Use of an electronic tongue in the assessment of highly diluted systems

Introduction: “Eletronic tongue” is a device commonly used in the analysis of tastants, heavy metal ions, fruit juice, wines and also in the development of biosensors [1-3]. Briefly, the e-tongue is constituted by sensing units formed by ultrathin films of distinct materials deposited on gold interdigitated electrodes, which are immersed in liquid samples, followed by impedance spectroscopy measurements [1]. The e-tongue sensor is based on the global selectivity concept, i.e., the materials forming the sensing units are not selective to any substance in the samples, therefore, it allows the grouping of information into distinct patterns of response, enabling the distinction of complex liquid systems [1]. Aim: Our aim was to use e-tongue system for the assessment the homeopathic medicine Belladonna at different degrees of dilution, in attempt to differentiate highly diluted systems. Methods: Ultrathin films forming the sensing units were prepared by the layer-by-layer technique [4], using conventional polyelectrolytes such as poly(sodium styene sulfonate) (PSS) and poly(allylamine) hydrochloride (PAH), chitosan and poly(3,4-ethylenedioxythiophene) (PEDOT). Homeopathic medicines (Belladonna 1cH, 6cH, 12cH and 30cH) were prepared by dilution and agitation according to Hahnemann´s method [5], using ethanol at 30% (w/w) as vehicle. Experimental data acquisition was conducted by blind tests measurements involving Belladonna samples and the vehicle used in the dilutions. Five independent and consecutive measurements were taken for each solution at 1 kHz, which were further analysed by Principal Component Analysis (PCA), a statistical method largely employed to reduce the dimensionality of the original data without losing information in the correlation of the samples [3]. Results: Figure 1 shows that the five independent measurements are grouped quite closed each other for each solution analysed, with a clear distinction of them. Therefore, it was noticed a change in the observed pattern measured at different days, indicating a reduced reproducibility, although the groups of data could still be identified. Discussion: PCA is a powerful tool highly employed to extract relevant information in the correlation of data analysis of e-tongue systems. PCA plots showed a good statistical correlation of the systems (PC1 + PC2 ³ 90%), with the solutions being straightforwardly distinguished each other and also from the vehicle used. Conclusion: Despite the differences of data obtained along distinct days of analysis, the e-tongue could detect differences among the samples tested, even considering the highly diluted cases studied.

Biomimetic “Nacre-like” Films Prepared via Layer-by- Layer Self-assembly of Mica, Polyvinyl Alcohol and Polymethyl Methacrylate

"Mortar" and "brick" structure is a general model to construct nanocomposites. A film with "brick-and-mortar" structure was prepared by LBL (Layer-by-Layer) technique using polyvinyl alcohol (PVA) and polymethyl methacrylate (PMMA) as the flexible material or "mortar" and mica as the rigid material or "brick". The film deposited on a glass slide after self-assembly cycles was ~3μm thick with an uneven, wavy surface. The film showed enhanced mechanical properties with the hardness and indentation modulus values up to 6.14 GPa and 68.41 GPa, respectively. It was found that the hardness and elastic toughness depended on the ratio of mica, the number of self-assembly cycles, and the pretreatment method of the mica suspension. The self-assembly process was believed to be attributable to the hydrogen bonds between the silanol groups of mica and the hydroxyl groups of PVA and carbonyl groups of PMMA.

Graded Reconstruction Strategy Using a Multi-Layer Technique without Lumbar Drainage After Endoscopic Endonasal Surgery

Introduction Sellar reconstruction following endoscopic endonasal surgery (EES) requires modification based on the degree of cerebrospinal fluid (CSF) leak. For high-flow (grade II or III) intraoperative CSF leak, lumbar drainage (LD), in addition to the multi-layer closing technique, is generally recommended. However, LD has complications occasionally, including post-puncture headache, over-drainage symptoms, and increased length of stay (LOS). We retrospectively evaluated the outcome of our graded reconstruction strategy using a multi-layer technique with a novel material, without LD, after EES.Methods Ninety-seven patients who underwent EES with grade II or III intraoperative CSF leak between June 2020 and March 2021 were retrospectively reviewed. For grade II CSF leak, fibrin sealant and a nasoseptal flap (NSF) were placed; for grade III CSF leak, a multi-layer technique was utilized in combination with collagen matrix, an acellular dermal graft, injectable hydroxyapatite (HXA), and an NSF. Postoperatively, routine LD was not performed.Results This study included 48 (49.5%) grade II and 49 (50.5%) grade III CSF leaks. Upon follow-up period (mean, 8.7 months), no patient showed postoperative CSF leak in either group. The postoperative LOS was not significantly different between the grade II (6.68 [range, 3–14] days) and grade III CSF leak groups (7.38 [range, 4–15] days) (p>0.05). No HXA-associated complications occurred.ConclusionsA graded surgical repair strategy after EES could avoid postoperative CSF leak. Combined use of injectable HXA and acellular dermal grafts for high-flow CSF leak can limit LD requirement, without significant risks.

Single Layer Versus Double Layer Anastomosis of Small Intestine – A Comparative Study from Karnataka, India

BACKGROUND Intestinal anastomosis is an operative procedure that is of importance in the practice of surgery. It is a very commonly performed technique in today’s surgical era. We wanted to study the postoperative complications like anastomotic leak and abscess formation and duration of hospital stay in single layer and double layer anastomosis and compare the same. METHODS In our prospective observational study, 80 patients were reviewed and were divided into 2 groups. Cases were allotted to either group based on the odd even method requiring single- and double-layer anastomosis, odd being single layer and even being double layer anastomosis. Intestinal anastomosis was carried out in single layer technique with delayed absorbable suture material and double layer technique with inner transmural layer with delayed absorbable suture material and seromuscular layer with non-absorbable suture material. RESULTS Each group had 40 patients, there was significant difference noted between the groups. Mean duration of hospital stay in single layer group was 17.85 ± 7.62 days and in double layer group was 26.20 ± 16.12 days (P = 0.043 *). In single group, mean time taken for anastomosis was 18.50 ± 1.73 and in double group was 29.05 ± 2.19. There was significant difference in time taken between two groups (P < 0.001). In single group, majority of subjects had no anastomotic Leak (95 %) and 5 % had leak. In double group 70 % had no leak and 30 % had leak. P value was statistically significant (P = 0.037). CONCLUSIONS Single layer anastomosis was better in terms of duration of hospital stay, postoperative anastomotic leaks and time taken for anastomosis. KEY WORDS Single Layer, Double Layer, Small Bowel, Duration of Hospital Stay, Anastomotic Leaks

Polyelectrolyte Multilayers: An Overview on Fabrication, Properties, and Biomedical and Environmental Applications

Polyelectrolyte multilayers are versatile materials that are used in a large number of domains, including biomedical and environmental applications. The fabrication of polyelectrolyte multilayers using the layer-by-layer technique is one of the simplest methods to obtain composite functional materials. The properties of the final material can be easily tuned by changing the deposition conditions and the used building blocks. This review presents the main characteristics of polyelectrolyte multilayers, the fabrication methods currently used, and the factors influencing the layer-by-layer assembly of polyelectrolytes. The last section of this paper presents some of the most important applications of polyelectrolyte multilayers, with a special focus on biomedical and environmental applications.

BULKFILL TECHNIQUES WITH INTERMEDIATE LAYER TO MARGINAL ADAPTATION RESTORATION OF CLASS II COMPOSITE RESIN

Background: Dental caries is a hard tissue disease caused by bacterial metabolic activity that causes demineralization, teeth that have caries should be filled in order to function again. One of the restorative materials closer to natural teeth is composite resin because it is the same colour as natural teeth and is easy to shape. As for the placement technique, bulkfill is also used because it is more time-efficient, and irradiation is accompanied by applying the restoration material in one batch. However, the bulkfill technique often causes micro-leakage of dental caries deposition. The intermediate layer is an intermediate layer used to prevent micro-leakage at the edges of the restoration as a base layer for restoration to create a good adaptation before applying packable composite resin. Therefore, bulkfill coating technique with the intermediate layer can reduce the risk of microleakage. Purpose: To describe the bulkfill technique with an intermediate layer against marginal adaptation with class II composite resin restorations. Review: The literature sources used in the preparation of the articles through several databases with descriptions. More journals say that micro-leakage in class II cavity deposition with the intermediate layer technique is better than the bulkfill technique because the intermediate layer technique has better bond strength than the bulkfill technique. If the Bulkfill technique is modified with the Intermediate layer technique, it can show good correlation and internal adaptation. Conclusion: Bulkfill technique with an intermediate layer against marginal adaptation with class II composite resin restorations can reduce the microleakage rate by reducing the polymerization's shrinkage strain.