Simultaneous time and frequency detection in femtosecond coherent Raman spectroscopy. I. Theory and model calculations

For coherent Raman spectroscopies, common femtosecond pulses often lie in an intermediate regime: their bandwidth is too wide for measurements in the frequency domain, but their temporal width is too broad for homodyne measurements in the time domain. A recent paper [S. Nath et al., Phys. Rev. Lett. 97, 267401 (2006)] showed that complete Raman spectra can be recovered from intermediate length pulses by using simultaneous time and frequency detection (TFD). Heterodyne detection and a phase-stable local oscillator at the anti-Stokes frequency are not needed with TFD. This paper examines the theory of TFD Raman in more detail; a companion paper tests the results on experimental data. Model calculations illustrate how information on the Raman spectrum is transferred from the frequency domain to the time domain as the pulse width shortens. When data are collected in both dimensions, the Raman spectrum is completely determined to high resolution, regardless of the probe pulse width. The loss of resolution in many femtosecond coherent Raman experiments is due to the restriction to one-dimensional data collection, rather than due to a fundamental restriction based on the pulse width.     

Numerical calculation of the combinatorial entropy of partially ordered ice

Using a one-parameter case as an example, we demonstrate that multicanonical simulations allow for accurate estimates of the residual combinatorial entropy of partially ordered ice. For the considered case, corrections to an (approximate) analytical formula are found to be small, never exceeding 0.5%. The method allows one as well to calculate combinatorial entropies for other systems.     

Measurements on the coercive force of ticonal down to liquid helium temperatures

Summary Measurements have been made on the coercive forceH _c as a function of temperature of two samples of ticonal and one sample of steel. TheH _c versusT curves for the ticonals show the same minimum without saturation down to liquid helium temperatures. The curve for the steel sample, however, shows an increase below liquid nitrogen temperatures and also a saturation in the liquid helium range.     

Glycogen storage disease type II: birth prevalence agrees with predicted genotype frequency

OBJECTIVES: To compare the overall birth prevalence of diagnosed glycogen storage disease type II (GSD II) with the predicted frequency based on mutation screening, in order to determine whether GSD II is an underdiagnosed condition, and to analyze which medical disciplines recognize GSD II. METHODS: Retrospective data on all enzymatic diagnoses of GSD II were collected from diagnostic labs throughout the Netherlands, covering the period from January 1, 1972 to December 31, 1996. Age-specific diagnostic incidence rates were calculated for the entire study period. By adding together the diagnostic incidences for all age groups, we calculated the birth prevalence of diagnosed GSD II and compared these figures with the predicted frequency based on mutation screening in a random sample from the general population. The medical specialization of the referring clinicians was also recorded. RESULTS: GSD II was diagnosed in 154 individuals, including 11 prenatal diagnoses. The birth prevalences of the various phenotypes were 1/101,000 (infantile form), 1/720,000 (juvenile form) and 1/53,000 (adult form). The birth prevalence of the adult and infantile phenotype together was 1/35,000. Eighty-two percent of the patients were diagnosed in university hospitals. Of the patients with infantile GSD II, 71% were diagnosed by a pediatrician, whereas most patients with adult GSD II were diagnosed by a neurologist (80%). CONCLUSIONS: There is no evidence for the underdiagnosis of GSD II in the Netherlands, as the calculated birth prevalences of the disease are consistent with previous predictions based on mutation screening in a random sample of newborns. The worldwide birth prevalence of the disease may well be higher than 1 in 100,000. GSD II is mainly diagnosed in university hospitals.     

Countercurrent extraction separation of some platinum group metals: part III

The bromo complexes of platinum(IV), palladium(II), rhodium(III), and iridium(IV) were prepared and studies were made on their distribution between hydrobromic acid solutions and various common solvents. The solvents employed were n-tributyl phosphate (TBP), methyl isobutyl ketone, amyl acetate, and various TBP-benzene mixtures. Distribution coefficients as a function of HBr concentration are given for each metal for each solvent system. A careful study of the measured distribution coefficients clearly showed that a number of binary and ternary mixtures of the metals can be resolved with a Craig countercurrent distribution apparatus. Rh-Pt and Rh-Pd mixtures in 4.38M HBr solutions were quantitatively separated on a Io-stage Craig apparatus using a 90% TBP-10% benzene solvent. Rh-Ir mixtures in 4.38 M HBr were resolved by 3 consecutive batch extractions with 90% TBP-10% benzene. Mixtures of Pd, Rh, and Ir in 4.38 M HBr were resolved in 90 stages using methyl isobutyl ketone as the solvent. Pd, Rh and Ir were recovered in 97.0, 87.6 and 94.5% yields, respectively. Mixtures of Pd, Rh and Pt in 4.38 M HBr were resolved in 90 stages using amyl acetate and methyl isobutyl ketone as solvents. Pd, Rh and Pt were recovered in 90.0, 96.0 and 94.0% yields, respectively. Two computer programs for the IBM 1620 Computer are given ; these facilitate the comparison of theoretical and actual solute distributions.     

An approach to the understanding of radiation chemistry in the condensed phase

This paper describes a purely electronic mechanism by which ≈ 20 eV excitations in condensed phases relax to lower energy states. The mechanism utilizes an “energy fission” process whereby an ionic or excitonic state splits into two lower energy states, at least one being localized. The mechanism explains not only the known rapidity of such processes but also suggests an explanation for the proportionation of the chemistry between ionic and electronically excited states.     

Investigation of reactions in solids by DTA

Journal of Thermal Analysis and Calorimetry - Reactions in mixtures of solid alkali metal sulphates with barium chloride were investigated by DTA. The decisive role of an intermediate liquid was...     

Non-electrophoretic differential detergent fractionation proteomics using frozen whole organs

Non-electrophoretic methods based on two-dimensional liquid chromatography followed directly by tandem mass spectrometry (2D-LC/MS(2)) have become the preferred method for high-throughput expression proteomics and are widely applied to fresh tissues. Pre-fractionation techniques are also used in combination with 2D-LC/MS(2) to both increase the proteome size and to assign cellular locations. Data from such experiments have become central to systems biology analyses. Here we apply a differential detergent (pre)fractionation (DDF) followed by 2D-LC/MS(2) to frozen archival tissues. Our results show that by using frozen archival tissues, we do not lose proteome coverage or the ability to assign proteins to cellular compartments. In addition, we were able to assign 'biological process' Gene Ontology (GO) annotations, which will facilitate systems biological modeling of our proteomics data.     

Viability study of HL60 cells in contact with commonly used microchip materials

This paper presents a study in which different commonly used microchip materials (silicon oxide, borosilicate glass, and PDMS) were analyzed for their effect on human promyelocytic leukemic (HL60) cells. Copper-coated silicon was analyzed for its toxicity and therefore served as a positive control. With quantitative PCR, the expression of the proliferation marker Cyclin D1 and the apoptosis marker tissue transglutaminase were measured. Flow cytometry was used to analyze the distribution through the different phases of the cell cycle (propidium iodide, PI) and the apoptotic cascade (Annexin V in combination with PI). All microchip materials, with the exception of Cu, appeared to be suitable for HL60 cells, showing a ratio apoptosis/proliferation (R(ap)) comparable to materials used in conventional cell culture (polystyrene). These results were confirmed with cell cycle analysis and apoptosis studies. Precoating the microchip material surfaces with serum favor the proliferation, as demonstrated by a lower R(ap) as compared to uncoated surfaces. The Cu-coated surface appeared to be toxic for HL60 cells, showing over 90% decreased viability within 24 h. From these results, it can be concluded that the chosen protocol is suitable for selection of the cell culture material, and that the most commonly used microchip materials are compatible with HL60 culturing.