Mid-infrared single-photon upconversion spectroscopy enabled by nonlocal wavelength-to-time mapping.

Ultrasensitive spectroscopy is an essential component in mid-infrared (MIR) technology. However, the drawbacks of MIR detectors pose challenges to robust MIR spectroscopy at the single-photon level. We propose an MIR single-photon frequency upconversion spectroscopy nonlocally mapping the MIR information to the time domain. Broadband MIR photons from spontaneous parametric downconversion are frequency-upconverted to the near-infrared band with quantum correlation preservation. Via the group delay of fiber, the MIR spectral information within a 1.18-micrometer bandwidth of 2.76 to 3.94 micrometers is then successfully projected to arrival times of correlated photon pairs. Under the conditions of 6.4 × 106 photons per second illumination, the transmission spectra of polymers with single-photon sensitivity are demonstrated using single-pixel detectors. The developed approach circumvents scanning and frequency selection instability, which stands out for its inherent compatibility for evolving environments and scalability for various wavelengths. Because of its high sensitivity and robustness, characterization of biochemical samples and weak measurement of quantum systems are possible to foresee.

Wide-field mid-infrared hyperspectral imaging beyond video rate.

Mid-infrared hyperspectral imaging has become an indispensable tool to spatially resolve chemical information in a wide variety of samples. However, acquiring three-dimensional data cubes is typically time-consuming due to the limited speed of raster scanning or wavelength tuning, which impedes real-time visualization with high spatial definition across broad spectral bands. Here, we devise and implement a high-speed, wide-field mid-infrared hyperspectral imaging system relying on broadband parametric upconversion of high-brightness supercontinuum illumination at the Fourier plane. The upconverted replica is spectrally decomposed by a rapid acousto-optic tunable filter, which records high-definition monochromatic images at a frame rate of 10 kHz based on a megapixel silicon camera. Consequently, the hyperspectral imager allows us to acquire 100 spectral bands over 2600-4085 cm-1 in 10 ms, corresponding to a refreshing rate of 100 Hz. Moreover, the angular dependence of phase matching in the image upconversion is leveraged to realize snapshot operation with spatial multiplexing for multiple spectral channels, which may further boost the spectral imaging rate. The high acquisition rate, wide-field operation, and broadband spectral coverage could open new possibilities for high-throughput characterization of transient processes in material and life sciences.

Approaching Effective Differential Centrifugal Fractionation by Combining Image Analysis with Analytical Ultracentrifugation.

Centrifugation is one of the most commonly used methods for separation in biology and chemistry. However, effective fractionation is not always easy to obtain, as preparative centrifuge experiments are mostly conducted in an empirical way, even when it is guided by the quantitative results from analytical ultracentrifuge (AUC). Very few works have been performed to enhance the fractionation resolution of the differential centrifugation method in a swing-out rotor. This is primarily due to the absence of a characterization tool for sedimentation in the preparative centrifuge. In this study, we utilized image analysis to map the particle concentration distribution throughout the preparative centrifuge tube, revealing an unexpected and abnormal sedimentation process. By characterizing the sedimentation coefficient distributions of the fractionated product via AUC, we demonstrated that the overall sedimentation efficiency in a swing-out preparative centrifuge was significantly reduced. Furthermore, effective fractionation was confined to the intermediate phase of the entire sedimentation process. We propose that the mechanism here is a combination of the inverse Boycott effect and droplet sedimentation. The actual sedimentation process within a preparative centrifuge can be described by modifying the Lamm equation phenomenologically, which simply results in an effective sedimentation coefficient. Our work builds a foundation for determining the optimal preparative centrifugation conditions for various systems.

Polysaccharides from Dendrobium officinale improve obesity-induced insulin resistance through the gut microbiota and the SOCS3-mediated insulin receptor substrate-1 signaling pathway.

BACKGROUND: Obesity induces insulin resistance and chronic inflammation, impacting human health. The relationship between obesity, gut microbiota, and regulatory mechanisms has been studied extensively. Dendrobium officinale polysaccharide (DOP), a traditional Chinese herbal medicine, potentially reduces insulin resistance. However, the mechanism through which DOP affects gut microbiota and alleviates obesity-induced insulin resistance in rats requires further investigation. RESULTS: The current study aimed to assess the impact of DOP on gut microbiota and insulin resistance in rats on a high-fat diet. The results revealed that DOP effectively reduced blood lipids, glucose disorders, oxidative stress, and inflammatory infiltration in the liver of obese Sprague Dawley rats. This was achieved by downregulating SOCS3 expression and upregulating insulin receptor substrate-1 (IRS-1) by regulating the JAK/STAT/SOCS3 signaling pathway. Notably, DOP intervention enhanced the abundance of beneficial gut microbiota and reduced harmful microbiota. Correlation analysis demonstrated significant associations among intestinal microbiota, SOCS3-mediated IRS-1 expression, and inflammatory factors. CONCLUSION: Dendrobium officinale polysaccharide regulated the gut microbiota, enhanced IRS-1 expression, and mitigated liver injury and insulin resistance due to a high-fat diet. These findings depict the potential anti-insulin resistance properties of DOP and offer further evidence for addressing obesity and its complications. © 2023 Society of Chemical Industry.

Ensaio de dissolução de cápsulas de fluconazol: problemas encontrados na determinação por espectrofotometria na região do UV / Fluconazole capsule dissolution test: problems encountered in UV spectrophotometry determination

Entre as classes terapêuticas analisadas no Programa Nacional de Verificação da Qualidade de Medicamentos (PROVEME), o antifúngico fluconazol constava na apresentação de cápsulas de diferentes procedências. Na realização dos ensaios de dissolução conforme as técnicas dos fabricantes, constatou-se que os valores obtidos por espectrofotometria-UV foram superiores aos obtidos nos ensaios de teor e uniformidade de conteúdo, cuja determinação foi por CLAE-UV. Considerando este fato, foi objetivo deste trabalho realizar o ensaio de dissolução destas amostras pelos respectivos métodos dos fabricantes e o quantitativo do ensaio por espectrofotometria no UV e por CLAE-UV, a fim de avaliar as possíveis interferências dos excipientes nestas determinações. Os valores obtidos por espectrofotometria foram superiores aos obtidos por CLAE, confirmando a interferência dos excipientes. Concluiu-se que a metodologia a ser empregada na análise de fármacos deve ser criteriosamente selecionada, a fim de evitar resultados não condizentes com a real formulação do produto.

Among the therapeutic classes analyzed in the Programa Nacional de Verificação da Qualidade de Medicamentos (PROVEME) consisted the antifungal fluconazole in the dosage form of capsules from different origins. In dissolution tests, according to manufacturers techniques, it was found that the values obtained by UV-spectrophotometry were higher than those obtained from tests of content and content uniformity, whose determination was by HPLC-UV. Considering this fact, the objective of this study was to perform the dissolution test of these samples by the respective manufacturers methods and the quantitative assay by UV-spectrophotometry and HPLC-UV, to evaluate possible interferences of excipients in these determinations. The values obtained by spectrophotometry were higher than those obtained by HPLC, confirming the excipients interference. It was concluded that the methodology to be employed in drug analysis should be carefully selected in order to avoid results not commensurate with the real product formulation.

Detección viral en infecciones respiratorias agudas del lactante / Viral detection in acute respiratory infections in infants

Los virus respiratorios se detectan en un alto porcentaje en la patología respiratoria aguda que afecta al lactante. No nos debe llamar la atención que un alto porcentaje de virus detectados aparecieron en los cuadros de Neumonitis. Es llamativo el alto porcentaje de positividad viral encontrado en las Bronconeumonias. Por último, el aumento de la detección viral observada en los últimos años se debe fundamentalmente a la introducción de nuevas técnicas, específicamente, la detección de antígenos virales por inmunofluorescencia directa y aislamiento viral a partir del aspirado nasofaríngeo y también, a la adecuada toma, envío y procesamiento de las muestras

Interferon humano: propiedades y mecanismos de accion. / Human interferon properties and mechanisms of action

Se describen las principales caracteristicas estructurales de los interferons humanos, su induccion, transcripcion y traduccion. Se analiza la actividad antiviral,asi como las vias metabolicas inducidas por interferon. Finalmente, se comenta la relacion entre interferon y sistema inmune

Sarampion. / Measles

Se revisaron las fichas de 229 casos de sarampion hospitalizados en el San Juan de Dios durante la epidemia que se produjo en Chile 1978-79, se efectuo un estudio clinico y de laboratorio y se comparo los resultados con dados de la literatura medica chilena y exTranjera. Cabe destacar los siguintes resultados: 1. Mayor amplitud de edades comprometidas actualmente por el sapampion; 2. Un alto porcentaje de ninos enfermos con antecedentes de haber recebido la vacunacion especifica y, 3. Variacion en el espectro de las complicaciones, aunque las del aparato respiratorio siguen siendo las mas frecuentes e importantes