[Elesclomol-Cu Induces Cuproptosis in Human Acute Myeloid Leukemia Cells].

OBJECTIVE: To investigate the effects of elesclomol-Cu (ES-Cu) on the proliferation and cuproptosis of human acute myeloid leukemia (AML) cells. METHODS: The effects of ES-Cu on the proliferation of AML cells and the AML cells pre-treated with ammonium tetrathiomolybdate (TTM) were examined by CCK-8 assay. The Calcein/PI kit was used to detected the changes in activity and cytotoxicity of AML cells induced by ES-Cu. Flow cytometry and Cytation3 fully automated cell imaging multifunctional detection system were used to analyze DCFH-DA fluorescence intensity, so as to determine the level of reactive oxygen species (ROS). The GSH and GSSG detection kits were used to measure the intracellular GSH content. Western blot was used to detected the expression of cuproptosis-related proteins ATP7B, FDX1, DLAT and DPYD. RESULTS: ES-Cu inhibited the proliferation of Kasumi-1 and HL-60 cells in a concentration-dependent manner (r Kasumi-1=-0.99， r HL-60=-0.98). As the concentration of ES-Cu increased, the level of intracellular ROS also increased (P <0.01-0.001). TTM could significantly reverse the inhibitory effect of ES-Cu on cell proliferation and its promoting effect on ROS. With the increase of ES-Cu concentration, the content of GSH was decreased (r =-0.98), and Western blot showed that the protein expressions of ATP7B, FDX1, DLAT and DPYD were significantly reduced (P <0.05). CONCLUSION: ES-Cu can induce cuproptosis in AML cells, which provides a new idea for the treatment of AML.

Identification of agricultural surface source pollution in plain river network areas based on 3D-EEMs and convolutional neural networks.

Agricultural non-point sources, as major sources of organic pollution, continue to flow into the river network area of the Jiangnan Plain, posing a serious threat to the quality of water bodies, the ecological environment, and human health. Therefore, there is an urgent need for a method that can accurately identify various types of agricultural organic pollution to prevent the water ecosystems in the region from significant organic pollution. In this study, a network model called RA-GoogLeNet is proposed for accurately identifying agricultural organic pollution in the river network area of the Jiangnan Plain. RA-GoogLeNet uses fluorescence spectral data of agricultural non-point source water quality in Changzhou Changdang Lake Basin, based on GoogLeNet architecture, and adds an efficient channel attention (ECA) mechanism to its A-Inception module, which enables the model to automatically learn the importance of independent channel features. ResNet are used to connect each A-Reception module. The experimental results show that RA-GoogLeNet performs well in fluorescence spectral classification of water quality, with an accuracy of 96.3%, which is 1.2% higher than the baseline model, and has good recall and F1 score. This study provides powerful technical support for the traceability of agricultural organic pollution.

Model evaluation of total phosphorus prediction based on model accuracy and interpretability for the surface water in the river network of the Jiangnan Plain, China.

Due to climatic and hydrological changes and human activities, eutrophication and frequent outbreaks of cyanobacteria are prominent in the Jiangnan Plain basin of China. Therefore, building a suitable model to accurately predict the phosphorus concentration in surface water is of practical significance to prevent the above problems. This study built 10 models to predict the phosphorus element in the surface water of the river network in the Jiangnan Plain. The main water types in the basin include the Yangtze River, the Beijing-Hangzhou Canal, and the Gehu Lake. The 10 models in different datasets have been comprehensively evaluated by the prediction accuracy and interpretability of the model, and the calculation of the partial dependence diagram (PDP) and SHAP has proved that there is a transparent response relationship between phosphorus and different factors. The results show that the Yangtze River, Beijing-Hangzhou Canal, and Gehu Lake are suitable for random forest, linear regression, and random forest models, respectively, under the comprehensive evaluation of the prediction accuracy and interpretability of the model. Models with low prediction accuracy often show strong interpretability. In different water body types, turbidity, water temperature, and chlorophyll-a are the three factors that affect the model in predicting phosphorus.

Growth prediction of Microcystis aeruginosa based on a secondary decomposition integration model.

Microcystis aeruginosa is the dominant species in the blooms of eutrophic lakes such as Taihu Lake in China. Chlorophyll-a is one of the most common indicators to characterize its biomass. The nonlinearity and unsteadiness of the chlorophyll-a sequence decrease the prediction accuracy. In this paper, a secondary decomposition prediction method based on the integration of wavelet decomposition, variational modal decomposition, and gated recurrent unit (WD-VMD-GRU) is proposed. First, the original sequence is decomposed once using wavelet decomposition (WD). Then, the components with higher sample entropy values are decomposed using variational modal decomposition (VMD). Finally, each component is predicted using a gated recurrent unit (GRU), and the final prediction results are obtained by reconstructing each component result. The decomposition effect is ranked as VMD > WD > CEEMDAN > EMD. The WD-VMD-GRU model has a significant advantage compared to the basic model, with an increase of over 6.5% in R2. The secondary decomposition reduces the difficulty of predicting GRU components and has better prediction performance. The RMSE, MAE, and R2 were 1.752, 1.450, 0.969 at 2-day prediction, and 3.169, 2.711, 0.908 at 6-day prediction. Therefore, the WD-VMD-GRU model is superior in accuracy to other methods and can provide a scientific basis for the growth prediction research of M. aeruginosa.

Association of CFH and MAP1LC3B gene polymorphisms with age-related macular degeneration in a high-altitude population.

AIM: To evaluate the association of complement factor H (CFH) and microtubule-associated protein 1 light chain 3 beta (MAP1LC3B) gene polymorphisms with the risk of age-related macular degeneration (AMD) in a high-altitude population. METHODS: The study group consisted of 172 participants with symptoms of AMD who were examined and diagnosed between January 2019 and June 2020. The control group was composed of 120 healthy individuals. Each participant was required to provide two milliliters of peripheral blood for DNA extraction. Two single nucleotide polymorphisms (SNPs) of CFH (rs1061170 and rs800292) and two SNPs of MAP1LC3B (rs8044820 and rs9903) were genotyped. The genotypes and allele frequencies of the SNPs in the study and control groups were further compared using Chi-square and Fisher's exact tests. RESULTS: In a high-altitude population, the nominally significant differences of rs800292 and rs9903's genotype AG frequencies were observed in the AMD group (P=0.034 and 0.004, respectively). The frequencies of allele G of rs800292 and allele A of rs9903 were also significantly different in the AMD group compared to the control [(P=0.034, OR=0.70, 95%CI: 0.50-0.98) and (P=0.004, OR=1.60, 95%CI: 1.15-2.22), respectively]. No significant differences in the genotype distributions (P=0.16 and 0.40, respectively) and allele frequencies (P>0.05) of rs1061170 and rs8044820 were observed in the AMD group. CONCLUSION: Genotype AG of rs800292 may be a protective factor for AMD. Conversely, rs9903 seems to be a risk factor for AMD. Therefore, allele G of rs800292 may be a protective factor, and allele A of rs9903, a risk factor for AMD in Qinghai high-altitude population.

Bioequivalence of two tablet formulations of cefpodoxime proxetil in beagle dogs.

The pharmacokinetic profiles and bioequivalence of two cefpodoxime proxetil tablets were investigated in Beagle dogs. A single-dose, four-way complete replication and crossover design was used in the present study. A total of 28 healthy Beagle dogs (half male and female) with an average body weight of 11.1 kg were randomly allocated to this study. A whole reference or test tablet containing the equivalent of 100 mg of cefpodoxime was administered orally to each dog. Serial plasma samples were collected, and cefpodoxime concentrations were determined by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS). Then a non-compartmental method was used to calculate the pharmacokinetic parameters of both tablet formulations. The average bioequivalence (ABE) or reference-scaled average bioequivalence (RSABE) methods were used to determine the 90% confidence interval (CI) of AUCINF_obs and Cmax. No significant differences were observed for both parameters between both tablets. The test formulation was bioequivalent to the reference one because the 90% CI ranges of Cmax and AUCINF_obs were all between 80 and 125%.

High incidence of multi-drug resistance and heterogeneity of mobile genetic elements in Escherichia coli isolates from diseased ducks in Sichuan province of China.

Harmonious ecological environment is a major concern with rising feeding and consumption of ducks, as these waterfowl birds can promote the spread of antibiotic resistant genes (ARGs). Therefore, this study was conducted to know diversity of antimicrobial resistance (AMR), integrons, and mobile genetic elements (MGEs) in Escherichia coli (E. coli) isolated from intestinal contents or pericardial effusion of diseased ducks from 2018 to 2020 in Sichuan, China. The AMR phenotype was determined via disk diffusion test in 165 E. coli isolates. Further, the integrase genes of integron (intI1, intI2 and intI3 genes), gene cassettes (GCs) and MGEs were screened by PCR and sequencing. The results indicated 100% isolates were resistant to at least one antibiotic and 98.8% were multidrug-resistant strains. Highest AMR phenotype was recorded to rifampin (97.0%) followed by ampicillin (95.8%), chloramphenicol (89.7%), trimethoprim-sulfamethoxazole (84.2%), ciprofloxacin (83.0%), cefotaxime (80.0%), streptomycin (75.8%), doxycycline (49.7%), amikacin (10.3%), amoxicillin/clavulanic acid (3.6%), polymyxin B (1.2%) and ertapenem (0.6%). Further, class 1 and 2 integrons were found in 87.3% and 17.6% isolates, respectively. All isolates were negative for intI3 gene. The variable region of class 1 and 2 integrons contained total 13 different GCs, including arr-3+dfrA27, dfrA1+aadA1, dfrA17+aadA5, dfrA12, dfrA1+sat2+aadA1, dfrA12+aadA2, dfrA5, aadA2+ere(A)+dfrA32, aac(6')-Ib-cr, aadA22, aadA5, dfrA17, and dfrA27. Moreover, 13 MGEs in 69 different combinations were observed with predominance of IS26 followed by tnpA/Tn21, trbC, ISEcp1, merA, ISAba1, tnsA, tnsB, tnsC, IS1133, tnsD, ISCR3/14, and tnsE. Thus, the monitoring of integrons, MGEs and ARGs is important to understand the complex mechanism of AMR, which might help to introduce interventions for prevention and control of AMR in duck farms in China.

Distribution and association of antimicrobial resistance and virulence traits in Escherichia coli isolates from healthy waterfowls in Hainan, China.

There are rising concerns about microbes harboring antibiotic resistance genes (ARGs) and virulence-associated genes (VAGs) in humans and food-producing animals. Moreover, ARGs are considered as emerging environmental pollutants, posing probable life-threatening complications in humans and animals. Commensal Escherichia coli (E. coli) strain can carry a large number of VAGs, which may become opportunistic pathogen. The objective of this study was to determine the prevalence and possible association of ARGs and VAGs in E. coli isolates from clinically healthy waterfowls in China's tropical island, Hainan. For this purpose, 311 non-repeating E. coli isolates were evaluated for phenotypic drug resistance linked with ARGs. Additionally, strains were examined for subsequent resistance and virulence genes by uniplex or multiplex PCR and sequencing. Overall, 89 types of antibiotic resistance patterns were analysed, while 25 ARGs and 23 VAGs were observed, of which qnrS (99.4%) and iucD (99.7%) were the most commonly found genes, respectively. Significant positive associations were observed among ARGs and VAGs (p<0.05, OR>1). The strongest association between resistance and virulence gene was observed for qnrS and iss (OR, 76.25; 95% CI, 4.02-1445.42). Our results propose that waterfowls serve as a reservoir of E. coli carrying multi ARGs and various ExPEC associated VAGs. Therefore, this study provides necessary information on the occurrence and possible associations of ARGs and VAGs in healthy waterfowls, which may act as a reference for the regulatory use of antibiotics to stop the direct or indirect spread of these resistant and potential virulent microbes to natural environment.

Stretching Force of Incision Affects Early Clinical Results After Primary Total Knee Arthroplasty: A Retrospective Study.

OBJECTIVE: To investigate the impact of different skin incisions on recovery from total knee arthroplasty (TKA). METHODS: This is a retrospective study conducted in a tertiary hospital. A total of 1210 patients accepted primary and unilateral total knee arthroplasty (TKA) at the authors' affiliated institutions between January 2015 and January 2019. Patients who accepted primary and unilateral TKA due to OA under epidural anesthesia were included. Excluded cases included patients who had no completed follow-up; preoperative flexion contracture greater than 15° and preoperative flexion less than 90°; paresthesia in lower limb; scar within the knee area; patella alta or baja. We recorded and analyzed the following data, including each patient's characteristics, incision stretching index (IS index), perioperative information, and follow-up assessments. Patients were grouped by trisecting the range of IS index we observed in the present study. The primary outcome measure was the visual analog scale (VAS) pain score rated on a scale of 0-10 from no pain to severe pain. Secondary outcome measures include knee girth reflecting postoperative swelling, knee range of motion (ROM), sensory testing, and the strength of quadriceps. These measures were completed 2 weeks postoperatively. RESULTS: A total of 1089 patients undergoing primary and unilateral TKA in our two institutions were screened for final analysis, and 121 ones were excluded. The patients were followed up for an average of 13.3 months postoperatively. The mean length of FL was 28.3 cm (range: 21.0-38.8 cm). The mean IS index was 2.7 cm (range: 0.4-5.1 cm). We found no significant difference in those data among groups (P > 0.05). VAS pain scores among group IS A, IS B, and IS C were significantly different (2.3 ± 0.6 vs 3.4 ± 1.6 vs 3.9 ± 1.5, P = 0.0001). Similar situations were seen in knee circumference, ROM, area of abnormal sensation, and quadriceps strength among groups (all P < 0.05). With the increase in the IS index, VAS pain score, knee circumference, area of abnormal sensation, and incision problems were significantly increased (P < 0.05). At the same time, ROM and the strength of quadriceps decreased (P < 0.05). With the increase in the IS index, the number of patients with incision problems was increased significantly (P < 0.05). Besides, no significant difference in PJI and DVT among groups was observed (P > 0.05). CONCLUSIONS: Proper incision stretching can improve postoperative pain relief, surgical swelling, ROM, sensory disturbance of the knee, and the strength of quadriceps with reduced risk of incision complications.

Raloxifene Prevents Early Periprosthetic Bone Loss for Postmenopausal Women after Uncemented Total Hip Arthroplasty: A Randomized Placebo-Controlled Clinical Trial.

OBJECTIVE: To examine the results of raloxifene for prevention of periprosthetic bone loss around the femoral stem in patients undergoing total hip arthroplasty (THA). METHODS: Between January 2015 and May 2017, 240 female patients between 55 and 80 years underwent primary THA and were randomly allocated to receive 60 mg raloxifene hydrochloride per day (treatment group, TG, n = 120) or placebo (control group, CG, n = 120) orally at bedtime using computer-generated randomization sequence generation. Baseline data, the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC), women's quality of life (QoL) score, bone mineral density (BMD) around the prosthesis, and adverse events were compared between the two groups. The measuring range of BMD around the prosthesis was divided into seven regions of interest (ROI). The sample size was calculated to detect a mean difference in BMD of 0.15 g/cm2 with a standard deviation (SD) of 0.3. The error was set at 0.05 and the power level at 90% with additional compensation for a possible dropout rate of 20%. RESULTS: A total of 240 participants in the study up to 24 months after THA. There were no significant differences in the mean BMD of all the zones between groups before surgery (all P > 0.05). However, there were significant differences in the BMD of Gruen zones 4 and 7 between groups at 6 months postoperatively (both P < 0.05); there were significant differences in Gruen zones 1, 4, 6, and 7 at 12 months postoperatively (all P < 0.01); there were significant differences in Gruen zones 1, 2, 4, 6, and 7 at 24 months postoperatively (all P < 0.001). Patients taking raloxifene reported higher QoL scores, with better improvement in BMD in all areas except in zones 3 and 5 compared with the control group. There were no significant differences in WOMAC pain (P = 0.4045), WOMAC function (P = 0.4456) and women's QoL scores (P = 0.5983) between groups before surgery. However, WOMAC pain, WOMAC function and women's QoL score in the treatment group were significantly better at all time points (all P < 0.05). Patients in the treatment group showed no increased adverse events, including cardiac events, stroke, venous thromboembolism, and gynecological cancer (all P > 0.05), but did show decreased odds of breast cancer in comparison with those using a placebo (P = 0.0437). CONCLUSION: Raloxifene can help inhibit bone loss around the prosthesis and improve the QoL of postmenopausal women after THA with no increased adverse events, and can even decrease the odds of breast cancer.

High prevalence of CTX-M belonging to ST410 and ST889 among ESBL producing E. coli isolates from waterfowl birds in China's tropical island, Hainan.

The epidemiology and genetic characteristics of extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli (E. coli) have been widely studied in human and veterinary settings. ESBL-producing E. coli are generally reported in pigs, poultry, and dairy farm animals. Here, we report on the prevalence and genetic characteristics of beta-lactamase producing E. coli isolated from waterfowl birds in Hainan, China. After phenotypic confirmation, genes encoding blaCTX-M, blaSHV and blaTEM were detected by polymerase chain reaction (PCR). The isolates were assigned to different phylogenetic groups, and multi-locus sequence typing (MLST). Taken as a whole, 289 (92.9%) out of 311 E. coli isolates from waterfowl birds were confirmed as ESBL phenotypes by double-disk synergy testing. Subsequent PCR analysis revealed that blaCTX-M was the predominant ESBL gene identified in 146 (46.9%) isolates, followed by the combination of blaCTX-M and blaTEM in 70 (22.5%) isolates. The majority of these positive isolates were assigned to phylogroup B2 (46.2%) followed by phylogroup A (43.6%). In addition, MLST assigned representative ESBL positive isolates (n = 40) to 18 STs, and ST410 (ST23cplx) was the most prevalent population (22.5%). The high prevalence of CTX-M and STs frequently associating with E. coli infections should be of concern as it poses threats to animal and public health. To the best of our knowledge, this is the first comprehensive study to report on the occurrence of ESBL producing E. coli from waterfowl birds in China.

Engineering of Heterojunction-Mediated Biointerface for Photoelectrochemical Aptasensing: Case of Direct Z-Scheme CdTe-Bi2S3 Heterojunction with Improved Visible-Light-Driven Photoelectrical Conversion Efficiency.

This work presents a heterojunction-mediated photoelectrochemical (PEC) biointerface for selective detection of microcystin-LR (MC-LR) by introducing a direct Z-scheme heterojunction as efficient visible-light-driven photoactive species. Specifically, the Z-scheme type CdTe-Bi2S3 heterojunction was designed and synthesized as an ideal photoactive material, which exhibited higher PEC activity as compared with either CdTe quantum dots or Bi2S3 nanorods due to the improved photogenerated charges separation efficiency of heterojunction. Then the MC-LR aptamer was employed for selective recognition of MC-LR target, which was immobilized on the CdTe-Bi2S3 film by the formation of phosphor-amidate bonds between the phosphate group of aptamer and amino group of the chitosan film on the electrode. The proposed aptasensor showed a photocurrent signal due to the photoactive CdTe-Bi2S3 heterojunction, while the presence of MC-LR resulted in a dose-responsive decrease in PEC response, which allowed the quantification analysis of MC-LR by measuring the photocurrent signal of the fabricated aptasensor. Under optimal conditions, the resulted PEC aptasensor showed wide linear range (0.01-100 pM) and low detection limit (0.005 pM) for MC-LR determination with high selectivity and acceptable reproducibility. Finally, the proposed aptasensing method was successfully applied in MC-LR detection in real water samples.

Butein inhibits cell proliferation and induces cell cycle arrest in acute lymphoblastic leukemia via FOXO3a/p27kip1 pathway.

Acute lymphoblastic leukemia (ALL) is a common hematological malignancy characterized by the uncontrolled proliferation of leukemia cells in children. Discovering and developing effective chemotherapeutic drugs are needed for ALL. In this study, we investigated the anti-leukemic activity of butein and its action mechanisms in ALL. Butein was found to significantly suppress the cellular proliferation of ALL cell lines and primary ALL blasts in a dose-dependent manner. It also induced cell cycle arrest by decreasing the expression of cyclin E and CDK2. We also found that butein promoted nuclear Forkhead Class box O3a (FOXO3a) localization, enhanced the binding of FOXO3a on the p27kip1 gene promoter and then increased the expression of p27kip1. Moreover, we showed that FOXO3a knockdown significantly decreased the proliferation inhibition by butein, whereas overexpression of FOXO3a enhanced the butein-mediated proliferation inhibition. However, overexpression of FOXO3a mutation (C-terminally truncated FOXO3a DNA-binding domain) decreased the proliferation inhibition by butein through decreasing the expression of p27kip1. Our results therefore demonstrate the therapeutic potential of butein for ALL via FOXO3a/p27kip1 pathway.

4-Hydroxy cinnamic acid as mushroom preservation: Anti-tyrosinase activity kinetics and application.

Tyrosinase is a key enzyme in post-harvest browning of fruit and vegetable. To control and inhibit its activity is the most effective method for delaying the browning and extend the shelf life. In this paper, the inhibitory kinetics of 4-hydroxy cinnamic acid on mushroom tyrosinase was investigated using the kinetics method of substrate reaction. The results showed that the inhibition of tyrosinase by 4-hydroxy cinnamic acid was a slow, reversible reaction with fractional remaining activity. The microscopic rate constants were determined for the reaction on 4-hydroxy cinnamic acid with tyrosinase. Furthermore, the molecular docking was used to simulate 4-hydroxy cinnamic acid dock with tyrosinase. The results showed that 4-hydroxy cinnamic acid interacted with the enzyme active site mainly through the hydroxy competed with the substrate hydroxy group. The cytotoxicity study of 4-hydroxy cinnamic acid indicated that it had no effects on the proliferation of normal liver cells. Moreover, the results of effects of 4-hydroxy cinnamic acid on the preservation of mushroom showed that it could delay the mushroom browning. These results provide a comprehensive underlying the inhibitory mechanisms of 4-hydroxy cinnamic acid and its delaying post-harvest browning, that is beneficial for the application of this compound.

Amplified solid-state electrochemiluminescence detection of cholesterol in near-infrared range based on CdTe quantum dots decorated multiwalled carbon nanotubes@reduced graphene oxide nanoribbons.

An amplified solid-state electrochemiluminescence (ECL) biosensor for detection of cholesterol in near-infrared (NIR) range was constructed based on CdTe quantum dots (QDs) decorated multiwalled carbon nanotubes@reduced graphene nanoribbons (CdTe-MWCNTs@rGONRs), which were prepared by electrostatic interactions. The CdTe QDs decorated on the MWCNTs@rGONRs resulted in the amplified ECL intensity by ~4.5 fold and decreased onset potential by ~100 mV. By immobilization of the cholesterol oxidase (ChOx) and NIR CdTe-MWCNTs@rGONRs on the electrode surface, a solid-state ECL biosensor for cholesterol detection was constructed. When cholesterol was added to the detection solution, the immobilized ChOx catalyzed the oxidation of cholesterol to generate H2O2, which could be used as the co-reactant in the ECL system of CdTe-MWCNTs@rGONRs. The as-prepared biosensor exhibited good performance for cholesterol detection including good reproducibility, selectivity, and acceptable linear range from 1 µM to 1mM with a relative low detection limit of 0.33 µM (S/N=3). The biosensor was successfully applied to the determination of cholesterol in biological fluid and food sample, which would open a new possibility for development of solid-state ECL biosensors with NIR emitters.

Label-free impedimetric aptasensor for detection of femtomole level acetamiprid using gold nanoparticles decorated multiwalled carbon nanotube-reduced graphene oxide nanoribbon composites.

Gold nanoparticles (Au NPs) decorated multiwalled carbon nanotube-reduced graphene oxide nanoribbon (Au/MWCNT-rGONR) composites were synthesized by a one-pot reaction. By employing the resulting Au/MWCNT-rGONR composites as the support for aptamer immobilization, we developed an ultrasensitive label-free electrochemical impedimetric aptasensor for acetamiprid detection, which was based on that the variation of electron transfer resistance was relevant to the formation of acetamiprid-aptamer complex at the modified electrode surface. Compared with pure Au NPs and MWCNT-rGONR, the Au/MWCNT-rGONR composites modified electrode was the most sensitive aptasensing platform for the determination of acetamiprid. The proposed aptasensor displayed a linear response for acetamiprid in the range from 5×10(-14) M to 1×10(-5) M with an extremely low detection limit of 1.7×10(-14) M (S/N=3). In addition, this impedimetric aptasensor possessed great advantages including the simple operation process, low-cost, selectivity and sensitivity, which provided a promising model for the aptamer-based detection with a direct impedimetric method.

"Signal on" electrochemiluminescence pentachlorophenol sensor based on luminol-MWCNTs@graphene oxide nanoribbons system.

A "signal on" electrochemiluminescence (ECL) sensor for pentachlorophenol (PCP) detection was constructed based on the amplified ECL of luminol at a multiwalled carbon nanotubes@graphene oxide nanoribbons (MWCNTs@GONRs) modified electrode. Due to the good electrocatalytic activity of MWCNTs@GONRs toward luminol system, the oxidation peak current of luminol at the MWCNTs@GONRs modified electrode was enhanced for ~6-fold than that of the bare electrode; and the ECL intensity of luminol was amplified for ~5.3-fold correspondingly. Furthermore, the amplified ECL signal of luminol was linear with the concentration of PCP in the range between 2 pg mL(-1) and 10 ng mL(-1) with a detection limit of 0.7 pg mL(-1) (S/N=3). With the merits of good reproducibility, acceptable stability, wide linear range, low detection limit and simplicity, the proposed luminol ECL sensor showed great potential in the field of analytical applications.

[Diagnostic value of serum procalcitonin in urinary tract infection].

OBJECTIVE: To analyze the serum level of procalcitonin (PCT) in urinary tract infection (UTI) patients with urinary obstruction or bacteremia, and to investigate the value of PCT in diagnosing UTI. METHODS: A total of 102 patients with UTI hospitalized from January to December 2013 in the Second Hospital of Tianjin Medical University were categorized into obstructed UTI (n=60) and non-obstructed UTI (n=42), whose serum PCT concentrations were compared. Blood cultures were implemented in 44 patients, including 13 with positive findings (bacteremia) and 31 with negative findings (non-bacteremia). Serum PCT levels were also compared between the bacteremia and non-bacteremia groups. Receiver operating characteristic (ROC) curves were constructed to illustrate the performance of PCT in diagnosing urinary obstruction and bacteremia. RESULTS: The median serum concentration of PCT in the obstructed UTI group (1.71 (0.10-53.20) mg/L)was higher than that in the non-obstructed UTI group (0.21 (0.10-10.00) mg/L, P<0.001); the serum concentration of PCT in the bacteremia group (2.73 (0.10-41.60) mg/L) was higher than that in the non-bacteremia group (0.42 (0.10-53.20) mg/L, P=0.030). The area under ROC curve of PCT in diagnosing urinary obstruction and bacteremia was 0.80 (95% CI 0.71-0.89) and 0.71 (95% CI 0.53-0.88). The maximum negative predictive value (NPV) was 0.90 and 0.87, respectively, when the serum concentrations of PCT diagnosing bacteremia and urinary obstruction was 0.51 mg/L and 0.35 mg/L. CONCLUSION: PCT may be of some value in diagnosing UTI with urinary obstruction or bacteremia.

Alpha-substituted derivatives of cinnamaldehyde as tyrosinase inhibitors: inhibitory mechanism and molecular analysis.

Alpha-substituted derivatives of cinnamaldehyde (alpha-bromocinnamaldehyde, alpha-chlorocinnamaldehyde, and alpha-methylcinnamaldehyde) were used as inhibitors on mushroom tyrosinase. The result showed that three compounds can reduce both monophenolase and diphenolase activity on tyrosinase, and the inhibition was reversible. The IC50 values of alpha-bromocinnamaldehyde, alpha-chlorocinnamaldehyde, and alpha-methylcinnamaldehyde were 0.075, 0.140, and 0.440 mM on monophenolase and 0.049, 0.110, and 0.450 mM on diphenolase, respectively. The inhibition types and constants on diphenolase for these inhibitors were further studied. The molecular inhibition mechanisms of tyrosinase by the derivatives were investigated by UV-scanning study, fluorescence quenching, and molecular docking. These assays demonstrated that the derivatives could decrease the formation of o-quinones, and all derivatives were static quenchers of mushroom tyrosinase. Docking results implied that they could not form metal interactions with the copper ions of the enzyme, whereas they could interact with the amino acid residues of active site center. This research on alpha-substituted derivatives of cinnamaldehyde as tyrosinase inhibitors would lead to advances in the field of antityrosinase.

Graphene quantum dots enhanced electrochemiluminescence of cadmium sulfide nanocrystals for ultrasensitive determination of pentachlorophenol.

An ultrasensitive electrochemiluminescence (ECL) sensor based on the ECL amplifying behavior of the graphene quantum dots-CdS nanocrystals (GQDs-CdS NCs) was constructed for the detection of pentachlorophenol (PCP). Because of the presence of doped GQDs, the resulting GQDs-CdS NCs exhibited 5-fold enhanced ECL intensity than pure CdS NCs with the ECL onset potential positively shifted by 80 mV. Furthermore, based on the effective inhibition of the ECL response of GQDs-CdS NCs film by PCP, a simple method for ultrasensitive determination of PCP was devised, which showed a wide linear range of 0.01-500 ng mL(-1) and a low detection limit of 3 pg mL(-1) (S/N = 3) with good stability, reproducibility and applicability for PCP detection in real water samples. Thus, it can be expected that GQDs-based composites with excellent performance may play a more important role in pesticide determination.