The role of PKC in X-ray-induced megakaryocyte apoptosis and thrombocytopenia.

Thrombocytopenia is a critical complication after radiation therapy and exposure. Dysfunction of megakaryocyte development and platelet production are key pathophysiological stages in ionizing radiation (IR)-induced thrombocytopenia. Protein kinase C (PKC) plays an important role in regulating megakaryocyte development and platelet production. However, it remains unclear how PKC regulates IR-induced megakaryocyte apoptosis. In this study, we found that pretreatment of PKC pan-inhibitor Go6983 delayed IR-induced megakaryocyte apoptosis, and inhibited IR-induced mitochondrial membrane potential and ROS production in CMK cells. Moreover, suppressing PKC activation inhibited cleaved caspase3 expression and reduced p38 phosphorylation levels, and IR-induced PKC activation might be regulated by p53. In vivo experiments confirmed that Go6983 promoted platelet count recovery after 21 days of 3 Gy total body irradiation. Furthermore, Go6983 reduced megakaryocyte apoptosis, increased the number of megakaryocyte and polyploid formation in bone marrow, and improved the survival rate of 6 Gy total body irradiation. In conclusion, our results provided a potential therapeutic target for IR-induced thrombocytopenia.

Direct Degradation of Fresh and Dried Macroalgae by Agarivorans albus B2Z047.

Marine macroalgae are increasingly recognized for their significant biological and economic potential. The key to unlocking this potential lies in the efficient degradation of all carbohydrates from the macroalgae biomass. However, a variety of polysaccharides (alginate, cellulose, fucoidan, and laminarin), are difficult to degrade simultaneously in a short time. In this study, the brown alga Saccharina japonica was found to be rapidly and thoroughly degraded by the marine bacterium Agarivorans albus B2Z047. This strain harbors a broad spectrum of carbohydrate-active enzymes capable of degrading various polysaccharides, making it uniquely equipped to efficiently break down both fresh and dried kelp, achieving a hydrolysis rate of up to 52%. A transcriptomic analysis elucidated the presence of pivotal enzyme genes implicated in the degradation pathways of alginate, cellulose, fucoidan, and laminarin. This discovery highlights the bacterium's capability for the efficient and comprehensive conversion of kelp biomass, indicating its significant potential in biotechnological applications for macroalgae resource utilization.

Hydrogen bond network dynamics of heavy water resolved by alcohol hydration under an intense laser.

Despite a great deal of effort spanning for decades, it remains yet puzzling concerning how alcohol molecules functionalize the hydrogen bond (H-bond) networks of water. We employed an isotopic substitution method (using alcohol-heavy water system) to avoid spectral overlap between the alcohol hydroxyl groups and water hydrogen bonds. We showed spectrometrically that under the strong pulse laser, the low mixing ratio (VA < 20%) of alcohol can strengthen the H-bond network structure of D2O through :ÖC2H6↔ D2Ö: compression. But when VA > 20%, H-bond network of D2O will deform via the self-association between alcohol molecules. Our experiments not only reveal the H-bond kinetics of heavy water-alcohol interactions but also provide important reference for understanding the distinctive properties of H-bond in water-organic system.

Probing natural gas components with Raman integrating sphere technology.

Raman spectroscopy is a powerful method of probing natural gas components, but higher sensitivity, greater miniaturization, and lower cost techniques are required. Therefore, we designed a Raman integrating sphere-enhanced spectroscopy technology in a volume of 40 × 40 × 20 cm3 based on the principle of integrating sphere reflection. This technology consists of two parts: the first is an integrating sphere model to collect scattered signals, and the second is a right-angle light-boosting system to increase the optical path of the pump light in the sample. Raman integrating sphere technology has a detection limit of 0.5 ppm in the air with an exposure time of 600 s under room temperature and ambient pressure conditions. Experiments of natural gas detection display that the detection limits of ethane, propane, n-butane, isobutane, n-pentane, and isopentane are 28, 28, 95, 28, 189, and 95 ppm, respectively. In addition, there is a linear relationship between the relative Raman intensity and the concentration of each component in natural gas, which can be used as a probe for detecting unknown natural gas components in gas wells.

Temperature dependence of stimulated Raman scattering from a VYO4 crystal.

The microstructural, electrical, and optical properties of crystals are critical to laser device performance, and the temperature-dependence effect of crystals has gained a great deal of attention in research. The linewidth, stimulated Raman scattering (SRS) shift, and intensity of the characteristic peak at 890 cm-1 of YVO4 crystal have been investigated between 148 and 448 K. As the crystal temperature increases, the bond length increases and the crystal force constant decreases, and the phonon softening process arises in the crystal at high temperature. The temperature effect on Raman shift and full width at half maximum is explained in detail in terms of the phonon anharmonic effect. The temperature dependence of SRS can be well demonstrated by an empirical equation. This work can provide new insights into the further understanding of lattice anharmonicity and contribute to the discovery of new optoelectronic materials.

Cationic complex-enhanced C-H stimulated Raman scattering in naphthalene-benzene solution.

Ring skeleton vibrations of aromatic series are dominant in Raman spectroscopy compared with the C-H stretching vibrations. When a laser-induced plasma (LIP) was generated in a mixed solution of naphthalene and benzene, an anomalous enhancement was observed in stimulated Raman scattering (SRS) of aromatic C-H stretching vibrations of naphthalene (3055 cm-1). However, SRS of C-H stretching vibrations of benzene at 3060 cm-1 disappeared. The LIP produced electrons and cations, and the transient production of ionized material contributed to the enhancement of SRS of C-H vibrations of naphthalene. Density functional theory calculations showed that the C-H Raman activity of the naphthalene molecules in (naphthalene-benzene)+ heterodimer was significantly enhanced compared with neutral naphthalene. In addition, SRS pulse durations were better compressed in pure benzene and naphthalene due to the self-focusing effect.

Enhancement of stimulated Raman scattering of a weak vibration mode in tetrahydrofuran through the energy-transfer resonance of lycopene.

A method of energy-transfer resonance of lycopene used to enhance stimulated Raman scattering (SRS) of a weak vibration C-O mode in tetrahydrofuran (THF) was developed in this study. Only C-H SRS was observed in pure THF at high energies. When lycopene was added, the C-O SRS located at 915 cm-1 of the weak vibration mode in THF was observed. The maximum SRS enhancement of the C-O mode was achieved when the concentration was 3.72 × 10-6 mol/L because of the resonance enhancement of the solute, which transferred the excess vibrational energy to the solvent. Moreover, the pulse width compression phenomenon of the C-H vibration in the presence of C-O SRS was obtained.

Exploring electronic energy level structure and excited electronic states of ß-carotene using DFT.

Carotenoids are a class of natural pigments that play a fundamental role in photosynthesis and optoelectronics. However, the complexity of their energy level structure and electronic states has prevented a clear interpretation of their photophysics and photochemistry. The mediating nonradiative decay of the bright S2 state to the dark S1 state of carotenoids involves a population of bridging intermediate state. Herein, time-dependent DFT was used to study the energy level and electronic excitation process of ß-carotene. A π-π* transition and π electron delocalization of electron excitation could be inferred based on the difference in the electron cloud distribution of the HOMO and LUMO orbitals. Through the electronic transition contribution in the UV-vis spectra and the electron density difference between the ground state and the excited state, the electronic energy level structure and possible dark state were analyzed. On this basis, the electronic excitation process of ß-carotene was theoretically studied by combining electron-hole analysis and transition density matrix (TDM). There was a charge transfer from the ß-ionone ring to the long-chain in the (S0) → (S2), (S0) → (S4) and (S0) → (S5).

Intermolecular energy transfer-enhanced super-broadband stimulated Raman scattering in cyclohexane-benzene mixtures.

Supercontinuum radiation has found numerous applications in diverse fields encompassing spectroscopy, pulse compression, and tunable laser sources. Anomalous enhanced stimulated Raman scattering (SRS) of cyclohexane-benzene mixtures was obtained in this study. SRS of the pure solvent, the multi-order Stokes of the strongest fundamental vibration modes, and energy transfer in intra-molecular modes were observed. SRS of the mixture revealed that the cross-pumping effect was generated between the C-H stretching (v2) mode of cyclohexane and the C=C ring skeleton (v1) mode of benzene, thereby producing the intermolecular secondary stimulated Raman emission and the appearance of two super-broadband radiations at 664.36-673.9 nm and 704.62-729.22 nm. The results suggest that the energy transfer of intermolecular vibrational modes, where the strongest vibrational mode excites other vibrational modes, is a simple approach for generating supercontinuum coherent radiation.

Trace Analysis of Gases and Liquids with Spontaneous Raman Scattering Based on the Integrating Sphere Principle.

Spontaneous Raman scattering is an attractive optical technique for the analysis of gases and liquids; however, their low densities and notoriously weak scattering cross sections demand an enhancement of the spontaneous Raman scattering signal for detection. Here, we have developed a simple but highly effective and fast technique to enhance the signal of spontaneous Raman scattering from gases and liquids. The technique is developed based on the principle of an integrating sphere, which realizes the multiple pass actions of low-energy pump light and the collection of all Raman scattered light for a sample volume of 2 mL. By measuring the ambient air sample with an exposure time of 180 s, we found the experimental detection limit of our spontaneous Raman scattering setup can reach 3 ppm. CH4 (<2 ppm) in air can be also examined by increasing the exposure time to 300 s. The performance of our setup used for the analysis of trace gases is further illustrated by characterizing ethane, propane, butane, and pentane in methane as well as isotopes of carbon dioxide. The results reveal that the detection limit of our setup for liquids can be improved by nearly 4 orders of magnitude compared to that of confocal Raman scattering spectroscopy with the same experimental conditions.

Investigated hydrogen-bond network kinetics of acetone-water solutions by spontaneous and stimulated Raman spectroscopy.

The hydrogen bond (HB) network structure and kinetics of the acetone-water mixed solutions were investigated by the spontaneous Raman and stimulated Raman scattering (SRS) spectra. The HB network of water molecules was enhanced when the volume fraction of acetone ranged from 0 to 0.25. Two new SRS peaks of water at 3272 and 3380 cm-1 were obtained, resulting from the cooperation of the polar carbonyl (C = O)-enhanced HB and the ice-like structure formed around the methyl groups. However, when the volume fraction went beyond 0.25, the spontaneous Raman main peak at 3445 cm-1 showed a significant blue-shift, and the corresponding SRS signal disappeared, indicating that the HB of water was weakened, which originated from the self-association of acetone. In the meantime, the fully tetrahedral HB structure among water molecules was destroyed at the higher volume fraction (≥ 0.8). Hopefully, our study here would advance the study of HB network structures and kinetics in other aqueous solutions.

Efficient frequency conversion and the crossing-pump effect of stimulated Raman scattering in an aqueous sodium sulfate solution.

The cascaded stimulated Raman scattering (SRS) of an aqueous sodium sulfate solution was investigated as well as the generation of the crossing-pump effect. With the introduction of dual sample cells, the first-order Stokes of the O-H stretching vibrational mode was able to act as the pump light to excite the Stokes of the S-O stretching vibrational mode, and a new Raman peak was obtained at 4423 cm-1. The dual sample cell device not only lowered the SRS threshold, but also enhanced the four-wave mixing (FWM) process. Compared to the input laser of 7 ns/pulse, the first-order Stokes of O-H was compressed to a pulse width of 413 ps after passing through the dual sample cells. The SRS of aqueous sodium sulfate solution covered an ultrabroad wavelength ranging from 441 nm to 720 nm (a Raman shift ranging from -3859 cm-1 to 4923 cm-1). The cone-shaped launch ring of the FWM process was also recorded. This work provides a reference for the establishment of laser frequency conversion devices using an aqueous sodium sulfate solution as the Raman medium.

Coherent Raman comb generation in H2O2aqueous solutions by crossing-pump stimulated Raman scattering.

The cascaded stimulated Raman scattering (SRS) of 30% H2O2 aqueous solutions was investigated using a pulsed Nd: YAG laser with a wavelength of 532 nm. The transfer of excess electrons between H2O2 and H2O molecules enhanced the SRS. Together, the decomposition of H2O2 and the intense SRS Stokes led to the generation of the crossing-pump effect of H2O2 aqueous solutions and the appearance of a new peak at 4229 cm-1 that is excited by Stokes as the pump source. Crossing-pump not only reduced the threshold but also generated the broadband-coherent Raman comb, defined as a coherent radiation wavelength ranging from 434 to 831 nm (i.e., a Raman shift ranging from -4225 to 6756 cm-1). The anti-Stokes SRS was attributed to the four-wave mixing (FWM) process.

Generation of dual-supercontinuum coherent radiation in acetone mixed with carbon disulfide by stimulated Raman scattering.

Stimulated Raman scattering (SRS) in a liquid has been a major focus of nonlinear optics. Traditional SRS generates single or cascaded Stokes components arising from spontaneous Raman noise. Herein, we report the formation mechanism of a specific spectrum-continuous spectroscopy technique based on SRS of mixed liquids. SRS of a mixed acetone and carbon disulfide solution is investigated by a pulsed Nd:YAG laser with a wavelength of 532 nm. Two remarkably asymmetric broadened SRS lines are obtained. When the volume ratio is 7:3, the broadened spectral bands are optimized. The supercontinuum spectroscopy phenomenon is explained by hydrogen bond formation, adjacent vibrational modes coupling, and laser-induced plasma generation. This technique has the potential to contribute to the development of a supercontinuum Raman laser.

Use of catalytic wet air oxidation (CWAO) for pretreatment of high-salinity high-organic wastewater.

Catalytic wet air oxidation (CWAO) coupled desalination technology provides a possibility for the effective and economic degradation of high salinity and high organic wastewater. Chloride widely occurs in natural and wastewaters, and its high content jeopardizes the efficacy of Advanced oxidation process (AOPs). Thus, a novel chlorine ion resistant catalyst B-site Ru doped LaFe1-xRuxO3-δ in CWAO treatment of chlorine ion wastewater was examined. Especially, LaFe0.85Ru0.15O3-δ was 45.5% better than that of the 6%RuO2@TiO2 (commercial carrier) on total organic carbon (TOC) removal. Also, doped catalysts LaFe1-xRuxO3-δ showed better activity than supported catalysts RuO2@LaFeO3 and RuO2@TiO2 with the same Ru content. Moreover, LaFe0.85Ru0.15O3-δ has novel chlorine ion resistance no matter the concentration of Cl- and no Ru dissolves after the reaction. X-ray diffraction (XRD) refinement, X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), and X-ray absorption fine structure (XAFS) measurements verified the structure of LaFe0.85Ru0.15O3-δ. Kinetic data and density functional theory (DFT) proved that Fe is the site of acetic acid oxidation and adsorption of chloride ions. The existence of Fe in LaFe0.85Ru0.15O3-δ could adsorb chlorine ion (catalytic activity inhibitor), which can protect the Ru site and other active oxygen species to exert catalytic activity. This work is essential for the development of chloride-resistant catalyst in CWAO.

Estimating the effective pressure from nanosecond laser-induced breakdown in water.

Nanosecond laser-induced breakdown (LIB) in liquids (e.g., water) can produce dynamic high pressure and high temperature. However, since high pressure needs to negate the effect of high temperature to some degree, it is only partially effective. As a result, it is difficult to directly measure the effective pressure due to the transient and complex LIB process. Here, we presented a simple method based on Raman spectroscopy to indirectly determine the effective pressure caused by LIB in liquid pure H2O and low concentration H2O-H2O2 mixtures. By comparing the Raman shifts of the ice-VII mode for pure H2O and H2O-H2O2 mixtures under laser pumping and static high pressure, the LIB effective pressure can be first estimated. The empirical equation was then derived base on the correlation of the LIB effective pressure to ice-VII-point stimulated Raman scattering thresholds for pure and mixture water solutions, which can be used to estimate the LIB effective pressures for other different mixture water solutions with the uncertainty of 0.14-0.25 Gpa. Hopefully, our study here would advance the measurements of effective pressure in the LIB process.

Determination of temperature-dependent Fermi resonance in acetonitrile-water binary solution by two-dimensional correlation Raman spectroscopy.

Acetonitrile (AN), as an organic solvent, has a wide range of applications. The C≡N stretching vibration mode (ν2) and the combination mode (ν3 + ν4) are coupled by Fermi resonance (FR). In this work, the phase transition and the interaction mechanism of the 60% AN-water binary solution (AN-Water) were analyzed by calculating FR parameters and two-dimensional correlation Raman spectroscopy (2DCRS). The change in the ν2 band and the base bands ν3 and ν4 caused energy transfer by anharmonic interaction, which led to a change in FR parameters. With a reduced temperature, the energy transfer was caused by microheterogeneity and the energy transfer effect (293-273 K), the phase separation (263-233 K), and the phase transition of AN (223-173 K). The 2DCRS and Gaussian deconvolution provided more information on FR, which revealed the interaction mechanism of the Fermi doublet. The polarity and binding modes of molecules provided a new perspective for analyzing the transmission of electrons and ions in the electrolyte at different temperatures.

Investigated coherent anti-Stokes Raman scattering in the process of cascaded stimulated Raman scattering in liquid and ice-Ih D2O.

Stimulated Raman scattering (SRS) of liquid and ice-Ih D2O was investigated using a pulsed Nd:YAG laser with a wavelength of 532 nm. The high-order Stokes peaks and corresponding anti-Stokes SRS [Coherent Anti-Stokes Raman Spectroscopy (CARS)] peaks were obtained. Two symmetric and antisymmetric Raman modes of stretching vibrations were observed in liquid D2O, while only a symmetric stretching vibration mode was observed in ice-Ih D2O. Pure Stokes SRS is always collinear with the pump beam along the axial direction. Some ring-like Stokes SRS and CARS shifts, which originate from four-wave mixing processes, can also be observed only in the forward direction along with different angles meeting the phase-matching criteria, respectively. Simultaneously, the temporal behavior of SRS in liquid and ice-Ih D2O was examined, and the temporal waveforms of the pump laser pulse, transmitted pump pulse, and the forward SRS pulse were measured. In both cases, SRS was the dominant contributor to stimulated scattering. However, the efficiency values drastically decreased due to the self-termination behavior of SRS in liquid D2O, which arose from the thermal self-defocusing of both the pump beam and the SRS beam, owing to the Stokes shift-related opto-heating effect. In contrast, for the SRS process in ice-Ih D2O, the thermal self-defocusing influence was negligible, benefitting from a much greater thermal conductivity and a higher conversion efficiency of SRS generation retained under both of the conditions.

Short-pulse broadband stimulated Raman scattering in carbon disulfide via resonance cascading.

Cascaded stimulated Raman scattering (SRS) of carbon disulfide (CS2) was investigated by a pulsed Nd:YAG laser with a wavelength of 532 nm. The fourth-order Stokes and second-order anti-Stokes lines were generated when the pump laser energy was about 1.909 mJ in one sample cell (C1) only. However, the same result was obtained in the second sample cell (C2) with a pump energy of 0.883 mJ. At the same time, the fifth-order Stokes line was produced in C2 when the pump energy increased to 1.208 mJ, and the coherent radiation wavelength ranged from 498 to 644 nm. The result was attributed to the resonance enhancement effect, where the frequency difference between the pump laser and the Stokes light emitted from the working medium (CS2) self-matched with the vibrational energy level of C=S, which resulted in the generation of the cascaded broadband SRS. The anti-Stokes SRS was attributed to four-wave mixing. Simultaneously, the pulse durations of the Stokes and anti-Stokes were compressed to about 380 ps by SRS and laser-induced breakdown. The resonance effect not only reduced the threshold, but it also generated broadband and short-pulse SRS.

Efficient removal of acetic acid by a regenerable resin-based spherical activated carbon.

Carboxylic acids are the main pollutant of industrial wastewater during the advanced oxidation process (AOPs). In this study, a resin-based spherical activated carbon (RSAC, AF5) as an adsorbent was examined and acetic acid was used as a model substrate for adsorption investigation. The pH = 3, temperature = 298 K were fixed by batch technique. The pseudo-second-order kinetic model, the intraparticle and external models are fitted well, and it was found that the adsorption of acetic acid onto AF5 was controlled by liquid film diffusion. A Freundlich model indicated that the adsorption process was heterogeneous multimolecular layer adsorption on the surface. AF5 shows good regenerative ability; the recovery rate of adsorption capacity was ∼88% after five cycles. Chemical oxygen demand (COD) adsorption removal rate could be maintained at 100% for over 35 h in an actual AOPs effluent, and could be eluted for 100% after 8 h by 0.8wt% NaOH. Characterizations, including XRF, XRD, TG/DSC,FTIR, SEM and N2 adsorption, showed that the excellent adsorption performance was mainly due to the microporous structure and large specific surface area (1,512.88 m2/g), the adsorption mechanism mainly included pore filling effect and electrostatic attraction. After five adsorption recycles, AF5's pore characteristic did not change significantly. This study provides a scientific basis for the wastewater standard discharge process of AOPs coupled adsorption.