bluuebunny/crossref_metadata_2025 huggingface dataset:
LEVEL REPULSION IN INTEGRABLE SYSTEMS
Authors: MA TAO , SEROTA R. A.
Published: May 2012

We provide evidence that level repulsion in semiclassical spectrum is not just a feature of classically chaotic systems, but classically integrable systems as well. While in chaotic systems level repulsion develops on a scale of the mean level spacing, regardless of the location in the spectrum, in integrable systems it develops on a much longer scale — such as geometric mean of the mean level spacing and the running energy in the spectrum for hard wall billiards. We show that at this scale level correlations in integrable systems have a universal dependence on the level separation, as well as discuss their exact form at any scale. These correlations have dramatic consequences, including deviations from the Poissonian statistics in the nearest level spacing distribution and persistent oscillations of the level number variance over an energy interval as a function of the interval width. We illustrate our findings on two specific models — rectangular infinite well and a modified Kepler problem — that serve as generic types of a hard wall billiard and a potential problem without extra symmetries. Our theory and numerical work are based on the concept of parametric averaging that allows sampling of a statistical ensemble of integrable systems at a given spectral location (running energy).
FILTRATIONS IN ABELIAN CATEGORIES WITH A TILTING OBJECT OF HOMOLOGICAL DIMENSION TWO
Authors: JENSEN BERNT TORE , MADSEN DAG OSKAR , SU XIUPING
Published: April 2012

We consider filtrations of objects in an abelian category [Formula: see text] induced by a tilting object T of homological dimension at most two. We define three extension closed subcategories [Formula: see text] and [Formula: see text] with [Formula: see text] for j > i, such that each object in [Formula: see text] has a unique filtration with factors in these categories. In dimension one, this filtration coincides with the classical two-step filtration induced by the torsion pair. We also give a refined filtration, using the derived equivalence between the derived categories of [Formula: see text] and the module category of [Formula: see text].
A NOTE ON THE NUMBER OF ZEROS IN THE COLUMNS OF THE CHARACTER TABLE OF A GROUP
Authors: ZHANG JINSHAN , SHEN ZHENCAI , WU SHULIN
Published: April 2012

The finite groups in which every irreducible character vanishes on at most three conjugacy classes were characterized [J. Group Theory13 (2010) 799–819]. Dually, we investigate the finite groups whose columns contain a small number of zeros in the character table.
A ZERO-DIVISOR GRAPH FOR MODULES WITH RESPECT TO THEIR (FIRST) DUAL
Authors: BAZIAR M. , MOMTAHAN E. , SAFAEEYAN S.
Published: April 2012

Let M be an R-module. We associate an undirected graph Γ(M) to M in which nonzero elements x and y of M are adjacent provided that xf(y) = 0 or yg(x) = 0 for some nonzero R-homomorphisms f, g ∈ Hom (M, R). We observe that over a commutative ring R, Γ(M) is connected and diam (Γ(M)) ≤ 3. Moreover, if Γ(M) contains a cycle, then gr (Γ(M)) ≤ 4. Furthermore if ∣Γ(M)∣ ≥ 1, then Γ(M) is finite if and only if M is finite. Also if Γ(M) = ∅, then any nonzero f ∈ Hom (M, R) is monic (the converse is true if R is a domain). For a nonfinitely generated projective module P we observe that Γ(P) is a complete graph. We prove that for a domain R the chromatic number and the clique number of Γ(M) are equal. When R is self-injective, we will also observe that the above adjacency defines a covariant functor between a subcategory of R-MOD and the Category of graphs.
A COMPARISON OF THE FUNCTORS OF POINTS OF SUPERMANIFOLDS
Authors: BALDUZZI L. , CARMELI C. , FIORESI R.
Published: April 2012

We study the functor of points and different local functors of points for smooth and holomorphic supermanifolds, providing characterization theorems and fully discussing the representability issues. In the end we examine applications to differential calculus including the transitivity theorems.
WHEN EXT COMMUTES WITH DIRECT SUMS
Authors: BREAZ SIMION , SCHULTZ PHILL
Published: April 2012

We characterize the abelian groups G for which Ext (G, -) commutes with direct sums.
THE POLYNILPOTENT MULTIPLIER OF LIE ALGEBRAS
Authors: SALEMKAR ALI REZA , RIYAHI ZAHRA
Published: April 2012

Let [Formula: see text] be the variety of polynilpotent Lie algebras of class row (c1, …, cn). The paper is devoted to present the concepts of polynilpotent multiplier [Formula: see text] and cover of a Lie algebra L with respect to the variety [Formula: see text], and compute [Formula: see text] for some known Lie algebras. Also, we determine the structure of all covers of Lie algebras whose polynilpotent multipliers are finite-dimensional, and investigate some common properties between covers.
A CHARACTERIZATION OF SPORADIC SIMPLE GROUPS BY NSE AND ORDER
Authors: ASBOEI ALIREZA KHALILI , AMIRI SEYED SADEGH SALEHI , IRANMANESH ALI , TEHRANIAN ABOLFAZL
Published: April 2012

Let G be a finite group and nse (G) the set of numbers of elements with the same order in G. In this paper, we prove that if ∣G∣ = ∣S∣ and nse (G) = nse (S), where S is a sporadic simple group, then the finite group G is isomorphic to S.
MODULES WHICH ARE INVARIANT UNDER AUTOMORPHISMS OF THEIR INJECTIVE HULLS
Authors: LEE TSIU-KWEN , ZHOU YIQIANG
Published: April 2012

A module is defined to be an automorphism-invariant module if it is invariant under automorphisms of its injective hull. Quasi-injective modules and, more generally, pseudo-injective modules are all automorphism-invariant. Here we develop basic properties of these modules, and discuss when an automorphism-invariant module is quasi-injective or injective. Some known results on quasi-injective and pseudo-injective modules are extended.
Extracting two thousand years of latin from a million book library
Authors: Bamman David , Smith David
Published: May 2012

With the rise of large open digitization projects such as the Internet Archive and Google Books, we are witnessing an explosive growth in the number of source texts becoming available to researchers in historical languages. The Internet Archive alone contains over 27,014 texts catalogued as Latin, including classical prose and poetry written under the Roman Empire, ecclesiastical treatises from the Middle Ages, and dissertations from 19th-century Germany written—in Latin—on the philosophy of Hegel. At one billion words, this collection eclipses the extant corpus of Classical Latin by several orders of magnitude. In addition, the much larger collection of books in English, German, French, and other languages already scanned contains unknown numbers of translations for many Latin books, or parts of books.

The sheer scale of this collection offers a broad vista of new research questions, and we focus here on both the opportunities and challenges of computing over such a large space of heterogeneous texts. The works in this massive collection do not constitute a finely curated (or much less balanced) corpus of Latin; it is, instead, simply
all
the Latin that can be extracted, and in its reach of twenty-one centuries (from approximately 200 BCE to 1922 CE) arguably spans the greatest historical distance of any major textual collection today. While we might hope that the size and historical reach of this collection can eventually offer insight into grand questions such as the evolution of a language over both time and space, we must contend as well with the noise inherent in a corpus that has been assembled with minimal human intervention.
The Mississippi Delta Region: Past, Present, and Future
Authors: Blum Michael D. , Roberts Harry H.
Published: May 2012

The Mississippi delta region of south Louisiana houses a wealth of resources within a dynamic, subsiding landscape. Foundations for the delta region reflect Neogene evolution of the depocenter, whereas details of the modern landscape reflect late Pleistocene to Holocene evolution of the alluvial-deltaic plain. The Holocene delta plain was constructed by cyclical growth of deltaic headlands, followed by avulsion and relocation of the fluvial sediment source. Abandoned headlands were then submerged and reworked while a new headland was created at the site of active fluvial sediment input. Historic-period levees have decoupled the delta plain from its fluvial sediment source at the same time global sea-level rise was accelerating, which has accelerated delta-plain submergence. Diversions of Mississippi River water and sediment are necessary to achieve delta plain sustainability, but upstream dams trap ∼50% of the total sediment load, and there is not enough supply to keep pace with subsidence and accelerated sea-level rise. The future delta region will not resemble the recent past, and significant drowning is inevitable.
End-Permian Mass Extinction in the Oceans: An Ancient Analog for the Twenty-First Century?
Authors: Payne Jonathan L. , Clapham Matthew E.
Published: May 2012

The greatest loss of biodiversity in the history of animal life occurred at the end of the Permian Period (∼252 million years ago). This biotic catastrophe coincided with an interval of widespread ocean anoxia and the eruption of one of Earth's largest continental flood basalt provinces, the Siberian Traps. Volatile release from basaltic magma and sedimentary strata during emplacement of the Siberian Traps can account for most end-Permian paleontological and geochemical observations. Climate change and, perhaps, destruction of the ozone layer can explain extinctions on land, whereas changes in ocean oxygen levels, CO2, pH, and temperature can account for extinction selectivity across marine animals. These emerging insights from geology, geochemistry, and paleobiology suggest that the end-Permian extinction may serve as an important ancient analog for twenty-first century oceans.
The Deep, Dark Energy Biosphere: Intraterrestrial Life on Earth
Authors: Edwards Katrina J. , Becker Keir , Colwell Frederick
Published: May 2012

Most ecosystems on Earth exist in permanent darkness, one or more steps removed from the light-driven surface world. This collection of dark habitats is the most poorly understood on Earth, in particular the size, function, and activity of these ecosystems and what influence they have on global biogeochemical processes. The vastest of these ecosystems constitute the “deep biosphere”—habitats physically located below the surface of continents and the bottom of the ocean. The deep biosphere has been the subject of considerable—and increasing—study and scrutiny in recent years. New deep biosphere realms are being explored from deep in mines in South Africa, to sediments in the middle of oceanic gyres—and beyond. New technologies are emerging, permitting researchers to do active, manipulable experimentation in situ within the subsurface. This review highlights recent history of the research and the exciting new directions this field of research is going in, and discusses some of the most active and interesting field realms currently under scrutiny by researchers examining this deep, dark, intraterrestrial life.
Magma Oceans in the Inner Solar System
Authors: Elkins-Tanton Linda T.
Published: May 2012

Theory and observations point to the occurrence of magma ponds or oceans in the early evolution of terrestrial planets and in many early-accreting planetesimals. The apparent ubiquity of melting during giant accretionary impacts suggests that silicate and metallic material may be processed through multiple magma oceans before reaching solidity in a planet. The processes of magma ocean formation and solidification, therefore, strongly influence the earliest compositional differentiation and volatile content of the terrestrial planets, and they form the starting point for cooling to clement, habitable conditions and for the onset of thermally driven mantle convection and plate tectonics. This review focuses on evidence for magma oceans on planetesimals and planets and on research concerning the processes of compositional differentiation in the silicate magma ocean, distribution and degassing of volatiles, and cooling.
Extratropical Cooling, Interhemispheric Thermal Gradients, and Tropical Climate Change
Authors: Chiang John C.H. , Friedman Andrew R.
Published: May 2012

Recent studies suggest the existence of a global atmospheric teleconnection of extratropical cooling to the tropical rainfall climate, mediated through the development of a thermal contrast between the hemispheres—an interhemispheric thermal gradient. This teleconnection has been largely motivated by studies that show a global synchronization of rapid climate change during abrupt climate changes of the last glacial period, in addition to attribution studies of twentieth-century Sahel drought and studies that examined the climate impacts of anthropogenic aerosols. This research has led to interesting developments in atmospheric dynamics of the underlying mechanisms and in applications toward understanding past and present tropical climate change. The emerging teleconnection hypothesis promises to offer new insights into understanding future patterns of tropical rainfall changes due to interhemispheric thermal gradients from greenhouse warming, aerosols, and land-use change.
Improved blood glucose disposal and altered insulin secretion patterns in adenosine A1receptor knockout mice
Authors: Yang Gary K. , Fredholm Bertil B. , Kieffer Timothy J. , Kwok Yin Nam
Published: May 2012

Type 2 diabetes mellitus (T2DM) is characterized by the inability of the pancreatic β-cells to secrete enough insulin to meet the demands of the body. Therefore, research of potential therapeutic approaches to treat T2DM has focused on increasing insulin output from β-cells or improving systemic sensitivity to circulating insulin. In this study, we examined the role of the A1receptor in glucose homeostasis with the use of A1receptor knockout mice (A1R−/−). A1R−/−mice exhibited superior glucose tolerance compared with wild-type controls. However, glucose-stimulated insulin release, insulin sensitivity, weight gain, and food intake were comparable between the two genotypes. Following a glucose challenge, plasma glucagon levels in wild-type controls decreased, but this was not observed in A1R−/−mice. In addition, pancreas perfusion with oscillatory glucose levels of 10-min intervals produced a regular pattern of pulsatile insulin release with a 10-min cycling period in wild-type controls and 5 min in A1R−/−mice. When the mice were fed a high-fat diet (HFD), both genotypes exhibited impaired glucose tolerance and insulin resistance. Increased insulin release was observed in HFD-fed mice in both genotypes, but increased glucagon release was observed only in HFD-fed A1R−/−mice. In addition, the regular patterns of insulin release following oscillatory glucose perfusion were abolished in HFD-fed mice in both genotypes. In conclusion, A1receptors in the pancreas are involved in regulating the temporal patterns of insulin release, which could have implications in the development of glucose intolerance seen in T2DM.
QT-RR hysteresis is caused by differential autonomic states during exercise and recovery
Authors: Pelchovitz Daniel J. , Ng Jason , Chicos Alexandru B. , Bergner Daniel W. , Goldberger Jeffrey J.
Published: April 2012

QT-RR hysteresis is characterized by longer QT intervals at a given RR interval while heart rates are increasing during exercise and shorter QT intervals at the same RR interval while heart rates are decreasing during recovery. It has been attributed to a lagging QT response to different directional changes in RR interval during exercise and recovery. Twenty control subjects (8 males, age 51 ± 6 yr), 16 subjects with type 2 diabetes (12 males, age 56 ± 8 yr), 71 subjects with coronary artery disease (CAD) and preserved left ventricular ejection fraction (LVEF) (≥50%) (51 males, age 59 ± 12 yr), and 17 CAD subjects with depressed LVEF (<50%) (13 males, age 57 ± 10 yr) underwent two 16-min exercise tests followed by recovery. In session 2, parasympathetic blockade with atropine (0.04 mg/kg) was achieved at end exercise. QT-RR hysteresis was quantified as: 1) the area bounded by the QT-RR relationships for exercise and recovery in the range of the minimum RR interval at peak exercise to the minimum RR interval + 100 ms and 2) the difference in QT interval duration between exercise and recovery at the minimum RR interval achieved during peak exercise plus 50 ms (ΔQT). The effect of parasympathetic blockade was assessed by substituting the QT-RR relationship after parasympathetic blockade. QT-RR hysteresis was positive in all groups at baseline and reversed by parasympathetic blockade ( P < 0.01). We conclude that QT-RR hysteresis is not caused by different directional changes in RR interval during exercise and recovery. Instead, it is predominantly mediated by differential autonomic nervous system effects as the heart rate increases during exercise vs. as it decreases during recovery.
Lack of effect of ovarian cycle and oral contraceptives on baroreceptor and nonbaroreceptor control of sympathetic nerve activity in healthy women
Authors: Middlekauff Holly R. , Park Jeanie , Gornbein Jeffrey A.
Published: April 2012

Endogenous and exogenous female hormones regulate sympathetic nerve activity (SNA) in animal models, but their impact in humans is controversial. The purpose of this study is to investigate the effects of the ovarian cycle and oral contraceptive pills (OCPs) on SNA. We hypothesized that the effects of endogenous hormones were baroreflex (BR)-mediated and that these cyclical changes in BR control were blunted by OCPs. Furthermore, we hypothesized that the nocturnal fall in blood pressure (BP) (“dipping”), which is sympathetically mediated, also varied with the ovarian cycle. In 23 healthy females (13 OCP users, 10 age-matched, no OCPs), SNA was recorded (microneurography) at rest, during BR activation/deactivation, and cold pressor test (CPT) during low and high hormonal phases. Furthermore, 24-h BP monitoring was performed during low and high hormonal phases. SNA was lower during the low vs. high hormone phase in non-OCP users (17.3 ± 2.4 vs. 25.4 ± 3.2 bursts/min, P < 0.001) but was not different between phases in OCP users [15.5 ± 1.7 vs. 16.6 ± 2.0 bursts/min, P = not significant (NS)]. BR control of SNA was not different during the hormone phases in either group [SNA (total activity/min) mean slope %change from baseline, no OCP users, low vs. high hormone phase 35.4 ± 6.2 vs. 29.6 ± 3.4%, P = NS and OCP users, low vs. high hormone phase 35.7 ± 3.9 vs. 33.5 ± 3.5%, P = NS]. SNA activation during CPT was not impacted by hormonal phase or OCP use. Finally, nondipping was not different between OCP users and nonusers, although there was a trend for nondipping to occur more frequently in the OCP users. SNA varies during the ovarian cycle in women in the absence of OCPs. This modulation cannot be attributed to cyclical changes in the BR sensitivity.
Cardiomyocyte-restricted inhibition of G protein-coupled receptor kinase-3 attenuates cardiac dysfunction after chronic pressure overload
Authors: von Lueder Thomas G. , Gravning Jørgen , How Ole-Jakob , Vinge Leif E. , Ahmed Mohammed Shakil , Krobert Kurt A. , Levy Finn Olav , Larsen Terje S. , Smiseth Otto A. , Aasum Ellen , Attramadal Håvard
Published: April 2012

Transgenic mice with cardiac-specific expression of a peptide inhibitor of G protein-coupled receptor kinase (GRK)3 [transgenic COOH-terminal GRK3 (GRK3ct) mice] display myocardial hypercontractility without hypertrophy and enhanced α1-adrenergic receptor signaling. A role for GRK3 in the pathogenesis of heart failure (HF) has not been investigated, but inhibition of its isozyme, GRK2, has been beneficial in several HF models. Here, we tested whether inhibition of GRK3 modulated evolving cardiac hypertrophy and dysfunction after pressure overload. Weight-matched male GRK3ct transgenic and nontransgenic littermate control (NLC) mice subjected to chronic pressure overload by abdominal aortic banding (AB) were compared with sham-operated (SH) mice. At 6 wk after AB, a significant increase of cardiac mass consistent with induction of hypertrophy was found, but no differences between GRK3ct-AB and NLC-AB mice were discerned. Simultaneous left ventricular (LV) pressure-volume analysis of electrically paced, ex vivo perfused working hearts revealed substantially reduced systolic and diastolic function in NLC-AB mice ( n = 7), which was completely preserved in GRK3ct-AB mice ( n = 7). An additional cohort was subjected to in vivo cardiac catheterization and LV pressure-volume analysis at 12 wk after AB. NLC-AB mice ( n = 11) displayed elevated end-diastolic pressure (8.5 ± 3.1 vs. 2.9 ± 1.2 mmHg, P < 0.05), reduced cardiac output (3,448 ± 323 vs. 4,488 ± 342 μl/min, P < 0.05), and reduced dP/d tmaxand dP/d tmin(both P < 0.05) compared with GRK3ct-AB mice ( n = 16), corroborating the preserved cardiac structure and function observed in GRK3ct-AB hearts assessed ex vivo. Increased cardiac mass and myocardial mRNA expression of β-myosin heavy chain confirmed the similar induction of cardiac hypertrophy in both AB groups, but only NLC-AB hearts displayed significantly elevated mRNA levels of brain natriuretic peptide and myocardial collagen contents as well as reduced β1-adrenergic receptor responsiveness to isoproterenol, indicating increased LV wall stress and the transition to HF. Inhibition of cardiac GRK3 in mice does not alter the hypertrophic response but attenuates cardiac dysfunction and HF after chronic pressure overload.
A finer tuning of G-protein signaling through regulated control of RGS proteins
Authors: Kach Jacob , Sethakorn Nan , Dulin Nickolai O.
Published: April 2012

Regulators of G-protein signaling (RGS) proteins are GTPase-activating proteins (GAP) for various Gα subunits of heterotrimeric G proteins. Through this mechanism, RGS proteins regulate the magnitude and duration of G-protein-coupled receptor signaling and are often referred to as fine tuners of G-protein signaling. Increasing evidence suggests that RGS proteins themselves are regulated through multiple mechanisms, which may provide an even finer tuning of G-protein signaling and crosstalk between G-protein-coupled receptors and other signaling pathways. This review summarizes the current data on the control of RGS function through regulated expression, intracellular localization, and covalent modification of RGS proteins, as related to cell function and the pathogenesis of diseases.
Pregnancy reduces RhoA/Rho kinase and protein kinase C signaling pathways downstream of thromboxane receptor activation in the rat uterine artery
Authors: Goulopoulou Styliani , Hannan Johanna L. , Matsumoto Takayuki , Webb R. Clinton
Published: April 2012

During pregnancy, reduced vascular responses to constrictors contribute to decreased uterine and total vascular resistance. Thromboxane A2(TxA2) is a potent vasoconstrictor that exerts its actions via diverse signaling pathways, and its biosynthesis increases in preeclampsia. In this study, we hypothesized that maternal vascular responses to TxA2will be attenuated via Rho kinase, PKC, p38 MAPK, and ERK1/2 signaling pathways. Isolated ring segments of uterine and small mesenteric arteries from late pregnant (19–21 days) and virgin rats were suspended in a myograph, and isometric force was measured. Pregnancy did not affect uterine and mesenteric artery responses to the TxA2analog U-46619 (10−9–10−5M), but transduction signals associated with these contractions were different between pregnant and nonpregnant rats. Inhibition of Rho kinase (10−6M Y-27632) reduced sensitivity to U-46619 in virgin uterine vessels but did not inhibit these contractions in pregnant uterine arteries and had no effect on mesenteric vessels. Treatment of arterial segments with a PKC inhibitor (10−6M bisindolylmaleimide I) reduced U-46619-induced contractions in virgin uterine and mesenteric arteries and in pregnant mesenteric arteries. Pregnant uterine arteries, however, were unresponsive to PKC inhibition. Inhibition of ERK1/2 (10−5M PD-98059) and p38 MAPK (10−5M SB-203580) reduced U46619-induced contractions in nonpregnant vessels and in pregnant uterine and mesenteric vessels. These data suggest that normal pregnancy does not affect uterine and mesenteric contractile responses to TxA2but reduces the contribution of Rho kinase and PKC signaling pathways to these contractions in the uterine vasculature. In contrast, the role of ERK1/2 and p38 MAPK in U-46619-induced uterine contractions remains unchanged with pregnancy. TxA2-associated transduction signals and its regulators might present potential targets for the development of new treatments for preeclampsia and other pregnancy-associated vascular diseases.
Effect of different agents onto multidrug resistant tumor cells revealed by fluorescence correlation spectroscopy
Authors: Boutin Céline , Roche Yann , Millot Christine , Deturche Régis , Plain JérÔme , Jeannesson Pierre , Manfait Michel , Royer Pascal , Millot Jean-Marc , Jaffiol Rodolphe
Published: April 2012

Fluorescence correlation spectroscopy (FCS) has been used to analyze the plasma membrane fluidity and heterogeneity of multidrug resistant cells. At the single cell level, the effects of different membrane agents present in the extra-cellular medium have been explored. Firstly, we reveal a modification of plasma membrane heterogeneities according to the addition of a fluidity modulator, benzyl alcohol. On the other hand, revertants such as verapamil and cyclosporin-A appear to act more specifically on the slow diffusion sites, such as lipids microdomains.
Preparation, spectral characterization and antibacterial studies of silver(I) complexes of 2-mercaptopyridine and thiomalate
Authors: Hanif Muhammad , Saddiqa Aisha , Hasnain Shahida , Ahmad Saeed , Rabbani Ghulam , Isab Anvarhusein A.
Published: April 2012

Silver(I) complexes of 2-mercaptopyridine (Mpy), [Ag(Mpy)]NO3and [Ag(Mpy)2]NO3, and the first mixed-ligand complex having a thione and thiolate coordinated to Ag(I), [Mpy–Ag–Tm] (Tm═thiomalate) have been prepared and characterized by IR and NMR spectroscopy. The1H and13C NMR spectra show the presence of both ligands in the mixed-ligand complex, [Mpy–Ag–Tm]. An upfield shift is observed in the >C═S resonance of Mpy and C═O resonances of thiomalate in13C NMR, while the other resonances are shifted downfield. The complexes showed relatively high antibacterial activity (inhibition zone of 6–11 mm) against a gram +ve bacterium,Bacillus subtilis, as compared to that (inhibition zone of 4 mm) against a gram –ve bacterium,Escherichia coli.
A study on the early detection of colon cancer using the methods of wavelet feature extraction and SVM classifications of FTIR
Authors: Cheng Cun-Gui , Tian Yu-Mei , Jin Wen-Ying
Published: April 2012

This paper introduces a new method for the early detection of colon cancer using a combination of feature extraction based on wavelets for Fourier Transform Infrared Spectroscopy (FTIR) and classification using the Support Vector Machine (SVM). The FTIR data collected from 36 normal SD rats, 60 1,2-DMH-induced SD rats, and 44 second generation rats of those induced rats was first preprocessed. Then, 12 feature variants were extracted using continuous wavelet analysis. The extracted feature variants were then inputted into the SVM for classification of normal, dysplasia, early carcinoma, and advanced carcinoma. Among the kernel functions the SVM used, the Poly and RBF kernels had the highest accuracy rates. The accuracy of the Poly kernel in normal, dysplasia, early carcinoma, and advanced carcinoma were 100, 97.5, 95% and 100% respectively. The accuracy of RBF kernel in normal, dysplasia, early carcinoma, and advanced carcinoma was 100, 95, 95% and 100% respectively. The results indicated that this method could effectively and easily diagnose colon cancer in its early stages.
Analysis of the alteration in the optical configuration of Raman spectrometer: Optimization of signal-to-noise ratio (SNR) in a specific wavelength range of clinical interest
Authors: Lázaro João Carlos , de Lima Carlos J. , Moreira Leonardo M. , Silveira Jr. Landulfo , da Silveira Nelson J. F. , Villaverde Antonio Balbin , Pacheco Marcos Tadeu T.
Published: April 2012

The present article is focused on the optimization of the optical parameters of a Raman spectrometer in order to obtain a minimum width of its spectral lines. In this way, using as reference the width of a fingerprint band of a calcified biological tissue, a spectral line without distortion or any loss of resolution was identified. This optimization is employed with the aim of improvement of the signal-to-noise ratio (SNR). A great improvement in the efficiency of the spectral collect was obtained, which can reduce significantly the time of diagnosis of target tissues, such as the calcified coronarian tissue. Therefore, the potential application of this new spectroscopic system increases the efficiency and precision, favoring the security of this technique to futurein vivoapplications. The excellent results obtained in this work become this spectroscopic system a powerful tool to the clinical diagnosis of several diseases.
Reduction of ferric hemoglobin fromTrematomus bernacchiiin a partial bis-histidyl state produces a deoxy coordination even when encapsulated into the crystal phase
Authors: Merlino Antonello , Verde Cinzia , di Prisco Guido , Mazzarella Lelio , Vergara Alessandro
Published: April 2012

Crystallographic and spectroscopic evidences on Antarctic fish hemoglobins (AFHbs) have revealed that their ferric tetramers at physiological pH are in a mixed |α(aquo-met)/β(bis-histidyl) coordination state and show a quaternary structure intermediate between the classical R and T states (H state). Ferric bis-histidyl adducts (hemichromes) have been also observed in some mammalian Hbs. In order to clarify whether hemichrome in AFHbs can be converted into a ferrous bis-histidyl adduct (hemochrome), at least in the crystal phase, chemical reduction of ferric hemoglobins fromTrematomus bernacchii(HbTb) single crystals has been followed via Raman microscopy. The results of this analysis reveal that in HbTb, upon reduction, the bis-histidyl coordination is disrupted in favor of a penta-coordinated ferrous deoxy state, with no evidence of hemochrome. These data are in agreement with UV/Vis absorption spectra in solution. Furthermore, our data are also indirectly supported by the observation that upon reduction with dithionite, the ferric HbTb crystals crack and lose their diffraction power: in the crystalline state, the quaternary structure transition from the H to the T state is not compatible with the crystal packing. Altogether these data indicate that if bis-histidyl adducts have a functional significance in AFHbs, this function refers to a stable ferric state, or to a transient, though never detected, ferrous species.
Development of a new analytical spectroscopic methodology based on the competitive aggregation in a dye–surfactant–drug system: Application to the determination of gemfibrozil
Authors: Amjadi Mohammad , Manzoori Jamshid L. , Farzampour Leila
Published: April 2012

A new analytical methodology based on the competitive aggregation in a dye–surfactant–drug system is developed for the determination of gemfibrozil. Eriochrome Blue Black R (EBBR) and Didodecyldimethylammonium bromide (DDABr) were the dye and surfactant used, respectively. In the proposed method, the anions of the dye bind to the cationic surfactant molecules to form dye–surfactant aggregates, which are monitored from changes in UV-Vis absorption features of the dye. In the ternary EBBR–DDABr–drug mixtures, the drug competes with the dye to interact with the surfactant, which results in a decrease in dye–surfactant aggregates formation. This, again, causes a change in absorption properties of the dye. The measurement parameter is the difference between the absorption of the dye in the presence and absence of the drug. In the appropriate experimental conditions the absorbance differences are directly proportional to the drug concentration. The influence of several experimental variables such as pH, concentrations of buffer, EBBR and DDABr on the measurement parameter were studied. Under the optimum conditions, the calibration graph was linear up to 6.0 μg ml−1with the correlation coefficient of 0.998. The limit of detection and quantification were found to be 0.044 and 0.15 μg ml−1, respectively. The method was validated and applied to the determination of gemfibrozil in pharmaceutical preparations.
Identification of hepatitis C in human blood serum by near-infrared Raman spectroscopy
Authors: Saade Jamil , Pacheco Marcos Tadeu Tavares , Rodrigues Maira Regina , Jr. Landulfo Silveira
Published: April 2012

Hepatitis C has become one of the higher health problems around the world. Near-infrared Raman spectroscopy had been used to spectrally differentiate among health human blood serum from the one with hepatitis C contaminationin vitro. In this study a Raman spectrometer with 80 mW, 830 nm excitation, liquid-nitrogen cooled CCD and imaging spectrograph were used to collect Raman scattering from 24 blood samples (14 healthy and 10 diseased) with collection time of 120 s. It has been used an algorithm based on the Principal Components Analysis (PCA) for main spectral features identification and Mahalanobis distance for blood spectrum classification depending on the serology. It was observed that the highest spectral differences between the two types of human blood serum were found in 1002, 1169, 1262 and 1348 cm−1Raman bands. The spectral analysis using multivariate statistics presented good results when compared to classical diagnosis for viral hepatitis C, showing that Raman spectroscopy can classify human blood serum spectrum in one of the two categories by identifying biochemical alterations that occur in the presence of viral infections.
Spectroscopic investigation of the interaction of bovine serum albumin with a novel cardiac agent V-09
Authors: Chen Changyun , Ma Meihua , Zhang Junqi , Wang Lichen , Xiang Bingren
Published: April 2012

This study employs fluorescence spectroscopy to characterize the binding properties of a newly synthesized cardiac agent, V-09, on bovine serum albumin (BSA). This compound shows the highest cardiac activity in the whole series. The binding constantsKat 25°C and 37°C are obtained, the values are 7.12×104l mol–1, 4.66×104l mol–1, respectively. The standard enthalpy change (ΔH0) and the standard entropy change (ΔS0) are calculated to be –27.13 KJ mol–1and 1.854 J mol–1K–1, which indicated that hydrophobic forces play major role in the interaction between V-09 and BSA. The binding average distance between V-09 and BSA (2.57 nm) is obtained on the basis of the theory of Főrster energy transfer.
The combination of resonance Raman spectroscopy, optical tweezers and microfluidic systems applied to the study of various heme-containing single cells
Authors: Ramser K. , Wenseleers W. , Dewilde S. , Doorslaer S. Van , Moens L.
Published: April 2012

Several recent studies on the function of neuroglobin (Ngb), a hemoprotein predominantly expressed in the brain, point toward a neuro-protective role during hypoxic-ischemic injuries. The exact mechanism by which Ngb protects the cell against H2O2-induced cell death remains to be elucidated. Hence, new tools need to be developed in order to study the proteinin vivoor under physiological conditions. In this summary of our work, we demonstrate how resonance Raman spectroscopy, optical tweezers and microfluidic systems were combined to mimicin vivoconditions in anin vitromilieu. The setup has been tested on several globin-containing cells: hemoglobin (Hb) within single red blood cells (RBCs), a nerve globin present in the nerve cord of the annelidAphrodite aculeata(A. aculeata), and wild-type (wt) human neuroglobin (NGB) overexpressed inEscherichia coli(E. coli) bacteria. The feasibility of the setup regarding sensitivity and photo-induced effects and the results regarding the oxygen uptake and release will be discussed and compared for each system. The summary of the results show that the method is promising and the setup will be developed further to monitor the dependence of the neuronal action potential on nerve globins.
Impact of an electric field on P-type ATPases
Authors: Weidemüller Christian , Hauser Karin
Published: April 2012

P-type ATPases are membrane proteins acting as ion pumps that drive an active transport of cations across the membrane against a concentration gradient. The required energy for the ion transport is provided by binding and hydrolysis of ATP. A reaction mechanism of ion transport and energy transduction is assumed to be common for all P-type ATPases and generally described by the Post-Albers cycle. Transient currents and charge translocation of P-type ATPases were extensively investigated by electrical measurements that apply voltage jumps to initiate the reaction cycle. In this study, we simulate an applied voltage across the membrane by an electric field and perform electrostatic calculations in order to verify the experimentally-driven hypothesis that the energy transduction mechanism is regulated by specific structural elements. Side chain conformational and ionization changes induced by the electric field are evaluated for each transmembrane helix and the selectivity in response is qualitatively analyzed for the Ca2+-ATPase as well as for structural models of the Na+/K+-ATPase. Helix M5 responds with more conformer changes as compared to the other transmembrane helices what is even more emphasized when the stalk region is included. Thus our simulations support experimental results and indicate a crucial role for the highly conserved transmembrane helix M5 in the energy transduction mechanism of P-type ATPases.
Structural dynamics of the Ca2+-ATPase studied by time-resolved infrared spectroscopy
Authors: Barth Andreas
Published: April 2012

This review discusses the contribution of time-resolved infrared spectroscopy to the understanding of the Ca2+pump in the sarcoplasmic reticulum membrane of skeletal muscle cells (SERCA1a). The focus is on interactions of the substrate ATP with the ATPase and on the bond parameters of the phosphoenzyme phosphate group. Functional groups throughout the ATP molecule are important for stabilising the closed conformation of the ATP–ATPase complex and for fast phosphorylation of the ATPase. Dissociation of the reaction product ADP after phosphorylation leads to a more open average conformation of the enzyme and does not trigger the transition from the first phosphoenzyme Ca2E1P to the second E2P. The P–O bond between phosphate and aspartyl moieties is weaker in Ca2E1P and E2P than in acetyl phosphate in aqueous solution, which explains the high reactivity of the phosphoenzymes. This ground state property of the phosphoenzymes prepares for a phosphate transfer reaction with dissociative character.
Trace elemental analysis of mitral valves by EDXRF
Authors: Ates A. , Simsek O. , Ertugral B. , Ertugrul M.
Published: April 2012

The elemental analysis of mitral valves from 12 patients with rheumatic mitral valve disease was performed using radioisotope excited energy dispersive X-ray fluorescence (EDXRF) technique. An annular 50 mCi55Fe radioactive source was used for excitation of characteristic K X-rays of the trace elements in the samples. A high resolution Si(Li) detector, which has a 160 eV full width at half maximum for 5.9 keV photons, was used for intensity measurements. Concentrations of the elements P, S, K and Cl in the mitral valve samples were determined by using standard addition method. Deficiencies or excesses of these trace elements cause the valves to run irregularly. Abnormal value of these elements may also result in rheumatic valve disease.
Raman spectroscopic study on the subpicosecond dynamics in calf-thymus DNA, upon lowering the pH and in the presence of Mn2+ions
Authors: Muntean Cristina M. , Bratu Ioan
Published: April 2012

In this paper the Raman total half bandwidths of calf-thymus DNA vibrations have been measured as a function of pH (3.45–6.4), in the presence of Mn2+ions, respectively. The dependencies of the half bandwidths and of the global relaxation times, on DNA molecular subgroup structure and on pH, are reported. It is shown that changes in the subpicosecond dynamics of molecular subgroups in calf-thymus DNA can be monitored with Raman spectroscopy.

Particularly, the Raman band parameters for the vibrations at 728 cm–1(dA), 787 cm–1(dC), 1093 cm–1(PO2–), 1376 cm–1(dA, dG, dT, dC), 1489 cm–1(dG, dA) and 1578 cm–1(dG, dA) of MnDNA complexes, at reduced and low pH values, are presented. In our study, the full widths at half-maximum (FWHM) of the bands in calf-thymus DNA are typically in the wavenumber range from 11 to 27 cm–1. It can be observed that the molecular relaxation processes studied in this work, have a global relaxation time smaller than 0.965 ps and larger than 0.393 ps. The limit values are characteristic for dA and dC residues, respectively (vibrations at 728 and 787 cm–1).

Low pH-induced melting of double helical structure in calf-thymus DNA, in the presence of Mn2+ions, results for some bands in smaller global relaxation times, and larger bandwidths, respectively, as a consequence of the increased interaction of the base moieties with the solvent molecules. This behaviour is most evident for the bands at 787 cm–1up to pH 3.8, at 1578 cm–1up to pH 3.45 and is partially confirmed for the DNA backbone PO2–symmetric stretching vibration at 1093 cm–1.

The fastest molecular dynamics was obtained for the adenine band at 728 cm–1in the pH interval 3.45–3.8 (global relaxation time 0.885 ps), for the cytosine ring breathing mode near 787 cm–1around the pH 3.8 (global relaxation time 0.393 ps), for the band at 1093 cm–1in the pH interval 3.8–4.4 (global relaxation time 0.518 ps) and for the vibration near 1578 cm–1at pH 3.45 (global relaxation time 0.544 ps).

A comparison between different time scales of the vibrational energy transfer processes, characterizing the protonated MnDNA structural subgroups has been given.

We have found that metal ion's type and concentration are modulators for the (sub)picosecond dynamics of protonated DNA molecular subgroups.
Optical spectroscopy investigation of peptides issued from the AML1-ETO–E-protein complex relevant to acute myeloid leukemia
Authors: Porumb H.
Published: April 2012

The expression of AML1-ETO, resulting from thet(8; 21) chromosomal translocation causes 15% of acute myeloid leukaemias. The NHR2 region of ETO, bearing the motif LxxLL, is involved in the oligomerisation of the AML1-ETO. “Peptide NHR2” is one of the objects of the present investigation. The TAFH region of ETO may recruit AML1-ETO to transcription activators, such as E-protein. “Peptide TAFH” is another object of the present investigation. TAFH interacts with E-protein through the AD1 domain of the latter, which possesses an LxxLL motif as well. “Peptide AD1” is the third object of the present investigation. By CD, ANS fluorescence and intrinsic fluorescence, we suggest an antiparallel coiled-coil encounter of two NHR2 molecules (Kd═2.8–4 µM) as a prerequisite to tetramer formation. On the other hand, we show that the TAFH domain would probably recognize another partner bearing the LxxLL motif and, before binding to AD1 (Kd═28 nM), the first such interaction is likely to beintramolecular, with the NHR2 domain of the AML1-ETO protein itself (Kd═1.28 nM). Furthermore, a possible interaction of NHR2 with AD1 is also revealed (Kd═240 nM). The biological implications of the results are discussed.
Application of spin markers for study of liposome prepared by the modified reverse-phase evaporation method
Authors: Pentak Danuta , Sułkowski Wiesław W. , Wolińska Agnieszka , Maślanka Sławomir , Bojko Barbara , Maciążek Małgorzata , Równicka Joanna , Sułkowska Anna
Published: April 2012

The EPR spectroscopy was used to determine the structure and physicochemical properties of liposomes prepared from L-α-phosphatidylcholine dipalmitoyl (DPPC) by the modified reverse-phase evaporation method (mREV). EPR study was carried out in the temperature range from 297 K to 340 K i.e. below and above the phase transition temperatureTCof DPPC. On the basis of EPR spectra of spin marker 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) incorporated into the liposome, the parameterfwas determined. TEMPO dissolves easily in water and in the fluid lamellar smectic liquid-crystaline phase of lipid bilayer but is largely excluded from the solid, gel-phase. Thus TEMPO can be used to observe the change in the partition between aqueous and fluid lipid regions. The change in the relative value offas a function of temperature for DPPC shows that, in the presence of water excess, this phospholipids undergoes a transition from a “gel phase” to a lamellar smectic liquid crystalline phase. On the basis of EPR spectra of spin marker 2-(3carboxypropyl)-4,4-dimethyl-2-tridecyl-3-oxazolidinloxyl (5-DOXYL) incorporated into liposome, the parametera'Nwas determined. The isotropic14N-hyperfine coupling constanta'Nof nitroxide spin label depends on the local environmental polarity. The increase ofa'Nvalue reflects the rise of polarity of spin label environment. Temperature, cholesterol and pH dependent structural changes were also described.
A transvaginal probe for near infrared spectroscopic monitoring of the bladder detrusor muscle and urethral sphincter
Authors: Shadgan Babak , Stothers Lynn , Macnab Andrew
Published: April 2012

The majority ofin vivoapplications of near infrared spectroscopic (NIRS) monitoring use transcutaneous optode placement over the tissue of interest. Invasive application of optodes is occasionally described for monitoring tissue too deep for transcutaneous study, principally in animal models, but sometimes in humans. Invasive fibre-optic probes have been developed for a range of other spectroscopic applications including somein vivo. We describe the design and feasibility testing in a human subject of a vaginal probe to extend the scope of recently developed techniques for NIRS monitoring in urology.

Design criteria included: use of optodes and cables with dimensions compatible with appropriate overall probe size; dual channel capability (for simultaneous monitoring of bladder wall and urethral sphincter); secure interoptode separation at correct distance for required penetration; ease of insertion, orientation and avoidance of movement artifact.

Components were obtained that met design criteria and allowed use of the probe connected to a commercial NIRS instrument. Iterative development established optimal interoptode distance and secure positioning of a probe that could be housed forin vivostudy within a disposable vaginal speculum.

The feasibility of monitoring changes in chromophore concentration in the bladder detrusor and urethral sphincter using this intravaginal probe was evident from four separate studies during voiding and a series of physiologic events (cough, Valsalva and Kiegel contractions) in a healthy female volunteer. This small series suggests that reproducible data free of movement artifact, with consistent patterns and magnitudes of chromophore change can be obtained with the probe designed.