We demonstrate coherent Raman spectroscopy (CRS) using a tunable excitation source based on a single femtosecond fiber laser. The frequency difference between the pump and the Stokes pulses was generated by soliton self-frequency shifting (SSFS) in a nonlinear optical fiber. Spectra of C-H stretches of cyclohexane were measured simultaneously by stimulated Raman gain (SRG) and coherent anti-Stokes Raman scattering (CARS) and compared. We demonstrate the use of spectral focusing through pulse chirping to improve CRS spectral resolution. We analyze the impact of pulse stretching on the reduction of power efficiency for CARS and SRG. Due to chromatic dispersion in the fiber-optic system, the differential pulse delay is a function of Stokes wavelength. This differential delay has to be accounted for when performing spectroscopy in which the Stokes wavelength needs to be scanned. CARS and SRG signals were collected and displayed in two dimensions as a function of both the time delay between chirped pulses and the Stokes wavelength, and we demonstrate how to find the stimulated Raman spectrum from the two-dimensional plots. Strategies of system optimization consideration are discussed in terms of practical applications.
Background Although the lack of estrogen receptor β (ERβ) is a risk factor for the development of inflammatory bowel disease (IBD) and psychiatric disorders, the underlying cellular and molecular mechanisms are not fully understood. Herein, we revealed the role of gut microbiota in the development of IBD and related anxiety-like behavior in ERβ-deficient mice. Results In response to dextran sodium sulfate (DSS) insult, the ERβ knockout mice displayed significant shift in α and β diversity in the fecal microbiota composition and demonstrated worsening of colitis and anxiety-like behaviors. In addition, DSS-induced colitis also induced hypothalamic-pituitary-adrenal (HPA) axis hyperactivity in ERβ-deficient mice, which was associated with colitis and anxiety-like behaviors. In addition, RNA sequencing data suggested that ErbB4 might be the target of ERβ that is involved in regulating the HPA axis hyperactivity caused by DSS insult. Gut microbiota remodeling by co-housing showed that both the colitis and anxiety-like behaviors were aggravated in co-housed wild-type mice compared to single-housed wild-type mice. These findings suggest that gut microbiota play a critical role in mediating colitis disease activity and anxiety-like behaviors via aberrant neural processing within the gut-brain axis. Conclusions ERβ has the potential to inhibit colitis development and anxiety-like behaviors via remodeling of the gut microbiota, which suggests that ERβ is a promising therapeutic target for the treatment of IBD and related anxiety-like behaviors.
We demonstrate multi-mode microscopy based on a single femtosecond fiber laser. Coherent anti-Stokes Raman scattering (CARS), stimulated Raman scattering (SRS) and photothermal images can be obtained simultaneously with this simplified setup. Distributions of lipid and hemoglobin in sliced mouse brain samples and blood cells are imaged. The dependency of signal amplitude on the pump power and pump modulation frequency is characterized, which allows to isolate the impact from different contributions.
Background An ongoing global pandemic of pneumonia caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused thousands of deaths in China since December, 2019. We aimed to describe the clinical course of patients died of SARS-CoV-2 infection.Methods In this retrospective study, we reviewed 194 patients with SARS-CoV-2 infection, who died consecutively between Feb 3 to 24, 2020 in Tongji Hospital (Wuhan, China). Basic demographic and clinical information, laboratory findings, complications and treatments were extracted from electronic medical records of Hospital Information System. Unpaired t test was employed to evaluate the statistical differences of the serum level of high-sensitive cardiac troponin I (hs-cTnI) among different age or sex groups. The relationship between hs-cTnI and inflammatory cytokines were estimated using Spearman correlation analysis.Results The death patients aged 69.62 ± 10.98, in which 68.6% were male. 74.7% patients had underlying chronic illnesses. The most common symptoms were fever (83%), cough (69.3%), and dyspnea (65.6%). Decreased lymphocyte count (91.4%), elevated level of hs-cTnI (82.9%) and inflammatory parameters in serum were commonly seen. The hs-cTnI level was significantly higher in the group aged 60–79 and male patients. A week positive correlation was observed between hs-cTnI values and D-dimer values (r = 0.343, p༜0.05). Acute respiratory distress syndrome was the main complication. Assisted respiration, antimicrobial drugs, glucocorticoids and immune globulin were the major treatments.Conclusion Most non-survivors with SARS-CoV-2 infection were old with chronic illnesses, complicated by multiple organ dysfunction. Prevention is better than cure in high-risk population.
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