We provide a complete description of the edge-to-edge tilings with a regular triangle and a shield-shaped hexagon with no right angle. The case of a hexagon with a right angle is also briefly discussed.

Background: Several landmine detection methods, based on nuclear techniques, have been suggested during the recent years. Neutron energy moderation, neutron-induced gamma emission, neutron and amma attenuation, and fast neutronbackscattering are nuclear-based methods used for landmine detection. The aim of this study is to use backscattered neutron for landmine detection. Materials and Methods: MCNP code, a well-known Monte Carlo particle-transport code, was theoretically used for backscattered neutron counts. An Am-Be neutron source and a single thermal neutron detector were experimentally applied to detect the buried sample. Results: The experimental results obtained in this way have been in good agreement with the theoretical results obtained by MCNP. Therefore, the shield of neutron source plays an important role on landmine detection. Conclusion: Hydrogenous material such as polyethylene and boric acid can be used as suitable shields. They can increase neutron counts in detector and facilitate detection process.

International humanitarian law, as a significant branch of international law, encompasses a variety of regulations aimed at limiting the devastating effects of armed conflict. This body of law, primarily focused on the protection of civilians, plays a crucial role in mitigating the impact of war. One specific area within these regulations concerns the use of human shields. Belligerent parties, often in an attempt to deter enemy attacks, may employ individuals as human shields. These individuals may include captured combatants or even civilians who voluntarily expose themselves to enemy fire.Various forms of human shields have been observed in past armed conflicts. This article seeks to conceptually analyze the notion of human shields, categorize their types, and examine the applicable legal framework governing each category. The existing rules generally prohibit the use of human shields; however, the legal implications may vary depending on the nature of the conflict—whether international or non-international. A key issue that arises is the question of absolute prohibition. The First Additional Protocol to the Geneva Conventions suggests that under certain conditions, the use of human shields might be conceivable under the doctrine of necessity, a concept examined in this study. It appears that, despite the desirability of a categorical prohibition, international humanitarian law does not currently recognize an absolute ban. Moreover, the phenomenon of voluntary human shields presents a legal dilemma: how should the law protect individuals who deliberately place themselves in harm’s way? Although international legal provisions in this area are often vague and general, it is argued that the rules governing involuntary human shields should likewise apply to voluntary cases.

Introduction: In the nuclear medicine departments, staff exposure to radiation is inevitable during patient positioning and radiopharmaceutical preparation. There is controversy regarding the use of usual lead aprons with respect to penetrating gamma rays used in nuclear medicine departments as well as production of characteristic lead x-ray from aprons.Methods: This research compares the shielding properties of poly vinyl alcohol reinforced by lead acetate, with lead shield based on biological damage to blood cells from the Technetium-99m source. All computations have been carried out by using the WinXcom program. In addition, the alkaline comet assay has been used to estimate DNA damage at the single cell level. Statistical comparisons were analyzed by using the T-test.Results: Calculated value of μm is 0.7616 (cm2/ g), HVL is 7.4 mm and density is 1.224 g/cm3. A significant difference in reducing the amount of DNA damage by 0.5mm sheet of lead was not found.Conclusion: Considering the effects of distance and time on lead acetate composite, results showed that increasing the distance has a significant impact on harm reduction. Even at a distance of 100 cm from the source at all exposure times, the damage is much reduced, compared to the groups with and without a lead shield.

Corneal shield ulcer is an uncommon but serious complication of vernal keratoconjunctivitis (VKC) that can threaten visual acuity. We present a 12-year-old case with a corneal shield ulcer on the superior part of the cornea in the right eye. We learned from his history that he was treated with topical cyclosporine A (CsA) and corneal debridement was performed for the same complaints six months ago. His complaints recurred six months after ceasing topical CsA voluntarily. Topical anti-allergic and CsA treatments were commenced, we also performed corneal debridement. During his followups, the corneal ulcer healed leaving a scar as opacity and neovascularization. This case highlights the role of the anti-inflammatory effect of CsA in preventing the recurrence of shield ulcers.

Colorectal Cancer (CRC) represents an important global health challenge, standing as the third most prevalent cancer and the second major cause of cancer-related deaths worldwide. Nowadays, the relationship between intestinal microbiota and colorectal cancer has recently attracted increasing interest; probiotics have shown promise as a complementary approach in cancer prevention and treatment strategies. The purpose of this review was to examine the effects of probiotics, prebiotics, and synbiotics on intestinal microbiota, as well as their potential benefits in improving results for CRC cells and patients. The findings indicated that the administration of probiotics increases intestinal microbiota by promoting the growth of beneficial bacteria, and reducing the presence of harmful pathogens. Probiotic intervention also increased antimicrobial release, improved intestinal permeability, and reduced the occurrence of tight junction functions and surgical infections in CRC patients. To conclude, probiotics play a beneficial role in modifying intestinal microbiota, increasing postoperative results, strengthening intestinal obstruction function, and reducing inflammatory markers in patients with CRC. It is recommended that future research should focus on planning a case-control design with a sufficient sample size, complemented by molecular-talented probes to detect the specific effects of probiotics in colorectal cancer and the mechanisms well.