Enhancing the sensitivity of a surface plasmon resonance-based optical sensor for zinc ion detection by the modification of a gold thin film

Surface plasmon resonance (SPR) sensors as novel optical sensors for the detection of a variety of analytes have been receiving increasing attention and their sensitivity has become the research hotspot recently. In this study, the sensitivity of an SPR optical sensor was enhanced by modifying a gold thin film with a nanocrystalline cellulose (NCC)-based material for zinc ion (Zn²⁺) detection that exists in the environment due to industrial processing. By replacing the gold thin film with a novel modified-gold thin film, Zn²⁺ can be detected from the range of 0 to 10 ppm using SPR. It is believed that the Zn²⁺ may interact with the negative charge molecules that exist on the modified-gold thin film, and this was confirmed via X-ray photoelectron spectroscopy (XPS). Moreover, this modified-gold-SPR has a high sensitivity of 1.892° ppm⁻¹ up to 0.1 ppm with an enhanced detection of Zn²⁺ as low as 0.01 ppm. The SPR results also followed the Langmuir isotherm model with a binding affinity of 1.927 × 10³ M⁻¹, which further confirmed the sensitivity of the SPR sensor. In addition, using the modified-gold thin film, SPR has a higher affinity towards Zn²⁺ compared to other metal ions, i.e. Ni²⁺, Fe²⁺, Cr²⁺, Mn²⁺, and Co²⁺.

This work focus on sensitivity enhancement of surface plasmon resonance (SPR) optical sensor by modifying the gold thin film with nanocrystalline cellulose (NCC) based material for zinc ion (Zn²⁺) detection.     

Sustainable Production of Arecanut Husk Ash as Potential Silica Replacement for Synthesis of Silicate-Based Glass-Ceramics Materials

Arecanut husk (AH) was selected as a material for silica replacement in the synthesis process of glass-ceramics zinc silicate and also the fact that it has no traditional use and often being dumped and results in environmental issues. The process of pyrolysis was carried out at temperature 700 °C and above based on thermogravimetric analysis to produce arecanut husk ash (AHA). The average purity of the silica content in AHA ranged from 29.17% to 45.43%. Furthermore, zinc oxide was introduced to AHA and zinc silicate started to form at sintering temperature 700 °C and showed increased diffraction intensity upon higher sintering temperature of 600 °C to 1000 °C based on X-ray diffraction (XRD) analysis. The grain sizes of the zinc silicate increased from 1011 nm to 3518 nm based on the morphological studies carried out by field emission scanning electron microscopy (FESEM). In addition, the optical band gap of the sample was measured to be in the range from 2.410 eV to 2.697 eV after sintering temperature. From the data, it is believed that a cleaner production of low-cost zinc silicate can be achieved by using arecanut husk and have the potential to be used as phosphors materials.     

Factors associated with health-related quality of life (HRQOL) in adults with short stature skeletal dysplasias

Quality of Life Research - Numerous factors associate with health disparities. The extent to which such factors influence health-related quality of life (HRQOL) among adults with short stature...     

Effects of acute alcohol consumption on alcohol-related cognitive biases in light and heavy drinkers are task-dependent

We investigated (1) the effects of alcohol on cognitive biases for alcohol-related cues, (2) the effects of drinking status on alcohol-related cognitive biases and (3) the similarity of any effects of alcohol across two measures of alcohol cognitive bias. Healthy, heavy and light social alcohol users (n = 72) were examined in a single-blind placebo-controlled design. Participants received 0.00 g/kg, 0.13 g/kg or 0.40 g/kg of alcohol in a between-subjects design and then completed both a modified Stroop task and a visual probe task. Modified Stroop data indicated a main effect of cue type, which was qualified by drinking status, with heavier drinkers slower to respond to alcohol-related cues. Visual probe data, in contrast, indicated a significant interaction effect between validity (valid: alcohol-related, invalid: neutral) and drink condition. Participants receiving a moderate dose of alcohol (0.40 g/kg) were faster to respond to alcohol-related stimuli compared with participants receiving a low dose of alcohol or placebo. These data indicate that the cognitive processes assayed by the visual probe and Stroop tasks may not be mediated by a common underlying mechanism.     

Continuous and intermittent transcranial magnetic theta burst stimulation modify tactile learning performance and cortical protein expression in the rat differently

Repetitive transcranial magnetic stimulation (rTMS) can modulate cortical excitability in a stimulus-frequency-dependent manner. Two kinds of theta burst stimulation (TBS) [intermittent TBS (iTBS) and continuous TBS (cTBS)] modulate human cortical excitability differently, with iTBS increasing it and cTBS decreasing it. In rats, we recently showed that this is accompanied by changes in the cortical expression of proteins related to the activity of inhibitory neurons. Expression levels of the calcium-binding protein parvalbumin (PV) and of the 67-kDa isoform of glutamic acid decarboxylase (GAD67) were strongly reduced following iTBS, but not cTBS, whereas both increased expression of the 65-kDa isoform of glutamic acid decarboxylase. In the present study, to investigate possible functional consequences, we applied iTBS and cTBS to rats learning a tactile discrimination task. Conscious rats received either verum or sham rTMS prior to the task. Finally, to investigate how rTMS and learning effects interact, protein expression was determined for cortical areas directly involved in the task and for those either not, or indirectly, involved. We found that iTBS, but not cTBS, improved learning and strongly reduced cortical PV and GAD67 expression. However, the combination of learning and iTBS prevented this effect in those cortical areas involved in the task, but not in unrelated areas. We conclude that the improved learning found following iTBS is a result of the interaction of two effects, possibly in a homeostatic manner: a general weakening of inhibition mediated by the fast-spiking interneurons, and re-established activity in those neurons specifically involved in the learning task, leading to enhanced contrast between learning-induced and background activity.     

The prevention and management of anaphylaxis

Anaphylaxis is defined as a serious allergic reaction that is rapid in onset and may cause death. The incidence of anaphylaxis is increasing. Clinicians are highly likely to encounter a case during their career, hence they need to be equipped to make a diagnosis through taking a thorough history, mast cell tryptase levels and allergy testing. After confirming the allergen trigger, prevention of anaphylaxis is through avoidance of the allergen, optimal management of co-morbidities such as asthma, desensitization and adjuncts such as anti-IgE therapies. The management of anaphylaxis is different in hospital and community settings, but in both the key emphasis is the prompt administration of adrenaline. Patients therefore need to be empowered to manage potential anaphylactic reactions with training in the use of adrenaline auto-injectors and personalized emergency management plans.