Thin-layer Gel Research Articles

An Improved Method and Device for Nucleic Acid Isolation Using a High-Salt Gel Electroelution Trap.

The success of DNA analytical methods, including long-read sequencing, depends on the availability of high-quality, purified DNA. Previously, we developed a method and device for isolating high-molecular-weight (HMW) DNA for long-read sequencing using a high-salt gel electroelution trap. Here, we present an improved version of this method for purifying nucleic acids with high yield and purity from even the most challenging biological samples. The proposed method is a significant improvement over the previously published procedure, offering a simple, fast, and efficient solution for isolating HMW DNA and smaller DNA and RNA molecules. The method utilizes vertical gel electrophoresis in two nested, partially overlapping electrophoretic columns. The upper, smaller-diameter column has a thin layer of agarose gel at the bottom, which separates nucleic acids from impurities, and an electrophoresis buffer on top. After the target nucleic acid has been gel-purified on the upper column, a larger-diameter column with a layer of high-salt gel overlaid with electrophoresis buffer is inserted from below. The purified nucleic acid is then electroeluted into the buffer-filled gap between the separating gel and the high-salt gel, where excess counterions from the high-salt gel slow its migration and cause it to accumulate. The proposed vertical purification system outperforms the previously described horizontal system in terms of ease of use, speed, scalability, and compatibility with high-throughput workflows. Furthermore, the vertical system allows for the sequential purification of several nucleic acid species from the same sample using interchangeable salt-gel columns.

The Effect of Aloe vera on the Healing of Diabetic Foot Ulcer: A Randomized, Double-blind Clinical Trial.

Diabetic foot ulcer (DFU) is a prevalent complication of diabetes that can result in severe consequences. The cost of treating DFUs is high, and there is a lack of new therapies available in developing countries. This has created a demand for complementary and alternative treatments. The objective of this study was to assess the impact of aloe vera gel on the healing process of diabetic foot ulcers. The study was a double-blind, randomized, controlled clinical trial. The study samples were 66 patients with diabetic foot ulcers who were randomly assigned to two groups (intervention and control). All ulcers in both groups were washed with normal saline and dressed in sterile gauze. The ulcers in the intervention group were covered with a thin layer of Aloe Vera gel before the dressing. The Bates-Jensen Wound Assessment Tool (BWAT) was used on three occasions, including before the intervention period and at the end of each week. Data were analyzed using SPSS 16. After three weeks, there was a notable contrast in the recovery pattern of the two groups. The patients who had aloe vera gel added to their dressing showed a more substantial decrease in the mean scores of their BWAT. These findings are promising and suggest that Aloe vera may be a safe and effective adjunctive treatment for diabetic foot ulcers. However, further research is needed to confirm these results and to investigate the underlying mechanisms of aloe vera's therapeutic effect on diabetic foot ulcers.

'Gel-Stacks' gently confine or reversibly immobilize arrays of single DNA molecules for manipulation and study.

Large DNA molecules (>20kb) are difficult analytes prone to breakage during serial manipulations and cannot be 'rescued' as full-length amplicons. Accordingly, to present, modify and analyze arrays of large, single DNA molecules, we created an easily realizable approach offering gentle confinement conditions or immobilization via spermidine condensation for controlled delivery of reagents that support live imaging by epifluorescence microscopy termed 'Gel-Stacks.' Molecules are locally confined between two hydrogel surfaces without covalent tethering to support time-lapse imaging and multistep workflows that accommodate large DNA molecules. With a thin polyacrylamide gel layer covalently bound to a glass surface as the base and swappable, reagent-infused, agarose slabs on top, DNA molecules are stably presented for imaging during reagent delivery by passive diffusion.

Wrinkling instabilities of swelling hydrogels.

We investigate the formation of wrinkling instabilities at the interface between layers of hydrogel and water, which arise to relieve horizontal compressive stresses caused by either differential swelling or confinement. Modelling the gel using a linear-elastic-nonlinear-swelling approach, we determine both a criterion for marginal stability and the growth rates of normal modes. Furthermore, our formalism allows us to understand the influence of differential swelling on the stability of hydrogels brought into contact with water, and we find three distinct phases of the instability. Initially, when only a thin skin layer of gel has swollen, buckles grow rapidly and the gel deforms as an incompressible material. A balance between normal elastic stress and pore pressure selects a wavelength for these buckles that increases with the square root of time. At late times, when the gel approaches a uniformly swollen state, buckles can only grow by differential swelling on much slower timescales determined by solvent transport. At intermediate times, growth is driven by the same fluid transport process as at late times but gradients in fluid pressure in the gel as it swells destabilize the interface, driving faster growth of wrinkles. We also explain why some instabilities can be transient, "healing" as time progresses, while others must remain for all time.

Cleaning testing of nineteenth-century plaster surface models with thin polyacrylamide-based gel layers attached to flexible polyethylene films

This paper explores the cleaning efficacy of polyethylene-supported 15-min photo-crosslinked poly (acrylamide-co-benzophenone) surface-attached gels (SAGs) on gypsum plaster surface models inspired by nineteenth-century casts. Cleaning tests were performed on plaster surface models with and without organic and inorganic coatings, which had been exposed to accelerated ageing by heat, humidity, and light after artificial soiling. The specific types of SAG systems were selected based on their water loading and dehydration capacities. The SAGs were loaded with customized solutions and applied on the plaster models for one minute. Cleaning efficacy was evaluated with visible reflectance, UV fluorescence photography, scanning electron microscopy, colorimetry, UV/Vis spectrophotometry, glossimetry, high resolution 3D microscopy, attenuated total reflection Fourier transform infrared spectroscopy and 2D Fourier transform infrared imaging. The SAGs provided fast and minimal wetting of the substrates, prevented excessive liquid spreading and allowed the effective liquid contact with the soiled gypsum plaster surface. A striking removal of soils from the gypsum plaster surface models was observed, which suggests convenient application of the SAG systems for the cleaning of historical plaster objects.

A supramolecular gel with unique rheological properties for treating corneal virus infection

Herpes simplex keratitis (HSK) caused by herpes simplex virus-1 infection of the cornea has taken a significant toll on the visual health of people worldwide. Anti-viral hydrogels are preferred in the treatment of HSK due to enhanced topical drug retention and reduced side effects, however, current polymer-based gelling systems usually generate clumpy or uneven gel layers on ocular surface, and are easily cleared by eyelid blinking. This study proposes a supramolecular gel co-assembled by all-small-molecule building blocks including ganciclovir and 2′-deoxyguanosine in the presence of potassium ions. The developed gel performs fascinating rheological and texture properties including high viscoelastic, good spread ability, and deformation recovery behavior, enabling the formation of a uniform and thin gel layer on ocular surface to resist the clearance by eyelid blinking and tear washing. The gel shows similar ocular convenience, but much longer drug retention in ocular tissues and higher therapeutic efficacy compared to the clinical ganciclovir gel on the primary and recurrent mouse HSK models, rabbit HSK models, and also efficiently inhibited the HSV-1 replication in ex vivo human corneal tissues. The results suggest that this all-small-molecule supramolecular gel could be a promising drug formulation for treating HSK. Data and materials availabilityThe main data supporting the results in this study are available within the paper and its Supplementary Information. The associated raw data and analyzed datasets are too large to be readily shared publicly, but they are available from the corresponding author on reasonable request.

Temperature-Modulated Changes in Thin Gel Layer Thickness Triggered by Electrochemical Stimuli.

A series of thermoresponsive hydrogels containing positively charged groups in the polymeric network were synthesized and modified with the electroactive compound 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS). ABTS, which forms a dianion in aqueous solutions, acts as an additional physical cross-linker and strongly affects the swelling ratio of the gels. The influence of the amount of positively charged groups and ABTS oxidation state on the volume phase transition temperature was investigated. A hydrogel that possesses a relatively wide and well-defined temperature window (the temperature range where changes in the ABTS oxidation state affects the swelling ratio significantly) was found. The influence of the presence and oxidation state of ABTS on mechanical properties was investigated using a tensile machine and a rheometer. Then, a very thin layer of the gel was deposited on an Au electrochemical quartz crystal microbalance with dissipation (EQCM-D) electrode using the electrochemically induced free radical polymerization method. Next, chronoamperometry combined with quartz crystal microbalance measurements, obtained with an Au EQCM-D electrode modified by the gel, showed that the size of the thin layer could be controlled by an electrochemical trigger. Furthermore, it was found that the electrosensitivity could be modulated by the temperature. Such properties are desired from the point of view construction of electrochemical actuators.

Spontaneous motion of a passive fluid droplet in an active microchannel.

We numerically study the dynamics of a passive fluid droplet confined within a microchannel whose walls are covered with a thin layer of active gel. The latter represents a fluid of extensile material modelling, for example, a suspension of cytoskeletal filaments and molecular motors. Our results show that the layer is capable of producing a spontaneous flow triggering a rectilinear motion of the passive droplet. For a hybrid design (a single wall covered by the active layer), at the steady state the droplet attains an elliptical shape, resulting from an asymmetric saw-toothed structure of the velocity field. In contrast, if the active gel covers both walls, the velocity field exhibits a fully symmetric pattern considerably mitigating morphological deformations. We further show that the structure of the spontaneous flow in the microchannel can be controlled by the anchoring conditions of the active gel at the wall. These findings are also confirmed by selected 3D simulations. Our results may stimulate further research addressed to design novel microfludic devices whose functioning relies on the collective properties of active gels.

Effects of topical timolol for the prevention of radiation-induced dermatitis in breast cancer: a pilot triple-blind, placebo-controlled trial

IntroductionRadiation therapy is one of the standard methods in the treatment of breast cancer. Radiotherapy-induced dermatitis (RID) is a common complication of radiotherapy (RT) resulting in less tolerance in RT and even discontinuation of treatment. Timolol is a β-adrenergic receptor antagonist that presents the best wound healing effects on both chronic and incurable wound healing. Topical forms of timolol could be effective in the prevention of RID due to the role of β-adrenergic receptors in skin cells and keratinocyte migration, as well as the anti-inflammatory effect of timolol. However, no placebo-controlled randomized trial is available to confirm its role. The current trial aimed to evaluate the efficacy of topical timolol 0.5% (w/w) on the RID severity and patients' quality of life (QOL).MethodPatients aged older than 18 years with positive histology confirmed the diagnosis of invasive and localized breast cancer were included. Patients were randomized based on the random number table to receive each of the interventions of timolol 0.5% (w/w) or placebo topical gels from the first day of initiation of RT and for 6 weeks, a thin layer of gel twice daily. Patients were asked to use a thin layer of gel for at least two hours before and after radiation therapy. Primary outcomes were acute radiation dermatitis (ARD) grade using Radiation Therapy Oncology Group and the European Organization for Research and Treatment of Cancer (RTOG/EORTC) scale and severity of desquamation based on Common Terminology Criteria for Adverse Events (CTCAE), version 5.0. Secondary outcomes were QOL based on Skindex16 (SD-16), maximum grade of ARD, and time of initial RD occurrence.ResultsA total of 64 female patients with an age range of 33 to 79 years were included. The means (SD) of age were 53.88 (11.02) and 54.88 (12.48) in the control and timolol groups, respectively. Considering the RTOG/EORTC and CTCAE scores the difference between groups was insignificant (P-Value = 0.182 and P-Value = 0.182, respectively). In addition, the mean (SD) of time of initial RID occurrence in placebo and timolol groups were 4.09 (0.588) and 4.53 (0.983) weeks, respectively (P-Value = 0.035). The maximum grade of RID over time was significantly lower in the timolol group. During the study period, 75.0% of patients in placebo groups had grade 2 of ARD while in the timolol group it was 31.3% (P-Value = 0.002). QoL was not significantly different between groups (P-Value = 0.148).ConclusionAlthough the topical formulation of timolol, 0.5% (w/w), was found to reduce the average maximum grade of ARD and increase the mean (SD) time of initial RID occurrence, it showed no effect on ARD, severity, and QOL. However, future clinical trials should be performed to assess timolol gel formulation in larger study populations.Trial registrationhttps://irct.ir/ IRCT20190810044500N11 (17/03/2021).

Dual‐templating surface gel into thin SSZ‐13 zeolite membrane for fast selective hydrogen separation

AbstractHighly permeable zeolite membranes are desirable for fast gas separation in the industry. Reducing the membrane's thickness is deemed to be an optimal solution for permeability improvement. Herein, we report the synthesis route of thin SSZ‐13 zeolite membranes via the conversion of template‐contained surface gels. The synthesis gel is fully crystallized into crack‐free SSZ‐13 membranes assisted with dual templates of N,N,N‐trimethyl‐1‐adamantammonium hydroxide (TMAdaOH) and tetraethylammonium hydroxide (TEAOH). The specific functions of TMAdaOH for structure directing and TEAOH for crystallization regulating are well discussed. Thin surface gel layer is impregnated onto porous alumina with subsequent crystallization into a 500 nm thick membrane. This submicron‐thick membrane exhibits high H2 permeance with 50 × 10−8 mol s−1 m−2 Pa−1 during hydrogen separation. Meanwhile, the separation factors are retained around 23.0 and 31.5 for H2/C2H6 and H2/C3H8, respectively. This approach offers a possibility for obtaining high‐quality zeolite membranes for efficient hydrogen separation.

Fundamental investigation on the development of composite membrane with a thin ion gel layer for CO2 separation

A composite membrane with a thin defect-free ion gel layer was developed in this study. The ion gel layer containing an interpenetrating polymer network (IPN) and high ionic liquid (IL) content (80–90 wt%) was prepared on a poly(dimethylsiloxane) gutter layer by spin coating. The thickness of the IPN ion gel layer was reduced from 20 μm to 600 nm by increasing the dilution ratio of the ion gel precursor solution, and the CO2 permeance of the composite membrane was increased from 45 to 613 GPU. By increasing the IL content of the IPN ion gel layer to 90 wt%, the prepared composite membrane exhibited the CO2 permeance of 778 GPU and CO2/N2 selectivity of 15. The CO2 permeance and CO2/N2 permselectivity of the IPN ion gel layer alone having 90 wt% IL were respectively estimated to be 1860 GPU and 27. The excellent gas permeation performance proves that IPN ion gel is a good optional material as a selective layer of a composite membrane for efficient CO2 separation.

Abstract P1130: A Minimally Invasive Injectable Syncsc Adhesive (misa) For Aging Rats With Chemotherapy-induced Heart Failure

Statement of Purpose: Long-term chemotherapy in cancer treatment may lead to serious myocardiopathy that then prompts heart failure (HF) or even death. Additionally, patients over 65 years of age are likely to have complications in other organs, making the treatment an insurmountable obstacle. In previous studies, regenerative therapy has been reported as a robust method to improve HF. Despite the successful proof of concept, one big challenge for clinical translational is to deliver the therapeutics in a minimally invasive way. To that end, we sought to develop a minimal-invasively injectable synthetic cardiac stromal cells (synCSC) adhesive (MISA) that could be delivered with small incisions on the chest wall, without an open-chest surgery. The MISA should be gelatinized easily right after transplantation to increase the retention of synCSCs in the pericardium cavity. To mimic aging patients with cardiomyopathy caused by HF, we have established an aging rat model with HF induced by doxorubicin. The overarching hypothesis is that minimal-invasively delivery of MISA improves synCSC therapeutic efficacy in the aging rat model of HF. Methods: We created an injectable MISA by embedding optimized synCSCs into a myoECM-fibrinogen gel in an adjusted concentration. MISA retains my ECM proteins and peptide fragments while gelatinizing fast after injection. After MISA fabrication, we characterized its 3D morphological features to determine synCSC embedding efficiency. To determine the safety, efficacy, and mechanism of MISA treatment, we employed multiple doxorubicin intraperitoneal injections as an oxidant generator and topoisomerase II inhibitors to create an aging rat model of HF. Results: MISA improved therapeutic efficacy in HF treatment after being injected minimal-invasively. Also, MISA polymerized fast after administration and formation of a thin layer of regenerative gel that released regenerative factors to the myocardium in a sustained release manner while degradation. MISA as therapeutic biologics has the potential to revolutionize cardiovascular regenerative medicine.

Spermidine Crosslinked Gellan Gum-Based "Hydrogel Nanofibers" as Potential Tool for the Treatment of Nervous Tissue Injuries: A Formulation Study.

PurposeAim of the work was to develop a potential neural scaffold, endowed with neuroprotective and neuroregenerative potential, to be applied at the site of nervous tissue injuries: nanofibers, consisting of gellan gum (GG), spermidine (SP) and gelatin (GL), were prepared via electrospinning. SP was selected for its neuroprotective activity and cationic nature that makes it an ideal GG cross-linking agent. GL was added to improve the scaffold bioactivity.MethodsMixtures, containing 1.5% w/w GG and increasing SP concentrations (0–0.125% w/w), were prepared to investigate GG/SP interaction and, thus, to find the best mixture to be electrospun. Mixture rheological and mechanical properties were assessed. The addition of 0.1% w/w GL was also investigated. The most promising GG/SP/GL mixtures were added with poly(ethylene oxide) (PEO) and poloxamer (P407) and, then, electrospun. The resulting fibers were characterized in terms of size and mechanical properties and fiber morphology was observed after soaking in water for 24 hours. Nanofiber biocompatibility was assessed on Schwann cells.ResultsMore and more structured GG/SP mixtures were obtained by increasing SP concentration, proving its cross-linking potential. After blending with PEO and P407, the mixture consisting of 1.5% w/w GG, 0.05% w/w SP and 0.1% w/w GL was electrospun. The resulting nanofibers appeared homogenous and characterized by a plastic behavior, suggesting a good mechanical resistance when applied at the injury site. Nanofibers were insoluble in aqueous media and able to form a thin gel layer after hydration. GG/SP/GL nanofibers showed a higher compatibility with Schwann cells than GG/SP ones.ConclusionSP and GL allowed the production of homogenous GG-based nanofibers, which preserved their structure after contact with aqueous media and showed a good compatibility with a neural cell line. After local application at the injury site, nanofibers should support and guide axonal outgrowth, releasing SP in a controlled manner.

SYNTHESIS OF A NOVEL SILICONE- AND TRIAZINE-BASED COPOLYMER WITH FURFURYL SIDE GROUPS

S-triazine derivatives are known to have great potential in diversifying the structural design of polymer materials due to the stepwise reaction of cyanuric chloride, particularly in optoelectronic applications. In addition, the hydrogen bonds formed by the triazine ring are known to play an important role in molecular arrangement, providing triazine-based polymer materials with excellent mechanical properties. In the present work, a triazine-furan precursor will be combined with polydimethylsiloxane (PDMS) and polyoxypropylenediamine to create a novel polymer that bears furfuryl side groups. This polymer has great potential to be used for self-healing applications due to the reversibility of triazine π-π stacking and hydrogen bonding as well as the ability of the furfuryl group to form dynamic covalent bonds. Thin-layer chromatography (TLC) and gel permeation chromatography (GPC) was used to investigate the reaction conditions (GPC). The research of this reaction revealed that the best conditions for the synthesis of this copolymer were at a temperature of 110 oC for 24 hours and determined an average molecular weight (Mn) of around 19800 (g/mol). Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) are used to determine the structure of the synthesized compounds. Besides that, from the 1H-NMR spectrum NMR was found that feeding molar of 21.32/1/19.50 for TF, PDMS, and Jeffamine, respectively.

A Portable Controllable Compressive Stress Device to Monitor Human Breast Cancer Cell Protrusions at Single-Cell Resolution.

In vitro devices offer more numerous methods than in vivo models to investigate how cells respond to pressure stress and quantify those responses. Several in vitro devices have been developed to study the cell response to compression force. However, they are unable to observe morphological changes of cells in real-time. There is also a concern about cell damage during the process of harvesting cells from 3D gels. Here we report a device employing transparent, thin gel layers to clamp cells between the interfaces and applied a controllable compression force by stacking multiple layers on the top. In this approach, cells can be monitored for alteration of cellular protrusions, whose diversity has been proven to promote cancer cell dissemination, with single-cell resolution under compression force. Furthermore, p-Rac-1 and rhodamine staining on the device directly to confirm the actin filaments of lamellipodia. The method was able to fulfill real-time live-cell observation at single-cell resolution and can be readily used for versatile cell analysis. MDA-MB-231 and MCF7 breast cancer cells were utilized to demonstrate the utility of the device, and the results showed that the stimuli of compression force induce MDA-MB-231 and MCF7 to form lamellipodia and bleb protrusions, respectively. We envision the device may be used as a tool to explore mechanisms of membrane protrusion transitions and to screen drug candidates for inhibiting cancer cell protrusion plasticity for cancer therapy.

Integrated microfluidic single-cell immunoblotting chip enables high-throughput isolation, enrichment and direct protein analysis of circulating tumor cells

Effective capture and analysis of a single circulating tumor cell (CTC) is instrumental for early diagnosis and personalized therapy of tumors. However, due to their extremely low abundance and susceptibility to interference from other cells, high-throughput isolation, enrichment, and single-cell-level functional protein analysis of CTCs within one integrated system remains a major challenge. Herein, we present an integrated multifunctional microfluidic system for highly efficient and label-free CTC isolation, CTC enrichment, and single-cell immunoblotting (ieSCI). The ieSCI-chip is a multilayer microfluidic system that combines an inertia force-based cell sorter with a membrane filter for label-free CTC separation and enrichment and a thin layer of a photoactive polyacrylamide gel with microwell arrays at the bottom of the chamber for single-cell immunoblotting. The ieSCI-chip successfully identified a subgroup of apoptosis-negative (Bax-negative) cells, which traditional bulk analysis did not detect, from cisplatin-treated cells. Furthermore, we demonstrated the clinical application of the ieSCI-chip with blood samples from breast cancer patients for personalized CTC epithelial-to-mesenchymal transition (EMT) analysis. The expression level of a tumor cell marker (EpCAM) can be directly determined in isolated CTCs at the single-cell level, and the therapeutic response to anticancer drugs can be simultaneously monitored. Therefore, the ieSCI-chip provides a promising clinical translational tool for clinical drug response monitoring and personalized regimen development.

Determination of active substances of the class of sulphonyl urea in matrixes

Goal. Selection of chromatographic method and development of a method for controlling the content of active substances nicosulfuron, rimsulfuron and thifensulfuron-methyl separately and in a combined presence in different combinations in matrices (formulations).
 Methods. The active substances were determined by thin layer chromatography (TLC). The linear range of the dependence of the area of the chromatographic zones on the amount of active substance was estimated by statistical methods using correlation-regression analysis.
 Results. Determination of pesticides includes the main stages: characterization of active substances by polarity; extraction their from the analyzed matrix; chromatographic separation, detection and quantification. The limiting integral indicator in the analysis is the dipole moment (µ, D), which characterizes the polarity of the compounds and their physicochemical properties. Nicosulfuron, rimsulfuron and thifensulfuron-methyl are low-polar compounds (2 <µ ≤ 6, D) with dipole moments of 5.48; 5.30 and 5.28 D, respectively. Extraction of active substances is carried out with ethanol. Qualitative determination — in a thin layer of adsorbent silica gel in the mobile phase (hexane + chloroform + ethanol + ethanoic acid 30:10:5:1) and with a dielectric constant ε = 5.12. Compounds were identified under a chromatoscope (λ 254 nm) and using bromophenol blue developing reagent and subsequent bleaching of the chromatogram background with citric acid solution. The dependence of the area of the chromatographic zone of the compound (S, mm2) on its amount (C, µg) is linear in the detection range of 0.30—1.30 µg and is described by the regression equation for: thifensulfuron-methyl S = 25.057 C + 0.4367 (R2 = 1.00); nicosulfuron S = 22.272 C + 0.0532 (R2 = 1.00); rimsulfuron S = 17.519 C + 0.9456 (R2 = 1.00). The equations are used to quantify the active substances on the chromatogram.
 Conclusions. The use of TLC method allows to select selective conditions and to develop a method for determination of thifensulfuron-methyl, nicosulfuron and rimsulfuron in herbicide formulations separately and in combined presence in different combinations and quantities, which allows to determine three active substances in one analysis with high accuracy reproducibility (relative error, <5% at n = 5, P = 0.95). The introduction of the developed and patented method makes it possible to determine the active substances of the sulfonylurea class in herbicide formulations by analytical and toxicological laboratories, testing services without the use of expensive devices.

Electrochemical devices based on conducting surfaces modified with smart hydrogels: Outlook and perspective

AbstractThe unique properties of smart hydrogels combined with conducting surfaces opened new possibilities in the construction of novel electrochemical devices. Electrodes modified with thin gel layers demonstrate the properties that are usually unachievable for bare electrodes. Usually a thin gel layer provides a highly permeable matrix for analytes, and can also serve as an immobilizing/impermeable matrix for larger molecules. Hydrogel barriers/layers are able to protect the electrode surface against the unwanted influence of the environment and to isolate the environment from the usually metallic, stiff, and hard electrode surfaces. A layer of hydrogel attached to the electrode surface can also serve as solid electrolyte, buffer and a reservoir for electroactive probes. In addition, the ability of smart gel materials to undergo a reversible volume phase transition related to significant changes in their volume and shape is very interesting from the point of view of the construction of switchable electrochemical systems. Such properties are strongly desired for the construction of various electrochemical devices. This review is focused on recent progress in the above field.

A Parallel, Observer Blind Study of the Skin Protection Properties of Silicone-Based Gels after Radiotherapy Exposure

Objective: Radiotherapy of cancers are usually accompanied by some form of radiation induced skin toxicity (radiation dermatitis) in most patients receiving this type of treatment. It can vary from very mild disease to extensive and severe dermatitis limiting further treatment. It is therefore obvious that preventative care will optimise the outcome of radiation of the tumour while the skin’s integrity is preserved leading to a better clinical outcome overall. Methods: In Vitro: In the study a newly developed silicone topical device (RT-Gel Sun Pharma South Africa), is compared to a similar product StrataXRT as well as to a negative control group of no gel. Gels were tested to observe the effect on the radiation dose provided. All gels were applied as a thin layer to the surface of the bolus within the Farmer Chamber. In Vivo: In this multicentre study a newly developed silicone topical device (RT-Gel® Sun Pharma South Africa), applied as a thin layer gel, is compared to a similar product StrataXRT as well as to standard of care in practice. The aim was to compare patients’ preferences of treatment modalities as well as establishing differences in clinical outcomes focussing on grades of skin toxicity after radiation therapy. Patients were recruited at radiation oncology sites after being prescribed radiation dosages with curative intent for mostly breast and head and neck cancers. Results: In Vitro: The uncertainties pertaining to the theoretical dose changes and radiation measurements indicates clearly the differences caused by the application of a silicone-based gel during radiotherapy is small enough to be regarded as negligible. In Vivo: The primary outcomes demonstrate the patient’s satisfaction with RT-Gel® i.e. a significant preference for RT-Gel compared to both StrataXRT® (p< 0.02) and standard of care (p< 0.001). The clinicians’ toxicity scores also favoured RT-Gel® over StrataXRT (p< 0.04 ANOVA). Conclusion: It can thus be concluded that preventative treatment with RT-Gel® is at least as effective if not better than competitors, well tolerated and preferred by patients. . It furthermore indicates that dose is not affected by gel and that washing of treated area before next treatment is not required to “prevent build-up of gel”.

A nanotubular TiO2/SiOx/Si composite derived from cellulosic cotton as an anode material for lithium-ion batteries with enhanced electrochemical performance

A TiO2/SiOx/Si composite derived from cellulosic cotton as the structural template was biomimetically synthesized. Modified sol–gel deposition processes were performed to coat each cellulose nanofiber with a SiO2 thin gel layer, followed by layer-by-layer self-assembly processes to form an external TiO2 coating with controllable thickness. The resulted matter was calcined in air to obtain the TiO2/SiO2 composite, which was successively put in N2 atmosphere and treated with magnesiothermic reduction reaction, resulting in the final TiO2/SiOx/Si composite. The composite possessed a typical hierarchical three-dimensional (3D) nanotubular network microstructure precisely inherited from the cellulosic cotton template, and each nanotube had a core-shell nanostructure with Si-based matters as the core and TiO2 coating as the shell. Compared with the bare nanotubular SiOx/Si material, the TiO2/SiOx/Si composite showed a highly enhanced electrochemical performance as an anode material for lithium-ion batteries (LIBs), delivering an initial discharge capacity of 2370 mAh g−1 at a current density of 0.2 A g−1 (an initial Coulombic efficiency of 56.4%), a reversible capacity of 682 mAh g−1 after 100 discharge/charge cycles, and a discharge capacity of 241 mAh g−1 at a high current density of 2.0 A g−1. The excellent specific capacity, cycling stability and rate capability are ascribed to the synergistic effect of the unique 3D porous nanotubular network structure and the uniform TiO2 coating layer, which accommodates the volume variation of Si-based components during cycling, offers sufficient ion transport pathways and improves the electron transfer efficiency. This work provides a facile biomass-based strategy for fabrication of metal oxide/Si composites with well-defined microstructures that exhibit significant potential as anode materials for LIBs.