Monitoring the Reaction of the Body State to Antibiotic Treatment against Helicobacter pylori via Infrared Spectroscopy: A Case Study

The current understanding of deviations of human microbiota caused by antibiotic treatment is poor. In an attempt to improve it, a proof-of-principle spectroscopic study of the breath of one volunteer affected by a course of antibiotics for Helicobacter pylori eradication was performed. Fourier transform spectroscopy enabled searching for the absorption spectral structures sensitive to the treatment in the entire mid-infrared region. Two spectral ranges were found where the corresponding structures strongly correlated with the beginning and end of the treatment. The structures were identified as methyl ester of butyric acid and ethyl ester of pyruvic acid. Both acids generated by bacteria in the gut are involved in fundamental processes of human metabolism. Being confirmed by other studies, measurement of the methyl butyrate deviation could be a promising way for monitoring acute gastritis and anti-Helicobacter pylori antibiotic treatment.     

Doubling Förster Resonance Energy Transfer Efficiency in Proteins with Extrinsic Thioamide Probes: Implications for Thiomodified Nucleobases

Designing a potential protein–ligand pair is pivotal, not only to track the protein structure dynamics, but also to assist in an atomistic understanding of drug delivery. Herein, the potential of a small model thioamide probe being used to study albumin proteins is reported. By monitoring the Förster resonance energy transfer (FRET) dynamics with the help of fluorescence spectroscopic techniques, a twofold enhancement in the FRET efficiency of 2-thiopyridone (2TPY), relative to that of its amide analogue, is observed. Molecular dynamics simulations depict the relative position of the free energy minimum to be quite stable in the case of 2TPY through noncovalent interactions with sulfur, which help to enhance the FRET efficiency. Finally, its application is shown by pairing thiouracils with protein. It is found that the site-selective sulfur atom substitution approach and noncovalent interactions with sulfur can substantially enhance the FRET efficiency, which could be a potential avenue to explore in the design of FRET probes to study the structure and dynamics of biomolecules.     

New substituted 2-aminomethyl-2-oxo-2λ5-perhydro-[1,3,2]oxazaphospholo [3,4-a]pyridine: Design,synthesis and antimicrobial activity

The synthesis of a new series of P-heterocyclic compounds, substituted 2-aminomethyl-2-oxo-2λ⁵-perhydro-[1,3,2]oxazaphospholo[3,4-a]pyridine derivatives 8(a-j), was accomplished. A key intermediate, 2-(chloromethyl)-2-oxo-2λ⁵-perhydro-[1,3,2]oxazaphospholo[3,4-a]pyridine (6) was primarily synthesized by the condensation of (±)-2-piperidinemethanol (4) and chloromethylphosphonic dichloride (5); subsequently, it was treated with various heterocyclic amines/benzylamines/aminoacid esters, 7(a-j) to obtain the desired products. The structures of the newly synthesized compounds were elucidated by ¹H, ¹³C, and ³¹P NMR spectroscopy, mass spectra and elemental analyses. The biological potency of title products was investigated by screening in vitro antimicrobial activity. The bio-screening data revealed that most of the synthesized derivatives showed potent growth of inhibition against fungi while compared with bacteria. Particularly, compounds 8c and 8i against bacterial strains, and 8a and 8f against fungi exhibited promising activity.     

Significance of plaque morphology in modifying flow characteristics in a diseased coronary artery: Numerical simulation using plaque measurements from intravascular ultrasound imaging

The paper deals with numerical investigation of the effect of plaque morphology on the flow characteristics in a diseased coronary artery using realistic plaque morphology. The morphological information of the lumen and the plaque is obtained from intravascular ultrasound imaging measurements of 42 patients performed at Cleveland Clinic Foundation, Ohio. For this data, study of Bhaganagar et al. (2010) [1] has revealed the stenosis for 42 patients can be categorized into four types – type I (peak-valley), type II (ascending), type III (descending), and type IV (diffuse). The aim of the present study is to isolate the effect of shape of the stenosis on the flow characteristics for a given degree of the stenosis. In this study, we conduct fluid dynamic simulations for the four stenosis types (type I–IV) and analyze the differences in the flow characteristics between these types. Finely refined tetrahedral mesh for the 3-D solid model of the artery with plaques has been generated. The 3-D steady flow simulations were performed using the turbulence (k–ε) model in a finite volume based computational fluid dynamics solver. The axial velocity, the radial velocity, turbulence kinetic energy and wall shear stress profiles of the plaque have been analyzed. From the axial and radial velocity profiles results the differences in the velocity patterns are significantly visible at proximal as well as distal to the throat, region of maximum stenosis. Turbulent kinetic energy and wall shear stress profiles have revealed significant differences in the vicinity of the plaque. Additional unsteady flow simulations have been performed to validate the hypothesis of the significance of plaque morphology in flow alterations in diseased coronary artery. The results revealed the importance of accounting for plaque morphology in addition to plaque height to accurately characterize the turbulent flow in a diseased coronary artery.     

Étale covers of affine spaces in positive characteristicRevêtements étales des espaces affines en caractéristique positive

We prove that every projective, geometrically reduced scheme of dimension n over an infinite field k of positive characteristic admits a finite morphism over some finite radicial extension k′ of k to projective n-space, étale away from the hyperplane H at infinity, which maps a chosen Weil divisor into H and a chosen smooth geometric point of X not on the divisor to some point not in H. To cite this article: K.S. Kedlaya, C. R. Acad. Sci. Paris, Ser. I 335 (2002) 921–926.     

An algebraic approach to q-partial fractions and Sylvester denumerants

The Ramanujan Journal - In 1857, Sylvester established an elegant theory that certain counting functions (which he termed denumerants) are quasi-polynomials by decomposing them into periodic and...     

The Ulam number of infinite graphs

The following is a conjecture of Ulam: In any partition of the integer lattice on the plane into uniformly bounded sets, there exists a set that is adjacent to at least six other sets. Two sets are adjacent if each contain a vertex of the same unit square. This problem is generalized as follows. Given any uniformly bounded partitionP of the vertex set of an infinite graphG with finite maximum degree, letP (G) denote the graph obtained by letting each set of the partition be a vertex ofP (G) where two vertices ofP (G) are adjacent if and only if the corresponding sets have an edge between them. The Ulam number ofG is defined as the minimum of the maximum degree ofP (G) where the minimum is taken over all uniformly bounded partitionsP. We have characterized the graphs with Ulam number 0, 1, and 2. Restricting the partitions of the vertex set to connected subsets, we obtain the connected Ulam number ofG. We have evaluated the connected Ulam numbers for several infinite graphs. For instance we have shown that the connected Ulam number is 4 ifG is an infinite grid graph. We have settled the Ulam conjecture for the connected case by proving that the connected Ulam number is 6 for an infinite triangular grid graph. The general Ulam conjecture is equivalent to proving that the Ulam number of the infinite triangular grid graph equals 6. We also describe some interesting geometric consequences of the Ulam number, mainly concerning good drawings of infinite graphs.     

Nonlinear optical study of palladium Schiff base complex using femtosecond differential optical Kerr gate and Z-scan techniques

A femtosecond differential optical Kerr gate (DOKG) and Z-scan techniques, have been applied to investigate the third-order optical nonlinearity of composite film of the coordination complex [PdLPPh₃] (L=N-(2-pyridyl)-N′-(salicylidene)hydrazine, PPh₃=triphenylphosphine). Film exhibits superior nonlinear optical properties in the near-infrared spectral region. The nonlinear response time and third-order nonlinear optical susceptibility of complex were found to be≤90 fs and 3.9×10^?10 esu, respectively. The Z-scan result shows that saturable absorption property of the film and its nonlinear absorption coefficient of the sample was found to be ?23 cm/GW.     

Synthesis,Spectroscopy, In Vitro Biological Activity and X-ray Structure of (4-Methylpiperidine-dithiocarbamato-<Emphasis Type="Italic">S</Emphasis>,<Emphasis Type="Italic">S</Emphasis>′)triphenyltin(IV)

Abstract (4-Methylpiperidine-dithiocarbamato-S,S′)triphenyltin(IV) derivative of 4-methyl-1-piperidine carbodithioic acid (4-MePCDTA) have been synthesized and characterized by elemental, IR, multinuclear NMR (¹H and ¹³C) and mass spectrometric studies. The crystal structure of the complex has been determined by X-ray single crystal analysis, which shows unsymmetrical nature of the ligand towards coordination to tin. It crystallizes in monoclinic P21/c space group with the crystal cell parameters: a = 10.1863(10) ?, b = 21.200(2) ?, c = 11.7332(11) ?, β = 111.2020(10)°, Z = 4 and V = 2,362.2(4) ?³. The tin atom is coordinated to the two sulfur atoms of the dithiocarbamate ligand and three carbon atoms of the phenyl groups are in distorted trigonal bipyramid geometry. This complex was tested for its antimicrobial activity against six different plant and human pathogens. The screening results show that the complex exhibit higher antibacterial and antifungal activity than the free ligand. Index abstract Synthesis, Spectroscopy, in vitro Biological Activity and X-Ray Structure of (4-Methylpiperidine-dithiocarbamato-S,S′)triphenyltin(IV) Saira Shahzadi, Saqib Ali and Mohammmed Fettouhi 4-Methyl-1-piperidine carbodithioic acid behaves as anisobidentate ligand and chelates the tin atom by means of sulfur atoms giving cis-trigonal bipyramid geometry around the tin atom. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.