Fluorescent aptasensor for the ultrasensitive detection of antibiotic residue in food samples based on dumbbell DNA-mediated signal amplification.

Sensitive and reliable detection of antibiotics is of great significance for environmental and food safety due to its high risk in trace concentrations. Herein, we developed a fluorescence sensing system for chloramphenicol (CAP) detection based on dumbbell DNA-mediated signal amplification. Two hairpin dimers (2H1 and 2H2) were employed as the building blocks to construct the sensing scaffolds. The CAP-aptamer binding in another hairpin H0 can liberate the trigger DNA, which then activates the cyclic assembly reaction between 2H1 and 2H2. The separation of FAM and BHQ in the formed product of cascaded DNA ladder yields a high fluorescence signal for CAP monitoring. Compared with the monomer hairpin assembly between H1 and H2, the dimer hairpin assembly between 2H1 and 2H2 exhibits enhanced signal amplification efficiency and reduced reaction time. The developed CAP sensor showed a wide linear range from 10 fM to 10 nM with a detection limit of 2 fM. Importantly, this sensing platform has been successfully applied to the determination of CAP in fish, milk, and water samples with satisfactory recovery and accuracy. With the advantages of high sensitivity, mix-and-read pattern, and robustness, our proposed CAP sensor can be used as a simple and routine tool for the detection of trace amounts of antibiotic residues.

Portable biosensor for on-site detection of kanamycin in water samples based on CRISPR-Cas12a and an off-the-shelf glucometer.

On-site and cost-effective monitoring of antibiotic residue in water samples using a ubiquitous device that is readily available to the general public is a big challenge. Herein, we developed a portable biosensor for kanamycin (KAN) detection based on a glucometer and CRISPR-Cas12a. The aptamer-KAN interactions liberate the trigger C strand, which can initiate the hairpin assembly to produce numerous double-stranded DNA. After recognition by CRISPR-Cas12a, Cas12a can cleave the magnetic bead and invertase-modified single-stranded DNA. After magnetic separation, the invertase can convert sucrose into glucose, which can be quantified by a glucometer. The linear range of the glucometer biosensor is from 1 pM to 100 nM and the detection limit is 1 pM. The biosensor also exhibited high selectivity and the nontarget antibiotics had no significant interference with KAN detection. The sensing system is robust and can work in complex samples with excellent accuracy and reliability. The recovery values were in the range of 89-107.2 % for water samples and 86-106.5 % for milk samples. The relative standard deviation (RSD) was below 5 %. With the advantages of simple operation, low cost, and easy accessibility to the public, this portable pocket-sized sensor can realize the on-site detection of antibiotic residue in resource-limited settings.

Ultrasensitive Aptasensor for Microcystin-LR Detection in Food Samples Based on Target-Activated Assembly of Y-Shaped Hairpin Probes.

As a kind of algal toxin, microcystin-LR (MC-LR) causes a tremendous treat to food safety and the detection of trace levels of MC-LR is highly desirable. Herein, we developed an ultrasensitive aptasensor for MC-LR detection based on target-activated assembly of Y-shaped hairpins. The aptamer-target recognition initiates the assembly step between two Y-shaped hairpin probes through toehold-mediated DNA replacement. One of the hairpins was modified with FAM and BHQ. Through cyclic assembly reactions, a high fluorescence signal can be observed in the product. The detection limit is 0.2 pM for MC-LR detection. In addition, the biosensor is robust and has been successfully explored to assess the MC-LR concentrations in real fish and water samples with satisfactory recovery rates and good accuracy. The signal amplification can be gained through the cyclic Y-shaped hairpin assembly, which offers a simple, ultrasensitive, and reliable method for MC-LR monitoring in food samples.

Fluorescent Detection of Two Pesticides Based on CRISPR-Cas12a and Its Application for the Construction of Four Molecular Logic Gates.

An intelligent detection platform was developed through molecular logic gate operation based on CRISPR-Cas12a and signal amplification circuits using two kinds of pesticides [acetamiprid (ACE) and atrazine (ATR)] as inputs. The pesticide-aptamer bindings activate the signal amplification process to produce numerous double-stranded DNA, which can be identified by CRISPR-Cas12a. Under the optimal assay conditions, the sensor exhibits excellent analytical performance, with the detection limits for ACE and ATR of 2.5 and 0.2 pM, respectively. The practicality of the platform was verified by testing pesticide concentrations in food samples. Several molecular logic gates (OR, AND, XOR, and INHIBIT) were constructed using "0" and "1" to encode the target pesticides and the fluorescence readout. The logic detection platform with simple operation, high sensitivity, and multiple logic functions is promising to become a powerful sensing system for the intelligent assay of different pesticides in food samples.

Toehold-Mediated Cascade Catalytic Assembly for Mycotoxin Detection and Its Logic Applications.

In this work, an enzyme-free biosensor is reported for mycotoxin detection based on a toehold-mediated catalytic hairpin assembly (CHA) and a DNAzyme-cascaded hydrolysis reaction. In the presence of a mycotoxin, the recognition between an aptamer and the mycotoxin releases the trigger DNA. The trigger DNA initiates the toehold-mediated CHA, generating large amounts of partial duplex B/C with four toeholds, which can be used to assemble the DNAzyme-cascaded hydrolysis reaction. Furthermore, through a collaborative autoassembly reaction among the B/C duplex, DNA1, and DNA2, supramolecular nanostructures corresponding to Mg2+-dependent DNAzymes can be formed. With the incubation of Mg2+, the dual-modified (TAMRA/BHQ2) substrate strand DNA2 will be cleaved into two fragments, yielding a high TAMRA fluorescence signal for mycotoxin testing. Under optimal conditions, the sensing system was ultrasensitive and showed low detection limits of 0.2 pM for ochratoxin A (OTA), 0.13 pM for aflatoxin B1 (AFB1), and 0.17 pM for zearalenone (ZEN). The mycotoxin aptasensor also exhibited high selectivity and was successfully applied for the quantitative analysis of OTA, AFB1, and ZEN in wine samples. Due to the advantages of flexibility and versatility, this mycotoxin platform was used to fabricate several concatenated logic gates including "AND-INHIBIT", "INHIBIT-OR", "OR-AND", and "OR-INHIBIT" logic biocomputings. Such multiple functions of the logic system provided a universal sensing strategy for the intelligent detection of multiplex mycotoxins, demonstrating considerable potential in food safety and environmental monitoring.

Continuous Rhomboid Intercostal Block for Thoracoscopic Postoperative Analgesia.

BACKGROUND: Rhomboid intercostal block is a type of plane block used for postoperative analgesia after video-assisted thoracoscopic surgery. This prospective randomized controlled trial was conducted to investigate the effects of ultrasound-guided continuous rhomboid intercostal block (CRIB) on the global Quality of Recovery (QoR-40) scores and postoperative analgesia after video-assisted thoracoscopic surgery. METHODS: A total of 66 adult patients scheduled for elective unilateral video-assisted thoracoscopic surgery were randomly allocated to group C and group CRIB. In group C, patients were administered patient-controlled intravenous analgesia with sufentanil after operation. Patients in group CRIB received patient-controlled analgesia with ropivacaine CRIB. All patients completed the QoR-40 test during the preoperative evaluation and again 24 hours after the operation. Information on 48-hour postoperative pain and adverse events was recorded. RESULTS: The QoR-40 scores of group C were significantly lower than the scores of group CRIB (155.4 ± 6.1 vs 172.6 ± 6.3; P < .001), with a mean difference of -17.2 (95% CI, -20.4 to -13.9) 24 hours after operation. The postoperative numeric rating scale scores in group CRIB at 6, 12, 18, and 24 hours after the surgical procedure, when patients were at rest, were significantly lower than the scores in group C (all P < .05). The postoperative numeric rating scale scores in group CRIB at 1, 3, 6, 12, 18, 24, and 36 hours after surgical procedure, when patients were moving, were significantly lower than the scores in group C (all P < .05). CONCLUSIONS: In patients who underwent video-assisted thoracoscopic surgery, CRIB led to improved quality of recovery and postoperative analgesia.

Visual Test Paper for on-Site Polychlorinated Biphenyls Detection and Its Logic Gate Applications.

A visual detection method was proposed for polychlorinated biphenyls (PCBs) detection using lateral flow test paper as the sensing platform. The aptamer sequence was used to recognize the target 3,3',4,4'-tetrachlorobiphenyl (PCB77). The integration of Zn2+-dependent DNAzyme with toehold-mediated strand displacement reaction significantly improved the response signals. Gold nanoparticles were utilized as the signal tracers in the test paper, making the results visible directly by the naked eye. Under optimal conditions, the paper enables the visual detection of PCB77 as low as 10 pM without additional instrumentation. The assay displays a high selectivity for PCB77 against potential interfering molecules. The visual test paper is robust and has been applied to the detection of PCB77 in milk samples with good recovery and satisfactory accuracy. Using two different PCBs (PCB77 and PCB72) as inputs, we further fabricated OR and AND logic gates, which is conducive to the development of an intelligent detection strategy for PCBs monitoring. Given the attractive characteristics of disposability, low cost, logic operation, and intuitive output, the test paper shows great promise for on-site screening of PCBs in resource-limited areas.

Scalable Logic Circuits with Multiple Outputs and an Automatic Reset Function Based on DNAzyme-Mediated Branch Migration.

A scalable logic platform made up of multilayer DNA circuits was constructed using Pb2+, Cu2+, and Zn2+ as the three inputs and three different fluorescent signals as the outputs. DNAzyme-guided cyclic cleavage reactions and DNA toehold-mediated strand branch migration were utilized to organize and connect nucleic acid probes for building the high-level logic architecture. The sequence communications between each circuit enable the logic network to work as a keypad lock, which is an information protection model at the molecular level. The multi-output mode was used to monitor the gradual unlocking process of the security system, from which one can determine which password is correct or not immediately. The autocatalytic cleavage of DNAzyme makes the biocomputing circuit feasible to realize the reset function automatically without external stimuli. Importantly, the logic platform is robust and can work effectively even in complex environmental samples.

Effect of Therapy of Tonifying Kidney,Activating Bone-marrow,and Unblocking Collaterals on Thromboelastogram Platelet Maximum Amplitude Value of Patients with Chronic Aplastic Anemia / 广州中医药大学学报

Objective To observe the therapeutic effect of therapy of tonifying kidney,activating bone-marrow, and unblocking collaterals for patients with chronic aplastic anemia (CAA), and to investigate its effect on thromboelastogram platelet maximum amplitude (Ma) value for exlporing its therapeutic mechanism. Methods Sixty CAA patients were randomized into trial group and control group, 30 cases in each group. The control group was given oral use of Stanozolol and Cyclosporin A, and the trial group was orally given the recipe with the actions of tonifying kidney,activating bone-marrow,and unblocking collaterals,which is mainly composed of Radix Rehmanniae,Radix Rehmanniae Preparata,Caulis Spatholobi,Semen Cuscutae,Fructus Lycii,Radix Angelicae Sinensis, Fructus Ligustri Lucidi, Herba Ecliptae, Pheretima, and Semen Strychni Preparata. The clinical efficacy was evaluated after treatment,and peripheral hemogram and thromboelastogram Ma value of the two groups were compared before and after treatment. Results (1)The trial group had better western medicine therapeutic effect and traditional Chinese medicine (TCM)syndrome therapeutic effect than the control group, the difference being signficant (P < 0.01).(2) After treatment, TCM syndrome scores, parameters of blood routine test,thromboelastogram Ma value of the two groups were improved compared with those before treatment (P < 0.05 or P < 0.01),and the improvement in the trial group was superior to that in the control group (P <0.05). Conclusion Therapy of tonifying kidney, activating bone-marrow, and unblocking collaterals is effective on improving blood coagulation function by increasing the quality and amount of platelet.

Stress-Induced Cubic-to-Hexagonal Phase Transformation in Perovskite Nanothin Films.

The strong coupling between crystal structure and mechanical deformation can stabilize low-symmetry phases from high-symmetry phases or induce novel phase transformation in oxide thin films. Stress-induced structural phase transformation in oxide thin films has drawn more and more attention due to its significant influence on the functionalities of the materials. Here, we discovered experimentally a novel stress-induced cubic-to-hexagonal phase transformation in the perovskite nanothin films of barium titanate (BaTiO3) with a special thermomechanical treatment (TMT), where BaTiO3 nanothin films under various stresses are annealed at temperature of 575 °C. Both high-resolution transmission electron microscopy and Raman spectroscopy show a higher density of hexagonal phase in the perovskite thin film under higher tensile stress. Both X-ray photoelectron spectroscopy and electron energy loss spectroscopy does not detect any change in the valence state of Ti atoms, thereby excluding the mechanism of oxygen vacancy induced cubic-to-hexagonal (c-to-h) phase transformation. First-principles calculations show that the c-to-h phase transformation can be completed by lattice shear at elevated temperature, which is consistent with the experimental observation. The applied bending plus the residual tensile stress produces shear stress in the nanothin film. The thermal energy at the elevated temperature assists the shear stress to overcome the energy barriers during the c-to-h phase transformation. The stress-induced phase transformation in perovskite nanothin films with TMT provides materials scientists and engineers a novel approach to tailor nano/microstructures and properties of ferroelectric materials.

[Combined inflating lung and insufflating calf pulmonary surfactant under general anesthesia in the treatment of postoperative intractable atelectasis].

OBJECTIVE: To explore the efficacy and safety of combined inflating lung and insufflating calf pulmonary surfactant under general anesthesia for treating postoperative intractable atelectasis. METHODS: From August 2006 to January 2013, 15 patients with obstinate postoperative atelectasis receiving pressure control lung expansion were enrolled. The bronchial cannula was intubated into the affected side to assist the expanding of the lung, and the calf pulmonary surfactant was insufflated selectively. The chest auscultation and computed tomography (CT) scan was performed at 1 d and 5 d after the procedure respectively, to evaluation the effect. The airway pressure, mean arterial pressure (MAP), heart rate (HR), respiratory rate (RR) and oxygen saturation (SpO2) were recorded before the treatment, during the treatment and after the treatment.Monitoring arterial blood gas before and after treatment. RESULTS: After the expansion of the lung and insufflation of calf pulmonary surfactants, the iconographic scan showed that collapsed alveolar was reinflated in 12 (80.0%) patients at 1 d after the treatment and in 14 patients(93.3%) at 5 d after the procedure.There were not notable vital sign change and complications during the treatment.At after the treatment, 1, 3, 5 and 7 d after the treatment, PaO2 was higher (P < 0.05), and there were not significantly difference in the PaCO2 and pH (P > 0.05) . CONCLUSION: Combined pressure control lung expansion with selectively insufflating calf pulmonary surfactant under general anesthesia may be an effective therapy for postoperative intractable atelectasis.

[Effect of bronchial intubation for constant-pressure expanding ipsilateral lung on postoperatively intractable atelectasis in hypo-analgesia and muscle relaxation].

OBJECTIVE: To investigate the effect of bronchial intubation for constant-pressure expanding ipsilateral lung on postoperative intractable atelectasis. METHODS: For this prospective study, we recruited 18 patients with pulmonary atelectasis who could not been relieved by bronchoscopic suctioning, closed thoracic drainage, backslap, blowing hall and other routine treatments for over a week. After bronchial intubation, ipsilateral lung was expanded with a constant pressure. And the therapeutic effect was evaluated by chest radiographic examination and auscultation at the following day. RESULTS: Collapsed lung tissue were examined in 15 patients (83.3%) after the first treatment and in 2 patients (11.1%) after twice inflation. And another case failed even after three times treatment. During the procedure, the vital signs of all patients were stable and no complication occurred. CONCLUSION: Constant-pressure expanding of ipsilateral lung during bronchial intubation is a safe and effective treatment for postoperative intractable atelectasis.

Effects of early Xuebijing injection(血必净注射液) treatment on the change of prognosis in patients with multiple traumas / 中国中西医结合急救杂志

15 scores were randomly divided into therapeutic group (30 cases)and control group(30 cases).The two groups were treated with the same conventional therapy. From the 1st day of admission,Xuebijing injection 80 ml was given by intravenous drip once for every 12 hours for 7 days to the therapeutic group.The level of tumor necrosis factor-?(TNF-?),interleukin-1?(IL-1?),IL-6,IL-10,and APACHEⅡscore were tested on 1,3,5 and 7 days after admission.The case fatality and incidences rates of sepsis and MODS in both groups were recorded.Results Compared with the control group,APACHEⅡscore,TNF-?,IL-1?,IL-6 and IL-10 of the therapeutic group were lower significantly on the 3rd day after admission,especially on the 5th day(all P