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Showing papers by "Waseda University published in 2001"


Journal ArticleDOI
K. Adcox1, S. S. Adler2, N. N. Ajitanand3, Y. Akiba  +319 moreInstitutions (36)
TL;DR: In this paper, the authors measured the transverse momentum spectra for charged hadrons and neutral pions in the range 1 Gev/c < P-T < 5 GeV/c.
Abstract: Transverse momentum spectra for charged hadrons and for neutral pions in the range 1 Gev/c < P-T < 5 GeV/c have been measured by the PHENIX experiment at RHIC in Au + Au collisions at rootS(NN) = 130 GeV. At high p(T) the spectra from peripheral nuclear collisions are consistent with scaling the spectra from p + p collisions by the average number of binary nucleon-nucleon collisions. The spectra from central collisions are significantly suppressed when compared to the binary-scaled p + p expectation, and also when compared to similarly binary-scaled peripheral collisions, indicating a novel nuclear-medium effect in central nuclear collisions at RHIC energies.

803 citations


Journal ArticleDOI
TL;DR: A new technique for blind source separation of speech signals by applying the decorrelation method proposed by Molgedey and Schuster in the time–frequency domain based on the temporal structure ofspeech signals is introduced.

577 citations


Journal ArticleDOI
TL;DR: In this experiment, it is determined whether RF resets the expression of circadian clock genes in the mouse liver with or without participation of the SCN.
Abstract: Background There are two main stimuli that entrain the circadian rhythm, the light-dark cycle (LD) and restricted feeding (RF). Light-induced entrainment requires induction of the Per1 and Per2 genes in the suprachiasmatic nucleus (SCN), the locus of a main oscillator. In this experiment, we determined whether RF resets the expression of circadian clock genes in the mouse liver with or without participation of the SCN. Results Mice were allowed access to food for 4 h during the daytime (7 h advance of feeding time) under LD or constant darkness (DD). The peaks of mPer1, mPer2, D-site-binding protein (Dbp) and cholesterol 7α-hydroxylase (Cyp7A) mRNA in the liver were advanced 6–12 h after 6 days of RF, whereas those in SCN were unaffected. The advance of mPer expression in the liver by RF was still observed in SCN-lesioned mice. A 7 h advance in the LD cycle advanced the peaks of clock gene expression in both the liver and SCN, whereas, a shift in the LD did not move the phase of the liver clock when the shift was carried out under a fixed RF schedule during the night-time. Conclusions These results suggest that restricted feeding strongly entrained the expression of circadian clock genes in the liver without the participation of an SCN clock function.

530 citations


Journal ArticleDOI
TL;DR: In this article, a NaOH alkali solution was applied to the ZSM-5 zeolite and the changes in structural and acidic properties were investigated, showing that adsorptive and diffusive properties of cumene through micropores were increased by the creation of mesopores.
Abstract: ZSM-5 zeolite having a SiO2/Al2O3 molar ratio of 39.4 was treated in a NaOH alkali solution and the changes in structural and acidic properties were investigated. A siliceous species was selectively dissolved from the framework of zeolite, although a lower amount of Al was also eluted. In this procedure, mesopores with a uniform size were formed on the zeolite, while the microporous structure remained. The acidic property was changed very little quantitatively or qualitatively, even though the catalytic activity for cracking of cumene was enhanced by the alkali-treatment. This can be explained by the facts that adsorptive and diffusive properties of cumene through micropores of the ZSM-5 are increased by the creation of mesopores.

426 citations


Journal ArticleDOI
TL;DR: Evidence is provided of an association between food‐entrainable oscillations and the expression of mPer1 and mPer2 in the cerebral cortex and hippocampus in SCN‐lesioned mice.
Abstract: Daily restricted feeding (RF) can produce food-entrainable oscillations in both intact and suprachiasmatic nucleus (SCN)-lesioned animals. Thus, there are two circadian rhythms, one of which is SCN-dependent and the other SCN-independent. Recently, it has been established that several mouse clock genes, such as mPer1, mPer2 and mPer3 are expressed in the SCN and other brain tissues. Although the role of mPer genes expressed in the SCN has recently been evaluated in the SCN-dependent rhythm, their function in the SCN-independent rhythm is still poorly understood. In order to understand the role of these genes in SCN-independent rhythm, we examined the expression pattern of mPer1 and mPer2 mRNA in each brain area of mice under RF. Mice were allowed access to food for 4 h during either the daytime under a light-dark cycle or the subjective daytime under constant dark. After 6 days of scheduled RF, the night-time or subjective night-time peak of mPer mRNA changed to a daytime peak in the cerebral cortex and hippocampus, with moderate expression in the striatum, pyriform cortex and paraventricular nucleus, and no expression in the SCN. The daytime peak in the cerebral cortex returned to a night-time peak after the release of RF to a free-feeding schedule. Although the basal rhythm of mPer expression disappeared in SCN-lesioned mice, RF produced mPer mRNA rhythm in the cerebral cortex of these mice. The present results provide evidence of an association between food-entrainable oscillations and the expression of mPer1 and mPer2 in the cerebral cortex and hippocampus.

308 citations


Journal ArticleDOI
05 Oct 2001
TL;DR: An algorithm which is using rough set theory with greedy heuristics for feature selection and selects the features that do not damage the performance of induction is proposed.
Abstract: Practical machine learning algorithms are known to degrade in performance (prediction accuracy) when faced with many features (sometimes attribute is used instead of feature) that are not necessary for rule discovery. To cope with this problem, many methods for selecting a subset of features have been proposed. Among such methods, the filter approach that selects a feature subset using a preprocessing step, and the wrapper approach that selects an optimal feature subset from the space of possible subsets of features using the induction algorithm itself as a part of the evaluation function, are two typical ones. Although the filter approach is a faster one, it has some blindness and the performance of induction is not considered. On the other hand, the optimal feature subsets can be obtained by using the wrapper approach, but it is not easy to use because of the complexity of time and space. In this paper, we propose an algorithm which is using rough set theory with greedy heuristics for feature selection. Selecting features is similar to the filter approach, but the evaluation criterion is related to the performance of induction. That is, we select the features that do not damage the performance of induction.

295 citations


Journal ArticleDOI
TL;DR: Parabens have ER-dependent estrogenic activities, and their effects on the intracellular signaling pathway might be different from that of 17beta-estradiol.

277 citations


Journal ArticleDOI
TL;DR: A geometric criterion is proposed for a transition to occur between these two regimes of quantum Zeno effect, where the decay can be accelerated or slowed down, depending on the features of the interaction Hamiltonian.
Abstract: The temporal evolution of an unstable quantum mechanical system undergoing repeated measurements is investigated. In general, by changing the time interval between successive measurements, the decay can be accelerated (inverse quantum Zeno effect) or slowed down (quantum Zeno effect), depending on the features of the interaction Hamiltonian. A geometric criterion is proposed for a transition to occur between these two regimes.

271 citations


Journal ArticleDOI
TL;DR: A protein kinase that is yet to be identified is responsible for the activation of transcription factors and plays a key role in the responses of antiviral responses.
Abstract: Background Infection by virus or treatment with double-stranded RNA (dsRNA) results in the activation of transcription factors including IRF-3, IRF-7 and a pleiotropic regulator NF-kappaB by specific phosphorylation. These factors are important in triggering a cascade of antiviral responses. A protein kinase that is yet to be identified is responsible for the activation of these factors and plays a key role in the responses. Results The signal cascade was analysed using sensitive assays for the activation of IRF-3 and NF-kappaB, and various inhibitors. We found that the activation of IRF-3 and NF-kappaB by dsRNA or virus involves a process that is sensitive to Geldanamycin. Although the induction of NF-kappaB by dsRNA/virus and TNF-alpha involves common downstream pathways including IKK activation, the upstream, Geldanamycin-sensitive process was unique to the dsRNA/virus-induced signal. By an in vitro assay using cell extract, we found an inducible protein kinase activity with physiological specificity of IRF-3 phosphorylation. Furthermore, the same extract specifically phosphorylated IRF-7 in a similar manner. Conclusions Double-stranded RNA or virus triggers a specific signal cascade that results in the activation of the IRF-3/-7 kinase we detected, which corresponds to the long-sought signalling machinery that is responsible for triggering the early phase of innate response. The signal branches to a common NF-kappaB activation cascade, thus resulting in the activation of a set of critical transcription factors for the response.

266 citations


Journal ArticleDOI
TL;DR: In this paper, the authors examined the susceptibility to hydrogen embrittlement of martensitic steels by means of a delayed-fracture test and hydrogen thermal desorption analysis.
Abstract: The susceptibility to hydrogen embrittlement (HE) of martensitic steels has been examined by means of a delayed-fracture test and hydrogen thermal desorption analysis. The intensity of a desorptionrate peak around 50 °C to 200 °C increased when the specimen was preloaded and more remarkably so when it was loaded under the presence of hydrogen. The increment appeared initially at the low-temperature region in the original peak. As hydrogen entry proceeded, the increment then appeared at the high-temperature region, while that in the low-temperature region was reduced. The alteration occurred earlier in steels tempered at lower temperatures, with a higher embrittlement susceptibility. A defect acting as the trap of the desorption in the high-temperature region was assigned to large vacancy clusters that have higher binding energies with hydrogen. Deformation-induced generation of vacancies and their clustering have been considered to be promoted by hydrogen and to play a primary role on the HE susceptibility of high-strength steel.

256 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the relationship of F-regular (resp. F-pure) rings and log terminal singularities, and extended the notions of Fregularity and F-purity to F-singularities of pairs.
Abstract: In this paper, we investigate the relationship of F-regular (resp. F-pure) rings and log terminal (resp. log canonical) singularities. Also, we extend the notions of F-regularity and F-purity to "F-singularities of pairs." The notions of F-regular and F-pure rings in characteristic $p>0$ are characterized by a splitting of the Frobenius map, and define some classes of rings having "mild" singularities. On the other hand, there are notions of log terminal and log canonical singularities defined via resolutions of singularities in characteristic zero. These are defined also for pairs of a normal variety and a $\Bbb Q$-divisor $\Delta$ on it, and play an important role in birational algebraic geometry. As an analog of these singularities of pairs in characteristic zero, we define the notions of "F-singularities of pairs," namely strong F-regularity, divisorial F-regularity and F-purity for a pair $(A,\Delta)$ of a normal ring $A$ of characteristic $p > 0$ and an effective $\Bbb Q$-divisor $\Delta$ on $Y = Spec A$. The main theorem of this paper asserts that, if $K_Y + \Delta$ is $\Bbb Q$-Cartier, then the above three variants of F-singularitiesof pairs imply KLT, PLT and LC properties, respectively. We also prove some results for F-singularities of pairs which are analoguous to singularities of pairs in characteristic zero.

Journal ArticleDOI
Yasukata Yano1
TL;DR: This article proposed a set of standards for English as a Second Language (ESL) that would accommodate any variety of English as far as it is comprehensible to the educated users of any variety, native or not.
Abstract: Spreading at the present rate, English will further increase its importance as the global lingua franca in this century. At the same time, the rapid and extensive localization and nativization will accelerate the ramification of English into varieties in the ESL (English as a Second Language) regions. Our challenge then will be how to maintain common standards and mutual intelligibility among those varieties of English. The users of EFL (English as a Foreign Language) who are relatively free from the localization of English might be able to contribute to create, maintain, and develop the globalized standards of Englishes. Such Englishes would be characterized as simple, plain, and regular in their linguistic forms and socioculturally neutral in their interactional strategies. They would accommodate any variety of English as far as it is comprehensible to the educated users of any variety, native or not.

Journal ArticleDOI
TL;DR: X-ray crystallography and 1H NMR analyses of the cinchona alkaloids/Selectfluor combination have established that the species that mediate this novel reaction are N-fluoroammonium cinchonia alkaloid tetrafluoroborates, which adopt open conformations.
Abstract: Cinchona-alkaloid/Selectfluor combinations efficiently fluorinate a variety of carbonyl compounds in a highly enantioselective manner to furnish chiral alpha-fluorocarbonyl compounds. The DHQB/Selectfluor combination is effective for the enantioselective fluorination of indanones and tetralones 1 in up to 91% ee. The first enantioselective syntheses of chiral derivatizing reagents 3 was accomplished with high ee and in high chemical yields by the DHQDA/Selectfluor combination. 3-Fluorooxindoles 7 were prepared with ee up to 83% using the (DHQ)2AQN/Selectfluor or the (DHQD)2PYR/Selectfluor combination. Since the combinations are conveniently prepared in situ from readily available reagents, the present system represents a practical method for enantioselective fluorination. X-ray crystallography and 1H NMR analyses of the cinchona alkaloids/Selectfluor combination have established that the species that mediate this novel reaction are N-fluoroammonium cinchona alkaloid tetrafluoroborates, which adopt open conformations.

Journal ArticleDOI
TL;DR: It is found that mGluR1 agonist-induced currents and [Ca2+]i increases in PCs were enhanced following co-activation of GABAB receptors, and the interaction between the two types of metabotropic receptors provides a likely mechanism for regulating cerebellar synaptic plasticity.
Abstract: Metabotropic gamma-aminobutyric acid type B (GABAB) and glutamate receptors (mGluRs) are postsynaptically co-expressed at cerebellar parallel fiber (PF)-Purkinje cell (PC) excitatory synapses, but their functional interactions are unclear. We found that mGluR1 agonist-induced currents and [Ca2+]i increases in PCs were enhanced following co-activation of GABAB receptors. A GABAB antagonist and a G-protein uncoupler suppressed these effects. Low-concentration baclofen, a GABAB agonist, augmented mGluR1-mediated excitatory synaptic current produced by stimulating PFs. These results indicate that postsynaptic GABAB receptors functionally interact with mGluR1 and enhance mGluR1-mediated excitatory transmission at PF-PC synapses. The interaction between the two types of metabotropic receptors provides a likely mechanism for regulating cerebellar synaptic plasticity.

Journal ArticleDOI
K. Adcox1, S. S. Adler2, N. N. Ajitanand3, Y. Akiba  +318 moreInstitutions (36)
Abstract: We present results for the charged-particle multiplicity distribution at midrapidity in Au-Au collisions at square root of [s(NN)] = 130 GeV measured with the PHENIX detector at RHIC. For the 5% most central collisions we find dN(ch)/d eta(vertical line eta = 0) = 622+/-1(stat)+/-41(syst). The results, analyzed as a function of centrality, show a steady rise of the particle density per participating nucleon with centrality.

Journal ArticleDOI
TL;DR: Results obtained by simultaneous recordings of EMG, MMG, and NIRS demonstrate that the restriction of blood flow due to high intramuscular mechanical pressure is one of the most important factors in muscle fatigue in the lower-back muscles.
Abstract: We have investigated the etiology of lower-back muscle fatigue using simultaneous recordings of electromyography (EMG), mechanomyography (MMG), and near-infrared spectroscopy (NIRS) in an attempt to shed some light on the electrophysiological, mechanical, and metabolic characteristics, respectively. Eight male subjects performed isometric back extensions at an angle of 15° with reference to the horizontal plane, for a period of 60 s. Surface EMG, MMG and NIRS signals were recorded simultaneously from the center of the erector spinae at the level of L3. NIRS was measured to determine the level of muscle blood volume (BV) and oxygenation (Oxy-Hb). The root mean square amplitude value (RMS) of the EMG signal was significantly increased at the initial phase of contraction and then fell significantly, while mean power frequency (MPF) of the EMG signal decreased significantly and progressively as a function of time. There were also significant initial increases in RMS-MMG that were followed by progressive decreases at the end of fatiguing contractions. MPF-MMG remained unchanged. Muscle BV and Oxy-Hb decreased dramatically at the onset of the contraction and then remained almost constant throughout the rest of the contraction. These results, obtained by simultaneous recordings of EMG, MMG, and NIRS, demonstrate that the restriction of blood flow due to high intramuscular mechanical pressure is one of the most important factors in muscle fatigue in the lower-back muscles. In addition, the simultaneous recording system described here can be used to obtain more reliable information regarding the mechanism(s) of lower-back muscle fatigue.

Journal ArticleDOI
TL;DR: In this article, the role of deformation-induced defects that interact with hydrogen is discussed, and a model is proposed in which increased vacancy density and agglomeration lead to the promotion of failure.
Abstract: Various models so far proposed for the mechanism of hydrogen embrittlement (HE) of steels are critically reviewed with respect to the manifestation of hydrogen in the fracture process. Recent studies that elucidate the hydrogen states and their relevance to HE are discussed. Particular attention is paid to the role of deformation-induced defects that interact with hydrogen. A model is proposed in which increased vacancy density and agglomeration lead to the promotion of failure. The model ascribes HE to the context of ductile fracture in which vacancies play the primary role.

Journal ArticleDOI
TL;DR: Although the regulatory mechanism of ghrelin to induce GH secretion is evolutionary conserved, the structural changes in the different ghrelins result in species-specific receptor binding, as indicated by reverse transcription polymerase chain reaction analysis.

Journal ArticleDOI
TL;DR: In this paper, the authors studied cosmological perturbations generated from quantum fluctuations in multi-field inflationary scenarios in generalized Einstein theories, taking both adiabatic and isocurvature modes into account.

Journal ArticleDOI
TL;DR: Protective roles of CO against hepatobiliary dysfunction caused by heme overloading under stress conditions are suggested.

Journal ArticleDOI
TL;DR: In this article, the adsorption of O2 on Cu(1.1) at room temperature has been investigated by scanning tunneling microscopy (STM) and low energy electron diffraction (LEED).

Journal ArticleDOI
TL;DR: The present results suggest that the molecular mechanism of clock oscillation in theSCN, PVN, and pineal body is preserved against aging, whereas the impairment of Per1 induction in the SCN after light stimulation may result in impaired behavioral photic entrainment in aged rats.
Abstract: Aging alters circadian components such as the free-running period, the day-to-night activity ratio and photic entrainment in behavioral rhythms, and 2-deoxyglucose uptakes and neuronal firing in the suprachiasmatic nucleus (SCN). A core clock mechanism in the mouse SCN appears to involve a transcriptional feedback loop in which Period (Per) and Cryptochrome (Cry) genes play a role in negative feedback. The circadian rhythm systems include photic entrainment, clock oscillation, and outputs of clock information such as melatonin production. In this experiment, we examined clock gene expression to determine whether circadian input, oscillation, and output are disrupted with aging. Circadian expression profiles of rPer1, rPer2, or rCry1 mRNA were very similar in the SCN, the paraventricular nucleus of the hypothalamus (PVN), and the pineal body of young and aged (22-26 months) rats. On the other hand, the photic stimulation-induced rapid expression of Per1 and Per2 in the SCN was reduced with aging. The present results suggest that the molecular mechanism of clock oscillation in the SCN, PVN, and pineal body is preserved against aging, whereas the impairment of Per1 induction in the SCN after light stimulation may result in impaired behavioral photic entrainment in aged rats.

Journal ArticleDOI
TL;DR: B. subtilis WU-S2B is considered to have more beneficial properties than other desulfurizing bacteria such as Rhodococcus strains previously reported, particularly from the viewpoint of its capacity for thermophilic desulforization through the CS bond cleavage.

Journal ArticleDOI
Hideyo Okushi1
TL;DR: In this article, high-quality homoepitaxial diamond films with atomically flat surface by the microwave plasma chemical vapor deposition (CVD) using a low CH4 concentration of CH4/H2 gas system less than 0.15% CH4 ratio and Ib (001) substrates with low-misorientation angle less than 1.5°.

Journal ArticleDOI
26 Jan 2001-Science
TL;DR: Kinesin binds through two heads in the former and one head in the latter two states of adenosine 5'-diphosphate hydrolysis, which supports a major prediction of the hand-over-hand model.
Abstract: The motility of kinesin motors is explained by a "hand-over-hand" model in which two heads of kinesin alternately repeat single-headed and double-headed binding with a microtubule. To investigate the binding mode of kinesin at the key nucleotide states during adenosine 5'-triphosphate (ATP) hydrolysis, we measured the mechanical properties of a single kinesin-microtubule complex by applying an external load with optical tweezers. Both the unbinding force and the elastic modulus in solutions containing AMP-PNP (an ATP analog) were twice the value of those in nucleotide-free solution or in the presence of both AMP-PNP and adenosine 5'-diphosphate. Thus, kinesin binds through two heads in the former and one head in the latter two states, which supports a major prediction of the hand-over-hand model.

Journal ArticleDOI
TL;DR: Analysis of the spin mutant will give new insights into neurodegenerative diseases and aging.
Abstract: Mutations in the spin gene are characterized by an extraordinarily strong rejection behavior of female flies in response to male courtship. They are also accompanied by decreases in the viability, adult life span, and oviposition rate of the flies. In spin mutants, some oocytes and adult neural cells undergo degeneration, which is preceded by reductions in programmed cell death of nurse cells in ovaries and of neurons in the pupal nervous system, respectively. The central nervous system (CNS) of spin mutant flies accumulates autofluorescent lipopigments with characteristics similar to those of lipofuscin. The spin locus generates at least five different transcripts, with only two of these being able to rescue the spin behavioral phenotype; each encodes a protein with multiple membrane-spanning domains that are expressed in both the surface glial cells in the CNS and the follicle cells in the ovaries. Orthologs of the spin gene have also been identified in a number of species from nematodes to humans. Analysis of the spin mutant will give us new insights into neurodegenerative diseases and aging.

Journal ArticleDOI
TL;DR: In this article, a catalytic cycle is proposed to be composed of (a) oxidative addition of the ester to give acyl(aryloxo)palladium intermediate, (b) subsequent transmetallation with arylboron compounds, and (c) reductive elimination.
Abstract: Cross-coupling reaction of aryl trifluoroacetates with organoboron compounds catalyzed by palladium complexes gives trifluoromethyl ketones in moderate to excellent yields under mild conditions. The catalytic process has been designed on the basis of fundamental studies dealing with oxidative addition of phenyl trifluoroacetate to a Pd(0) complex to give a (phenoxo)(trifluoroacetyl)palladium(II) complex and its subsequent reaction with phenylboronic acid to liberate phenyl trifluoromethyl ketone. The catalytic cycle is proposed to be composed of (a) oxidative addition of the ester to give acyl(aryloxo)palladium intermediate, (b) the subsequent transmetallation with arylboron compounds, and (c) reductive elimination. Palladium(0) complexes, as well as catalysts prepared in situ from palladium acetate and 3 molar amounts of tributylphosphine or phosphite at room temperature, serve as convenient and effective catalysts. The process is applicable to a wide range of phenyl- and naphthylboronic acids to give va...

Journal ArticleDOI
TL;DR: Results show that elution of weakly charged bioactive compounds is readily regulated through the modulation of stationary-phase thermoresponsive hydrophilic/hydrophobic and charge density changes.
Abstract: Cross-linked poly(N-isopropylacrylamide-co-acrylic acid) (poly(IPAAm-co-AAc))-grafted silica bead surfaces were prepared and applied as new column matrix materials that exploit temperature-responsive anionic chromatography to separate basic bioactive compounds, specifically catecholamine derivatives, in aqueous mobile phases. Since poly(IPAAm-co-AAc) has a well-known temperature-responsive phase transition and apparent pKa shift, polymer-grafted silica bead surfaces are expected to exhibit simultaneous hydrophilic/hydrophobic and charge density alterations under thermal stimuli. Elution behavior of catecholamine derivatives from a copolymer-modified bead packed column was monitored using aqueous mobile-phase HPLC under varying temperature and pH. Catecholamine derivatives had higher retention times on poly(IPAAm-co-AAc) columns at higher pH in comparison with those on noncharged PIPAAm reference columns, suggesting an electrostatic interaction as a separation mode. Temperature also affected the retention ...

Journal ArticleDOI
TL;DR: In this paper, the authors examined three kinds of residential buildings with different construction techniques and estimated the decreased amount of energy consumption and resources resulting from use of recycled materials, and showed that the energy consumption needed to remake housing materials from recycled materials is lower than that to make new housing materials.

Journal ArticleDOI
Hiroshi Kawarada1, Yuta Araki1, Toshikatsu Sakai1, T. Ogawa1, Hitoshi Umezawa1 
TL;DR: In this paper, the diamond field effect transistors have operated in electrolyte solution for the first time since the hydrogen-terminated diamond surfaces are stable enough for the use as an electrochemical electrode, the diamond surface channels are exposed to the electrolyte in the transistor structure.
Abstract: Diamond field effect transistors have operated in electrolyte solution for the first time Since the hydrogen-terminated diamond surfaces are stable enough for the use as an electrochemical electrode, the diamond surface channels are exposed to the electrolyte in the transistor structure A perfect pinch-off and saturated current-voltage characteristics have been obtained for bias voltages within the potential window The threshold voltages are almost constant in electrolytes with different pH values of 7-13, indicating pH insensitiveness of the hydrogen-terminated diamond surface Based on this pH insensitive surface, ion selective regions can be fabricated to form transistor-based biosensors