted under the following conditions: an initial denaturation step (4 min at 95 °C), then 40 cycles (30 s at 95 °C, 30 s at 58 °C, 2 min at 72 °C) and a final extension step (72 °C for 5 min). PCR products migrating as a single unique band after electrophoresis

on an agarose gel were directly sequenced using nested Cas3-specific primers: CasW-E70-R01 for the 5′ flanking region and CasW-E70-F05 for the 3′ flanking region. A new set of primers (CasF20 and CasR28) was designed from both ends of the 5′ and 3′ flanking sequences and used to amplify the complete Cas3 or Cas4 sequence from isolates E70, E78, E79 and E139 using check details the AccuPrime™ Pfx proofreading DNA polymerase (Invitrogen, Paisley, UK) according to the manufacturer’s recommendations. All of the primers used in this study are listed in the Electronic Supplementary Material ESM 2. Bioinformatics All nucleotide and amino acid sequence analyses, alignments and annotations were conducted using the Geneious Pro program (Drummond et al. 2011). Homology searches were performed using the Blast program in the NCBI database. A phylogenetic tree of the cassiicolin gene diversity was constructed using MEGA5 software (Tamura et al. 2007) by the Neighbor-Joining method (Saitou and Nei 1987). The analysis involved six nucleotide sequences: JF915169, JF915170, JF915171,

JF915172, GU373809 and EF667973, for isolates E70, E78, E79, E139, CC004 and CCP respectively. The codon positions included in the analysis were 1st+2nd+3rd+Noncoding. All positions containing gaps and missing data were eliminated. There was a total of 574 positions in the final dataset. A bootstrap test of 1000 replicates was performed to obtain the percentage in which the associated taxa clustered together (Felsenstein 1985). The evolutionary 4��8C distances were computed using the p-distance method (Nei and Kumar 2000), and the results were expressed as the number of base differences per site. The synonymous (d S ) and non-synonymous (d N ) substitution rates were calculated by codeml in the PAML package (Goldman and Yang 1994). The prediction of the signal peptide in the protein was performed using SignalP software, version 3.0 (Bendtsen et al. 2004), and the program TMHMM, version 2.0, was used to check for the presence of transmembrane spanning regions in the protein (Krogh et al. 2001). The ProtComp program (version 9.0; http://​www.​softberry.​com) was used to predict the subcellular localization of the protein.

The subjective pain rating was assessed prior to MVIC, except during the POST assessments at visits 2 and 7 (Figure 1) when the subjective LY294002 pain rating was assessed after the MVIC. Resting blood pressure and resting heart rate The resting blood pressure and resting heart rate were measured after the participant had been sitting quietly for a period of at least 5 minutes prior to any other testing. Systolic and

diastolic resting blood pressure were measured in mmHg with an aneroid sphygmomanometer(MDF Instruments, Agoura Hills, CA) and a stethoscope (Marshall Nurse Stethoscope, Riverside, IL) according to the procedures described by Housh et al. [18]. Resting heart rate was measured by palpating the radial artery at the anterior-lateral surface of the wrist in line with the base of the thumb, just medial to the styloid process of the radius. Once the pulse was located, the number of beats that occurred in 30 s was measured and multiplied by two to selleck kinase inhibitor calculate the resting heart rate (bpm). Statistical analyses Four separate two-way repeated measures analyses of variance (ANOVAs) (condition [ANA vs. PLA] x time [PRE vs. POST vs. 24 h vs. 48 h vs. 72 h]) were used to analyze PT, hanging joint angle, relaxed arm circumference, and subjective pain rating. Three separate two-way repeated measures ANOVAs (condition [ANA vs. PLA] × time [PRE vs. 72 h]) were used to analyze systolic blood pressure, diastolic

blood pressure, and resting heart rate. When appropriate, follow-up analyses included one-way repeated measures ANOVAs and Bonferonni-corrected dependent samples t-tests. All statistical analyses were performed using IBM SPSS v. 21 (Chicago, IL), and a type I error rate of 5% was considered statistically significant for all comparisons. Results There were no condition x time (p > 0.05) interactions, there were no main effects for condition (p > 0.05), Edoxaban but there were main effects for time for PT (p < 0.001), hanging arm joint angle (p < 0.001),

relaxed arm circumference (p < 0.001), and subjective pain rating (p < 0.001). The marginal means for PT (collapsed across condition) decreased (p < 0.001) from PRE to POST, increased (p = 0.001) from POST to 24 h, and then plateaued (p > 0.05) from 48 h to 72 h (Figure 3a). The marginal means for hanging joint angle (collapsed across condition) decreased (p < 0.001) from PRE to POST and then did not change (p > 0.05) from POST to 72 h (Figure 3b). The marginal means for relaxed arm circumference (collapsed across condition) increased from PRE to POST (p < 0.001) and then plateaued (p > 0.05) from POST to 72 h (Figure 3c). The marginal means for subjective pain ratings (collapsed across condition) increased (p < 0.001) from PRE to POST, but did not change (p > 0.05) from POST to 72 h (Figure 3d). Figure 3 Recovery of the non-invasive measures of muscle function.

oneidensis Fur regulates genes involved in iron homeostasis and acid resistance [10–13]. Consistently, many of these target genes have a recognizable “”Fur box”" in their promoters. In the present study, we further characterize a fur null mutant of S. oneidensis with regard to its ability to utilize succinate and fumarate. Unexpectedly,

HPLC analysis showed that the fur mutant was able to metabolize succinate and fumarate, and the growth of the mutant was enhanced in the presence of succinate and fumarate, indicating that the mutant can utilize these compounds. In addition, the expression of the TCA cycle genes acnA and sdhA was not down-regulated in the Talazoparib mw mutant. These differences between S. oneidensis and E. coli were traced to the small RNA gene ryhB, which we identified LDK378 mw in several Shewanella species. Although S. oneidensis RyhB was up-regulated in the fur mutant, the TCA cycle genes did not appear to be regulated by RyhB. These results delineate differences in the gene regulation and physiological consequences of RyhB between S. oneidensis and E. coli. Results TCA cycle activity and regulation in the fur mutant We showed recently that S. oneidensis harboring a fur deletion in the genome was sensitive to acidic conditions and de-repressed genes encoding iron acquisition systems [11]. Similar observations

have been made in E. coli [14, 15], suggesting that the functional roles of Fur are conserved in these species. Since Fur acts as a pleiotropic transcription factor involved in multiple biological processes, we proceeded to examine its role in regulating TCA cycle enzymes. The involvement of Fur in this biological process has been established in E. coli and V. cholerae by observations that fur mutants are unable to grow in defined

media with succinate or fumarate as a carbon source [9, 16], and that genes encoding certain TCA cycle enzymes, such as succinate dehydrogenase (SdhABCD) and aconitase (AcnA), are significantly down-regulated in a fur mutant [7]. Our initial tests showed that neither succinate nor fumarate, when provided as the sole carbon source in M1 defined media, could support detectable growth of S. oneidensis type strain MR-1 (data not shown), making it unlikely to 4-Aminobutyrate aminotransferase analyze the growth of MR-1 and fur null mutant. However, the complete set of TCA genes is present in S. oneidensis genome, and recent studies have shown that the bacterium is capable of metabolizing succinate and fumarate [17, 18]. To compare the metabolizing rates of the carbonates between MR-1 and the fur mutant, both strains were grown to mid-log phase with 10 mM lactate as the carbon source. Then equal numbers of cells (5 × 109) were washed and resuspended in fresh M1 medium with 10 mM lactate, succinate or fumarate as the sole carbon source.

Thus, the band edge bending in the conduction and valence band was related to the change in surface charge check details distribution. Figure

5 I – V curves of Pd-sensitized ZnO nanorods from RT to 300°C. Alternating current (AC) impedance spectroscopy was used to investigate the sensing mechanism in which the potential contributors could be defined [29]. Generally, the conduction process (R) and polarization behavior (C) become dominant in sensing mechanism. The device microstructures are composed of grains, grain boundaries, and the metal/ZnO contact. In the Nyquist plot, the major role players in the high, intermediate, and low frequencies are grains (bulk), grain boundaries (R gb, C gb) and the metal-semiconductor contact (R c, C c) [30]. In order to achieve a single semicircle from the prescribed components, the time constant τ associated with these components must be identical [31]: (1) The total impedance Z T of the device structure

BI-6727 can be drawn as follows: (2) where Z g, Z gb, and Z c represent the complex impedance contribution of the grains, grain boundaries, and the electrode contacts, respectively [32]. The grain resistance can be estimated from the interception of the arc at high frequency with the real axis [32]. Every individual semicircles has its own unique relaxation frequency ω max (the frequency at the top of the arc), which can be represented as ω max RC = ω max τ = 1, where R and C represent the resistance and capacitance

of the equivalent circuit and τ represents the relaxation time that depends only on the intrinsic properties of the material [33]. The effect of hydrogen gas on the impedance behavior of the sensor at different concentrations is shown in Figure 6. Figure 6 Nyquist plot of Pd-sensitized ZnO nanorods as a function of different H 2 concentrations at room temperature. It was observed that when the gas concentration gradually increased from 40 to 360 ppm, Galactosylceramidase the diameter of the arc decreased. The Z′′ maximum values were smaller than the half values of the Z′ maximum, demonstrating the contribution from the constant phase elements (CPEs) in the equivalent circuit [29]. The best-fitted value for capacitance was obtained by replacing C with a CPE, which frequently describe the behavior of polycrystalline materials having inhomogeneous microstructures such as the grain boundary that gives rise to different distributions of respective relaxation time. The impedance of a CPE was clearly described in [34]. (3) where A is a constant and p is a dimensionless parameter with value of less than unity. When p = 1, the equation represents the characteristics of a capacitor with A = C. The values noted in Table 1 shows that the resistance R gb was varied because of the flow of different hydrogen concentrations.