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Abstract The aim of this work is to study the influence of the palm fibers treated with soda hydroxide solution on the properties of the compressed earth bricks stabilized (CEBs) with alkali‐activated binder. The improvement in their mechanical parameters is attributable with 15 wt.% of alkali‐activated binder‐based natural pozzolan. To achieve this objective, mortars composed of treated fibers at different levels (0.1, 0.2, 0.3, 0.4, and 0.5 wt.%) of lengths of 4 and 16 cm have been developed. These different mortars with and without fibers were subjected to mechanical (dry and wet compressive test, flexural test), physical (water absorption), mineralogical (XRD, FTIR), and microstructural (SEM/EDS) characterizations after 7 and 90 days. The results revealed that in general the incorporation of fibers improves the mechanical and physical properties of CEBs stabilized with 15 wt.% of alkali‐activated binder. Furthermore, the X‐ray diffraction analysis indicated that certain mineralogical phases of the raw materials dissolve during alkaline activation. The Fourier transform infrared spectra revealed the effectiveness of the fibers in sorption water molecules. Moreover, optical examination reveals that the binder utilized completely wraps the fibers. This demonstrates that the treated fibers function flawlessly as a filler in the matrix. At 90 days with the addition of 0.4 wt.% fibers, the maximum dry compressive strength and flexural strength values were 8.08±0.40 and 5.8±0.19 MPa, respectively. The stabilized earth bricks reinforced with 0.4 wt.% of palm fibers exhibited the mechanical properties values fitting the requirements of the materials candidate for the building construction applications especially as masonry bricks.

Appropriate medical management can be an alternative in those patients with submacular cysticercosis in whom achieving good visual outcome with vitreoretinal surgery is not possible. We report the case of a 25-year-old female who presented complaining of blurred vision in her left eye associated with photopsias and metamorphopsias of 3 months duration. Initial visual acuity in the right eye was 20/20 and 20/100 in the left eye. Upon indirect ophthalmoscopy in the left eye, a yellow-white, dome-shaped, elevated lesion with foveal involvement was observed. The rest of the ophthalmological examination proved normal. With clinical findings and images, submacular cysticercosis was diagnosed, and vitreoretinal surgery was suggested. Nevertheless, the patient did not accept the treatment; therefore, medical management was initiated. Central nervous system involvement was ruled out, and treatment with praziquantel and systemic prednisolone was initiated. Cysticercosis was resolved with significant improvement of her symptoms and visual acuity.

In this study, an ecofriendly binder was developed by using rice husk ash (RHA) and sodium hydroxide as the activator alongside fly ash (FA) as the aluminosilicate precursor at ambient conditions. The developed binder was used in the production of mortars with varying proportions of sand. A total of three mortar mixtures were developed with sand to binder ratios of 0.55, 0.83 and 1.11. The corresponding behaviour of the mortars and influence of the sand proportions was assessed in terms of the compressive strength, water absorption, density, porosity. Microstructural investigations such as scanning electron microscopy, energy dispersive x-ray spectroscopy, infrared spectrum analysis and mercury intrusion porosimetry were also used to validate the physical properties. The findings from this study demonstrated that RHA can be used successfully as an activator component in the production of mortars. In terms of the sand content, it was found out that increasing the sand to binder ratio has detrimental effects on the performance of the mortars due to the reduction in the binder content primarily. The microstructure analysis of the mortars made with sand to binder ratio of 0.55 showed a compact and strong structure justifying the higher compressive strength achieved. The MIP analysis confirmed that the formation of C-A-S-H gel at the advanced ages allowed the pores refinement with a significant decrease in the fraction of the capillary and macroscopic pores within the geopolymer mortars.

This paper investigates the direct transformation of laterites (natural iron-rich aluminosilicates) to cementitious composites with principal mineral phases being Gismondine and Stratlingite. The effects of particles size distribution and cement content (2 to 8 wt%) on the mechanical properties and microstructure of laterite-cement composites are assessed. Four grades of granulometry with various percentages of fine and coarse particles were considered. The Environment Scanning Electron Microscopy (ESEM), Mercury Intrusion Porosimetry (MIP), Fourier Transformed Infrared Spectroscopy (FT-IR) and X-ray Powder Diffractometry (XRD) were performed after 1, 90 and 365 days, to assess the phase’s evolution, mechanical performance and the microstructure of the laterite-cement composites. It is found that fines particles, essentially pozzolanic and amorphous, are responsible for the bonding strength while coarse particles improve the compressive strength. Dense and compact microstructure, water absorption under 18% and flexural strength above 6 MPa (compressive strength > 30 MPa) could be achieved as from 4 wt% of cement making the laterite-cement composite appropriate as building and construction materials. The choice of a highly corroded class of laterite and the selection of the particle size distribution allows the production of optimum composite that is presented as energy-efficient and sustainable. Thus, corroded or indurated laterites are considered as “green metakaolins” which do not require any energy for their transformation unlike clayey materials.

In this study, sugarcane bagasse fibres (SBF) were used as a sustainable alternative to reinforce laterite-based geopolymers. As geopolymers can be deemed an eco-friendly construction material, the sustainability of geopolymers can be further improved with the use of SBF which is an agricultural by-product as reinforcement. In addition, the use of natural fibres has been known to improve insulation properties resulting in more energy conservation when such materials reinforced with natural fibres are used for the construction of building elements. Thus, the influence of SBF at various dosages (i.e. 1.5%, 3%, 4.5%, 6% and 7.5%) on the properties of laterite-based geopolymer was evaluated in this study. The outcome of this study indicated that incorporating SBF into the laterite-based geopolymers resulted in a decrease in density and increase in the sonic rate which is beneficial to the acoustic and thermal insulation enhancement. In addition, it was found out that the use of SBF at a dosage of 3% improved the resistance of the geopolymers to wet-dry cycles. However, the presence of SBF in the geopolymers resulted in a decrease in the compressive strength and an increase in the permeability properties with higher content of SBF.

We report the clinical case of an 8-year-old girl who came to the clinic with intense pain in dental piece 4.6. Periapical radiography was taken. The diagnosis was symptomatic irreversible pulpitis in young permanent tooth with incomplete apical formation in null stage 8. It was decided to perform the apicoformation treatment, using the (MTA) Mineral Trioxide Aggregate: as an apical stop. The radiographic controls were performed at 1, 3, 11, 35 months and Cone Bean tomography 43 months after the end of treatment. The patient presented absence of clinical symptoms and, radiographically, deposits of bone tissue were observed at the apical level.

Se presenta el caso de un paciente de 10 años con diagnóstico de ectrodactilia-displasia ectodérmica-hendidura, con cuadro de oclusión congénita de vías lagrimales, complicado con blefaroconjuntivitis y queratitis bacteriana, a la exploración oftalmológica se encontró agenesia de punto lagrimal superior del ojo derecho, hipoplasia de glándulas de Meibomio de ambos ojos, además de laceración canalicular y falsa vía lagrimal del ojo izquierdo, por antecedente de dacriointubación cerrada previa. A la exploración sistémica se encontró: ectrodactilia de manos y pies, cicatriz de queiloplastia, alteraciones de piel y cabello, y anodoncia subtotal. Se realizó exploración de vías lagrimales encontrando obstrucción ósea de vía lagrimal del lado derecho. Se decidió manejo conservador de la vía lagrimal, para realizar dacriocistorrinostomía en ambos ojos al tener mayor desarrollo mediofacial con la edad.

Thyroid hormones play an important role in epididymal function. Hypothyroid animals experience a significant decrease in the number and forward motility of sperm and a remarkable impairment of epididymal morphology. However, it is yet unknown if such activity is due to direct actions of iodothyronines on the target epididymis. The eventual identification of T[sub 3] receptors in the nucleous of epididymal cells becomes relevant. For this reason, the authors searched for specific high-affinity binding of T[sub 3] to these nuclei. Twenty prepuberal male Wistar rats were used. The testes and epididymis were approached as one unit through a scrotal incision. The fat-free epididymides were subjected to standard techniques to prepare the nuclei for incubations with 125I-T[sub 3] concentrations, ranging from 0.5 × 10–9 to 2.0 × 10–11 M. Calculations of association constants and binding capacities were performed according to Scatchard. A single binding site with a K[sub a] of 3.06 ± 0.6 × 109 M–1 or K[sub d] of 3.26 ± 0.6 × 10–10 M and a maximal binding capacity of 0.11 ± 0.02 pmol T[sub 3]/µg DNA were observed. It is concluded that these nuclei contain a specific T[sub 3] receptor. This finding strongly suggests that thyroid hormones have direct effects on the epididymis. [ABSTRACT FROM AUTHOR]