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Background: Frontal asymmetry plays a major role in depression. However, patients with treatment-resistant depression (TRD) have widespread hypofrontality. We investigated whether patients with TRD have a characteristic frontal activation pattern in functional near-infrared spectroscopy (fNIRS) findings and how the frontal cortex responds to different levels of cognitive tasks. Methods: We enrolled 27 right-handed patients with TRD, 27 patients without TRD and 27 healthy controls. We used multichannel fNIRS to evaluate activation of the bilateral dorsolateral prefrontal cortex (DLPFC), ventrolateral prefrontal cortex (VLPFC) and left motor area in response to 3 tasks: finger tapping, a low cognitive-load motor task; verbal fluency, a moderate cognitive-load task; and a dual task involving simultaneous finger tapping and verbal fluency, a high cognitive-load task. Results: We found significant between-group differences in left DLPFC activation for all 3 tasks. The healthy controls had cortical activation in the left motor area during finger tapping and the bilateral frontal cortex during the dual task. However, patients without TRD had right VLPFC activation during finger tapping and left DLPFC activation during the dual task. Patients with TRD had bilateral DLPFC activation during finger tapping but exhibited increased bilateral VLPFC and left motor area activation during verbal fluency and increased left motor area activation during the dual task. In healthy controls and patients without TRD, we found that the right VLPFC was positively correlated with depression severity. Limitations: Our cohort included only patients with late-onset depression. Conclusion: We found different patterns of abnormal frontal activation between patients with and without TRD. In patients without TRD, the right prefrontal cortex (PFC) was recruited during simple motor tasks. However, in patients with TRD, the bilateral PFC was recruited during simple tasks and motor cortical resources were used compensatorily during PFC-demanding complex cognitive tasks., Introduction Major depressive disorder is the second-leading cause of disability. (1) It has a lifetime prevalence rate of 11.3 %. (2) Among patients with major depressive disorder (MDD), those with [...]

The proper functioning of living systems and physiological phenotypes depends on molecular composition. Yet simultaneous quantitative detection of a wide variety of molecules remains a challenge.sup.1-8. Here we show how broadband optical coherence opens up opportunities for fingerprinting complex molecular ensembles in their natural environment. Vibrationally excited molecules emit a coherent electric field following few-cycle infrared laser excitation.sup.9-12, and this field is specific to the sample's molecular composition. Employing electro-optic sampling.sup.10,12-15, we directly measure this global molecular fingerprint down to field strengths 10.sup.7 times weaker than that of the excitation. This enables transillumination of intact living systems with thicknesses of the order of 0.1 millimetres, permitting broadband infrared spectroscopic probing of human cells and plant leaves. In a proof-of-concept analysis of human blood serum, temporal isolation of the infrared electric-field fingerprint from its excitation along with its sampling with attosecond timing precision results in detection sensitivity of submicrograms per millilitre of blood serum and a detectable dynamic range of molecular concentration exceeding 10.sup.5. This technique promises improved molecular sensitivity and molecular coverage for probing complex, real-world biological and medical settings. A vibrational spectroscopy technique that measures the electric field emitted from organic molecules following infrared illumination allows their molecular fingerprints to be separated from the excitation background, even in complex biological samples., Author(s): Ioachim Pupeza [sup.1] [sup.2] , Marinus Huber [sup.1] [sup.2] , Michael Trubetskov [sup.2] , Wolfgang Schweinberger [sup.1] [sup.3] , Syed A. Hussain [sup.1] [sup.2] , Christina Hofer [sup.1] [sup.2] [...]

ABSTRACT. Fourier transform infrared spectroscopy (FTIR) was used to investigate the interactions between [C.sub.60] and [C.sub.70] molecules (nanoparticles in solutions) and dimethylacetamide, dimethylformamide, and acetamide using toluene as a solvent. [...]

Fourier transform infrared (FTIR) spectroscopy was used to investigate the interactions or complex formation between [C.sub.60] and [C.sub.70] molecules (nanoparticles in solutions) and phenylbutazone using toluene as a solvent. The carbonyl infrared absorptions of the phenylbutazone showed significant shifts to lower wavenumbers (lower energy) resulting from the phenylbutazone interaction with the [C.sub.60] or [C.sub.70] molecules (~1731 [cm.sup.-1] to ~1715 [cm.sup.-1]). Keywords: Infrared spectroscopy, nanoparticles, [C.sub.60] and [C.sub.70] molecules, fullerenes, fullerene/nanoparticle interactions, phenylbutazone, bute, INTRODUTION Infrared spectroscopy is an effective tool to study the interactions between molecular particles in solutions (Holleman et al. 1999; Nanocomposix 2012; Aksenova et al. 2013). In recent studies, shifts [...]

Background. Pyridoxine-dependent epilepsy (PDE-ALDH7A1) is an inborn error of lysine catabolism that presents with refractory epilepsy in newborns. Biallelic ALDH7A1 variants lead to deficiency of a-aminoadipic semialdehyde dehydrogenase/antiquitin, resulting in accumulation of piperideine-6-carboxylate (P6C), and secondary deficiency of the important cofactor pyridoxal-5-phosphate (PLP, active vitamin B6) through its complexation with P6C. Vitamin B6 supplementation resolves epilepsy in patients, but intellectual disability may still develop. Early diagnosis and treatment, preferably based on newborn screening, could optimize long-term clinical outcome. However, no suitable PDE-ALDH7A1 newborn screening biomarkers are currently available. Methods. We combined the innovative analytical methods untargeted metabolomics and infrared ion spectroscopy to discover and identify biomarkers in plasma that would allow for PDE-ALDH7A1 diagnosis in newborn screening. Results. We identified 2S,6S-/2S,6R-oxopropylpiperidine-2-carboxylic acid (2- OPP) as a PDE-ALDH7A1 biomarker, and confirmed 6-oxopiperidine-2-carboxylic acid (6-oxoPIP) as a biomarker. The suitability of 2-OPP as a potential PDE-ALDH7A1 newborn screening biomarker in dried bloodspots was shown. Additionally, we found that 2-OPP accumulates in brain tissue of patients and Aldh7a1-knockout mice, and induced epilepsy-like behavior in a zebrafish model system. Conclusion. This study has opened the way to newborn screening for PDE-ALDH7A1. We speculate that 2-OPP may contribute to ongoing neurotoxicity, also in treated PDE-ALDH7A1 patients. As 2-OPP formation appears to increase upon ketosis, we emphasize the importance of avoiding catabolism in PDE-ALDH7A1 patients. Funding. Society for Inborn Errors of Metabolism for Netherlands and Belgium (ESN), United for Metabolic Diseases (UMD), Stofwisselkracht, Radboud University, Canadian Institutes of Health Research, Dutch Research Council (NWO), and the European Research Council (ERC)., Introduction Pyridoxine-dependent epilepsy due to biallelic ALDH7A1 variants (OMIM 266100, PDE-ALDH7A1) is an inborn error of metabolism (IEM) that presents with refractory seizures in early infancy. These seizures are typically [...]

BACKGROUND/OBJECTIVES: The [sup.13]C mixed triglyceride (MTG) breath test has been proposed for the non-invasive assessment of fat digestion and absorption. To evaluate whether reference values for the adequacy of fat absorption, set in the non-dispersive infrared spectrometry (NDIRS) system software proposed for healthy children and adults using the [sup.13]C MTG breath test, are also applicable to infants of < 5 months of age. SUBJECTS/METHODS: [sup.13]C MTG breath testing with the NDIRS technique was performed in 54 healthy infants < 5 months of age (38 breast-fed, 16 formula-fed) and six infants diagnosed with cystic fibrosis (CF) using two NDIRS devices, IRIS and FANci2. RESULTS: The IRIS results were slightly higher compared with those assessed by the FANci2 device. The minimum cutoff value for pancreatic sufficiency (PS) is set as a cumulative percentage dose of [sup.13]C recovered (cPDR) after 5 h of 13.0%. Pancreatic function status of six CF infants, three with PS and three with pancreatic insufficiency (PI), according to the 72 h-faecal fat balance test could be correctly determined with the [sup.13]C MTG breath test using two NDIRS techniques. However, if these reference values had been used to determine pancreatic function status in healthy infants, 26 out of 54 infants would have been misclassified as pancreatic insufficient. CONCLUSIONS: Although the [sup.13]C MTG breath test with the MS technique has the potential to be a suitable assessment of fat absorption in infants, the technique of NDIRS appears too insensitive in an infant population group. European Journal of Clinical Nutrition (2016) 70, 959-962; doi:10.1038/ejcn.2015.228; published online 13 January 2016, INTRODUCTION Stable isotope breath tests are designed to offer a safe, simple, repeatable and non-invasive way for the clinical investigation of fat malabsorption due to impaired digestion or mucosal absorption. [...]

Combining cavity-enhanced direct frequency comb spectroscopy with buffer gas cooling enables rapid collection of well-resolved infrared spectra for molecules such as nitromethane, naphthalene and adamantane, confirming the value of the combined approach for studying much larger and more complex molecules than have been probed so far. Infrared spectra of complex molecules High-resolution infrared spectroscopy is well suited to the study of the structure and dynamics of small molecules, but becomes impractical for larger and more complex systems. Jun Ye and colleagues have used a combination of cavity-enhanced direct frequency comb spectroscopy (CE-DFCS) and buffer gas cooling to produce well-resolved infrared spectra for significantly larger and more complex molecules than have been probed so far using conventional methods. Using CE-DFCS, spectra were obtained for nitromethane, naphthalene and adamantane. For more than half a century, high-resolution infrared spectroscopy has played a crucial role in probing molecular structure and dynamics. Such studies have so far been largely restricted to relatively small and simple systems, because at room temperature even molecules of modest size already occupy many millions of rotational/vibrational states, yielding highly congested spectra that are difficult to assign. Targeting more complex molecules requires methods that can record broadband infrared spectra (that is, spanning multiple vibrational bands) with both high resolution and high sensitivity. However, infrared spectroscopic techniques have hitherto been limited either by narrow bandwidth and long acquisition time.sup.1, or by low sensitivity and resolution.sup.2. Cavity-enhanced direct frequency comb spectroscopy (CE-DFCS) combines the inherent broad bandwidth and high resolution of an optical frequency comb with the high detection sensitivity provided by a high-finesse enhancement cavity.sup.3,4, but it still suffers from spectral congestion.sup.5. Here we show that this problem can be overcome by using buffer gas cooling.sup.6 to produce continuous, cold samples of molecules that are then subjected to CE-DFCS. This integration allows us to acquire a rotationally resolved direct absorption spectrum in the C-H stretching region of nitromethane, a model system that challenges our understanding of large-amplitude vibrational motion.sup.7,8,9. We have also used this technique on several large organic molecules that are of fundamental spectroscopic and astrochemical relevance, including naphthalene.sup.10, adamantane.sup.11 and hexamethylenetetramine.sup.12. These findings establish the value of our approach for studying much larger and more complex molecules than have been probed so far, enabling complex molecules and their kinetics to be studied with orders-of-magnitude improvements in efficiency, spectral resolution and specificity., Author(s): Ben Spaun [sup.1] , P. Bryan Changala [sup.1] , David Patterson [sup.2] , Bryce J. Bjork [sup.1] , Oliver H. Heckl [sup.1] , John M. Doyle [sup.2] , Jun [...]

ABSTRACT. Fourier transform infrared spectroscopy was used to investigate the interactions between [C.sub.60] and [C.sub.70] nanoparticles and the amide functionality in formamide. Infrared spectra were collected for neat formamide, formamide [...]

Fourier transform infrared spectroscopy (FTIR) is a precise, non-destructive, and highly sensitive means of measuring volatile species in melt inclusions. Existing methods of applying FTIR to quartz-hosted melt inclusions, however, require challenging physical manipulation of the host quartz crystals, which can present a significant limitation. Here, we describe a technique for measuring the H.sub.2O and CO.sub.2 concentrations of melt inclusions fully enclosed in quartz crystals using transmission FTIR, where melt inclusion thickness is calculated using the host quartz silicate overtones. The greater thickness of quartz crystals permitted by this technique allows an additional assessment of volatile equilibrium by measuring structural OH.sup.- within the quartz host itself. To demonstrate the advantages of this technique, we applied it to quartz crystals from the Mesa Falls Tuff, Yellowstone. The majority of melt inclusions consist of transparent or brown glassy melt inclusions and record concentrations of 2.9-3.3 wt% H.sub.2O and 181-561 ppm CO.sub.2, with precision similar to that obtained by standard double-exposed FTIR. Based on volatile saturation models, such concentrations reflect a largely un-degassed magma body equilibrated at pre-eruptive pressures of 100-150 MPa. These H.sub.2O concentrations and equilibrium conditions are supported by independent assessments using mineral-mineral and mineral-melt thermohygrometry and thermodynamic modelling using rhyolite-MELTS. The preservation of pre-eruptive volatile concentrations is further corroborated by measurements of OH.sup.- in the quartz hosts. A clear decrease in hydroxyl concentrations from core to rim matches closely the zoning in Al, which, combined with the position of quartz infrared bands, most likely reflects variations in Al-moderated OH.sup.- solubility rather than diffusive loss. The outermost 200 [micro]m rims, however, show a sharper decline in OH.sup.- and corresponding increase in Li.sup.+ which is interpreted to record minor diffusive H.sup.+ loss and incorporation of Li.sup.+ to maintain charge balance. Our FTIR-based technique is simple, effective, and widely applicable to other quartz-bearing magmatic systems, opening up new possibilities to trace pre- syn- and post-eruptive volatile behaviour., Author(s): Peter Tollan [sup.1] , Ben Ellis [sup.2] , Juliana Troch [sup.2] , Julia Neukampf [sup.2] Author Affiliations: (Aff1) 0000 0001 0726 5157, grid.5734.5, Institut für Geologie, Universität Bern, , [...]

Spectrometry in the visible and IR regions is used to study complex formation in aqueous solutions of rhodanides of bivalent cations Cd, Hg, Ni, Mn, Fe, Zn, and Co. It is found that Cd(II), Hg(II), Ni(II), and Fe(II) coordinate NCS- by the thiocyanate type; Zn(II), by the isothiocyanate type; and Co(II) and Mn(II) change their coordination mode depending on the concentration of KNCS in the solution. The effect of the structure of metal rhodanide complexes on the selectivity of Zn[(NCS).sup.2-.sub.4] - and Co[(NCS).sup.2- .sub.4] -selective electrodes (SE) is revealed. It is shown that hydrophobic ions of Zn[(NCS).sup.2-.sub.4], and ions (2.0 M)-C0[(NCS).sup.2-.sub.4], at high concentrations of KNCS (2.0 M) exhibit the strongest affinity to the membrane phase of electrodes. This ensures the selective potentiometric determination of zinc and cobalt on their simultaneous presence. Keywords: rhodanide complexes, ion-selective electrodes, selectivity coefficient, IR spectrometry DOI: 10.1134/S1061934815020148, It was shown previously [1] that the mode of coordination of NCS- ions is to a high extent determined by the nature of anion-exchange extraction of metal rhodanide complexes by [...]

Pyrazinylketene (9) and 4-pyrimidinylketene (11), identified by their IR absorption at 2128 and 2130 [cm.sup.-1], respectively, are formed in C[H.sub.3]CN as transient intermediates by photolysis of the corresponding diazoketones. The corresponding ylides 10 and 12 are formed concurrently as longer-lived intermediates identified by their distinctive IR and UV absorption. Reactions of 2-pyridylketene and of 9 and 11 with diethylamine form initial amide enol intermediates leading to dihydroheteroarene intermediates and then to amides, whereas amide enols are not observed in reactions with n-butylamine. Reactions with water give observable dihydroheteroarenes. 2,5-Bis(ketenyl)pyrazine (33) is formed by photolysis of 2,5-bis(diazoacetyl)pyrazine (32) together with the corresponding bis(ylide) 35. The latter is calculated to have two geometrically isomeric structures (bond-stretch isomers) with similar energies, one with a central six-membered aromatic ring and another with a 10-pi electron aromatic system. Key words: ketenes, cycloadditions, ylides, amination, hydration, kinetics, pyrimidines, pyrazines. Le pyrazinylcetene (9) et le 4-pyrimidinylcetene (11), identifies respectivement par leur pic d'absorption IR a 2 128 et a 2 130 [cm.sup.-1], se forment dans l'acetonitrile, comme intermediates de transition, par photolyse des diazocetones correspondantes. Les ylures correspondants 10 et 12, qui se forment simultanement comme intermediates plus durables, ont ete identifies par leurs pics d'absorption IR et UV distinctifs. Les reactions entre le 2-pyridylcetene, les composes 9 et 11 et la diethylamine forment initialement des enols d'amides intermediates, qui se transforment ensuite en dihydroheteroarenes intermediates, et enfin, en amides, tandis que l'on n'observe pas la formation d'enols d'amides dans les reactions avec la n-butylamine. Dans les reactions avec l'eau, on peut observer la formation de dihydroheteroarenes. La 2,5-bis(cetenyl)pyrazine (33) est formee par photolyse de la 2,5-bis(diazoacetyl)pyrazine (32), en meme temps que le bis(ylure) 35 correspondant. On obtient par calcul que ce dernier peut exister sous deux formes isomeriques geometriques (isomeres d'elongation) d'energies semblables, l'une etant formee d'un cycle aromatique central a six atomes et l'autre, d'un systeme aromatique a dix electrons pi. [Traduit par la Redaction] Mots-cles : cetenes, cycloadditions, ylures, amination, hydratation, cinetique, pyrimidines, pyrazines., Introduction Heteroarylketenes (1) are prominent members of the ketene family, (2,3) and we have been engaged in efforts to prepare and observe further examples of these species and to delineate [...]