Approach to quantitative spectroscopy of atomic vapor in optical nanocells.

We present a method for recovery of narrow homogeneous spectral features out of a broad inhomogeneous overlapped profile based on second-derivative processing of the absorption spectra of alkali metal atomic vapor nanocells. The method is shown to preserve the frequency positions and amplitudes of spectral transitions, thus being applicable for quantitative spectroscopy. The proposed technique was successfully applied and tested for measurements of hyperfine splitting and atomic transition probabilities, development of an atomic frequency reference, determination of isotopic abundance, study of atom-surface interaction, and determination of magnetic-field-induced modification of atomic transition frequency and probability. The obtained experimental results are fully consistent with theoretical modeling.

Cognitive regulation of saccadic velocity by reward prospect.

It is known that expectation of reward speeds up saccades. Past studies have also shown the presence of a saccadic velocity bias in the orbit, resulting from a biomechanical regulation over varying eccentricities. Nevertheless, whether and how reward expectation interacts with the biomechanical regulation of saccadic velocities over varying eccentricities remains unknown. We addressed this question by conducting a visually guided double-step saccade task. The role of reward expectation was tested in monkeys performing two consecutive horizontal saccades, one associated with reward prospect and the other not. To adequately assess saccadic velocity and avoid adaptation, we systematically varied initial eye positions, saccadic directions and amplitudes. Our results confirmed the existence of a velocity bias in the orbit, i.e., saccadic peak velocity decreased linearly as the initial eye position deviated in the direction of the saccade. The slope of this bias increased as saccadic amplitudes increased. Nevertheless, reward prospect facilitated velocity to a greater extent for saccades away from than for saccades toward the orbital centre, rendering an overall reduction in the velocity bias. The rate (slope) and magnitude (intercept) of reward modulation over this velocity bias were linearly correlated with amplitudes, similar to the amplitude-modulated velocity bias without reward prospect, which presumably resulted from a biomechanical regulation. Small-amplitude (≤ 5°) saccades received little modulation. These findings together suggest that reward expectation modulated saccadic velocity not as an additive signal but as a facilitating mechanism that interacted with the biomechanical regulation.

99% random telegraph signal-like noise in gold nanoparticle micro-stripes.

In this paper, we report on a process to prepare gold nanoparticle stripes on SiO(2) by convective/capillary assembly without any patterning of the substrate. Electrical devices were then fabricated using stencil lithography in order to avoid any contamination. I(V) measurements at room temperature show that these stripes have an ohmic behavior between +/- 0.5 V with a resistivity ranging from one to two orders higher than the gold bulk value. Furthermore, I(V) and I(t) measurements reveal current fluctuations that were interpreted in terms of charging and discharging of nanoparticle islands leading to a very large electrostatic perturbation of current conduction paths. Unconventional relative amplitudes of up to 99% RTS fluctuations were observed.

Objective Methodology to Assess Meaningful Research Productivity by Orthopaedic Residency Departments: Validation Against Widely Distributed Ranking Metrics and Published Surrogates.

The mission of any academic orthopaedic training program can be divided into 3 general areas of focus: clinical care, academic performance, and research. Clinical care is evaluated on clinical volume, patient outcomes, patient satisfaction, and becoming increasingly focused on data-driven quality metrics. Academic performance of a department can be used to motivate individual surgeons, but objective measures are used to define a residency program. Annual in-service examinations serve as a marker of resident knowledge base, and board pass rates are clearly scrutinized. Research productivity, however, has proven harder to objectively quantify. In an effort to improve transparency and better account for conflicts of interest, bias, and self-citation, multiple bibliometric measures have been developed. Rather than using individuals' research productivity as a surrogate for departmental research, we sought to establish an objective methodology to better assess a residency program's ability to conduct meaningful research. In this study, we describe a process to assess the number and quality of publications produced by an orthopaedic residency department. This would allow chairmen and program directors to benchmark their current production and make measurable goals for future research investment. The main goal of the benchmarking system is to create an "h-index" for residency programs. To do this, we needed to create a list of relevant articles in the orthopaedic literature. We used the Journal Citation Reports. This publication lists all orthopaedic journals that are given an impact factor rating every year. When we accessed the Journal Citation Reports database, there were 72 journals included in the orthopaedic literature section. To ensure only relevant, impactful journals were included, we selected journals with an impact factor greater than 0.95 and an Eigenfactor Score greater than 0.00095. After excluding journals not meeting these criteria, we were left with 45 journals. We performed a Scopus search over a 10-year period of these journals and created a database of articles and their affiliated institutions. We performed several iterations of this to maximize the capture of articles attributed to institutions with multiple names. Based off of this extensive database, we were able to analyze all allopathic US residency programs based on their quality research productivity. We believe this as a novel methodology to create a system by which residency program chairmen and directors can assess progress over time and accurate comparison with other programs.

Effect of phenobarbital on the oligosaccharide structure of rat alpha-acid glycoprotein.

We have recently shown that the administration of phenobarbital to rats leads to an increased serum alpha 1-acid glycoprotein content with alterations in the relative proportion of the sugar moiety. Therefore, alpha 1-acid glycoprotein was purified from normal (alpha 1-acid glycoproteine N) and phenobarbital-treated rats (alpha 1-acid glycoprotein PB) Glycans were separated by AX-10 chromatography and analysed by gas chromatography. It appears that, compared to alpha 1-acid glycoprotein N, alpha 1-acid glycoprotein PB had a higher carbohydrate content (31.7% compared to 26%) and a non-negligible amount of neutral oligosaccharide (12.2% compared to 1.3%). No tetrasialyl oligosaccharides in alpha 1-acid glycoprotein PB were detected, whereas their relative proportion in alpha 1-acid glycoprotein N was 27%.

Alterations in the carbohydrate moiety of alpha-1-acid glycoprotein purified from human cirrhotic ascitic fluid.

The carbohydrate analysis of alpha 1-AGPc purified from cirrhotic ascitic fluid was performed by immunoaffinity chromatography. It showed a large increase in the fucosyl molar ratio and sugar content (47%). The molar ratio of the oligosaccharides which were released by hydrazinolysis and fractionated by high-performance liquid chromatography confirms the marked increase in fucosyl residues in each fraction. A shift towards fractions with a high degree of branching was also observed. Moreover, the studies of sugar molar ratios and methylation of the tetrasialylated fraction indicated the simultaneous presence of sialyl and fucosyl residues on one of the outer branches.

Primary structure of a novel N-glycosidic carbohydrate unit, derived from hen ovomucoid. A 500-MHz 1H-NMR study.

The N-glycosidic carbohydrate chains of hen beta-ovomucoid were released from the protein by hydrazinolysis, and separated by HPLC. Primary structural analysis of 3 major fractions was conducted by applying 500-MHz 1H-NMR spectroscopy in combination with methylation analysis. One of the fractions investigated appeared to consist of an intersected penta-antennary structure extended with one Gal residue. The location of the latter in a certain branch could be established unambiguously by NMR. This structure is a novel member of the family of N-glycosidic carbohydrates of glycoproteins.

Triterpenoid saponins from Argania spinosa.

Five new oleanane saponins named arganine A, B, D, E and F and two known saponins: arganine C and mi-saponin A were isolated from the kernel of Argania spinosa. The structures of these saponins were elucidated by using 1H NMR, 1H-1H COSY NMR, 13C NMR, FAB mass spectrometry and chemical evidence.

An example of thermometry in volume by microwave radiometry.

We depict a method of determination of the size D depth z and temperature T0 + delta T of a cylindrical thermal structure embedded in an homogeneous glossy material, in the present case, water. A microwave radiometric image at 3 GHz points out the location of the thermal structure; its threshold provides the diameter D of the structure. The depth z derives from the ratio of the maximal radiometric intensities at 1.5 and 3 GHz. The combination of D,z and of the radiometric intensities gives delta T.

Determination of the sialylation level and of the ratio alpha-(2-->3)/alpha-(2-->6) sialyl linkages of N-glycans by methylation and GC/MS analysis.

A methodology for the determination of the sialylation pattern of N-glycans, extent of sialylation and the ratio between alpha-(2-->3) and alpha-(2-->6) sialyl linkages, is presented based on the labelling of the C-3 and C-6 hydroxyl groups of Gal residues obtained after permethylation, saponification, selective desialylation of sialylated oligosaccharides and methanolysis. Deuteromethylation and GC/MS analysis of Gal derivatives allow to determine the sialylation level of glycans. O-Ethyl ether labelling followed by GC analysis of the resulting Gal derivatives allows to obtain the ratio between alpha-(2-->3) and alpha-(2-->6) sialyl linkages. The method was applied to LNT (LcOse4: beta-D-Galp-(1-->3)-beta-D-GlcpNAc-(1-->3)-beta-D- Galp-(1-->4)-D-Glcp), LSTa (IV3NeuAcLcOse4: alpha-Neup5Ac-(2-->3)-beta-D-Galp-(1-->3)-beta-D- GlcpNac-(1-->3-beta-D-Galp-(1-->4)-D-Glcp), LSTc (IV6NeuAcn LcOse4: alpha-Neup5Ac-(2-->6)-beta-D-Galp-(1-->4)-beta-D-GlcpNAc-(1-->3)- beta-D-Galp-(1-->4)-D-Glcp) and a bisialylated biantennary N-glycan in which sialic acid is bound to Gal residues via an alpha-(2-->6) linkage. Using this method, it was found that 92.8% of N-glycans in bovine fetuin is sialylated and that the ratio of alpha-(2-->6) versus alpha-(2-->3) sialyl linkages was 31:19.

Collisional-activation tandem mass spectrometry of sodium adduct ions of methylated oligosaccharides: sequence analysis and discrimination between alpha-NeuAc-(2----3) and alpha-NeuAc-(2----6) linkages.

Collision-activated dissociation (c.a.d.) of sodium adducts of molecular ion species have been carried out on methylated beta-D-Galp-(1----4)-beta-D-GlcpNAc- (1----3)-beta-D-Galp-(1----4)-D-Glcp (1), beta-D-Galp-(1----3)-beta-D-GlcpNAc-(1----3)-beta-D-Galp-(1----4)-D-Glcp (2), alpha-D-NeuAc-(2----3)-beta-D-Galp-(1----3)-beta-D-GlcpNAc-(1----3)-beta -D-Galp - (1----4)-D-Glcp (3), alpha-D-NeuAc-(2----6)-beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----3)-beta -D-Galp - (1----4)-D-Glcp (4), and alpha-D-NeuAc-(2----6)-beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----2)-alph a-D- Manp-(1----3)-beta-D-Manp-(1----4)-D-GlcpNAc (5). The numerous daughter ions reflect the sequences, clearly differentiate (1----3) and (1----4) linkages, and discriminate between alpha-NeuAc-(2----3) and alpha-NeuAc-(2----6) linkages.

A convenient method for methylation of glycoprotein glycans in small amounts by using lithium methylsulfinyl carbanion.

Treatment of dimethyl sulfoxide with butyllithium leads to rapid formation of lithium methylsulfinyl carbanion. The reaction products tend to be significantly freer from impurities when lithium methylsulfinyl carbanion is used rather than sodium or potassium methylsulfinyl carbanion. This reagent gives less background in g.l.c. and thus may be used to methylate micro-quantities of glycoprotein glycans (down to 10 micrograms) without the necessity of identifying methyl ethers by mass spectrometry.

Herniaria saponin B. a novel triterpenoid saponin from Herniaria fontanesii.

The aerial parts of Herniaria fontanesii have yielded a new saponin named herniaria saponin B. Its structure was characterized by means of mass spectrometry. NMR techniques, and chemical analysis gave 28-O-[alpha-L-rhamnopyranosyl-(1-->2)-[(alpha-L-rhamnopyranosyl-(1--> 3)]-beta-D-xylopyranosyl (1-->2)-beta-D-fucopyranosyl) ester of 3-O-[beta-D-glucopyranosyl uronic-(1-->4)-alpha-L-rhamnopyranosyl]-2 beta. 3 beta-16 alpha-trihydroxy-olean-12-ene-23, 24-dioic acid.

Non-invasive microwave radiometry thermometry.

Near-field microwave radiometry and radiometric imaging are non-invasive techniques that are able to provide temperature information at a depth of up to several centimetres in subcutaneous tissues. They are based on the measurement of microwave electromagnetic thermal noise. This paper describes the basic principles, measurement methods and limitations of the techniques and the results of clinical studies, and it reviews recent progress.

Bilateral cleft lip and palate associated with increased nuchal translucency and maternal cocaine abuse at 14 weeks of gestation.

A case of bilateral cleft lip and palate associated with increased fetal nuchal translucency detected at 14 weeks of gestation in a cocaine abusing pregnant woman is presented. There were no other associated structural or chromosomal abnormalities. We propose that systematic examination in both the sagittal and parasagittal plane of the fetal profile and recognition of the characteristic ultrasound appearance of a premaxillary protruding echogenic mass should make detection of this type of cleft relatively easy at the moment of the first trimester scan. First trimester diagnosis of cleft lip and palate can facilitate the parental decision-making process on continuing or terminating the pregnancy and should open the perspective of fetal surgery.

[Ultrasound screening and diagnosis of fetal structural abnormalities between 11-14 gestational weeks]. / Ultrazvukov skrining i diagnostika na strukturnite anomalii na ploda mezhdu 11-14 g.s.

AIM OF THE STUDY: To assess the feasibility of ultrasound screening and diagnosis of structural fetal anomalies at the 11-14 week scan. METHODS: An observational prospective follow up study from March 2000 till May 2003 was performed at three referral centers by seven experienced sonographers with high-resolution ultrasound equipment. 1135 singleton pregnancies between 11+0 and 14+6 weeks gestation (w.g.) participated in the study. The first trimester scan included assessment of fetal number, viability and biometry, nuchal translucency [NT] measurement and fetal anatomy survey performed according to standardized published protocols. Increased NT > or = 95th centile and/or diagnosis of structural fetal anomaly was considered as indication for invasive prenatal diagnosis, early fetal echocardiogram and follow-up scans, including a detailed fetal anomaly scan at 18-22 w.g. and a third scan at 28-32 w.g. Pregnancy outcome was ascertained from hospital records, referring physicians or the patients themselves. RESULTS: The overall prevalence of structural fetal anomalies in the present study was 4.6% (53/1135). 22% (12/53) of the structural anomalies were detected between 11-14 w.g. 9 of those had normal karyotype, and 3 were associated with chromosomal anomalies. Furthermore, 10 cases of increased NT, with or without non-immune hydrops fetalis, were associated with congenital heart disease, rare genetic syndromes and adverse pregnancy outcome later in gestation. The ultrasound detection rate of structural fetal anomalies in the present study increased from 22% (12/53), to 69% (37/53) and 79% (42/53) for the first trimester scan, the first and second trimester scans, and the combination of all three scans, respectively. 21% (11/53) of all structural fetal anomalies were missed by prenatal ultrasound. CONCLUSIONS: The first trimester scan is a method of choice for the diagnosis of major structural fetal anomalies. NT measurement is a useful screening test for chromosomal anomalies. In cases with increased NT subsequent development of congenital heart disease, rare genetic syndromes or adverse pregnancy outcome should be ruled out. At present, the second trimester scan constitutes an indispensable tool for the detection of most structural abnormalities. Even in advanced gestation the prenatal diagnosis of certain anomalies is difficult and often unfeasible.

[First trimester ultrasound screening for structural and chromosomal anomalies in multiple pregnancy]. / Ultrazvukov skrining za strukturni i khromozomni anomalii pri mnogoplodna bremennost v purvi trimectur.

AIM OF THE STUDY: To assess the feasibility of first trimester ultrasound screening for structural and chromosomal fetal anomalies in multiple gestations. METHODS: An observational prospective follow up study was carried out in 32 cases of multiple pregnancies. Two scans were scheduled in each case--the first, between 6-9 weeks of gestation (w.g.) and the second, between 11-14 w.g. The aim was assessment of fetal number, viability, chorionicity/amnionicity and fetal biometry. In addition, nuchal translucency [NT] measurement, assessment of risk for chromosomal anomalies and fetal anatomy survey were always performed. Increased NT > or = 95 percentile and/or detection of structural anomaly were considered indications for invasive prenatal diagnosis and fetal karyotyping. Selective fetocide was considered in cases of chromosomal or structural anomalies and in high-order multiple gestations (> or = 3 fetuses). Pregnancy outcome was ascertained by the physical examination of the fetuses, placentas and membranes postpartum, the hospital records, the referring physicians or the parents. RESULTS: From 32 cases of multiple pregnancies included in the study, 28 were twins, and 4--triplets. 68% (19/28) of the twin pregnancies were bichorionic-biamniotic [Bi-Bi], 25% (7/28)--monochorionic-biamniotic [Mo-Bi] and 7% (2/28)--monochorionic-monoamniotic [Mo-Mo]. 4 cases of increased NT in one of the twins (1--associated with trisomy 21) were observed, as well as 2 cases of structural fetal anomalies (1--discordant for exencephaly, and 1--with conjoint twins), 2 cases of feto-fetal transfusion syndrome that developed in the second trimester (1--associated with increased NT between 11-14 w.g.), 1 case of TRAP syndrome [twin-reversed arterial perfusion] and 1 case of cord entanglement in monoamniotic twins. In addition, there were 4 cases of a vanishing twin in the first trimester, and in 2 other cases spontaneous miscarriage of both twins occurred before 24 w.g. In two of the triplet pregnancies selective fetocide was performed, one was successfully delivered at 33 w.g. and in the last case the parents chose to terminate the pregnancy. CONCLUSIONS: First trimester ultrasound is a method of choice for detection of major structural fetal anomalies in multiple gestations. Increased NT between 11-14 w.g. in multiple pregnancies is a useful screening tool for detection of chromosomal fetal anomalies, while in monochorionic twins its presence might predict the development of fetofetal transfusion syndrome. First trimester selective fetocide in high-order multiple gestations or in affected twins is one of the options in pregnancy management.

Gas-liquid chromatography of the heptafluorobutyrate derivatives of the O-methyl-glycosides on capillary columns: a method for the quantitative determination of the monosaccharide composition of glycoproteins and glycolipids.

We have developed a method involving the formation of hepta-fluorobutyrate derivatives of O-methyl-glycosides liberated from glycoproteins and glycolipids following methanolysis. The stable derivatives of the most common monosaccharides of these glycoconjugates (Ara, Rha, Xyl, Fuc, Gal, Man, Glc, GlcNAc, GalNAc, Neu5Ac, KDN) can be separated and quantitatively and reproducibly determined with a high degree of sensitivity level (down to 25 pmol) in the presence of lysine as an internal standard. The GlcNAc residue bound to Asn in N-glycans is quantitatively recovered as two peaks. The latter were easily distinguished from the other GlcNAc residues of N-glycans, thus allowing a considerable improvement of the data on structure of N-glycans obtained from a single carbohydrate analysis. The most common contaminants present in buffers commonly used for the isolation of soluble or membrane-bound glycoproteins (SDS, Triton X-100, DOC, TRIS, glycine, and polyacrylamide or salts, as well as monosaccharide constituents of proteoglycans or degradation products of nucleic acids) do not interfere with these determinations. A carbohydrate analysis of glycoproteins isolated from a SDS/PAGE gel or from PDVF membranes can be performed on microgram amounts without significant interferences. Since fatty acid methyl esters and sphingosine derivatives are separated from the monosaccharide peaks, the complete composition of gangliosides can be achieved in a single step starting from less than 1 microg of the initial compound purified by preparative Silicagel TLC. Using electron impact ionization mass spectrometry, reporter ions for the different classes of O-methyl-glycosides (pentoses, deoxy-hexoses, hexoses, hexosamines, uronic acids, sialic acid, and KDN) allow the identification of these compounds in very complex mixtures. The mass of each compound can be determined in the chemical ionization mode and detection of positive or negative ions. This method presents a considerable improvement compared to those using TMS derivatives. Indeed the heptafluorobutyrate derivatives are stable, and acylation of amino groups is complete. Moreover, there is no interference with contaminants and the separation between fatty acid methyl-esters and O-methyl glycosides is achieved.