127 research outputs found

    Interaction of [Rh2(O2CCH3)4(H2O)2] and [Rh2(O2CCH(OH)Ph)2(phen)2(H2O)2](O2C-CH(OH)Ph)2 With Sulfhydryl Compounds and Ceruloplasmin

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    The interaction of binuclear rhodium(II) complexes [Rh2(OOCCH3)4(H2O)2], [Rh2{OOCCH(OH)Ph}2(phen)2(H2O)2] {OOCCH(OH)Ph}2, [Rh2(OOCCH3)2(bpy)2(H2O)2](OOCCH3)2 and [Rh2Cl2(OOCMe)2(bpy)2](3H2O) with ceruloplasmin, cysteine, glutathione and coenzyme A have been investigated using. UV-Vis and CD spectroscopies. The complexes containing phen or bpy at pH = 7.4 and 4.0 are readily reduced with sulfhydryl compounds, while rhodium(II) acetate is relatively stable in these conditions. Complex [Rh2{OOCCH(OH)Ph}2(phen)2(H2O)2] strongly changes structure of ceruloplasmin leading to the decrease of of α-helix content and loss of oxidase activity

    Augmented versus Virtual Reality Laparoscopic Simulation: What Is the Difference?: A Comparison of the ProMIS Augmented Reality Laparoscopic Simulator versus LapSim Virtual Reality Laparoscopic Simulator

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    BACKGROUND: Virtual reality (VR) is an emerging new modality for laparoscopic skills training; however, most simulators lack realistic haptic feedback. Augmented reality (AR) is a new laparoscopic simulation system offering a combination of physical objects and VR simulation. Laparoscopic instruments are used within an hybrid mannequin on tissue or objects while using video tracking. This study was designed to assess the difference in realism, haptic feedback, and didactic value between AR and VR laparoscopic simulation. METHODS: The ProMIS AR and LapSim VR simulators were used in this study. The participants performed a basic skills task and a suturing task on both simulators, after which they filled out a questionnaire about their demographics and their opinion of both simulators scored on a 5-point Likert scale. The participants were allotted to 3 groups depending on their experience: experts, intermediates and novices. Significant differences were calculated with the paired t-test. RESULTS: There was general consensus in all groups that the ProMIS AR laparoscopic simulator is more realistic than the LapSim VR laparoscopic simulator in both the basic skills task (mean 4.22 resp. 2.18, P <0.000) as well as the suturing task (mean 4.15 resp. 1.85, P <0.000). The ProMIS is regarded as having better haptic feedback (mean 3.92 resp. 1.92, P <0.000) and as being more useful for training surgical residents (mean 4.51 resp. 2.94, P <0.000). CONCLUSIONS: In comparison with the VR simulator, the AR laparoscopic simulator was regarded by all participants as a better simulator for laparoscopic skills training on all tested feature

    Do Basic Psychomotor Skills Transfer Between Different Image-based Procedures?

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    Background - Surgical techniques that draw from multiple types of image-based procedures (IBP) are increasing, such as Natural Orifice Transluminal Endoscopic Surgery, fusing laparoscopy and flexible endoscopy. However, little is known about the relation between psychomotor skills for performing different types of IBP. For example, do basic psychomotor colonoscopy and laparoscopy skills interact? Methods - Following a cross-over study design, 29 naïve endoscopists were trained on the Simbionix GI Mentor and the SimSurgery SEP simulators. Group C (n = 15) commenced with a laparoscopy session, followed by four colonoscopy sessions and a second laparoscopy session. Group L (n = 14) started with a colonoscopy session, followed by four laparoscopy sessions and a second colonoscopy session. Results - No significant differences were found between the performances of group L and group C in their first training sessions on either technique. With additional colonoscopy training, group C outperformed group L in the second laparoscopy training session on the camera navigation task. Conclusions - Overall, training in the basic colonoscopy tasks does not affect performance of basic laparoscopy tasks (and vice versa). However, to limited extent, training of basic psychomotor skills for colonoscopy do appear to contribute to the performance of angled laparoscope navigation tasks. Thus, training and assessment of IBP typespecific skills should focus on each type of tasks independently. Future research should further investigate the influence of psychometric abilities on the performance of IBP and the transfer of skills for physicians who are experienced in one IBP type and would like to become proficient in another type of IBP.Industrial DesignIndustrial Design Engineerin

    Algebraically special axisymmetric solutions of the higher-dimensional vacuum Einstein equation

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    A d-dimensional spacetime is "axisymmetric" if it possesses an SO(d-2) isometry group whose orbits are (d-3)-spheres. In this paper, algebraically special, axisymmetric solutions of the higher dimensional vacuum Einstein equation (with cosmological constant) are investigated. Necessary and sufficient conditions for static axisymmetric solutions to belong to different algebraic classes are presented. Then general (possibly time-dependent) axisymmetric solutions are discussed. All axisymmetric solutions of algebraic types II, D, III and N are obtained.Comment: 28 page

    Structure-Function Relationships of the Mycobacterium tuberculosis Transcription Factor WhiB1

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    Background Members of the WhiB-like (Wbl) protein family possess iron-sulfur clusters and are implicated in the regulation of developmental processes in Actinomycetes. Mycobacterium tuberculosis possesses seven Wbl proteins. The [4Fe-4S] cluster of M. tuberculosis WhiB1 is relatively insensitive to O2 but very sensitive to nitric oxide (NO). Nitric oxide nitrosylates the WhiB1 iron-sulfur cluster and promotes DNA-binding; the apo-forms of WhiB1 also bind DNA. However, the molecular requirements for iron-sulfur cluster acquisition and for DNA-binding by WhiB1 are poorly characterized. Methods and Findings WhiB1 variants were created by site-directed mutagenesis and the abilities of the corresponding proteins to acquire an iron-sulfur cluster and/or bind to whiB1 promoter DNA were assessed. All four Cys residues (Cys9, 37, 40, and 46) in the N-terminal region of WhiB1 were required for incorporation of a [4Fe-4S] cluster, whereas a possible alternative cluster ligand Asp13 (by analogy with M. smegmatis WhiB2) was not. The C-terminal region of WhiB1 is predicted to house the DNA-binding domain of the protein consisting of a predicted β-turn (58GVWGG62) followed by two amino acid motifs (72KRRN75 and 78TKAR81) that are conserved in WhiB1 proteins. Gly residues (Gly58, 61 and 62) in the β-turn and positively-charged residues (Lys72, Arg73, Arg74, Lys79 and Arg81) in the downstream conserved regions were required for binding of WhiB1 DNA. Conclusions Site-directed mutagenesis of M. tuberculosis whiB1 and characterization of the corresponding proteins has been used to explore structure-function relationships of the NO-responsive transcription factor WhiB1. This showed that all four conserved Cys residues in the N-terminal region are required for incorporation of iron-sulfur clusters but not for DNA-binding. Analysis of variants with amino acid substitutions in the C-terminal region revealed the crucial roles played by a predicted β-turn and two conserved positively-charged motifs in facilitating DNA-binding, but not iron-sulfur cluster acquisition, by WhiB1

    Ten-year outcomes of a randomised trial of laparoscopic versus open surgery for colon cancer

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    Background: Laparoscopic surgery for colon cancer is associated with improved recovery and similar cancer outcomes at 3 and 5 years in comparison with open surgery. However, long-term survival rates have rarely been reported. Here, we present survival and recurrence rates of the Dutch patients included in the COlon cancer Laparoscopic or Open Resection (COLOR) trial at 10-year follow-up. Methods: Between March 1997 and March 2003, patients with non-metastatic colon cancer were recruited by 29 hospitals in eight countries and randomised to either laparoscopic or open surgery. Main inclusion criterion for the COLOR trial was solitary adenocarcinoma of the left or right colon. The primary outcome was disease-free survival at 3 years, and secondary outcomes included overall survival and recurrence. The 10-year follow-up data of all Dutch patients were collected. Analysis was by intention-to-treat. The trial was registered at ClinicalTrials.gov (NCT00387842). Results: In total, 1248 patients were randomised, of which 329 were Dutch. Fifty-eight Dutch patients were excluded and 15 were lost to follow-up, leaving 256 patients for 10-year analysis. Median follow-up was 112 months. Disease-free survival rates were 45.2 % in the laparoscopic group and 43.2 % in the open group (difference 2.0 %; 95 % confidence interval (CI) −10.3 to 14.3; p = 0.96). Overall survival rates were 48.4 and 46.7 %, respectively (difference 1.7 %; 95 % CI −10.6 to 14.0; p = 0.83). Stage-specific analysis revealed similar survival rates for both groups. Sixty-two patients were diagnosed with recurrent disease, accounting for 29.4 % in the laparoscopic group and 28.2 % in the open group (difference 1.2 %; 95 % CI −11.1 to 13.5; p = 0.73). Seven patients had port- or wound-site recurrences (laparoscopic n

    Prioritizing orphan proteins for further study using phylogenomics and gene expression profiles in Streptomyces coelicolor

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    BACKGROUND:Streptomyces coelicolor, a model organism of antibiotic producing bacteria, has one of the largest genomes of the bacterial kingdom, including 7825 predicted protein coding genes. A large number of these genes, nearly 34%, are functionally orphan (hypothetical proteins with unknown function). However, in gene expression time course data, many of these functionally orphan genes show interesting expression patterns.RESULTS:In this paper, we analyzed all functionally orphan genes of Streptomyces coelicolor and identified a list of "high priority" orphans by combining gene expression analysis and additional phylogenetic information (i.e. the level of evolutionary conservation of each protein).CONCLUSIONS:The prioritized orphan genes are promising candidates to be examined experimentally in the lab for further characterization of their functio

    Suturing training in Augmented Reality: gaining proficiency in suturing skills faster

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    Background: Providing informative feedback and setting goals tends to motivate trainees to practice more extensively. Augmented Reality simulators retain the benefit of realistic haptic feedback and additionally generate objective assessment and informative feedback during the training. This study researched the performance curve of the adapted suturing module on the ProMIS Augmented Reality simulator. Methods: Eighteen novice participants were pretrained on the MIST-VR to become acquainted with laparoscopy. Subsequently, they practiced 16 knots on the suturing module, of which the assessment scores were recorded to evaluate the gain in laparoscopic suturing skills. The scoring of the assessment method was calculated from the “time spent in the correct area” during the knot tying and the quality of the knot. Both the baseline knot and the knot at the top of the performance curve were assessed by two independent objective observers, by means of a standardized evaluation form, to objectify the gain in suturing skills. Results: There was a statistically significant difference between the scores of the second knot (mean 72.59, standard deviation (SD) 16.28) and the top of the performance curve (mean 95.82, SD 3.05; p < 0.001, paired t-test). The scoring of the objective observers also differed significantly (mean 11.83 and 22.11, respectively; SD 3.37 and 3.89, respectively; p < 0.001) (interobserver reliability Cronbach’s alpha = 0.96). The median amount of repetitions to reach the top of the performance curve was eight, which also showed significant differences between both the assessment score (mean 88.14, SD 13.53, p < 0.001) and scoring of the objective observers of the second knot (mean 20.51, SD 4.14; p < 0.001). Conclusions: This adapted suturing module on the ProMIS Augmented Reality laparoscopic simulator is a potent tool for gaining laparoscopic suturing skills.Industrial DesignIndustrial Design Engineerin

    Custom Made Candy Plug for Distal False Lumen Occlusion in Aortic Dissection: International Experience

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    Objective: To evaluate early and midterm outcomes of the Candy Plug (CP) technique for distal false lumen (FL) occlusion in thoracic endovascular aortic repair for aortic dissection (AD) in a more real world cohort of patients from an international multicentre registry. Methods: A multicentre retrospective study was conducted of all consecutive patients from the contributing centres with subacute and chronic AD treated with the CP technique from October 2013 to April 2020 at 18 centres. Results: A custom made CP was used in 155 patients (92 males, mean age 62 ± 11 years). Fourteen (9%) presented with ruptured false lumen aneurysms. Technical success was achieved in all patients (100%). Clinical success was achieved in 138 patients (89%). The median hospital stay was 7 days (1 – 77). The 30 day mortality rate was 3% (n = 5). Stroke occurred in four patients (3%). Spinal cord ischaemia occurred in three patients (2%). The 30 day computed tomography angiogram (CTA) confirmed successful CP placement at the intended level in all patients. Early complete FL occlusion was achieved in 120 patients (77%). Early (30 day) CP related re-intervention was required in four patients (3%). The early (30 day) stent graft related re-intervention rate was 8% (n = 12). Follow up CTA was available in 142 patients (92%), with a median follow up of 23 months (6 – 87). Aneurysmal regression was achieved in 68 of 142 patients (47%); the aneurysm diameter remained stable in 69 of 142 patients (49%) and increased in five of 142 patients (4%). A higher rate of early FL occlusion was detected in the largest volume centre patients (50 [88%] vs. 70 [71%] from other centres; p = .019). No other differences in outcome were identified regarding volume of cases or learning curve. Conclusion: This international CP technique experience confirmed its feasibility and low mortality and morbidity rates. Aortic remodelling and false lumen thrombosis rates were high and support the concept of distal FL occlusion in AD using the CP technique
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