-
Journal of Personalized Medicine Jul 2023Vernal keratoconjunctivitis (VKC) severely affects the quality of life of affected patients. The development of a shield ulcer is considered one of the most severe... (Review)
Review
BACKGROUND
Vernal keratoconjunctivitis (VKC) severely affects the quality of life of affected patients. The development of a shield ulcer is considered one of the most severe late-stage complications, which when untreated leads to irreversible vision loss. In this systematic review, we outlined the results of surgical treatments of corneal shield ulcers in VKC.
METHODS
We searched 12 literature databases on 3 April 2023 for studies of patients with VKC in which shield ulcers were treated by any surgical treatment. Treatment results were reviewed qualitatively. Assessments of the risk of bias of individual studies were made using the Clinical Appraisal Skills Programme.
RESULTS
Ten studies with 398 patients with VKC were eligible for the qualitative review. Two categories of surgical approaches were described: supratarsal corticosteroid injection and debridement with or without amniotic membrane transplantation. Almost all patients experienced resolution or improvement of their shield ulcers, regardless of treatment modality. Time to healing was faster with surgical debridement. A small proportion experienced recurrence and side effects.
CONCLUSIONS
Surgical treatment for shield ulcers in VKC seems highly effective, but careful post-operative treatment and follow-ups are necessary due to the risk of recurrence and potential side effects.
PubMed: 37511705
DOI: 10.3390/jpm13071092 -
Small Methods Jul 2023The development of new materials for electromagnetic interference (EMI) shielding is an important area of research, as it allows for the creation of more effective and... (Review)
Review
The development of new materials for electromagnetic interference (EMI) shielding is an important area of research, as it allows for the creation of more effective and high-efficient shielding solutions. In this sense, MXenes, a class of 2D transition metal carbides and nitrides have exhibited promising performances as EMI shielding materials. Electric conductivity, low density, and flexibility are some of the properties given by MXene materials, which make them very attractive in the field. Different processing techniques have been employed to produce MXene-based materials with EMI shielding properties. This review summarizes processes and the role of key parameters like the content of fillers and thickness in the desired EMI shielding performance. It also discusses the determination of power coefficients in defining the EMI shielding mechanism and the concept of green shielding materials, as well as their influence on the real application of a produced material. The review concludes with a summary of current challenges and prospects in the production of MXene materials as EMI shields.
PubMed: 37129581
DOI: 10.1002/smtd.202300112 -
Journal of the American Dental... Sep 2023The American Academy of Oral and Maxillofacial Radiology established an ad hoc committee to draft evidence-based recommendations and clinical guidance for the...
BACKGROUND
The American Academy of Oral and Maxillofacial Radiology established an ad hoc committee to draft evidence-based recommendations and clinical guidance for the application of patient contact shielding during dentomaxillofacial imaging.
TYPES OF STUDIES REVIEWED
The committee reviewed monographs and reports from radiation protection organizations and studies that reported radiation dose to gonads, breasts, and thyroid gland from dentomaxillofacial imaging.
RESULTS
Considering the absence of radiation-induced heritable effects in humans and the negligible dose to the gonads and fetus from dentomaxillofacial imaging, the committee recommends discontinuing shielding of the gonads, pelvic structures, and fetuses during all dentomaxillofacial radiographic imaging procedures. On the basis of radiation doses from contemporaneous maxillofacial imaging, the committee considered that the risks from thyroid cancer are negligible and recommends that thyroid shielding not be used during intraoral, panoramic, cephalometric, and cone-beam computed tomographic imaging.
PRACTICAL IMPLICATIONS
This position statement informs and educates the reader on evolving radiation protection practices and provides simple, unequivocal guidance to dental personnel to implement these guidelines. State and local authorities should be contacted to update regulations to reflect these recommendations.
Topics: Humans; Radiation Dosage; Radiography, Dental; Radiography, Panoramic; Radiology; Cone-Beam Computed Tomography
PubMed: 37530694
DOI: 10.1016/j.adaj.2023.06.015 -
Materials (Basel, Switzerland) Sep 2023All-in-one radiation shielding is an emerging concept in developing new-generation radiation protection materials since various forms of ionizing radiation, such as...
All-in-one radiation shielding is an emerging concept in developing new-generation radiation protection materials since various forms of ionizing radiation, such as neutrons and gamma rays, can occur simultaneously. In this study, we examine the ability of transition metal borides to attenuate both photon and particle radiation. Specifically, fourteen different transition metal borides (including inner transition metal borides) are selected for examination based on their thermodynamic stabilities, molecular weights, and neutron capture cross-sections of the elements they contain. Radiation shielding characteristics of the transition metal borides are computationally investigated using Phy-X/PSD, EpiXS and NGCal software. The gamma-ray shielding capabilities of the transition metal borides are evaluated in terms of the mass attenuation coefficient (), the linear attenuation coefficient (), the effective atomic number (), the half-value layer (HVL), the tenth-value layer (TVL), and the mean free path (MFP). The mass and linear attenuation factors are identified for thermal and fast neutrons at energies of 0.025 eV and 4 MeV, respectively. Moreover, the fast neutron removal cross-sections (∑R) of the transition metal borides are calculated to assess their neutron shielding abilities. The results revealed that borides of transition metals with a high atomic number, such as Re, W, and Ta, possess outstanding gamma shielding performance. At 4 MeV photon energy, the half-value layers of ReB and WB compounds were found as 1.38 cm and 1.43 cm, respectively. Most notably, these HVL values are lower than the HVL value of toxic Pb (1.45 cm at 4 MeV), which is one of the conventional radiation shielding materials. On the other hand, SmB and DyB demonstrated exceptional neutron attenuation for thermal and fast neutrons due to the high neutron capture cross-sections of Sm, Dy, and B. The outcomes of this study reveal that transition metal borides can be suitable candidates for shielding against mixed neutron and gamma radiation.
PubMed: 37834632
DOI: 10.3390/ma16196496 -
Polymers Jul 2023With the continuous advancement of wireless communication technology, the use of electromagnetic radiation has led to issues such as electromagnetic interference and... (Review)
Review
With the continuous advancement of wireless communication technology, the use of electromagnetic radiation has led to issues such as electromagnetic interference and pollution. To address the problem of electromagnetic radiation, there is a growing need for high-performance electromagnetic shielding materials. Graphene, a unique carbon nanomaterial with a two-dimensional structure and exceptional electrical and mechanical properties, offers advantages such as flexibility, light weight, good chemical stability, and high electromagnetic shielding efficiency. Consequently, it has emerged as an ideal filler in electromagnetic shielding composites, garnering significant attention. In order to meet the requirements of high efficiency and low weight for electromagnetic shielding materials, researchers have explored the use of graphene-polymer nanocomposite foams with a cellular structure. This mini-review provides an overview of the common methods used to prepare graphene-polymer nanocomposite foams and highlights the electromagnetic shielding effectiveness of some representative nanocomposite foams. Additionally, the future prospects for the development of graphene-polymer nanocomposite foams as electromagnetic shielding materials are discussed.
PubMed: 37571129
DOI: 10.3390/polym15153235 -
World Neurosurgery Mar 2024Few studies have compared the Pipeline Shield stents with previous generations of flow-diverting stents (FDSs) for the treatment of unruptured intracranial aneurysms....
BACKGROUND
Few studies have compared the Pipeline Shield stents with previous generations of flow-diverting stents (FDSs) for the treatment of unruptured intracranial aneurysms. This study aimed to evaluate the efficacy and safety of Pipeline Shield stents and FDSs without modified surfaces.
METHODS
The present evaluation is a retrospective cohort study of patients endovascularly treated with Pipeline Shield stents or FDSs without modified surfaces for unruptured intracranial aneurysms between January 2014 and June 2022. The data analyzed were obtained from the anonymized database of our institution's interventional radiology service.
RESULTS
A total of 147 patients with 155 unruptured intracranial aneurysms were included. Of the 155 aneurysms, 96 were treated with Pipeline Shield stents and 59 with FDSs without modified surfaces. The aneurysms treated with Pipeline Shield stents had higher 6-month (O'Kelly-Marotta [OKM] D; 87.5% vs. 71.4%; P = 0.025) and 1-year (OKM D; 82.5% vs. 63.0%; P = 0.047) occlusion rates than the aneurysms treated using FDSs without modified surfaces. No differences between the devices were found at the 1-year follow-up in the incidence of ischemic stroke (P = 0.939) or hemorrhagic complications (P = 0.559).
CONCLUSIONS
Pipeline Shield stents demonstrated superior complete occlusion rates (OKM D) at both the 6-month and the 1-year follow-up assessments compared with nonmodified surface FDSs. No significant differences were found in the safety profiles between the 2 types of stents with regard to thromboembolic complications and ischemic events. Further research with larger study populations is necessary to validate these findings.
Topics: Humans; Intracranial Aneurysm; Retrospective Studies; Treatment Outcome; Stents; Embolization, Therapeutic; Endovascular Procedures
PubMed: 38216035
DOI: 10.1016/j.wneu.2024.01.028 -
Scientific Reports Sep 2023Transnasal flexible laryngoscopy is considered an aerosol generating procedure. A negative pressure face shield (NPFS) was developed to control aerosol from the patient...
Transnasal flexible laryngoscopy is considered an aerosol generating procedure. A negative pressure face shield (NPFS) was developed to control aerosol from the patient during laryngoscopy. The purpose of this study was to determine the effectiveness of the NPFS at controlling virus aerosol compared to a standard disposable plastic face shield. The face shields were placed on a simulated patient coughing machine. MS2 bacteriophage was used as a surrogate for SARS-CoV-2 and was aerosolized using the coughing machine. The aerosolized virus was sampled on the inside and outside of the face shields. The virus aerosol concentration was not significantly different between the inside and outside of the traditional plastic face shield (p = 0.12). However, the particle concentrations across all particle sizes measured were significantly decreased outside the face shield. The virus and particle concentrations were significantly decreased (p < 0.01) outside the NPFS operating at a flow rate of 38.6 L per minute (LPM). When the NPFS was operated at 10 LPM, virus concentrations were not significantly different (p = 0.09) across the face shield. However, the number particle concentrations across all particle sizes measured were significantly different (p < 0.05).
Topics: Humans; COVID-19; SARS-CoV-2; Respiratory Aerosols and Droplets; Cough; Laryngoscopy
PubMed: 37730888
DOI: 10.1038/s41598-023-42403-8 -
Nanoscale Advances Jul 2023Electromagnetic interference (EMI) is a pervasive and harmful phenomenon in modern society that affects the functionality and reliability of electronic devices and poses... (Review)
Review
Electromagnetic interference (EMI) is a pervasive and harmful phenomenon in modern society that affects the functionality and reliability of electronic devices and poses a threat to human health. To address this issue, EMI-shielding materials with high absorption performance have attracted considerable attention. Among various candidates, two-dimensional MXenes are promising materials for EMI shielding due to their high conductivity and tunable surface chemistry. Moreover, by incorporating magnetic and conductive fillers into MXene/polymer composites, the EMI shielding performance can be further improved through structural design and impedance matching. Herein, we provide a comprehensive review of the recent progress in MXene/polymer composites for absorption-dominated EMI shielding applications. We summarize the fabrication methods and EMI shielding mechanisms of different composite structures, such as homogeneous, multilayer, segregated, porous, and hybrid structures. We also analyze the advantages and disadvantages of these structures in terms of EMI shielding effectiveness and the absorption ratio. Furthermore, we discuss the roles of magnetic and conductive fillers in modulating the electrical properties and EMI shielding performance of the composites. We also introduce the methods for evaluating the EMI shielding performance of the materials and emphasize the electromagnetic parameters and challenges. Finally, we provide insights and suggestions for the future development of MXene/polymer composites for EMI shielding applications.
PubMed: 37441247
DOI: 10.1039/d3na00130j -
Canadian Journal of Ophthalmology.... Aug 2023To evaluate the efficacy of patient-sided breath shields in preventing oronasal droplet transmission during slit-lamp examination.
OBJECTIVE
To evaluate the efficacy of patient-sided breath shields in preventing oronasal droplet transmission during slit-lamp examination.
DESIGN
Experimental study testing the efficacy of patient-sided breath shields on a slit lamp.
METHODS
Two commercially available patient-sided breath shields and a 3-dimensional (3D)-printed shield designed by the authors were attached to a slit-lamp chin rest for testing. Each shield was exposed to 3 standardized sprays of coloured dye from a spray gun with its nozzle adjusted to simulate the angular dispersion of a human sneeze. Any overspray not blocked by the shields was recorded and compared with spray with no shield (control). Image-processing software was used to ascertain the surface area of overspray not blocked by the tested shield compared with the control of no shield.
RESULTS
With typical use, both commercially available patient-sided shields and the 3D-printed shield blocked 100% of forward-travelling measurable droplets from a simulated sneeze spray. Even when set to the furthest distance setting to simulate the worst-case scenario, shield 1 and the 3D-printed shield blocked 99.96% and 99.65% of overspray, respectively. However, slow-motion footage did reveal that a considerable amount of spray rebounded off the shields and extended peripherally past its borders.
CONCLUSIONS
With typical use, all tested shields prevented 100% of oronasal transmission. To encourage accessibility, the authors offer a free 3D model and instructions for creating the tested patient-sided breath shield. Patient-sided shields should be combined with other infection-control measures to minimize transmission.
Topics: Humans; Slit Lamp Microscopy; Respiration; Protective Devices; Respiratory Aerosols and Droplets
PubMed: 35231395
DOI: 10.1016/j.jcjo.2022.02.002 -
Materials (Basel, Switzerland) Oct 2023In shield tunneling projects, the selection of an accurate model to calculate the mechanical response of segment structure plays a crucial role in the design and cost of...
In shield tunneling projects, the selection of an accurate model to calculate the mechanical response of segment structure plays a crucial role in the design and cost of the project. The shell-spring and beam-spring models are two widely used methods for this purpose. However, it is still not clear how accurate and different these models are in calculation results under surcharge load. Therefore, to accurately calculate the internal forces and deformation of the segment structure and clarify the difference between the two models' results, the shell-spring and beam-spring models were established based on a subway shield tunnel project in Zhengzhou city. The reliability of the models was verified by comparing and analyzing the differences in deformation results between the models and field measurements. Furthermore, the safety of the segment structure was evaluated according to the ultimate bearing capacity of the normal section. The results declare that: (1) In the shell-spring model, the internal force gradually reduces from the edges towards the center of the segment width, and the shield segment exhibits a prominent non-plane strain state. (2) The internal force of the beam-spring model is larger than that of the shell-spring model. The axial force difference between the two models is relatively small; meanwhile, there is a larger disparity in the bending moment. However, with an increase in surcharge loading, the discrepancy in internal forces between the two models gradually decreases. (3) The calculation results of the shell-spring model are close to the field-measured values and the shield tunnel model test values, which verifies the accuracy and reliability of the shell-spring model. Therefore, it is more reasonable to use the shell-spring model to calculate the mechanical response of the segment structure. (4) With an increase in surcharge loading, the safety of the shield tunnel decreases gradually. Therefore, surcharge loading above the shield tunnel should be reasonably controlled to meet the requirements of the normal use of the shield segment. This manuscript aims to provide a reference for the future design and optimization of the shield tunnels' lining structure.
PubMed: 37895787
DOI: 10.3390/ma16206806