超强力胶眼部损伤的研究进展

该研究旨在对超强力胶可能对眼部造成的损伤问题进行回顾。本文对以往有关强力胶有害影响的文献进行了系统的研究。在过去的30年中,超强力胶对眼部的损伤问题是很常见的,其中大多数是意外事件,虽然它对眼部组织具有毒性,但通过安全教育可以进行预防。本文阐述了眼部超强力胶损伤的处理方法,指出了预防眼部超强力胶损伤的重要性。     

Cyclic 100-ka (glacial-interglacial) migration of subseafloor redox zonation on the Peruvian shelf

The coupling of subseafloor microbial life to oceanographic and atmospheric conditions is poorly understood. We examined diagenetic imprints and lipid biomarkers of past subseafloor microbial activity to evaluate its response to glacial-interglacial cycles in a sedimentary section drilled on the Peruvian shelf (Ocean Drilling Program Leg 201, Site 1229). Multiple and distinct layers of diagenetic barite and dolomite, i.e., minerals that typically form at the sulfate−methane transition (SMT), occur at much shallower burial depth than the present SMT around 30 meters below seafloor. These shallow layers co-occur with peaks of ¹³C-depleted archaeol, a molecular fossil of anaerobic methane-oxidizing Archaea. Present-day, non-steady state distributions of dissolved sulfate also suggest that the SMT is highly sensitive to variations in organic carbon flux to the surface shelf sediments that may lead to shoaling of the SMT. Reaction-transport modeling substantiates our hypothesis that shallow SMTs occur in response to cyclic sediment deposition with a high organic carbon flux during interglacials and a low organic carbon flux during glacial stages. Long diffusion distances expectedly dampen the response of deeply buried microbial communities to changes in sediment deposition and other oceanographic drivers over relatively short geological time scales, e.g., glacial-interglacial periods. However, our study demonstrates how dynamically sediment biogeochemistry of the Peru Margin has responded to glacial-interglacial change and how these changes are now preserved in the geological record. Such changes in subsurface biogeochemical zonation need to be taken into account to assess the role of the subseafloor biosphere in global element and redox cycling.Microbial life beneath the ocean reacts to and alters the organic matter and sediment deposited on the seafloor and buried over geological time scales of millennia or more. This subseafloor biosphere mineralizes buried organic matter, changes the geochemical gradients, and affects the precipitation or dissolution of minerals (1–3). Discrete zones of microbial abundance and activity develop (4–7) where sulfate (SO₄²⁻) diffusing downward from the overlying seawater intersects with upward diffusing methane (CH₄). Here the anaerobic oxidation of methane (AOM) is coupled to sulfate reduction (5, 8), and both compounds become depleted in this sulfate methane transition (SMT). The SMT is typically located within the top few meters to tens of meters below seafloor in continental shelf and slope sediments. Under steady state conditions, i.e., when the rates of both organic and bulk sedimentation remain constant and the quality of the deposited organic matter is uniform over time, no significant change occurs in the fluxes of dissolved methane and sulfate, and the SMT remains at a constant depth beneath the seafloor (8, 9). Sedimentation and organic carbon flux, however, are seldom constant over time. Especially at ocean margins where the organic matter flux to the seafloor is large and variable, oceanographic changes may result in a strong response of subseafloor methane and sulfate gradients. For example, high sedimentation rates and high organic carbon fluxes lead to high microbial activity and, over time, to a shallow SMT (10). A lowered deposition rate of organic matter will reduce microbial activity and cause a downward migration of the SMT.The SMT depth is therefore controlled by past environmental changes that affect the rate of sediment deposition and burial and, thus, affect the amount and quality of organic matter that today serves as substrate for microbial processes in the subsurface (11). Pore water analyses and microbiological studies provide information on the current metabolic processes (5–7), but the factors controlling the SMT depth over geological time are not well constrained.Changes in the depth of the SMT as a result of variations in the flux of methane and sulfate leave diagenetic imprints, such as iron sulfides, barium sulfate (barite) or calcium carbonates (3, 9, 12, 13), and anomalous, non-steady state distributions in pore water chemistry (3, 9, 14). Carbon isotope signatures in diagenetic dolomites from a sedimentary sequence recovered from the Peru Margin suggested that biogeochemical conditions at the SMT are subject to strong variations over time (15). Regularly spaced diagenetic dolomite layers were interpreted as a consequence of periodic upward and downward migration of the SMT triggered by glacial-interglacial variation in sediment deposition (16). However, the mechanisms that drive the upward or downward shifts of the SMT and lead to episodic precipitation of diagenetic minerals remained unclear.We present here a high-resolution record of geochemical signatures indicative of the past location of the SMT from a sedimentary sequence drilled at Ocean Drilling Program (ODP) Site 1229 at 150 m water depth on the Peruvian continental shelf (10°59′ S, 77°57′ W; Fig. S1). We scanned entire core sections at high resolution (1 cm) using an X-ray fluorescence (XRF) scanner to screen for focused element enrichments indicative of diagenetic mineral phases, such as barite and authigenic carbonates. Total organic carbon (TOC) and lipid biomarkers indicative of microbial communities at the SMT were analyzed with a depth resolution of 20 cm (5 cm in the uppermost 5 m) and compound-specific isotopic compositions of the lipids were measured at selected depths. Based on the diagenetic and molecular fossil imprints, we identify past locations of the SMT in the subseafloor and reconstruct its migration history. To test the feasibility and to understand potential geochemical controls on an upward or downward migrating SMT, the SMT depth was simulated as a function of variable sedimentation rate and organic matter influx using a transient reactive transport model. Our results reveal how dynamically the deep biosphere reacts to changes in sediment input at the seafloor and, hence, how changes in oceanographic conditions at geological timescales may influence microbial life below the seafloor.     

Identifying Unmet Rehabilitation Needs in Patients After Stroke With a Graphic Rehab-CompassTM

Background

Unmet rehabilitation needs are common among stroke survivors. We aimed to evaluate whether a comprehensive graphic “Rehab-Compass,” a novel combination of structured patient-reported outcome measures, was feasible and useful in facilitating a capture of patients' rehabilitation needs in clinical practice.

The Osteoarthritis Knee Model: Psychophysical Characteristics and Putative Outcomes

The knee osteoarthritis (KOA) model is a convenient and coherent archetype that is frequently used in pharmaceutical trials of drugs with analgesic and/or anti-inflammatory properties; yet, little is known about its specific pathophysiology. The presumed chronic inflammatory etiology of osteoarthritis suggests that nociceptive processes and neurogenic inflammation predominate in this condition. However, most chronic pain conditions are associated with changes in peripheral and central processing. Recent data corroborate this as an important mechanism in KOA. We compared psychophysical characteristics (including thermal Quantitative Sensory Testing); thermal, mechanical, and functional wind-up; thermal and mechanical aftersensations; and pressure algometry of 37 subjects with KOA with 35 age- and sex-matched controls. A third of the KOA subjects demonstrated hypoesthesia to vibration and the 4.56 von Frey fiber, yet few showed allodynia in their worse knee. The majority of subjects had abnormalities to pinprick (41% were hyperalgesic and 27% were hypoesthetic). Compared to controls, the more painful knee was hypoesthetic to cold detection and had greater thermal wind-up, lower pressure-pain thresholds, thermal and mechanical aftersensations, and twice the pain ratings of controls after stair climb. Substantial intraindividual differences were found in KOA subjects and controls for mechanical wind-up and algometric thresholds.PerspectiveThese results develop the KOA model and suggest mechanistic hypotheses. Certain of these tests may ultimately prove to be responsive, quasi-objective, and quantitative outcomes for research and lend empirical support to the notion of measurable sensitization in osteoarthritis.     

Ocular toxoplasmosis in Iran: 40 cases analysis

AIM: To report ocular symptoms, funduscopic findings and demographic distribution of ocular toxoplasmosis in Iran METHODS: In this cross-sectional study, a total of 40 patients with ocular toxoplasmosis (24 female, 16 male) were enrolled. The distribution of symptoms and funduscopic findings were studied. RESULTS: The patients' age was in the range of 13-52 with the most common age of 19 years old. Twenty-four patients were female (60.0%). The most common presenting sign was visual loss. There was anterior chamber (AC) inflammation in 23 patients (57.5%). Vitritis was presented in 36 patients (90.0%). In 35 patients (87.5%), the retinal lesion was central. In patients with peripheral lesion, 3 patients (60.0%) had flashing vs 12.5% chance of flashing in all patients. Older patients had larger lesion (P=0.04). CONCLUSION: Ocular toxoplasmosis substantially varies among patients with different age, gender, status of immunity, site of lesion and other undetermined factors. One of ocular symptoms, flashing, may necessitate a more precise peripheral fundus examination.     

Monte Carlo calculations and experimental measurements of dosimetric parameters of the IRA-103Pd brachytherapy source

This article presents a brachytherapy source having 103Pd adsorbed onto a cylindrical silver rod that has been developed by the Agricultural, Medical, and Industrial Research School for permanent implant applications. Dosimetric characteristics (radial dose function, anisotropy function, and anisotropy factor) of this source were experimentally and theoretically determined in terms of the updated AAPM Task group 43 (TG-43U1) recommendations. Monte Carlo simulations were used to calculate the dose rate constant. Measurements were performed using TLD-GR200A circular chip dosimeters using standard methods employing thermoluminescent dosimeters in a Perspex phantom. Precision machined bores in the phantom located the dosimeters and the source in a reproducible fixed geometry, providing for transverse-axis and angular dose profiles over a range of distances from 0.5 to 5 cm. The Monte Carlo N-particle (MCNP) code, version 4C simulation techniques have been used to evaluate the dose-rate distributions around this model 103Pd source in water and Perspex phantoms. The Monte Carlo calculated dose rate constant of the IRA-103Pd source in water was found to be 0.678 cGy h(-1) U(-1) with an approximate uncertainty of +/-0.1%. The anisotropy function, F(r, theta), and the radial dose function, g(r), of the IRA- 103Pd source were also measured in a Perspex phantom and calculated in both Perspex and liquid water phantoms.