Immune to temperature interference sensor of carbon dioxide gas concentration based on a single modified fiber Bragg grating.

In this study, a novel method that can detect carbon dioxide (CO2) concentration and realize temperature immunity based on only one fiber Bragg grating (FBG) is proposed. The outstanding contribution lies in solving the temperature crosstalk issue of FBG and ensuring the accuracy of detection results under the condition of anti-temperature interference. To achieve immunity to temperature interference without changing the initial structure of FBG, the optical fiber cladding of FBG and adjacent optical fiber cladding at both ends of FBG are modified by a polymer coating. Moreover, a universal immune temperature demodulation algorithm is derived. The experimental results demonstrate that the temperature response sensitivity of the improved FBG is controlled within the range of 0.00407 nm/°C. Compared with the initial FBG (the temperature sensitivity of the initial FBG is 0.04 nm/°C), it decreases by nearly 10 times. Besides, the gas response sensitivity of FBG reaches 1.6 pm/ppm and has overwhelmingly ideal linearity. The detection error results manifest that the gas concentration error in 20 groups of data does not exceed 3.16 ppm. The final reproducibility research shows that the difference in detection sensitivity between the two sensors is 0.08 pm/ppm, and the relative error of linearity is 1.07%. In a word, the proposed method can accurately detect the concentration of CO2 gas and is efficiently immune to temperature interference. The sensor we proposed has the advantages of a simple production process, low cost, and satisfactory reproducibility. It also has the prospect of mass production.

Intraoperative Low-Dose S-Ketamine Reduces Depressive Symptoms in Patients with Crohn's Disease Undergoing Bowel Resection: A Randomized Controlled Trial.

Background: Patients with Crohn's disease (CD) undergoing bowel resection often suffer from depression and acute pain, which severely impairs their recovery. We aimed to investigate the effects of S-ketamine preconditioning on postoperative depression in patients with CD undergoing a bowel resection with mild to moderate depression and to observe whether it can relieve postoperative pain and anti-inflammation. Methods: A total of 124 adult patients were randomized into one of the two groups. Patients in the S-ketamine group received a 0.25 mg/kg S-ketamine intravenous drip under general anesthesia induction, followed by a continuous infusion of S-ketamine with 0.12 mg/kg/h for more than 30 min through target-controlled infusion. Patients in the placebo group received 0.9% saline at an identical volume and rate. The primary outcome measure was the 17-item Hamilton depression Scale (HAMD-17). The secondary outcomes were scores on the following questionnaires: a nine-item patient health questionnaire (PHQ-9); a quality of recovery (QoR-15) form; and a numeric rating scale (NRS). Additional secondary outcomes included the levels of C-reactive protein (CRP) and interleukin 6 (IL-6) on postoperative days (PODs) 1, 3, and 5, the length of hospital stay, and opioid use throughout the hospital stay. Results: The scores of PHQ-9 and HAMD-17 in the S-ketamine group were lower than those in the placebo group on postoperative days (PODs) 1, 2, and 7 (p < 0.05). The scores of QoR-15 in the S-ketamine group were higher than those in the placebo group on postoperative days (PODs) 3 and 5 (p < 0.05). The NRS scores of PACU, postoperative days 1 and 2 in the S-ketamine group were lower than those in the placebo group (p < 0.05). There was no significant difference in the CRP and IL-6 levels on postoperative days (PODs) 1, 3, and 5, postoperative complications, and hospital stay between the two groups (p > 0.05). Conclusions: The trial indicated that the intraoperative administration of low-dose S-ketamine could alleviate mild-to-moderate depressive symptoms and postoperative pain in patients with Crohn's disease undergoing bowel resection without worsening their safety.

The novel GLP-1/GIP dual receptor agonist DA3-CH is neuroprotective in the pilocarpine-induced epileptogenesis rat model.

AIMS: Glia-mediated neuro-inflammation and oxidative stress-induced neuronal apoptosis can contribute to epileptogenesis. We have demonstrated previously that mimetics of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) and dual-GLP-1/GIP receptor agonists protect the brain from inflammation, oxidative stress, apoptosis and neuronal loss in animal models of central nervous system diseases. METHODS: This study investigated for the first time whether the novel dual GLP-1/GIP receptor agonist DA3-CH has neuroprotective effects in the pilocarpine-induced status epilepticus (SE) rat model and the studies the underlying mechanisms. DA3-CH was administered once daily at 10 nmol/kg ip. following SE induction. The effect of DA3-CH was evaluated by immunohistochemistry and western blot at 12 h, 1 d, 3 d, 7 d after kindling. RESULTS: Our findings show that DA3-CH reduced the chronic inflammation response (astrogliosis and microgliosis), and the associated release of the pro-inflammatory cytokines interleukin-1ß (IL-ß) and tumor necrosis factor-α (TNF-α) in the hippocampal CA1 area. Furthermore, DA3-CH reduced the expression of the mitochondrial pro-apoptotic protein Bax, while increasing the expression of the anti-apoptotic protein Bcl-2. Neuronal numbers in the CA1 area were much reduced by pilocarpine treatment, and DA3-CH protected neurons from neurotoxicity. CONCLUSION: These results demonstrated that DA3-CH could mitigate pilocarpine-induced neuro-inflammation, mitochondrial apoptosis and neuronal loss. The findings encourage the development of dual agonists as novel therapeutic interventions for epilepsy.

Enhancement of Intramolecular Photocycloaddition of Bichromophoric Compounds via Inclusion in Low-Density Polyethylene Films.

The photocycloaddition of tetra- and penta(ethylene glycol) labeled at the chain terminals with 2-naphthoyl groups (N-Pn-N; n = 4 or 5) and tetra(ethylene glycol) terminated by 7-(4-methylcoumarinyl) groups (C-P4-C) has been investigated in hexane solutions and in low-density polyethylene (LDPE) films. At loading levels less than 1 × 10-2 mol/g-film, irradiation of the compounds in LDPE leads to formation of intramolecular photocyclomers to the exclusion of intermolecular products. Irradiations in hexane containing 1 × 10-3 M of a bichromophoric compound produce large amounts of oligomeric material. The difference between the results in solution and the film is explained in terms of the compartmentalization of the guest molecules in the LDPE amorphous regions. Cold-stretching the LDPE films significantly increases the relative efficiency of the intramolecular photocycloadditions due to reduction of the free volume at the reaction sites. This work reports a new approach to synthesize large-ring compounds in high chemical yields at relatively high substrate concentrations.