401 research outputs found
The anatomical landmarks effective in the localisation of the median nerve during orthopaedic procedures
Background: The aim of this study was to create a safe zone for surgeons who perform procedures in the wrist to avoid iatrogenic damage to the median nerve (MN) by identifying anatomical landmarks using ultrasound (USG).Materials and methods: We measured the distances between the MN and two easily identifiable anatomical landmarks at the level of the proximal border of carpal ligament using USG.Results: A total of 57 volunteers (n = 114 upper limbs) were included in this study. Our main findings revealed that the distance from the flexor carpi radialis tendon to MN (FCR-MN) was 7.87 mm (95% confidence interval 7.37–8.37) and the distance from flexor carpi ulnaris tendon to MN (FCU-MN) was 19.09 mm (95% confidence interval 18.51–19.67).Conclusions: The tendons of FCR and FCU are easily identifiable landmarks that can be distinguished using simple palpation. Based on our USG findings, the area around FCR should be carefully navigated to avoid iatrogenic injury to the MN during surgical procedures around the carpal tunnel
Induction of unique structural changes in guanine-rich DNA regions by the triazoloacridone C-1305, a topoisomerase II inhibitor with antitumor activities
We recently reported that the antitumor triazoloacridone, compound C-1305, is a topoisomerase II poison with unusual properties. In this study we characterize the DNA interactions of C-1305 in vitro, in comparison with other topoisomerase II inhibitors. Our results show that C-1305 binds to DNA by intercalation and possesses higher affinity for GC- than AT-DNA as revealed by surface plasmon resonance studies. Chemical probing with DEPC indicated that C-1305 induces structural perturbations in DNA regions with three adjacent guanine residues. Importantly, this effect was highly specific for C-1305 since none of the other 22 DNA interacting drugs tested was able to induce similar structural changes in DNA. Compound C-1305 induced stronger structural changes in guanine triplets at higher pH which suggested that protonation/deprotonation of the drug is important for this drug-specific effect. Molecular modeling analysis predicts that the zwitterionic form of C-1305 intercalates within the guanine triplet, resulting in widening of both DNA grooves and aligning of the triazole ring with the N7 atoms of guanines. Our results show that C-1305 binds to DNA and induces very specific and unusual structural changes in guanine triplets which likely plays an important role in the cytotoxic and antitumor activity of this unique compound
Clefting in a Pumpkin Balloon
NASA\u27s development of a large payload, high altitude, long duration balloon, the Ultra Long Duration Balloon, centers on a pumpkin shape super-pressure design. Under certain circumstances, it has been observed that a pumpkin balloon may be unable to pressurize into the desired cyclically symmetric equilibrium configuration, settling into a distorted, undesired state instead. In this paper, we will use th concept of stability to classify equilibrium shapes of fully pressurized/fully deployed strained ball oons
The Nylon Scintillator Containment Vessels for the Borexino Solar Neutrino Experiment
Borexino is a solar neutrino experiment designed to observe the 0.86 MeV Be-7
neutrinos emitted in the pp cycle of the sun. Neutrinos will be detected by
their elastic scattering on electrons in 100 tons of liquid scintillator. The
neutrino event rate in the scintillator is expected to be low (~0.35 events per
day per ton), and the signals will be at energies below 1.5 MeV, where
background from natural radioactivity is prominent. Scintillation light
produced by the recoil electrons is observed by an array of 2240
photomultiplier tubes. Because of the intrinsic radioactive contaminants in
these PMTs, the liquid scintillator is shielded from them by a thick barrier of
buffer fluid. A spherical vessel made of thin nylon film contains the
scintillator, separating it from the surrounding buffer. The buffer region
itself is divided into two concentric shells by a second nylon vessel in order
to prevent inward diffusion of radon atoms. The radioactive background
requirements for Borexino are challenging to meet, especially for the
scintillator and these nylon vessels. Besides meeting requirements for low
radioactivity, the nylon vessels must also satisfy requirements for mechanical,
optical, and chemical properties. The present paper describes the research and
development, construction, and installation of the nylon vessels for the
Borexino experiment
An anatomical investigation of rare upper limb neuropathies due to the Struthers’ ligament or arcade: a meta-analysis
Background: The Struthers’ ligament (SL) is a fibrous band that originates fromthe supracondylar humeral process and inserts into the medial humeral epicondyle, potentially compressing both the median nerve and brachial artery. The controversial Struthers’ arcade (SA) is a musculotendinous band found in the distal end of the arm that might compress the ulnar nerve. This study aimed to evaluate the pooled prevalence estimate of the SL and SA, and their anatomical features. Materials and methods: A meticulous search of major electronic medical databases was carried out regarding both structures. Applicable articles (and all relevant references) were analysed. Data from the eligible articles was extracted and evaluated. The quality and the potential risk of bias in the included studies were assessed using the AQUA tool. Results: The arcade was reported in 13 studies (510 arms), whereas the ligament in 6 studies (513 arms). The overall pooled prevalence estimate of the ligament was 1.8%, and 52.6% for the arcade. Most frequently, the ulnar nerve was covered by a tendinous arcade (42.2%). In all cases, the ligament inserted into the medial humeral epicondyle, but had various origins. Only 1 study reported compression of the median nerve by the ligament, whilst another contradicted this view. Conclusions: Although the SL is rare, and the SA is a valid anatomical entity (though with a variable presentation), clinically meaningful neurovascular entrapments caused by these structures are infrequent. Nonetheless, a better understanding of each may be beneficial for the best patient outcomes
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Spatial and Quantitative Approach to Incorporating Stakeholder Values into Total Maximum Daily Loads: Dominguez Channel Case Study
The Federal Clean Water Act (CWA) Section 303(d)(1)(A) requires each state to identify those waters that are not achieving water quality standards. The result of this assessment is called the 303(d) list. The CWA also requires states to develop and implement Total Maximum Daily Loads (TMDLs) for these waters on the 303(d) list. A TMDL specifies the maximum amount of a pollutant that a water body can receive and still meet water quality standards, and allocates the pollutant loadings to point and non-point sources. Nationwide, over 34,900 segments of waterways have been listed as impaired by the Environmental Protection Agency (EPA 2006). The EPA enlists state agencies and local communities to submit TMDL plans to reduce discharges by specified dates or have them developed by the EPA. The Department of Energy requested Lawrence Livermore National Laboratory (LLNL) to develop appropriate tools to assist in improving the TMDL process. An investigation of this process by LLNL found that plans to reduce discharges were being developed based on a wide range of site investigation methods. Our investigation found that given the resources available to the interested and responsible parties, developing a quantitative stakeholder input process and using visualization tools to display quantitative information could improve the acceptability of TMDL plans. We developed a stakeholder allocation model (SAM) which uses multi-attribute utility theory to quantitatively structure the preferences of the major stakeholder groups. We then applied GIS to display allocation options in maps representing economic activity, community groups, and city agencies. This allows allocation options and stakeholder concerns to be represented in both space and time. The primary goal of this tool is to provide a quantitative and visual display of stakeholder concerns over possible TMDL options
Generation and characterization of radiation in biomedical applications
This Creative Inquiry, Generation and Characterization of Radiation in Biomedical Applications, fuses two scientific disciplines, physics and bioengineering, seeking a common goal. Students under Dr. Takacs and Dr. Dean, including a doctoral candidate, are designing experiments to irradiate various biomaterials, including proteins and cancer cells, with monochromatic x-rays between 1000 eV to 15000 eV, and then study the results of those interactions. This specific creative inquiry\u27s (PHYS 2990-005 and BIOE 4510-025) goal for this semester is to further understand x-ray interactions with matter, specifically biomaterials. The bioengineering students are devising specific ways to cultivate certain proteins and cell cultures, and the physicists are designing parameters for the experiments, including the production and spectroscopy of x-rays. Several of the experiments will also be utilizing Clemson\u27s EBIT (electron beam ion trap, one of two in the country) as one of the sources for such radiation. With so little data collected using instrumentation of this precision, we feel that even our short-term goals will have far reaching implications
Quantitative and Qualitative Analyses of the Cell Death Process in Candida albicans Treated by Antifungal Agents
The death process of Candida albicans was investigated after treatment with the antifungal agents flucytosine and amphotericin B by assessing morphological and biophysical properties associated with cell death. C. albicans was treated varying time periods (from 6 to 48 hours) and examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). SEM and AFM images clearly showed changes in morphology and biophysical properties. After drug treatment, the membrane of C. albicans was perforated, deformed, and shrunken. Compared to the control, C. albicans treated with flucytosine was softer and initially showed a greater adhesive force. Conversely, C. albicans treated with amphotericin B was harder and had a lower adhesive force. In both cases, the surface roughness increased as the treatment time increased. The relationships between morphological changes and the drugs were observed by AFM clearly; the surface of C. albicans treated with flucytosine underwent membrane collapse, expansion of holes, and shrinkage, while the membranes of cells treated with amphotericin B peeled off. According to these observations, the death process of C. albicans was divided into 4 phases, CDP0, CDP1, CDP2, and CDP4, which were determined based on morphological changes. Our results could be employed to further investigate the antifungal activity of compounds derived from natural sources
Quantitative and Qualitative Analysis of the Antifungal Activity of Allicin Alone and in Combination with Antifungal Drugs
The antifungal activity of allicin and its synergistic effects with the antifungal agents flucytosine and amphotericin B (AmB) were investigated in Candida albicans (C. albicans). C. albicans was treated with different conditions of compounds alone and in combination (allicin, AmB, flucytosine, allicin + AmB, allicin + flucytosine, allicin + AmB + flucytosine). After a 24-hour treatment, cells were examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM) to measure morphological and biophysical properties associated with cell death. The clearing assay was conducted to confirm the effects of allicin. The viability of C. albicans treated by allicin alone or with one antifungal drug (AmB, flucytosine) in addition was more than 40% after a 24-hr treatment, but the viability of groups treated with combinations of more than two drugs was less than 32%. When the cells were treated with allicin alone or one type of drug, the morphology of the cells did not change noticeably, but when cells were treated with combinations of drugs, there were noticeable morphological changes. In particular, cells treated with allicin + AmB had significant membrane damage (burst or collapsed membranes). Classification of cells according to their cell death phase (CDP) allowed us to determine the relationship between cell viability and treatment conditions in detail. The adhesive force was decreased by the treatment in all groups compare to the control. Cells treated with AmB + allicin had a greater adhesive force than cells treated with AmB alone because of the secretion of molecules due to collapsed membranes. All cells treated with allicin or drugs were softer than the control cells. These results suggest that allicin can reduce MIC of AmB while keeping the same efficacy
Management earnings forecasts and IPO performance: evidence of a regime change
Companies undertaking initial public offerings (IPOs) in Greece were obliged to include next-year profit forecast in their prospectuses, until the regulation changed in 2001 to voluntary forecasting. Drawing evidence from IPOs issued in the period 1993–2015, this is the first study to investigate the effect of disclosure regime on management earnings forecasts and IPO long-term performance. The findings show mainly positive forecast errors (forecasts are lower than actual earnings) and higher long-term returns during the mandatory period, suggesting that the mandatory disclosure requirement causes issuers to systematically bias profit forecasts downwards as they opt for the safety of accounting conservatism. The mandatory disclosure requirement artificially improves IPO share performance. Overall, our results show that mandatory disclosure of earnings forecasts can impede capital market efficiency once it goes beyond historical financial information to involve compulsory projections of future performance
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