A dopamine electrochemical sensor based on a platinum–silver graphene nanocomposite modified electrode

A platinum–silver graphene (Pt–Ag/Gr) nanocomposite modified electrode was fabricated for the electrochemical detection of dopamine (DA). Electrochemical studies of the Pt–Ag/Gr nanocomposite towards DA detection were performed by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The CV analysis showed that Pt–Ag/Gr/GCE had enhanced electrocatalytic activity towards DA oxidation due to the synergistic effects between the platinum–silver nanoparticles and graphene. The DPV results showed that the modified sensor demonstrated a linear concentration range between 0.1 and 60 μM with a limit of detection of 0.012 μM. The Pt–Ag/Gr/GCE presented satisfactory results for reproducibility, stability and selectivity. The prepared sensor also showed acceptable recoveries for a real sample study.

A platinum–silver graphene nanocomposite was synthesized and characterized. A nanocomposite modified electrode was fabricated in order to investigate the electrochemical detection of dopamine.     

Discovery of 4-(2-(dimethylamino)ethoxy)benzohydrazide derivatives as prospective microtubule affinity regulating kinase 4 inhibitors

Microtubule affinity regulating kinase 4 (MARK4) is a Ser/Thr kinase, considered as a potential drug target for cancer, diabetes and neurodegenerative diseases. Due to its significant role in the development and progression of cancer, different in-house libraries of synthesized small molecules were screened to identify potential MARK4 inhibitors. A small library of hydrazone compounds showed a considerable binding affinity to MARK4. The selected compounds were further scrutinized using an enzyme inhibition assay and finally two hydrazone derivatives (H4 and H19) were selected that show excellent inhibition (nM range). These compounds have a strong binding affinity for MARK4 and moderate binding with human serum albumin. Anticancer studies were performed on MCF-7 and A549 cells, suggesting H4 and H19 selectively inhibit the growth of cancer cells. The IC₅₀ value of compound H4 and H19 was found to be 27.39 μM and 34.37 μM for MCF-7 cells, while for A549 cells it was 45.24 μM and 61.50 μM, respectively. These compounds inhibited the colonogenic potential of cancer cells and induced apoptosis. Overall findings reflect that hydrazones/hydrazone derivatives could be exploited as potential lead molecules for developing effective anticancer therapies via targeting MARK4.

Inhibition studies of MARK4 with selected hydrazone derivatives.     

Metal oxide QD based ultrasensitive microsphere fluorescent sensor for copper,chromium and iron ions in water

Herein we developed a rapid, cheap, and water-soluble ultra-sensitive ZnO quantum dot (QD) based metal sensor for detecting different hazardous metal ions up to the picomolar range in water. Various spectroscopic and microscopic techniques confirmed the formation of 2.15 ± 0.46 μm of ZnO QD conjugated CMC microspheres (ZCM microspheres) which contain 5.5 ± 0.5 nm fluorescent zinc oxide (ZnO) QDs. Our system, as a promising sensor, exhibited excellent photostability and affinity towards various heavy metal ions. The detection limits were calculated to be 16 pM for Cu²⁺ and 0.18 nM for Cr⁶⁺ ions which are better than previously reported values. The simple fluorescence ‘turn off’ property of our ZCM microsphere sensor system can serve a two-in-one purpose by not only detecting the heavy metals but also quantifying them. Nonetheless, pattern recognition for different heavy metals helped us to detect and identify multiple heavy metal ions. Finally, their practical applications on real samples also demonstrated that the ZCM sensor can be effectively utilized for detection of Cr⁶⁺, Fe³⁺, Cu²⁺ present in the real water samples. This study may inspire future research and design of target fluorescent metal oxide QDs with specific functions.

Herein we developed a rapid, cheap, and water-soluble ultra-sensitive ZnO quantum dot (QD) based metal sensor for detecting different hazardous metal ions up to the picomolar range in water.     

Early outcomes of antireflux surgery for United States lung transplant recipients

Background

This study aimed to evaluate early outcomes after antireflux surgery for lung transplant (LTx) recipients in the United States.

Methods

Adult patients undergoing elective antireflux surgery between 2003 and 2008 were identified in the Nationwide Inpatient Sample. A propensity-matched analysis compared early outcomes between prior LTx recipients and well-matched control subjects consisting of non-LTx patients undergoing elective antireflux surgery during the same era. The primary outcome was inpatient mortality, and the secondary outcomes were hospital length of stay (LOS), perioperative complications, and hospital costs.

Results

During the study period, 401 LTx recipients underwent elective antireflux surgery. These patients were well matched with 401 control patients in terms of age, sex, individual and overall comorbidity burden, hospital teaching status, hospital location, hospital antireflux volume, and open versus laparoscopic approach. The overall operative mortality rate was 1.4 %, with no difference between the groups. The overall and individual morbidity rates also were similar. The LOS and hospital costs were significantly greater in the LTx group. Multivariable logistic regression analysis confirmed that prior LTx did not confer an increased risk of inpatient mortality after antireflux surgery.

Conclusions

To date, this is the largest study to examine outcomes of antireflux surgery for LTx recipients. Operative mortality and morbidity appear to be comparable with those of the general population, although resource utilization is greater. Based on these data, trials to evaluate the role of antireflux surgery in preserving allograft function after LTx should not be hindered by a perceived notion of prohibitive operative risk in this patient population.     

Copper mediated one-pot synthesis of quinazolinones and exploration of piperazine linked quinazoline derivatives as anti-mycobacterial agents

A facile method was developed for the synthesis of quinazolinone derivatives in a one-pot condensation reaction via in situ amine generation using ammonia as the amine source and with the formation of four new C–N bonds in good to excellent yields. With the optimised method, we synthesized a library of piperazine linked quinazoline derivatives and the synthesized compounds were evaluated for their inhibitory activity against Mycobacterium tuberculosis. The compounds 8b, 8e, 8f, 8m, 8n and 8v showed potent anti-mycobacterial activity with MIC values of 2–16 μg mL⁻¹. All the synthesized compounds follow Lipinski''s rules for drug likeness.

A facile method was developed for the synthesis of quinazolinone derivatives in a one-pot condensation reaction via in situ amine generation using ammonia as the amine source and with the formation of four new C–N bonds in good to excellent yields.     

Assessing the Validity of Western Measurement of Online Risks to Children in an Asian Context

Before the advent of the Internet, television and film was the only audio-visual medium to which most children were exposed. The risks were primarily limited to children being exposed to sexual and violent materials, the nature of which were known and easy to control. Nowadays, children are surrounded by a variety of digital media and are exposed to different risks, many of which are still unknown. The Internet is fully integrated into children’s daily lives, along with the potential risks. The present study aimed to (i) describe the level of risks children are exposed to, and (ii) test the measurement validity of a total of 45 items assessing nine scales of online risk to children that were adapted from studies carried out in Europe and the United States. The study comprised 420 schoolchildren. The results showed that children were more exposed to ‘unwanted exposure to pornography’ and less to ‘conduct risk’ (e.g., accidental illegal downloading; creating profiles on inappropriate websites). Boys and older children were more exposed to the risks compared to girls and younger children. The study validated five dimensions (inappropriate materials, sexting, contact-related risks, risky online sexual behavior, and bullying/being bullied) assessing online risk to children by using exploratory and confirmatory factor analyses. The study found that scales developed in Europe and the United States are not wholly suitable to an Asian context and needed to be modified. Further investigation to classify online risks to children and offer a solutions to reducing the online risks.     

Clinical characteristics of bipolar disorder in very young children

BACKGROUND: Clinical information about bipolar disorder (BPD) in preschool-age (3-7 years old) children is extremely limited. This study examined clinical presentations, applicability of the DSM-IV diagnostic criteria, comorbidity, recovery and relapse rates, as well as some treatment strategies used in the management of BPD in preschoolers. METHODS: The charts of 26 outpatient children, ages 3-7, refereed to a child psychiatry outpatient clinic with mood and behavioral symptoms, were retrospectively reviewed. RESULTS: The majority of the patients were referred with the tentative diagnosis of ADHD but the most common diagnoses made by child and adolescent psychiatrists at the time of initial evaluation were BPD NOS (61.5%), followed by BPD I (26.9%), and mood disorder NOS (23.1%). Thirty-eight percent of the patients had one or more comorbid diagnoses. The most common presenting symptoms were irritability (84.6%) and aggression (88.5%). The most widely prescribed class of medications after diagnosis in the clinic was atypical antipsychotics and mood stabilizers. Twenty-six percent of the patients were treated with a combination of atypical antipsychotics and mood stabilizers. LIMITATIONS: Retrospective design; small sample size; lack of a comparison group. CONCLUSIONS: The course of BPD with onset in preschool years is complicated with high recovery and relapse rates. The questions of development of age-appropriate diagnostic criteria, long-term prognosis and treatment strategies used in this population require further intensive investigation.