Dynamic Fluorescence Sensing of Bromide Ions by Photochromic Bi(III)-Coordination Polymers Based on a Ligand Integrated by Naphthalene Diimides and Pyridinium in Solution and Films.

Bismuth(III)-based complexes have garnered increasing attention in fluorescence sensing due to their environmentally friendly and sustainable characteristics. A Bismuth(III) coordination polymer (CP),1-Cl based on a naphthalene diimides(NDI)-pyridinium is synthesized by an in situ reaction method. Notable for its sensitivity to visible light, 1-Cl shows excellent photochromic properties, and the integration of NDI and pyridinium in one ligand makes photogenerated radicals more stable. Structural analysis and theoretical calculations are employed to investigate the potential pathway of photoinduced electron transfer (ET) during the photochromic process. Notably, in aqueous solutions, 1-Cl displays an extraordinary fluorescence enhancement response to bromide ion (Br-), resulting in a distinct transition from yellow to orange in color. The potential mechanism of fluorescence sensing has been revealed through single-crystal X-ray diffraction analysis. This insight highlights a continuous substitution process where the Cl- ions are successively replaced by Br- ions. Consequently, a single-crystal-to-single-crystal transformation (SCSC) occurs, yielding the intermediate species, 1-Cl-Br, which ultimately transforms into the final product, 1-Br. Finally, the photochromic film is successfully prepared and applied to practical applications such as ink-free printing, information anti-counterfeiting, and the visual detection of Br- ions. This work combines photochromism with fluorescence sensing, broadening the research field and practical application of photochromic materials.

Conformation- and Coordination Mode-Dependent Stimuli-Responsive Salicylaldehyde Hydrazone Zn(II) Complexes.

Luminescent Zn(II) complexes that respond to external stimuli are of wide interest due to their potential applications. Schiff base with O,N,O-hydrazone shows excellent luminescence properties with multi-coordination sites for different coordination modes. In this work, three salicylaldehyde hydrazone Zn(II) complexes (1, 2a, 2b) were synthesized and their stimuli-responsive behaviors in different states were explored. Only complex 1 exhibits reversible and self-recoverable photochromic and photoluminescence properties in solution. This may be due to the configuration eversion and the excited-state intramolecular proton transfer (ESIPT) process. In the solid state, 2a has obvious mechanochromic luminescence property, which is caused by the destruction of intermolecular interactions and the transformation from crystalline state to amorphous state. 2a and 2b have delayed fluorescence properties due to effective halogen bond interactions in structures. 2a could undergo crystal-phase transformation into its polymorphous 2b by force/vapor stimulation. Interestingly, 2b shows photochromic property, which can be attributed to the electron transfer and generation of radicals induced by UV irradiation. Due to different conformations and coordination modes, the three Zn(II) complexes show different stimuli-responsive properties. This work presents the multi-stimuli-responsive behaviors of salicylaldehyde hydrazone Zn(II) complexes in different states and discusses the response mechanism in detail, which may provide new insights into the design of multi-stimuli-responsive materials.

Three-Dimensional Viologen-Based Lanthanide-Organic Frameworks: Photochromism and Fluorescence Detection of Quinolone Antibiotics.

Quinolone antibiotic residues, norfloxacin (NORF) and ciprofloxacin (CIP), have attracted more attention due to their frequent detection in surface water and food field, which seriously threaten the health of animals and humans. Rapid and efficient detection of NORF and CIP is critical for environmental testing and ecosystems. Herein, two novel isostructural viologen-functionalized Ln(III) complexes [Ln2L0.5(IPA)3]n (Ln = Eu, 1; Tb, 2; L = N,N'-bis (2-carboxyethyl)-4,4'-bipyridridylium dichloride, H2IPA = isophthalic acid) with a three-dimensional structure have been synthesized solvothermally. Complexes 1 and 2 exhibited reversible photochromism under UV light. In addition, complex 1 exhibits excellent pH tolerance and can be seen as an efficient fluorescent probe for the detection of NORF and CIP with detection limits of 7.90 × 10-7 and 9.48 × 10-7 M, respectively. Furthermore, the good photoresponsive and outstanding fluorescent properties of 1 were further exploited in dual-function paper involving erasable inkless printing and detection of NORF and CIP. Our work reports a new strategy for recognizing NORF and CIP based on the luminescent color change of the viologen-based Ln-MOFs, providing a new direction for the development of multifunctional materials.

Enhancement of Long-Lived Persistent Room-Temperature Phosphorescence and Anion Exchange with I- and SCN- via Metal-Organic Hybrid Formation.

An in-depth understanding of structure-property relationships and the construction of multifunctional stimuli-responsive materials are still difficult challenges. Herein, we discovered a 4,4'-bipyridinium derivative with both photochromism and dynamic afterglow at 77 K for the first time. A one-dimensional (1D) Cd(II) coordination polymer (1) assembled by only a 4,4'-bipyridinium derivative and cadmium chloride showed photochromism, room-temperature phosphorescence (RTP), and electrochromism. Interestingly, we found that 1 underwent single-crystal-to-single-crystal transformation during the anion exchange process, and the color of the crystal changed from colorless to yellow (1-SCN-) within 10 min. Complex 1 exhibited photochromism, whereas 1-SCN- did not. The difference in the photochromic behavior between the two complexes was ascribed to the electron transfer pathway between the carboxylate groups and viologen. The DFT calculation based on the crystal structure of 1-SCN- indicated that the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) were mainly located on bipyridine and cadmium atoms, eliminating the possibility of electron transfer, whereas for complex 1, electron transfer was probable from O and Cl atoms to pyridinium N atoms in viologen as demonstrated by density of states (DOS) calculations. In addition, complex 1 was successfully made into test paper for the rapid detection of I- and SCN- and displayed potential applications in inkless printing, multiple encryption, and anticounterfeiting.

Multistimuli-responsive materials based on a zinc(II) complex with high-contrast and multicolor switching.

The development of stimulus-responsive luminescent materials, especially those based on a single compound exhibiting multicolor and high-contrast (Δλem ≥ 100 nm) chromic properties, is a critical challenge. In this work, we synthesized and characterized a zinc(II) complex (1). As expected, 1 displays aggregation-induced emission enhancement (AIEE) in THF/H2O mixtures, and remarkable multicolor switching under external stimuli in the solid state. Complex 1 shows reversible mechanochromic luminescence behavior with a large wavelength shift (Δλem = 100 nm) during the grinding-fuming cycles, due to the phase transformation between the crystalline and amorphous states. More impressively, 1 exhibits obvious acidochromic properties (Δλem = 130 nm) which originate from the adsorption of vapor and a gas-solid reaction on the crystal surface. Furthermore, 1 exhibits electrochemical oxidation behavior accompanied by quenching of yellow-green emission due to the overlap of an emission band and an absorption band. The above-mentioned color changes under ambient light can also be observed by the naked eye during the mechanical, acid-base vapor and electrical stimulation. Based on the high-contrast and multicolor switching, complex 1 was successfully developed into test papers and films in the field of rapid detection of mechanical stimuli and HCl/NH3 vapors.

Solvent-Modulated Self-Assembly of Naphthalenediimide-Based Cd(II) Complexes and the Controllable Photochromism via Conformational Isomerization.

Rational regulation of the properties of photochromic materials is a challenging and meaningful work. In the present work, NDI-based complexes, namely, [Cd0.5(NDI)(HBDC)]·H2O (1) and a series of conformational isomers of {[Cd(NDI)0.5(BDC)]·MeCN}n (2), were synthesized by varying the solvent conditions (H2BDC = terephthalic acid, NDI = N,N'-bis(3-pyridylcarbonylhydrazine)-1,4,5,8-naphthalene diimide). Complex 1 exhibits a 0D mononuclear structure without photochromic behavior due to the bad conjugation of the naphthalene diimide moiety. The conformational isomers of complex 2 manifest a 3D network, showing ultra-fast photo-induced intermolecular electron transfer photochromic behavior under X-ray, UV, and visible light. However, they show different photochromic rates and coloring contrast upon photoirradiation, which originates from their difference in the distances of lone pair(COO)···π(NDI). This was realized via controlling the solvent ratio in the reaction system. In addition, compared to UV/X-ray light, 2 exhibits greater sensitivity to visible light and is an organic-inorganic hybrid material with photomodulated luminescence. Based on the excellent performance, complex 2 can be applied to filter paper, showing potential applications as an inkless printing medium and selective perception of ammonia and amine vapors in the solid state via different visual color changes.

Multistimuli-Responsive Materials Based on Zn(II)-Viologen Coordination Polymers and Their Applications in Inkless Print and Anticounterfeiting.

Recently, stimuli-responsive materials have attracted great attention, while most of them respond to single or two stimuli. Thus, it is essential to design multifunctional stimuli-responsive materials and develop their applications. The strategy that constructing high-dimensional coordination polymers facilitates the application scope of a viologen-based photochromic system is put forward and confirmed for the first time. Herein, a novel multistimuli-responsive viologen-based Zn-MOF with a two-dimensional framework has been successfully designed and synthesized. Complex 1 exhibits chromic behavior under a variety of external stimuli such as 365 nm UV, X-rays, heat, electricity, and ethylamine. More interestingly, the crystal state of complex 1 displays dual fluorescence and room-temperature phosphorescence (RTP) emission and emits a yellow afterglow when turning off the UV lamp. In addition, Eu(III)-functionalized hybrids, Eu3+@Zn-MOF, were prepared by coordinated postsynthetic modification based on viologen complexes for the first time. The sample of Eu3+@Zn-MOF inherits the photochromic characteristics of the viologen complexes and gives the distinctive fluorescence of the europium ions. Based on the multicolor switching of 1 and Eu3+@Zn-MOF, their possible practical utilization was successfully developed in the fields of inkless, erasable print media, electrochromic information tag printing, information encryption, and anticounterfeiting.

Hybrid endoscopic submucosal dissection: An alternative resection modality for large laterally spreading tumors in the cecum?

BACKGROUND: Endoscopic resection for large, laterally spreading tumors (LSTs) in the cecum is challenging. Here we report on the clinical outcomes of hybrid endoscopic submucosal dissection (ESD) in large cecal LSTs. METHODS: We retrospectively reviewed data from patients with cecal LSTs ≥ 2 cm who underwent ESD or hybrid ESD procedures between January of 2008 and June of 2019. We compared the baseline characteristics and clinical outcomes, including procedure time, the en bloc and complete resection rates, and adverse events. RESULTS: A total of 62 patients were enrolled in the study. There were 27 patients in the ESD group and 35 patients in the hybrid ESD group, respectively. Hybrid ESD was more used for lesions with submucosal fibrosis. No other significant differences were found in patient characteristics between the two groups. The hybrid ESD group had a significantly shorter procedure time compared with the ESD group (27.60 ± 17.21 vs. 52.63 ± 44.202 min, P = 0.001). The en bloc resection rate (77.1% vs. 81.5%, P = 0.677) and complete resection rate (71.4% vs. 81.5%, P = 0.359) of hybrid ESD were relatively lower than that of the ESD group in despite of no significant difference was found. The perforation and post-procedure bleeding rate (2.9% vs. 3.7%, P = 0.684) were similar between the two groups. One patient perforated during the ESD procedure, which was surgically treated. One patient in the hybrid ESD group experienced post-procedure bleeding, which was successfully treated with endoscopic hemostasis. Post-procedural fever and abdominal pain occurred in six patients in the ESD group and five patients in the hybrid ESD group. One patient in the ESD group experienced recurrence, which was endoscopically resected. CONCLUSION: The results of this study indicate that hybrid ESD may be an alternative resection strategy for large cecal LSTs with submucosal fibrosis.

Gradual replacement of all previously circulating respiratory syncytial virus A strain with the novel ON1 genotype in Lanzhou from 2010 to 2017.

ON1 is a novel genotype of human respiratory syncytial virus (HRSV) subtype A, in children with acute respiratory tract infections (ARTIs). However, there is not much data on the prevalence and clinical and molecular characterization in China.Our study is based on the children who had respiratory infections positive for RSV-A admitted by Gansu Provincial Maternity and Child-care Hospital in Lanzhou (northwestern China) during the last 7 epidemic seasons from 2010 to 2017.In our study, different strains of the novel RSV-A genotype ON1, first identified in Canada in December 2010, were first detected in Gansu Provincial Maternity and Child-care Hospital in August 2012 and then followed by an abrupt expansion in the number of ON1 variants in the beginning of 2014 and eventually replaced all other RSV-A strains from 2015 to 2017. ON1 is characterized by a 72-nt duplication in the C-terminal region of the highly variable attachment glycoprotein (G), predicted to lengthen the polypeptide with 24 amino acids, including a 23-aa duplication, which likely changes antigenicity. New N-glycosylation sites occurred within the 23-aa duplication and 24-aa insertion of the ON1 viruses in our study. Notably, RSV infections occurred later, but peaked sooner from the 2014/2015 to 2016/2017 epidemic seasons, compared with the previous 4 seasons.Our study concluded that genotype ON1 has caused larger outbreaks and became the predominate genotype for HRSV subgroup A in Lanzhou from 2013 to 2017, and became the sole genotype of RSV-A in 2015/2016 and 2016/2017. Our data indicate that northwest of China and the world will eventually be dominated by the ON1 RSV-A genotype, including the possibility for vaccine development. Based on trends seen in RSV-B BA genotype, which predominated for decades, there is a possibility to develop a vaccine for children in the next 10 years.

Sedation With Propofol Has No Effect on Capsule Endoscopy Completion Rates: A Prospective Single-Center Study.

Patients who need both capsule endoscopy (CE) and colonoscopy often undergo both examinations on the same day to avoid repeated bowel preparation and fasting. Sedation can relieve pain and is commonly used for colonoscopies but may influence the CE completion rate.To determine whether sedation with propofol influences the completion rate and small-bowel transit time (SBTT) of CE.From July 2014 to December 2014, patients (18-65 years old) who needed both CE and colonoscopy were assessed consecutively for enrollment in our study. Colonoscopies were performed with or without sedation based on patient preferences on the day of capsule ingestion. The completion rate, SBTT, and diagnostic yield of CEs were recorded. Patients' satisfaction and pain scores were also recorded.Sedation with propofol had no significant effect on CE completion rates (83.3% sedation group vs 81.8% nonsedation group, P = 0.86) but was associated with increased SBTT (403.6 ±â€Š160.3 sedation group vs 334.5 ±â€Š134.4 nonsedation group, P = 0.006). The diagnostic yields in the sedation and nonsedation groups were 69.4% and 65.9%, respectively (P = 0.74). The median satisfaction scores were 8.6 in the sedation group and 3.5 in the nonsedation group (P < 0.001). Median pain scores were 1.4 in the sedation group and 6.7 in the nonsedation group (P < 0.001).Sedation with propofol increased SBTT but had no effect on CE completion rates, suggesting that CE and colonoscopy with propofol can be performed on the same day (clinical trial registration number: ChiCTR-ONRC-14004866).

MYC regulation of CHK1 and CHK2 promotes radioresistance in a stem cell-like population of nasopharyngeal carcinoma cells.

Radiotherapy is the most successful nonsurgical treatment for nasopharyngeal carcinoma (NPC). Despite this, the prognosis remains poor. Although NPCs initially respond well to a full course of radiation, recurrence is frequent. The cancer stem cell (CSC) hypothesis provides a framework for explaining the discrepancy between the response of NPC to therapy and the poor survival rate. In this study, a stem cell-like subpopulation (PKH26+) was identified in NPC cell lines using a label-retention technique. PKH26+ cells were enriched for clonogenicity, sphere formation, side-population cells, and resistance to radiotherapy. Using genomic approaches, we show that the proto-oncogene c-MYC (MYC) regulates radiotolerance through transcriptional activation of CHK1 (CHEK1) and CHK2 (CHEK2) checkpoint kinases through direct binding to the CHK1 and CHK2 promoters. Overexpression of c-MYC in the PKH26+ subpopulation leads to increased expression of CHK1 and CHK2 and subsequent activation of the DNA-damage-checkpoint response, resulting in radioresistance. Furthermore, loss of CHK1 and CHK2 expression reverses radioresistance in PKH26+ (c-MYC high expression) cells in vitro and in vivo. This study elucidates the role of the c-MYC-CHK1/CHK2 axis in regulating DNA-damage-checkpoint responses and stem cell characteristics in the PKH26+ subpopulation. Furthermore, these data reveal a potential therapeutic application in reversal of radioresistance through inhibition of the c-MYC-CHK1/CHK2 pathway.

[Application of subclinical doses of pentazocine and propofol in painless vaginal egg retrieval].

OBJECTIVE: To assess the feasibility of using subclinical doses of pentazocine in painless egg retrieval. METHODS: Eighty-one patients undergoing painless egg retrieval were randomized into the observation group and the control group to receive 0.4 mg/kg pentazocine with 1.5 mg/kg propofol and 0.5 mg/kg pentazocine with 1.5 mg/kg propofol, respectively. The mean arterial pressure (MAP), heart rate (HR), SPO(2), respiratory rate (RR), unconsciousness time, awake time, hospital stay, complications, consciousness during the operation and adverse effects were compared between the two groups. RESULTS: The two groups showed no significant differences in the analgesic effect, dosage of propofol, adverse effects, unconsciousness time, awake time, or hospital stay. But compared with the control group, the observation group showed greater intraoperative consciousness but with more stable respiration. CONCLUSION: Subclinical doses of pentazocine can be used in the painless egg retrieval, but the dose of propofol should be increased to reduce the body activity during the operation.

[Effects of ambulatory labor analgesia on fetal oxygen saturation].

OBJECTIVE: To observe the effect of ambulatory labor analgesia on fetal oxygen saturation during labor. METHODS: Sixty parturients with uncomplicated term pregnancies were equally divided, according to their personal preference, into ambulatory analgesia group receiving combined spinal-epidural labor analgesia and control group without analgesia administration. All the parturients with ambulatory labor analgesia received sufentanil and ropivacaine administration. Fetal oxygen saturation was monitored continuously during the labor by recording the values every 5 minutes and the mean value was calculated. Umbilical blood was analyzed after fetal delivery and the pH, base excess (BE) value were recorded. RESULTS: In the analgesia group and the control group, the mean values of fetal oxygen saturation was (51.92+/-5.90)% and (50.77+/-6.47)%, respectively, during the first labor stage (P=0.48), and was (44.85+/-6.27)% and (43.12+/-7.34)% during the second labor stage (P=0.32), and the lowest values during the labor was (41.63+/-7.51)% and (40.96+/-7.48)%, respectively (P=0.73), showing no significant differences in the three values between the two groups. CONCLUSION: Ambulatory labor analgesia does not significantly affect fetal oxygen saturation during the entire course of labor.

[Intravenous propofol combined with fentanyl for anesthesia during ultrasound-guided transvaginal oocyte retrieval].

OBJECTIVE: To compare the clinical efficacy and safety of anesthesia with intravenous propofol combined with fentanyl for ultrasound-guided transvaginal oocyte retrieval. METHODS: Totally 100 unpremedicated infertile women (ASA I-II) scheduled for oocyte retrieval with ultrasound guidance were randomly divided into two groups to receive anesthesia with either intravenous propofol (group A, n=50) or the combination of propofol and fentanyl (group B, n=50). The time when consciousness loss and recovery occurred, dosage of propofol for anesthesia maintenance, mean arterial blood pressure (MAP), heart rate (HR) and oxygen saturation (SpO2) were recorded. RESULTS: There was no significant difference in the time of consciousness loss between groups A and B (58.8+/-3.8 s vs 57.7+/-5.2 s, P=0.283), but consciousness recovery occurred earlier in group B (6.0+/-0.6 min vs 5.7+/-0.4 min, P<0.01). The maintenance dosage of propofol in group B (0.20+/-0.03 mg/kg) was significantly lower than that in group A (0.52+/-0.05 mg/kg, P<0.01). At 2 min after anesthesia induction, the MAP decreased from 11.1+/-0.8 kPa to 8.0+/-0.6 kPa in group A (P<0.05), and from (10.9+/-0.9) kPa to (8.3+/-0.7) kPa in group B(P<0.05), and returned to normal within 2-3 min in both groups. The incidence of low SpO2 (<90%) was lower in group A than in group B ((52% vs 88%, P<0.001). CONCLUSION: Anesthesia with propofol combined with fentanyl may reduce the maintenance dosage of propofol, shorten the time of consciousness recovery during oocyte retrieval with ultrasound guidance, and can be helpful for the patients' early recovery and discharge from hospital.

[Anesthetic management during resection of intratracheal tumor: report of 23 cases].

OBJECTIVE: To summarize our experience in anaesthetic management during the resection of intratracheal tumor. METHODS: A retrospective analysis of the anaesthetic management was conducted in 23 cases of intratracheal tumor resection. The anaesthetic methods were determined according to the location of tumor, the degree of tracheal obstruction and the surgical procedures. RESULTS: No severe complications occurred in relation to the anesthetic procedures. During the operation, the saturation of pulse oxygen (SpO(2)) transiently decreased to below 90 % in 5 cases (21.7 %) but recovered to normal level by aspiration of airway secretions and/or lung inflation. Seventeen patients (73.9 %) were extubated after the operation and returned to the ward safely, while another 6 (26.1 %) were sent to intensive care unit and extubated within 24 h. CONCLUSION: Case-specific anaesthetic plan is necessary before the operation, and it is crucial to maintain good ventilation without interfering with the surgical procedures during the operation.