313 research outputs found
Clinical and Experimental Approach to the Benefits and Risks of Laser Treatment for Diabetic Macular Edema
Diabetic retinopathy is an ophthalmic complication of diabetes that currently affects 93 million people worldwide. Diabetic macular edema is a subtype of diabetic retinopathy that is characterized by leaking blood vessels in the central part of the retina, and it is a major cause of vision loss in individuals with diabetes. Screening for retinopathy is performed at regular intervals to identify subjects in need of treatment. In Sweden, the recommended screening interval for type 2 diabetic subjects with no diabetic retinopathy is 3 years. Laser treatment for diabetic macular edema has been used for decades, but studies have reported conflicting results regarding possible clinical complications following such therapy. Furthermore, the molecular events involved in the clinical benefits of laser treatment have not been fully explored. To determine the safety of the current screening interval, the 3-year incidence of diabetic retinopathy and macular edema was monitored in type 2 diabetic subjects with no retinopathy (Study I). To identify the long-term effects of laser treatment, the retinal sensitivity in 29 consecutively recruited subjects with diabetic macular edema was assessed by visual fields before and after laser treatment every 6 months during a period of 2 years (Study II). To investigate the cellular and molecular events that may be involved in the clinical benefits of laser treatment, a model of in vitro laser coagulation of the retinal pigment epithelium was established and used to evaluate cell death and cell repair (Study III). The same model was also used to explore the effects of laser treatment on mRNA and protein levels by analysis of microarray and proteomics data (Study IV). Study I demonstrated a very low incidence of sight-threatening diabetic retinopathy, which supports the current use of a 3-year retinal screening interval for the subgroup in question. Study II showed no change in retinal sensitivity following laser treatment for diabetic macular edema during the 2-year follow-up compared to baseline. Study III revealed that laser-induced damage involved both necrosis and apoptosis, and the repair process entailed both proliferation and migration. In study IV, the downregulation of the protein Carbonic anhydrase 9 and the upregulation of heat shock proteins 1A and 1B were the most interesting findings and might explain some of the beneficial effects of laser treatment for diabetic macular edema
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Security-aware selection of Web Services for Reliable Composition
Dependability is an important characteristic that a trustworthy computer system should have. It is a measure of Availability, Reliability, Maintainability, Safety and Security. The focus of our research is on security of web services. Web services enable the composition of independent services with complementary functionalities to produce value-added services, which allows organizations to implement their core business only and outsource other service components over the Internet, either pre-selected or on-the-fly. The selected third party web services may have security vulnerabilities. Vulnerable web services are of limited practical use. We propose to use an intrusion-tolerant composite web service for each functionality that should be fulfilled by a third party web service. The third party services employed in this approach should be selected based on their security vulnerabilities in addition to their performance. The security vulnerabilities of the third party services are assessed using a penetration testing tool. In this paper we present our preliminary research work
Asymmetrical Axillary Artery Deviations of the Brachial Plexus
Introduction: The relationship between the brachial plexus and other key axillary vascular structures have been explored extensively in medical literature highlighting different variations in the brachial plexus. Understanding variations provides valuable knowledge for surgical interventions. Typically at the axillary region, the lateral cord splits into the musculocutaneous nerve and the lateral root of the median nerve. The medial cord contributes the medial root to the median nerve where the axillary artery normally runs posteriorly.
Objective: The goal of this case report is to highlight a bilateral anatomical variation of the brachial plexus in relation of the progression of the axillary artery in a 71 year-old male cadaver.
Methods: During a routine dissection in a medical school Anatomy course, the axilla of a male cadaver was dissected bilaterally according to laboratory protocol. Digital photography was used to preserve visual observations.
Results: In the right axilla, the joining of the lateral root and medial root to form the median nerve occurs proximally in the axillary region. This junction occurs more distally in the brachial region of the left arm. In the left axilla, the axillary artery is running between the superior anterior division and the middle anterior division from anteriorly to posteriorly. More distally, the axillary emerges from the posterior side coming over the median nerve. The right axillary region has an axillary artery running above the median nerve as well.
Conclusion: Knowledge of anatomical variations in the brachial plexus is important for anatomists and surgeons during interventional procedures including nerve blocks and surgery. Here we report a unique variation of the brachial plexus and the position of the axillary artery in the left axilla as well as the right axilla
High Fidelity Quantum Gates in the Presence of Dispersion
We numerically demonstrate the control of motional degrees of freedom of an
ensemble of neutral atoms in an optical lattice with a shallow trapping
potential. Taking into account the range of quasimomenta across different
Brillouin zones results in an ensemble whose members effectively have
inhomogeneous control fields as well as spectrally distinct control
Hamiltonians. We present an ensemble-averaged optimal control technique that
yields high fidelity control pulses, irrespective of quasimomentum, with
average fidelities above 98%. The resulting controls show a broadband spectrum
with gate times in the order of several free oscillations to optimize gates
with up to 13.2% dispersion in the energies from the band structure. This can
be seen as a model system for the prospects of robust quantum control. This
result explores the limits of discretizing a continuous ensemble for control
theory
Non-invasive MRI quantification of cerebrospinal fluid dynamics in amyotrophic lateral sclerosis patients.
BACKGROUND: Developing novel therapeutic agents to treat amyotrophic lateral sclerosis (ALS) has been difficult due to multifactorial pathophysiologic processes at work. Intrathecal drug administration shows promise due to close proximity of cerebrospinal fluid (CSF) to affected tissues. Development of effective intrathecal pharmaceuticals will rely on accurate models of how drugs are dispersed in the CSF. Therefore, a method to quantify these dynamics and a characterization of differences across disease states is needed.
METHODS: Complete intrathecal 3D CSF geometry and CSF flow velocities at six axial locations in the spinal canal were collected by T2-weighted and phase-contrast MRI, respectively. Scans were completed for eight people with ALS and ten healthy controls. Manual segmentation of the spinal subarachnoid space was performed and coupled with an interpolated model of CSF flow within the spinal canal. Geometric and hydrodynamic parameters were then generated at 1 mm slice intervals along the entire spine. Temporal analysis of the waveform spectral content and feature points was also completed.
RESULTS: Comparison of ALS and control groups revealed a reduction in CSF flow magnitude and increased flow propagation velocities in the ALS cohort. Other differences in spectral harmonic content and geometric comparisons may support an overall decrease in intrathecal compliance in the ALS group. Notably, there was a high degree of variability between cases, with one ALS patient displaying nearly zero CSF flow along the entire spinal canal.
CONCLUSION: While our sample size limits statistical confidence about the differences observed in this study, it was possible to measure and quantify inter-individual and cohort variability in a non-invasive manner. Our study also shows the potential for MRI based measurements of CSF geometry and flow to provide information about the hydrodynamic environment of the spinal subarachnoid space. These dynamics may be studied further to understand the behavior of CSF solute transport in healthy and diseased states
BVVL/ FL: features caused by SLC52A3 mutations; WDFY4 and TNFSF13B may be novel causative genes
Brown-Vialetto-Van Laere (BVVL) and Fazio-Londe are disorders with amyotrophic lateral sclerosis-like features, usually with recessive inheritance. We aimed to identify causative mutations in 10 probands. Neurological examinations, genetic analysis, audiometry, magnetic resonance imaging, biochemical and immunological testings, and/or muscle histopathology were performed. Mutations in known causative gene SLC52A3 were found in 7 probands. More importantly, only 1 mutated allele was observed in several patients, and variable expressivity and incomplete penetrance were clearly noted. Environmental insults may contribute to variable presentations. Putative causative mutations in other genes were identified in 3 probands. Two of the genes, WDFY4 and TNFSF13B, have immune-related functions. Inflammatory responses were implicated in the patient with the WDFY4 mutation. Malfunction of the immune system and mitochondrial anomalies were shown in the patient with the TNFSF13B mutation. Prevalence of heterozygous SLC52A3 BVVL causative mutations and notable variability in expressivity of homozygous and heterozygous genotypes are being reported for the first time. Identification of WDFY4 and TNFSF13B as candidate causative genes supports conjectures on involvement of the immune system in BVVL and amyotrophic lateral sclerosis
Scheduling of grid tied battery energy storage system participating in frequency response services and energy arbitrage
Battery energy storage
systems
(BESS)
are
widely used to smooth
power
fluctuations
and maintain the voltage and
frequency of the power feeder at a desired level.
T
he National Grid Electricity Transmission (NGET), the primary electricity
transmission network operator in the UK, has introduced various frequency response servic
es that are
designed
to provide a
real
-
time response to deviations in the grid frequency.
In this study
,
a
control
algorithm is
developed
which generates a
charge/discharge power output with respect to deviations in
the grid frequency and the requisite
service
specifications. Using
historical
UK electricity prices, a new
balancing
service scheduling approach
has
also been
developed to
maximize
energy
arbitrage
revenue
by layering
different types of balancing services
throughout the day
. Simulation result
s show that the
proposed algorithm delivers both dynamic and non
-
dynamic firm frequency response (FFR) and also enhanced frequency
response (EFR) to
NGET
specifications while
generating arbitrage revenue
as well as service availability payment
s
in the
balancing market. A comparative study is also presented to compare the yearly arbitrage revenue
obtained
from
the work
presented in this
paper and
a
previous
reference study
.
Finall
y, exper
imental results of
a
grid
-
tied
2MW
/1MWh
BESS
have
been used
for verification purposes
Knowledge, attitude and practice of nuclear medicine staff towards radiation protection
Introduction: Ionizing radiation in medical imaging is one of the dominant sources of exposure, and correct knowledge of radiation protection, affects staff safety behaviors during procedures. This study aimed to assess the radiation protection Knowledge, Attitude and Practice (KAP) amongst nuclear medicine centers' staff in Iran. Methods: To evaluate the level of radiation protection KAP, a validated questionnaire was distributed between 243 participants considering demographic characteristics in different geographical regions in Iran from 2014 to 2015. Results: There were statistically significant differences in the level of nuclear medicine staff KAP radiation protection with gender (p0.05). Conclusion: Our findings have shown that radiation protection KAP level of nuclear medicine staff was inadequate in some regions. This might be due to the lack of continuous training and absence of adequate safety knowledge about ionizing radiation. It seems that awareness about radiation protection rules and regulations, along with continuous training and preparations has a direct effect on radiation practice leading to enhanced KAP of staff in nuclear medicine centers. © 2019 Tehran University of Medical Sciences. All rights reserved
Radiation protection knowledge, attitude, and practice (KAP) in interventional radiology
Objectives: Due to increasing cardiac disease and its mortality rate, the frequency of cardiac imaging has grown and, as a result, interventional cardiologists potentially receive high radiation doses in cardiac examinations. This study aimed to assess the knowledge, attitude, and practice (KAP) level of radiation protection (RP) among interventional radiology staff in Iranian health care centers across the country. Methods: We used a validated questionnaire survey consisting of 30 multiple-choice questions to perform a cross-sectional study. Participants were healthcare personnel working professionally with radiation at different levels (i.e., secretary, radiology technologists, nurse, and physician). The questionnaire was divided into three sections to assess KAP regarding RP. Results: Significant differences exist in RP KAP mean scores based on educational age (p 0.050). We found a significant difference between RP KAP mean scores and different regions (p < 0.050). Conclusions: Educational and practice age, sex, type of hospital, and geographical region affect he KAP of interventional radiology staff regarding RP. Since many of the subjective radiation harms for both medical team and patients, this can be easily controlled and prevented; a checkup for personnel of interventional radiology departments, considering samples from different parts of the country with different levels of education, continuous training, and practical courses may help map the status of KAP. The results of this study may also help authorized health physics officers design strategic plans to enhance the quality of such services in radiation departments. © 2018, Oman Medical Specialty Board. All rights reserved
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