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Interaction between CO2 and NbO2+: Infrared photodissociation spectroscopic and theoretical study
摘要： The mass-selected infrared photodissociation (IRPD) spectroscopy combined with quantum chemical calculations was utilized to study the interactions between niobium dioxide cation and carbon dioxide molecules. Experimental and calculated results indicate that the CO2 molecules are weakly bound to the NbO2+ cation in an end-on configuration via a charge-quadrupole electrostatic interaction. For n ≥ 6, CO2 molecules in the second shell no longer have contribution to CO2 activation. The similarity of experimental spectra for n ≥ 7 also indicates that ion cores of NbO2+(CO2)n cluster have not changed. Compared with the congeneric YO+ complexes (Phys. Chem. Chem. Phys., 2018, 20, 19314–19320), NbO2+ is found to be thermodynamically and kinetically more difficult to react with CO2.
关键词： Niobium dioxide cation,Infrared photodissociation spectroscopy,Structure,Quantum chemical calculation,Carbon dioxide
更新于2025-09-23 15:19:57
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Simple Universal Strategy for Quantification of Carboxyl Groups on Carbon Nanomaterials: Carbon Dioxide Vapor Generation Coupled to Microplasma for Optical Emission Spectrometric Detection
摘要： The physicochemical properties and applications of carbon nanomaterials are remarkably dependent on the amount of carboxyl group on their surfaces. Unfortunately, it is challenging to determine the carboxyl group on carbon nanomaterials at an ultralow density not only due to the low sensitivities of conventional techniques, but also because there are no matrix-matched certi?ed reference materials available. In this work, a novel strategy comprising coupling carbon dioxide vapor generation to a microplasma optical emission spectrometer was developed for the sensitive and accurate quanti?cation of surface carboxyl groups on carbon nanomaterials. The carboxyl group on multiwall carbon nanotubes (MWCNTs), graphene (G), or its oxide (GO) was converted to carboxylic acid using concentrated hydrochloric acid prior to quanti?cation. The generated carboxylic acid was puri?ed and then reacted with sodium bicarbonate to generate CO2, which was swept into a miniaturized point discharge optical emission spectrometer (μPD-OES) for the detection of carbon atomic emission lines. Potassium hydrogen phthalate (KHP) served as a calibration standard for quanti?cation of the carboxyl group on G/GO/MWCNTs, thus, overcoming the lack of CRMs. Owing to the high sensitivity of μPD-OES for the detection of CO2, a limit of detection of 0.1 μmol g?1 (1 nmol) was obtained for the carboxyl group based on a sample mass of 10 mg G/GO/MWCNTs, superior to that obtained using conventional methods. Moreover, the proposed method not only retains several unique advantages of good accuracy and elimination of the use of complicated, expensive, and high power-consumption instruments, but was also applicable to the quanti?cation of the carboxyl group on other nanomaterials such as carboxylated magnetic microspheres.
关键词： carbon dioxide vapor generation,microplasma optical emission spectrometer,carbon nanomaterials,quantification,carboxyl groups
更新于2025-09-23 15:19:57
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Experimental observation of the vibration-rotation radiation curves of <sup>12</sup> C <sup>16</sup> O <sub/>2</sub> and <sup>13</sup> C <sup>16</sup> O <sub/>2</sub> absorption constants ranging from 4860 to 4880 sm <sup>a??1</sup> by the tunable diode laser absorption spectroscopy method
摘要： We report the experimental observation of the absorption constant values of 12C16O2 and 13C16O2 using the tunable diode laser absorption spectroscopy method ranging from 4860 to 4880 sm?1 within the pressure limits of 8–240 mbar for the absorption curves (lines) R(18), R(20), R(22), R(24), R(26), R(28), R(30), R(32), R(34) and R(36) of the 20013–00001 molecule 12C16O2 vibration band, and within the pressure limits of 0.06–1.7 mbar for the absorption curves P(10), P(12), P(14), P(16), P(18), P(20) and P(22) of the 20012–00001 molecule 13C16O2 vibration band. In the work, as a mixture under analysis, a mixture of the isotopes 13C16O2 and 12C16O2 at the ratio of 1:140 was used. The results have been compared with the data of the HITRAN spectroscopic database.
关键词： tunable diode laser absorption spectroscopy,carbon dioxide,absorption coefficients
更新于2025-09-23 15:19:57
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Clinical and Histological Assessment of Combined Fractional CO <sub/>2</sub> Laser and Growth Factors Versus Fractional CO <sub/>2</sub> Laser Alone in the Treatment of Facial Mature Burn Scars: A Pilot Splita??Face Study
摘要： Background and Objectives: To investigate the therapeutic efficacy and safety of growth factors combined with fractional carbon dioxide (CO2) laser in comparison with fractional CO2 alone in a sample of patients with facial mature burn scars. Study Design/Materials and Methods: Fifteen Egyptian patients with bilateral facial burn scars were treated with six sessions of fractional CO2 laser at 6‐week intervals. Following each laser session, a topical growth factors cocktail was applied to one side of the face in a split‐face manner. Clinical evaluation by Vancouver Scar Scale (VSS), Patient and Observer Scar Assessment Scale (PSOS), and photography before and 2 months after the last laser session was done. Three millimeter punch biopsies were obtained from each side of the face pre‐ and 1‐month post-treatment to measure the mean area percent of collagen. Results: Posttreatment, both VSS and PSOS scores decreased on both sides of the face being more significant on the growth factors treated side, showing more scar pliability and shorter downtime (P = 0.001). A significant difference in the mean area percent of collagen was also noted on both sides. Conclusion: Adding topical growth factors to fractional CO2 laser treatments is effective and safe with better results as regards scar pliability and shorter downtime than fractional CO2 laser alone.
关键词： growth factors,burn,fractional carbon dioxide laser
更新于2025-09-23 15:19:57
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Impact of intramolecular H bond and n-π* interactions on photophysical and CO2 sensing properties of laterally appended D-π-A triarylboron compounds
摘要： Several examples of laterally appended donor-π-acceptor (D-π-A) boron compounds based on a biphenyl unit have been synthesized and fully characterized. Intramolecular H bonds or n-π* interactions have been found to have a great impact on the photophysical/fluorescent properties of these compounds. Some members of these compounds have been found to display fluorescent response toward CO2.
关键词： Triarylboron,Carbon dioxide sensing,Donor-acceptor compound
更新于2025-09-23 15:19:57
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Sunlight Induced Photo-thermal Synergistic Catalytic CO2 Conversion via Localized Surface Plasmon Resonance of MoO3-x
摘要： Photocatalytic conversion of CO2 to solar fuels is considered an alternative approach for simultaneously mitigating the greenhouse effect and solving energy shortage. The efficient light harvesting and the thermochemical conversion has been a demanding quest in photocatalysis due to the relatively low solar energy utilization efficiency. In this work, oxygen vacancies are induced in MoO3 for improving photo-thermal CO2 reduction efficiency by capturing near-infrared (NIR) photons. The localized surface plasmon resonance (LSPR) of MoO3-x triggered by oxygen vacancies endows the efficient capture of NIR photons. Additionally, oxygen vacancies can promote the carrier separation, improve CO2 adsorption on the defective surface and lower the barrier of CO2 hydrogenation during the conversion process. As a result, MoO3-x displayed dramatically enhanced photo-thermal synergistic CO2 reduction under simulated sunlight (UV-Vis-IR) irradiation than that of MoO3. The amount of CO produced by MoO3-x can reach 10.3 μmol·g-1·h-1, which is 20 times higher than that of MoO3 (0.52 μmol·g-1·h-1). And the CH4 production of MoO3-x can reach 2.08 μmol·g-1·h-1, which is 52 times higher than that of MoO3 (0.04 μmol·g-1·h-1). In-situ FT–IR and theoretical calculation also proved the enhanced activity of MoO3-x. This work highlights the significance of defect engineering for improving the photo-thermal catalytic conversion of CO2.
关键词： carbon dioxide,photothermal conversion,MoO3-x,solar energy
更新于2025-09-19 17:15:36
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All-Fiber CO2 Sensor Using Hollow Core PCF Operating in the 2 μm Region
摘要： A realistic implementation of an all-fiber CO2 sensor, using 74 cm of hollow core photonic crystal fiber (HC-PCF) as the cavity for light/gas interaction, has been implemented. It is based on CO2 absorbance in the 2 μm region. The working range is from 2% to 100% CO2 concentration at 1 atm total pressure and the response time obtained was 10 min. Depending on the concentration level, the sensor operates at one of three different wavelengths (2003.5 nm, 1997.0 nm and 1954.5 nm) to maintain a high sensitivity across all the working range.
关键词： gas,sensor,tunable laser,carbon dioxide monitoring,fiber bragg grating,photonic crystal fiber
更新于2025-09-19 17:15:36
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Reflectance confocal microscopy-guided carbon dioxide laser ablation of low-risk basal cell carcinomas: A prospective study
摘要： Background: Basal cell carcinoma (BCC) treatment modalities can be strati?ed by tumor subtype and recurrence risk. The main limitation of nonsurgical treatment modalities is the lack of histopathologic con?rmation. Re?ectance confocal microscopy (RCM) is a noninvasive imaging device that provides quasihistologic images. Objective: To evaluate the feasibility and ef?cacy of RCM-guided carbon dioxide (CO2) laser ablation of low-risk BCCs. Methods: Prospective study with biopsy specimeneproven low-risk BCCs imaged with RCM. RCM was performed on these sites before and after ablation. If residual tumor was found, a new series of laser passes were performed. The patients were then monitored for recurrence clinically and with RCM. Results: Twenty-two tumor sites in 9 patients (5 men, 4 women) were imaged and treated. Median age was 59 6 12.9 years (range, 30-74 years). Mean tumor size was 7.7 mm (range, 5-10 mm). Residual tumor was identi?ed in 5 of 22 cases (22.7%) under RCM on immediate ?rst-pass postablation sites, prompting additional laser passes. Median follow-up was 28.5 months (range, 22-32 months) with no recurrences found. Conclusions: Addition of RCM to laser ablation work?ow can detect subclinical persistent tumor after initial ablation and may serve as an aid to increase the ef?cacy of laser ablation.
关键词： laser,basal cell carcinoma,carbon dioxide laser,ablation,diagnosis,follow-up,re?ectance confocal microscopy,treatment
更新于2025-09-19 17:13:59
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Application of the least square method for processing the signal obtained by the tuneable diode laser absorption spectroscopy method in the range 4860a??4880a??cm <sup>a??1</sup> for the problem of measuring <sup>13</sup> CO <sub/>2</sub> content in exhaled air
摘要： The 1st, 2nd and 3rd order least square method (LSM-1, LSM-2 and LSM-3) is applied to smooth the experimental absorption signal of 13CO2 and 12CO2 obtained by the tuneable diode laser absorption spectroscopy method in the 4860–4880 cm?1 frequency range of a tuneable diode laser. It has been shown clearly that using LSM-2 with a filter window N ~ 100 allows the 13CO2 content in exhaled air to be measured at an error level of 0.28%, which meets breathing tests requirements.
关键词： gas analysis,biomedical analysis,carbon dioxide,tuneable diode laser absorption spectroscopy (TDLAS)
更新于2025-09-19 17:13:59
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Treatment of dermatosis papulosa nigra using a carbon dioxide laser
摘要： Background: Dermatosis papulosa nigra (DPN) is characterized by the presence of multiple, small, hyperpigmented, warty papules affecting the face, neck, and trunk that bear to histological semblance to seborrheic keratosis. Although the lesions are benign tumors, they can cause distress for cosmetic reasons. Objective: We, herein, report the cases of three female Japanese patients (mean age, 46 years) with DPN who were treated using a carbon dioxide (CO2) laser with a computerized scanner. The patients were all suffering from an increased number of brown asymptomatic papules (size, 1-5 mm), which were located all over the trunk. Histological examinations revealed acanthosis, hyperkeratosis and horn cyst formation in the epidermis. Methods: We performed CO2 laser (LASER 30C; Lumenis Inc) treatment (settings: 8-10 W; pulse duration, 0.05-seconds; rest duration, 0.36 seconds; laser spot size, 1.2 mm) for 5-10 months. Results: With CO2 laser treatment, were could completely remove the lesions and achieve excellent cosmetic results without scar formation in all cases. The treated lesions did not relapse for more than 1 year. Conclusion: In our opinion, CO2 laser treatment with a computerized scanner is an effective therapeutic option for DPN.
关键词： carbon dioxide surgical laser,Dermatosis papulosa nigra,skin
更新于2025-09-19 17:13:59