Formaldehyde Gas Sensors Fabricated with Polymer-Based Materials: A Review

Formaldehyde has been regarded as a common indoor pollutant and does great harm to human health, which has caused the relevant departments to pay attention to its accurate detection. At present, spectrophotometry, gas chromatography, liquid chromatography, and other methods have been proposed for formaldehyde detection. Among them, the gas sensor is especially suitable for common gaseous formaldehyde detection with the fastest response speed and the highest sensitivity. Compared with the formaldehyde sensors based on small molecules, the polymer-based sensor has higher selectivity but lower sensitivity because the polymer-based sensor can realize the specific detection of formaldehyde through a specific chemical reaction. Polymer-related formaldehyde sensors can be very versatile. They can be fabricated with a single polymer, molecularly imprinted polymers (MIP), polymer/metal-oxide composites, different polymers, polymer/biomass material composites, polymer/carbon material composites, and polymer composites with other materials. Almost all of these sensors can detect formaldehyde at ppb levels under laboratory conditions. Moreover, almost all polymer nanocomposite sensors have better sensitivity than single polymer sensors. However, the sensing performance of the sensor will be greatly reduced in a humid environment due to the sensitive coating on the gaseous formaldehyde sensor, which is mostly a hydrophilic polymer. At present, researchers are trying to improve the sensitive material or use humidity compensation methods to optimize the gaseous formaldehyde sensor. The improvement of the practical performance of formaldehyde sensors has great significance for improving indoor living environments

Predicting Factors Affecting Adolescent Obesity Using General Bayesian Network and What-If Analysis

With the remarkable improvement in people’s socioeconomic living standards around the world, adolescent obesity has increasingly become an important public health issue that cannot be ignored. Thus, we have implemented its use in an attempt to explore the viability of scenario-based simulations through the use of a data mining approach. In doing so, we wanted to explore the merits of using a General Bayesian Network (GBN) with What-If analysis while exploring how it can be utilized in other areas of public health. We analyzed data from the 2017 Korean Youth Health Behavior Survey conducted directly by the Korea Centers for Disease Control & Prevention, including 19 attributes and 11,206 individual data points. Our simulations found that by manipulating the amount of pocket money-between $60 and$80-coupled with a low-income background, it has a high potential to increase obesity compared with other simulated factors. Additionally, when we manipulated an increase in studying time with a mediocre academic performance, it was found to potentially increase pressure on adolescents, which subsequently led to an increased obesity outcome. Lastly, we found that when we manipulated an increase in a father’s education level while manipulating a decrease in mother’s education level, this had a large effect on the potential adolescent obesity level. Although obesity was the chosen case, this paper acts more as a proof of concept in analyzing public health through GBN and What-If analysis. Therefore, it aims to guide health professionals into potentially expanding their ability to simulate certain outcomes based on predicted changes in certain factors concerning future public health issues

Ginseng Rb fraction protects glia, neurons and cognitive function in a rat model of neurodegeneration.

The loss and injury of neurons play an important role in the onset of various neurodegenerative diseases, while both microgliosis and astrocyte loss or dysfunction are significant causes of neuronal degeneration. Previous studies have suggested that an extract enriched panaxadiol saponins from ginseng has more neuroprotective potential than the total saponins of ginseng. The present study investigated whether a fraction of highly purified panaxadiol saponins (termed as Rb fraction) was protective for both glia and neurons, especially GABAergic interneurons, against kainic acid (KA)-induced excitotoxicity in rats. Rats received Rb fraction at 30 mg/kg (i.p.), 40 mg/kg (i.p. or saline followed 40 min later by an intracerebroventricular injection of KA. Acute hippocampal injury was determined at 48 h after KA, and impairment of hippocampus-dependent learning and memory as well as delayed neuronal injury was determined 16 to 21 days later. KA injection produced significant acute hippocampal injuries, including GAD67-positive GABAergic interneuron loss in CA1, paralbumin (PV)-positive GABAergic interneuron loss, pyramidal neuron degeneration and astrocyte damage accompanied with reactive microglia in both CA1 and CA3 regions of the hippocampus. There was also a delayed loss of GAD67-positive interneurons in CA1, CA3, hilus and dentate gyrus. Microgliosis also became more severe 21 days later. Accordingly, KA injection resulted in hippocampus-dependent spatial memory impairment. Interestingly, the pretreatment with Rb fraction at 30 or 40 mg/kg significantly protected the pyramidal neurons and GABAergic interneurons against KA-induced acute excitotoxicity and delayed injury. Rb fraction also prevented memory impairments and protected astrocytes from KA-induced acute excitotoxicity. Additionally, microglial activation, especially the delayed microgliosis, was inhibited by Rb fraction. Overall, this study demonstrated that Rb fraction protected both astrocytes and neurons, especially GABAergic interneurons, and maintained microglial homeostasis against KA-induced excitotoxicity. Therefore, Rb fraction has the potential to prevent and treat neurodegenerative diseases

Removal of Formaldehyde and Its Analogues Using a Hybrid Assembly of Pyrene-Modified Hydrazide and rGO: A Negative Carbon Emission and Green Chemical Decomposition Method

Indoor gaseous formaldehyde is the main environmental pollutant that can cause fatal threats to human health. A number of physical and chemical methods have been developed to tackle this issue. However, the existing methods are still unsatisfactory to meet the requirement of sustainable development owing to the flaws of low efficiency and reversible or second pollution. Herein, a chemical method based on a nucleophilic reaction between hydrazine and aldehyde that generates the only by-product of H2O is designed for the removal of formaldehyde. 1-Pyrenebutyric hydrazide was synthesized by a simple esterification reaction and then self-assembled on reduced graphene oxide (rGO) with a large surface area by forming π–π stacking to obtain a composite for chemical removal of gaseous formaldehyde under ambient conditions. In a practical test, the formaldehyde removal rate could reach 91% of the theoretical value, which meets the requirement for commercial formaldehyde removal applications. After 10 times recycling, the formaldehyde removal rate still remains as high as 85%. Moreover, the composite could be regenerated in weak acidic media, which greatly reduce the manufacturing cost in practical applications

Some instructions for the methods.

<p>(A) Experimental design. Rb fraction (Rb) was administrated intraperitoneally 40 min before intracerebroventricular (icv) KA injection. Rats were sacrificed at 48 h (acute period) or 3 weeks (chronic period) after KA for histological assay. The Morris water maze task was conducted from the 16^th to 19^th day for the training test and the 20^th day for the probe trial after KA injection. (B) Division of the dorsal hippocampus. The CA2 subfield is small and difficult to separate from the CA1, and thus was included in the CA1 subfield. so, stratum oriens; sp, stratum pyramidale; sr, stratum radiatum; slm, stratum lacunosum-moleculare; DGub, dentate gyrus upper blade; DGlb, dentate lower blade; gcl, granule cell layer; ml, molecular layer; hl, hilus.</p

Rb fraction prevents KA-induced hippocampal-dependent spatial memory impairment.

<p>Rats received a single injection of saline as KA controls, Rb (30 mg/kg) or Rb (40 mg/kg) 40 min before icv KA administration, and saline controls (Saline) received icv saline injection. Sixteen days later, the Morris water maze task was conducted. (A) Escape latency (the time to reach the platform) in the training test. (B) The numbers of times rats crossed the area where the platform was located in the probe trial. (C) Swimming speed of rats during the training test. (D) Swimming speed of rats in the probe trial. Data are expressed as means ± SEM; n  =  6–8 per group; *<i>p</i> < 0.05, **<i>p</i> < 0.01, ***<i>p</i> < 0.001 by a one-way analysis of variance followed by Dunnet's post-test. Data of escape latency were analyzed by a two-way analysis of variance with repeated measures.</p

Rb fraction decreases KA-induced loss of hippocampal PV+ interneurons during chronic period after KA injection.

<p>Rats were pretreated with saline as KA controls, Rb fraction 30/kg (Rb30) or 40 mg/kg (Rb40) followed 40 min later by icv KA injection, and saline controls (Saline) received icv saline injection. After the Morris water maze task (3 weeks after KA), brains were removed and hippocampal PV+ interneurons were identified by immunohistochemical staining. (A) Numbers of PV+ interneurons in the hippocampal subfields of CA1, CA3a–b, hilus (including CA3c), and DG. (B) Representative photomicrographs (200×) of the CA1, CA3 a–b, and hilus in the experimental groups. Data are expressed as means ± SEM; n  =  6–8 per group; *<i>p</i> < 0.05, **<i>p</i> < 0.01, ***<i>p</i> < 0.001 by a one-way analysis of variance followed by Dunnet's post-test.</p

Rb fraction decreases KA-induced loss of hippocampal GAD67+ interneurons during chronic period after KA injection.

<p>Rats received a single injection of saline as KA controls, Rb (30 mg/kg) or Rb (40 mg/kg) 40 min before icv KA administration, and saline controls (Saline) received icv saline injection. After the Morris water maze task (3 weeks after KA), hippocampal GAD67+ interneurons were detected by immunohistochemical staining. (A) Numbers of GAD67+ interneurons in the hippocampal CA1, CA3a–b, hilus (including CA3c), and DG regions. (B) Representative photomicrographs (200×) of the CA1, CA3a–b, and hilus in the experimental groups. Data are expressed as means ± SEM; n  =  6–8 per group; *<i>p</i> < 0.05, **<i>p</i> < 0.01, ***<i>p</i> < 0.001 by a one-way analysis of variance followed by Dunnet's post-test.</p

Rb fraction prevents KA-induced acute loss of PV+ interneurons in the hippocampus.

<p>Rats were pretreated with saline as KA controls, Rb fraction 30/kg (Rb30) or 40 mg/kg (Rb40) for 40 min followed by icv KA injection, and saline controls (Saline) received icv saline injection. After 48 h, brains were removed and PV+ interneurons were identified by immunohistochemical staining. (A) Numbers of PV+ interneurons in the hippocampal subfields of CA1, CA3a-b, hilus (including CA3c), and DG. (B) Representative photomicrographs (200×) of the CA1, CA3 a-b, and hilus subfields stained with anti-PV in the experimental groups. Data are expressed as means ± SEM; n  =  6–8 per group; **<i>p</i> < 0.01, ***<i>p</i> < 0.001 by a one-way analysis of variance followed by Dunnet's post-test.</p