Biogels in Soils: Plant Mucilage as a Biofilm Matrix That Shapes the Rhizosphere Microbial Habitat

Mucilage is a gelatinous high-molecular-weight substance produced by almost all plants, serving numerous functions for plant and soil. To date, research has mainly focused on hydraulic and physical functions of mucilage in the rhizosphere. Studies on the relevance of mucilage as a microbial habitat are scarce. Extracellular polymeric substances (EPS) are similarly gelatinous high-molecular-weight substances produced by microorganisms. EPS support the establishment of microbial assemblages in soils, mainly through providing a moist environment, a protective barrier, and serving as carbon and nutrient sources. We propose that mucilage shares physical and chemical properties with EPS, functioning similarly as a biofilm matrix covering a large extent of the rhizosphere. Our analyses found no evidence of consistent differences in viscosity and surface tension between EPS and mucilage, these being important physical properties. With regard to chemical composition, polysaccharide, protein, neutral monosaccharide, and uronic acid composition also showed no consistent differences between these biogels. Our analyses and literature review suggest that all major functions known for EPS and required for biofilm formation are also provided by mucilage, offering a protected habitat optimized for nutrient mobilization. Mucilage enables high rhizo-microbial abundance and activity by functioning as carbon and nutrient source. We suggest that the role of mucilage as a biofilm matrix has been underestimated, and should be considered in conceptual models of the rhizosphere.

Dermoscopy as a diagnostic tool to differentiate between tinea pedis and plantar psoriasis

<p><strong>Background</strong>: Clinical differentiation between tinea pedis and plantar psoriasis may sometimes be challenging, with consequent diagnostic delays and unnecessary therapies; in such cases histopathological analysis helps to differentiate the 2 conditions. In this study we used a dermoscope as a non-invasive tool to investigate the significance of specific dermoscopic features and to improve their non-invasive differentiation.</p><p><strong>Methods:</strong> A clinical diagnosis of plantar psoriasis/tinea pedis was made on basis of accepted literature and proved by histopathology. Image capturing was performed using a dermoscope. Based on combination of history, clinical, and dermoscopic examination conclusive diagnosis with specific dermoscopic features for each disease was achieved.</p><p><strong>Results:</strong> The 15 patients of biopsy proven tinea pedis and 17 patients of biopsy proven plantar psoriasis were selected. We found that the presence of whitish powdery scales located in the furrows with apparently uninvolved skin in between was significant in tinea pedis whereas the presence of silvery white scales on a pinkish red erythematous background with regularly distributed red dots was significant in plantar psoriasis.</p><p><strong>Conclusions:</strong> Dermoscopy showed significant patterns in tinea pedis and plantar psoriasis due to their well-known different histological and physio pathological background, with white diffuse scales reflecting the dry and hyperkeratotic nature of plantar psoriasis and the red dots signifying the pin point blood vessels seen clinically as Auspitz sign. The peculiar scaling in tinea pedis might result from the predilection of dermatophytes to proliferate in moist environment, such as the furrows.</p>

Treatment of postoperative wounds using pectin-based reinforced dressings and their antimicrobial activity

A reinforced pectin-based dressing with a reinforcing element containing the antimicrobial agent chlorhexidine bigluconate has been developed. In vitro studies have shown that the hydrogel pectin dressing containing 0.03 ÷ 1.5 % chlorhexidine bigluconate inhibits the growth of both gram-positive (S. aureus) and gram-negative (P. aeruginosa) bacteria. The dressing can be used in the complex treatment of postoperative wounds with infectious-inflammatory process. The efficacy of different doses of chlorhexidine bigluconate was characterized by growth inhibition and increase of microorganism-free areas on the culture medium around the site of dressing localization, and regardless of the type of bacteria. Bacterial growth inhibition radius size depends on the dose of chlorhexidine in the hydrogel pectin dressing. The inhibition of growth of S. aureus and P. aeruginosa is directly proportional to chlorhexidine bigluconate content. The increase of dressing saturation with chlorhexidine to 1.0 and 1.5 % recorded the maximum inhibition of the growth of microorganisms. A veterinary clinical trial has shown a good therapeutic effect in the wound healing, in particular in the complex treatment of postoperative and accidental wounds both in the presence of infectious-inflammatory process and in its absence. The reinforced pectin-based dressing with cotton (or polypropylene) reinforcement element containing chlorhexidine bigluconate reduces the cost of dressings and bandaging frequency during wound healing. It protects the wound surface from contamination, mechanical irritation, bacterial contamination and the development of secondary infection. The dressing promotes good water, air and heat exchange between the wound and the environment, adsorbs excess exudate, maintains a moist environment and does not cause hyperosmotic damage and drying of the wound. Surgical wound healing occurred under the initial tension for 7 days. Considering the method of its application, this dressing is suitable for use on different parts of the animal's body (neck, withers, chest and abdomen, lower back, buttocks, thighs, shoulders, etc.).

Penetration and Tensile Strength of Various Impression Materials of Vinylsiloxanether, Polyether, and Polyvinylsiloxane Impression Materials

Objectives The aim of this study was to evaluate and compare penetration ability and tensile strength among vinylsiloxanether (VSE), polyether (PE), and polyvinylsiloxane (PVS) elastomeric dental impression materials. Materials and Methods The models were constructed for penetration ability test by simulated gingival sulcus width and moist environment. The 0.05, 0.1, and 0.2 mm of simulated gingival sulcus widths were used. Each simulated gingival sulcus width was impressed 10 repeats per one elastomeric impression material. All extension of elastomeric dental impression materials was scaled by Measuring Microscope (MM-11; Nikon, Tokyo, Japan). On the issue of the tensile strength study, the models were constructed following type 1 of the ISO 37:2017 specifications and/or type C of ASTM.D412 specifications. The two-way analysis of variance (ANOVA) and Tukey's honest significant difference test were performed in the penetration ability test. The one-way ANOVA and Dunnett's T3 test were performed in the tensile strength test. The significance level was set at 0.05. Results PE showed the best extension into all widths of simulated sulcus followed by VSE and PVS, respectively. PVS was significantly higher in tensile strength than VSE and PE, while VSE was significantly higher than PE. Conclusion Penetration ability of elastomeric dental impression materials was depended on gingival sulcus width. The wider the sulcular width, the better the penetration ability of elastomeric dental impression materials. PE presented the best penetration ability, while the novel PVS showed highest tensile strength.

Hydroxypropylmethylcellulose as a film and hydrogel carrier for ACP nanoprecursors to deliver biomimetic mineralization

Demineralization of hard tooth tissues leads to dental caries, which cause health problems and economic burdens throughout the world. A biomimetic mineralization strategy is expected to reverse early dental caries. Commercially available anti-carious mineralizing products lead to inconclusive clinical results because they cannot continuously replenish the required calcium and phosphate resources. Herein, we prepared a mineralizing film consisting of hydroxypropylmethylcellulose (HPMC) and polyaspartic acid-stabilized amorphous calcium phosphate (PAsp-ACP) nanoparticles. HPMC which contains multiple hydroxyl groups is a film-forming material that can be desiccated to form a dry film. In a moist environment, this film gradually changes into a gel. HPMC was used as the carrier of PAsp-ACP nanoparticles to deliver biomimetic mineralization. Our results indicated that the hydroxyl and methoxyl groups of HPMC could assist the stability of PAsp-ACP nanoparticles and maintain their biomimetic mineralization activity. The results further demonstrated that the bioinspired mineralizing film induced the early mineralization of demineralized dentin after 24 h with increasing mineralization of the whole demineralized dentin (3–4 µm) after 72–96 h. Furthermore, these results were achieved without any cytotoxicity or mucosa irritation. Therefore, this mineralizing film shows promise for use in preventive dentistry due to its efficient mineralization capability. Graphical Abstract

Hygrothermal performance of a massive natural stone masonry wall insulated from the internal side with hemp concrete – field measurements in cold climate

Improving of exterior walls in historic and traditional buildings is often only possible with interior thermal insulation. The actual structure and material properties of the existing exterior wall are usually the main unknown factors. Therefore, field measurements with small mock-ups are helpful before large-scale renovation. The current study analyses by field measurements the hygrothermal performance of internally insulated massive stone wall. Two different hemp concrete mixes were developed for the insulation. Temperature and humidity conditions were measured periodically over one year period. Results showed a very low drying rate of hemp concrete interior insulation. The external side of hemp concrete insulation will stay moist for a very long period. Temperature of coarse hemp concrete was slightly higher during the cold period. Wooden studs used to install hemp concrete will stay in moist areas for a long period. Temperature drop below 0 °C shows that interior insulation should be durable for freezing-thawing cycles. Drying out of constructional moisture is absolutely necessary for hygrothermal design. Before considering large-scale renovations, it is necessary to further assess the long term durability and performance of hemp concrete in a moist environment. The temperature increase on the interior surface could slightly improve indoor thermal comfort.

Hydrodynamics of Regional and Seasonal Variations in Congo Basin Precipitation

The processes that determine the seasonality of precipitation in the Congo Basin are examined using the atmospheric column moisture budget. Studying the fundamental determinants of Congo Basin precipitation seasonality supports process-based studies of variations on all time scales, including those associated with greenhouse gas-induced global warming. Precipitation distributions produced by the ERA5 reanalysis provide sufficient accuracy for this analysis, which requires a consistent dataset to relate the atmospheric dynamics and moisture distribution to the precipitation field. The Northern and Southern Hemisphere regions of the Congo Basin are examined separately to avoid the misconception that Congo Basin rainfall is primarily bimodal. While evapotranspiration is indispensable for providing moisture to the atmospheric column to support precipitation in the Congo Basin, its seasonal variations are small and it does not drive precipitation seasonality. During the equinoctial seasons, precipitation is primarily supported by meridional wind convergence in the moist environment in the 800 hPa to 500 hPa layer where moist air flows into the equatorial trough. Boreal fall rains are stronger than boreal spring rains in both hemispheres because low-level moisture divergence develops in boreal spring in association with the developing Saharan thermal low. The moisture convergence term also dominates the moisture budget during the summer season in both hemispheres, with meridional convergence in the 850-600 hPa layer as cross-equatorial flow interacts with the cyclonic flow about the Angola and Sahara thermal lows. Winter precipitation is low because of dry air advection from the winter hemisphere subtropical highs over the continent.

This Review Recent Advances in Chitosan and Alginate‐Based Hydrogels for Wound Healing Application

Wound healing is a complicated yet necessary event that takes place in both animals and human beings for the body to repair itself due to injury. Wound healing involves various stages that ensure the restoration of the injured tissue at the end of the process. Wound dressing material acts as a protective extracellular barrier against potential damage to the injury and microbial invasion. Naturally, polysaccharides (chitosan and alginate) have inherent properties that have made them attractive for their usage in wound healing therapy. Alginate and chitosan have been used to develop novel wound healing and smart biomaterials due to various functionalities such as reducing swelling, non-toxic nature, biocompatibility, antimicrobial potential, and maintenance moist environment, ability to absorb wound fluid, and skin regeneration promotion. Functionalization of polysaccharides is one of the many approaches that have been used to modify and enhance the wound healing properties of these biomaterials. Many studies have been done to modify the polysaccharide hydrogels. Some of these are highlighted in this paper. The designing and development of smart hydrogels that react to their environment have recently sparked a significant scientific and pharmaceutical interest. Smart hydrogel development has been the primary focal area for developing highly advanced and sophisticated wound healing therapeutic technologies. This paper seeks to comprehensively shed light on the advancements of functionalized chitosan and alginate-based hydrogels and their applicability in wound healing therapeutics. In addition to this, thus identifying critical drawbacks faced in existing hydrogel systems and how prospective technologies enable digitally controlled bio-platforms coupled with biomaterials to improve wound care. This review hopes to stimulate and encourage researchers to identify future avenues worth investigation.

Management of lagopthalmus with gold implant: A case report

Blinking covers the eye with a thin layer of tear fluid, thereby promoting a moist environment necessary for the cells of the exterior part of the eye. The tears also flush out foreign bodies and wash them away. This is crucial to maintain lubrication and proper health of the eye. In lagophthalmus, there is inability to close the eyelid and loss of blinking mechanism, thereby resulting in corneal dryness, ulceration, abrasion and infection. It may occur due to facial nerve damage secondary to trauma, iatrogenic due to surgery, tumour or Bell’s palsy. Initial symptomatic management is directed towards ocular surface lubrication. Viscous artificial tears are used or thin polyethylene film may be applied over the eyes to reduce evaporative drying. Temporary or permanent tarsorrhaphy may be required in some cases. Changing the position of either the top or bottom eyelid can help relieve the symptoms of lagopthalmus. A prosthetic procedure involves implanting gold weights into the upper eyelid, which allows the eyes to close by gravity. A case report of management of Lagophthalmus is presented here.

Prehispanic Highland Textile Technologies: A View from the First Millennium AD at Hualcayán, Ancash, Peru

The exceptional preservation of perishable artifacts on the arid west coast of the Andes has led to an abundance of knowledge on prehispanic textile production. Yet comparatively little of this knowledge is based on highland examples due to their poor preservation in the moist environment of the Andean sierra. Systematic excavations in 2011–2012 at the archaeological complex of Hualcayán in highland Ancash, Peru, revealed surprisingly well-preserved textiles and cordage from four partially looted machay-style tombs. In this article we provide an overview of textile forms, production techniques, and iconography from a sample of 292 textile and cordage fragments, equaling 20% of Hualcayán's assemblage. This work contributes to a better understanding of ancient Andean weaving in general and interregional interaction during the Early Intermediate period and Middle Horizon (ca. AD 1–1000) in particular. Significantly, we document variability in cotton yarn and a general uniformity in camelid yarn and weaving techniques in the overall sample. These findings, in combination with similarities in weaving techniques and style between coastal examples and Hualcayán's fabrics, suggest a coastal–highland relationship.