12 research outputs found
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Technological framework for ubiquitous interactions using context–aware mobile devices
This report presents research and development of dedicated system architecture, designed to enable its users to interact with each other as well as to access information on Points of Interest that exist in their immediate environment. This is accomplished through managing personal preferences and contextual information in a distributed manner and in real-time. The advantage of this system architecture is that it uses mobile devices, heterogeneous sensors and a selection of user interface paradigms to produce a sociotechnical framework to enhance the perception of the environment and promote intuitive interactions. The thrust of the work has been on software development and component integration. Iterative prototyping was adopted as a development method in order to effectively implement the users’ feedback and establish a platform for collaboration that closely meets the requirements and aids their decision-making process. The requirement acquisition was followed by the system-modelling phase in order to produce a robust software prototype. The implementation includes component-based development and extensive use of design patterns over native programming. Conclusively, the software product has become the means to evaluate differences in the use of mixed reality technologies in a ubiquitous scenario.
The prototype can query a number of context sources such as sensors, or details of the personal profile, to acquire relevant data. The data (and metadata) is stored in opensource structures, so that they are accessible at every layer of the system architecture and at any time. By proactively processing the acquired context, the system can assist the users in their tasks (e.g. navigation) without explicit input – e.g. by simply creating a gesture with the device. However, advanced interaction with the application via the user interface is available for requests that are more complex.
Representations of the real world objects, their spatial relations and other captured features of interest are visualised on scalable interfaces, ranging from 2D to 3D models and from photorealism to stylised clues and symbols. Two principal modes of operation have been implemented; one, using geo-referenced virtual reality models of the environment, updated in real time, and second, using the overlay of descriptive annotations and graphics on the video images of the surroundings, captured by a video camera. The latter is referred to as augmented reality.
The continuous feed of the device position and orientation data, from the GPS receiver and the digital compass, into the application, makes the framework fit for use in unknown environments and therefore suitable for ubiquitous operation. This is one of the novelties of the proposed framework, because it enables a whole range of social, peer-to-peer interactions to take place. The scenarios of how the system could be employed to pursue these remote interactions and collaborative efforts on mobile devices are addressed in the context of urban navigation. The conceptual design and implementation of the novel location and orientation based algorithm for mobile AR are presented in detail. The system is, however, multifaceted and capable of supporting peer-to-peer exchange of information in a pervasive fashion, usable in various contexts. The modalities of these interactions are explored and laid out in several scenarios, but particularly in the context of user adoption. Two evaluation tasks took place. The preliminary evaluation examined certain aspects that influence user interaction while being immersed in a virtual environment, whereas the second summative evaluation compared the utility and certain usability aspects of the AR and VR interfaces
Vitamin D receptor gene polymorphisms in multiple sclerosis patients in northwest Greece
<p>Abstract</p> <p>Background</p> <p>Polymorphisms of the vitamin D receptor (VDR) gene have been linked to both multiple sclerosis (MS) and osteoporosis. We examined the frequency of the Taq-I and Bsm-I polymorphisms of the vitamin D receptor (VDR) gene in 69 patients with MS and 81 age and sex-matched healthy individuals. Genotyping of Taq-I (rs731236) and Bsm-I (rs1544410) was performed using TaqMan<sup>® </sup>SNP Genotyping Assay. All patients and controls had determination of body mass index (BMI), bone mineral density (BMD) and smoking history.</p> <p>Results</p> <p>The mean age of patients was 39 ± 10.5 years compared to 38.7 ± 10.7 years of the controls (p = 0.86), the BMI was 24.8 ± 4.2 kg/m<sup>2 </sup>compared to 25.7 ± 4.8 kg/m<sup>2 </sup>of the controls (p = 0.23), the BMD in the lumbar spine 0.981 ± 0.15 compared to 1.025 ± 013 of the controls (p = 0.06) and the total hip BMD was 0.875 ± 0.14 compared to 0.969 ± 0.12 of the controls (p < 0.001). There were no differences of the Taq-I (TT, CT, CC) and Bsm-I genotypes (GG, GA, AA) and allelic frequencies between MS and control individuals. Multivariate analysis also failed to show any association of the Taq-I and Bsm-I polymorphisms and MS or sex, BMI, BMD and smoking history.</p> <p>Conclusions</p> <p>This study suggests that the Taq-I and Bsm-I polymorphisms of the VDR gene are not associated with MS risk, BMI or BMD in the Greek population studied.</p
Ultrasonographic Prevalence and Factors Predicting Left Ventricular Diastolic Dysfunction in Patients with Liver Cirrhosis: Is There a Correlation between the Grade of Diastolic Dysfunction and the Grade of Liver Disease?
Presence of cardiac dysfunction has been associated with an unfavorable prognosis in patients with liver cirrhosis. In the present study, 92 consecutive, newly-diagnosed patients with liver cirrhosis were prospectively evaluated. Liver disease was graded according to the modified Child-Turcotte-Pugh (CTP) score whereas left ventricular diastolic function was assessed by Doppler-echocardiography and graded (Stage 0 to 4) according to current guidelines. Overall, DD was diagnosed in 55/92 (59.8%) patients [DD-stage-1: 36/92 (39.1%), DD-stage-2: 19/92 (20.6%)]. Prevalence of DD-stage-1 among the different stages of liver cirrhosis was: CTP-class A: 11/29 (37.9%), B: 15/39 (38.5%), C: 10/24 (41.6%), (P>0.05 in all comparisons), whereas for DD-stage-2 the corresponding proportions were CTP-class A: 3/29 (10.3%), B: 5/39 (12.8%), C: 11/24 (45.8%), (P=0.0009 between CTP-class C versus A and B). Age > 53 years (Odd’s Ratio [OR]: 4.2; 95% confidence interval [CI]: 1.5–12.1) and CTP-class C (OR: 4.6; 95% CI: 1.1–20) could independently predict DD. No relation between presence of DD and the etiology of the liver disease was found. We conclude that DD is a common feature in liver cirrhosis. DD-stage-1 is fairly prevalent among all CTP-classes whereas DD-stage-2 seems to be characteristic of the advanced liver disease (CTP-class C). A high level of awareness for the presence of the syndrome is required, especially if cirrhotic patients are CTP-class C and/or of older age
The Effect of the Water Drinking Test on Ocular Parameters and Choroidal Thickness in Glaucoma Suspects
Background and objectives: We aimed to evaluate the effects of the water drinking test (WDT) on several systemic and ocular parameters, including choroidal thickness, which was assessed through optical coherence tomography angiography (OCTA), in glaucoma suspects. Materials and Methods: A total of 40 eyes from 20 glaucoma suspects without any systemic or ocular diseases were included in this prospective observational study. All the participants undertook the WDT, which required the drinking of 1 L of table water in 5 min. The outcome measures included IOP, systolic and diastolic blood pressure (SBP and DBP), mean arterial pressure (MAP), mean ocular perfusion pressure (MOPP), ocular pulse amplitude (OPA), and subfoveal and peripapillary choroidal thickness, which were assessed at baseline and at four 15 min intervals after the WDT. Generalized least squares models and mixed model analyses that take into account repeated measurements were used to assess the changes over time of these parameters. Results: All the ocular and systemic parameters showed statistically significant changes at all time points compared to baseline apart from choroidal thickness. The peak changes were an IOP of 20.1 mmHg versus 17.3 mmHg at 45 min, an SBP of 137.6 mmHg versus 125 mmHg at 30 min, a DBP of 95.9 mmHg versus 85.7 mmHg at 15 min, and an MOP of 53.51 mmHg versus 48.89 mmHg at 15 min. Conclusions: Despite elevations in IOP and significant changes in all the assessed systemic parameters, the WDT was not associated with changes in choroidal thickness in glaucoma suspects
Vase Life Evaluation of Three Greek Tulip Species Compared with a Commercial Cultivar
Aiming at evaluating new candidate species for the cut flower market of Greece and beyond, in this study, the vase life of three Greek tulip plant species, Tulipa cretica ‘Hilde’ (CRH, local endemic of Crete, Greece), T. clusiana ‘Chrysantha’ (CLC, naturalized in Chios Island, Greece), and T. australis (AUS, native in the Mediterranean and Greece), was investigated in comparison to the commercial tulip hybrid Île-de-France (IDF). To this end, pre-cooled at 4 °C bulbs of the abovementioned Greek tulip plant species were bought from Dutch nurseries and grown in pots placed in unheated greenhouses located at two different climatic conditions in Northern Greece. The plants were uprooted when the flowers reached a slightly open stage. Half of the flowering stems were immediately placed into bottles with deionized water, while the rest were placed in a preservative solution containing citric acid 5% and sulfuric acid 1% and then remained under laboratory conditions until the entire tepal wilted (end of vase life). The measurements performed concerned: (a) flower stem length and flower maximum diameter, (b) fresh weight (FW) of initial stems, leaves, flowers, and bulbs and at the end of vase life, (c) flower color parameters (L, a, b, c, and H) in all treated flowers, (d) leaf chlorophyll content (SPAD values), and (e) initial and final water volume after removing the flowering stems. The aforementioned measurements showed that CRH cut flowers may exhibit consistent floral opening patterns and were associated with a long mean vase life of 5.7 days, which can be further prolonged to 6.5 days by carefully selecting a cultivation location with proper climatic conditions. The vase life of CLC cut flowers was significantly affected by the climatic parameters (temperature) of the area where the plants were cultivated. The immersion of cut flowering stems in a preservative solution with citric and sulfuric acids did not yield a notable increase in the longevity of cut flowers during the postharvest period. Moreover, this treatment did not have any significant impact on leaf chlorophyll content or flower color at the end of the flowers’ vase life. The data of this work show that cut flowers from the native species T. cretica and T. clusiana have satisfactory vase life, especially when plants were grown in favorable climate condition; the latter is an important criterion for their entry into the cut flower market
Reduction of Foveal Avascular Zone After Vitrectomy Demonstrated by Optical Coherence Tomography Angiography
Purpose: To investigate the effect of pars plana vitrectomy on foveal
circulation, and in particular the foveal avascular zone (FAZ), using
optical coherence tomography angiography (OCTA).
Methods: This was a prospective, non-randomized, comparative case series
of patients that underwent vitrectomy. Twenty-six eyes of 26 patients
that underwent vitrectomy were studied postoperatively by OCTA. Our
patients underwent 23 or 25G pars plana vitrectomy (PPV) for any
posterior segment pathology. Three-dimensional OCTAs (DRI Triton Swept
Source OCT; Topcon) of the capillary plexus were obtained three months
post-operatively. The FAZ measurements of the fellow eyes were used as
controls.
Main outcome measures: Change in FAZ area between vitrectomized eyes and
controls.
Results: From a total of 26 patients, 17 underwent vitrectomy due to
retinal detachment (RD). Almost all patients demonstrated a
statistically significant reduction in FAZ size based on the OCTA
measurements..he mean difference in FAZ size for the superficial
capillary plexus (SCP) was -93.77 +/- 71.73 mu m and for the deep
capillary plexus (DCP) -88.87 +/- 75.41 mu m, both statistically
significant (p=0.000), while the amount of reduction in mu m was the
same for both SCP and DCP.
Conclusion: The foveal avascular zone seems to be reduced following
vitrectomy as shown by optical coherence tomography angiography. It is
postulated that this may be the result of changes in the physiology of
the vitrectomized eye, and that this change should be attributed to the
removal of the vitreous itself rather than other structures such as the
internal limiting membrane
Factors Associated with the Clinical Course of Vitreomacular Traction
Background. To analyze the optical coherence tomography (OCT) characteristics as well as the clinical and demographic features to investigate their possible role to the course of vitreomacular traction syndrome. Methods. The inclusion criteria were vitreomacular adhesion with traction causing distortion of the retinal architecture, with or without the presence of an epiretinal membrane, regardless of the size of the adhesion; age >18 years; follow-up of at least three months; and adequate quality OCT scan. Measurements of foveal thickness, average macular thickness, macular volume, maximum vertical and horizontal vitreomacular adhesion, nasal and temporal angles of traction, hyaloid hyperreflectivity, the presence of an epiretinal membrane (ERM), and cone outer segment tips detachment were obtained. Results. 150 eyes were included in the analysis. 36 eyes (24%) developed complete resolution at the last visit, 19 eyes (12.7%) formed a full-thickness macular hole, and 95 eyes (63.3%) showed no resolution of the traction. Better BCVA at the first visit was associated with an increased likelihood of resolution of the VMT, but increasing age, CMT, and BCVA in the end of the follow-up was associated with a reduction in the likelihood of resolving. Of the other variables that were studied, no statistical significant predictors were identified. Conclusions. Better BCVA in the first visit was associated with an increased likelihood of resolution of the VMT that occurred in 24% of our cases. Other factors such as the vertical area of adhesion and the angle of adhesion were not identified as prognostic factors affecting the clinical course of the disease
The surgical safety checklist and patient outcomes after surgery: a prospective observational cohort study, systematic review and meta-analysis
© 2017 British Journal of Anaesthesia Background: The surgical safety checklist is widely used to improve the quality of perioperative care. However, clinicians continue to debate the clinical effectiveness of this tool. Methods: Prospective analysis of data from the International Surgical Outcomes Study (ISOS), an international observational study of elective in-patient surgery, accompanied by a systematic review and meta-analysis of published literature. The exposure was surgical safety checklist use. The primary outcome was in-hospital mortality and the secondary outcome was postoperative complications. In the ISOS cohort, a multivariable multi-level generalized linear model was used to test associations. To further contextualise these findings, we included the results from the ISOS cohort in a meta-analysis. Results are reported as odds ratios (OR) with 95% confidence intervals. Results: We included 44 814 patients from 497 hospitals in 27 countries in the ISOS analysis. There were 40 245 (89.8%) patients exposed to the checklist, whilst 7508 (16.8%) sustained ≥1 postoperative complications and 207 (0.5%) died before hospital discharge. Checklist exposure was associated with reduced mortality [odds ratio (OR) 0.49 (0.32–0.77); P\u3c0.01], but no difference in complication rates [OR 1.02 (0.88–1.19); P=0.75]. In a systematic review, we screened 3732 records and identified 11 eligible studies of 453 292 patients including the ISOS cohort. Checklist exposure was associated with both reduced postoperative mortality [OR 0.75 (0.62–0.92); P\u3c0.01; I2=87%] and reduced complication rates [OR 0.73 (0.61–0.88); P\u3c0.01; I2=89%). Conclusions: Patients exposed to a surgical safety checklist experience better postoperative outcomes, but this could simply reflect wider quality of care in hospitals where checklist use is routine