Overcoming losses with gain in a negative refractive index metamaterial

On the basis of a full-vectorial three-dimensional Maxwell-Bloch approach we investigate the possibility of using gain to overcome losses in a negative refractive index fishnet metamaterial. We show that appropriate placing of optically pumped laser dyes (gain) into the metamaterial structure results in a frequency band where the nonbianisotropic metamaterial becomes amplifying. In that region both the real and the imaginary part of the effective refractive index become simultaneously negative and the figure of merit diverges at two distinct frequency points.Comment: 4 pages, 4 figure

Trainee participation and perioperative complications in benign hysterectomy: the effect of route of surgery

BACKGROUND: Intraoperative trainee involvement in hysterectomy is common. However, the effect of intraoperative trainee involvement on perioperative complications depending on surgical approach is unknown. OBJECTIVE: To estimate the effect of intraoperative trainee involvement on perioperative complication after vaginal, laparoscopic, and abdominal hysterectomy for benign disease. METHODS: Patients undergoing laparoscopic, vaginal, or abdominal hysterectomy for benign disease from 2010 to 2012 were identified from the American College of Surgeons National Surgical Quality Improvement Program database. Patients with and without trainee involvement were compared with regard to perioperative complications. Complications that occurred from the start of surgery to 30-days postoperatively were included. Perioperative complications were defined via the use of the validated Clavien-Dindo scale with ≥grade 3 complications defined as major and ≤grade 2 complications defined as minor. Major complications included myocardial infarction, pneumonia, venous thromboembolism, deep or organ space surgical-site infection, stroke, fascial dehiscence, unplanned return to the operating room, renal failure, cardiopulmonary arrest, sepsis, intubation greater than 48 hours, and death. Minor complications included urinary tract infection, blood transfusion, and superficial wound infection. To estimate the effect of trainee involvement depending on route of surgery, a stratified analysis was performed. Bivariable analysis and adjusted multivariable logistic regression were used. RESULTS: We identified 22,499 patients, of whom 42.1% had trainee participation. Surgical approaches were vaginal (22.7%), abdominal (47.1%), and laparoscopic (30.2%). The rate of major complication was 3.2%, and minor complication was 7.2%. In bivariable analysis, trainee involvement was associated with major complications in vaginal hysterectomy (3.3% vs 2.3%, P = .03), but not laparoscopic (3.0% vs 2.9%, P = .78) or abdominal hysterectomy (4.4% vs 3.6%, P = .07). Trainee involvement was also associated with minor complication in vaginal (7.3% vs 5.4%, P = .007), laparoscopic (5.9% vs 4.3%, P < .001), and abdominal hysterectomy (14.1% vs 9.2%, P < .001). In a multivariable analysis in which we adjusted for age, body mass index, medical comorbidity, American Society of Anesthesiologists score, and surgical complexity, the association between trainee involvement in vaginal hysterectomy and major complication persisted (adjusted odds ratio 1.45, 95% confidence interval 1.03-2.04); however, when operative time was added to the model, there was no longer an association between trainee involvement and major complication (adjusted odds ratio 1.26, 95% confidence interval 0.89-1.80). CONCLUSION: Surgical approach influences the relationship between trainee involvement and perioperative complication. Operative time is a key mediator of the relationship between trainee involvement and complication, and may be a modifiable risk factor

Letter from the Nuclear Security Women Editors

Letter from the Nuclear Security Women Editors for the IJNS and NSW Special Issue: Women in Nuclear Securit

Setting Up the Speech Production Network: How Oscillations Contribute to Lateralized Information Routing

Speech production involves widely distributed brain regions. This MEG study focuses on the spectro-temporal dynamics that contribute to the setup of this network. In 21 participants performing a cue-target reading paradigm, we analyzed local oscillations during preparation for overt and covert reading in the time-frequency domain and localized sources using beamforming. Network dynamics were studied by comparing different dynamic causal models of beta phase coupling in and between hemispheres. While a broadband low frequency effect was found for any task preparation in bilateral prefrontal cortices, preparation for overt speech production was specifically associated with left-lateralized alpha and beta suppression in temporal cortices and beta suppression in motor-related brain regions. Beta phase coupling in the entire speech production network was modulated by anticipation of overt reading. We propose that the processes underlying the setup of the speech production network connect relevant brain regions by means of beta synchronization and prepare the network for left-lateralized information routing by suppression of inhibitory alpha and beta oscillations

Venous Thromboembolism in Minimally Invasive Compared With Open Hysterectomy for Endometrial Cancer

OBJECTIVE: To evaluate whether minimally invasive surgery for endometrial cancer is independently associated with a decreased odds of venous thromboembolism compared with open surgery. METHODS: We performed a secondary analysis cohort study of prospectively collected quality improvement data and examined patients undergoing hysterectomy for endometrial cancer from 2008 to 2013 recorded in the National Surgical Quality Improvement Program database. Patients undergoing minimally invasive (laparoscopic or robotic) surgery were compared with those undergoing open surgery with respect to 30-day postoperative venous thromboembolism. Demographic and procedure variables were examined as potential confounders. Data regarding receipt of perioperative venous thromboembolism prophylaxis were not available. Bivariable tests and logistic regression were used for analysis. RESULTS: Of 9,948 patients who underwent hysterectomy for the treatment of endometrial cancer, 61.9% underwent minimally invasive surgery and 38.1% underwent open surgery. Patients undergoing minimally invasive surgery had a lower venous thromboembolism incidence (0.7%, n=47) than patients undergoing open surgery (2.2%, n=80) (P<.001). In a multivariate model adjusting for age, body mass index, race, operative time, Charlson comorbidity score, and surgical complexity, minimally invasive surgery remained associated with decreased odds of venous thromboembolism (adjusted odds ratio 0.36, 95% confidence interval 0.24-0.53) compared with open surgery. CONCLUSION: Minimally invasive surgery for the treatment of endometrial cancer is independently associated with decreased odds of venous thromboembolism compared with open surgery

RECOGNITION AND ESTIMATION OF HUMAN LOCOMOTION WITH HIDDEN MARKOV MODELS

INTRODUCTION: The Collaborative Research Centre “Humanoid Robots” situated at the University of Karlsruhe is aimed to construct a learning and cooperating service robot. To cope with its tasks it is necessary that the robot is able to identify diverse objects as well as different persons. Looking at stochastic models for pattern recognition Hidden Markov Models (HMMs) are described to be most suitable to classify time arranged data (Bilmes 2002). The objective of this study is to screen if the HMMs supply satisfying rates of recognition of human trajectory and angle data. METHOD: Kinematic data of eight men and three women was captured at different walking and running speed (1.2 m/s, 3 m/s, 4 m/s, 5 m/s) on a treadmill. Data acquisition was realised with an infrared camera system with a frequency of 250Hz. For each walking/running speed there were 120 gait cycles of every test person available. The construction and training of the stochastic model was based on the gait data. Due to the fixed sequence of gait phases a HMM with a simple linear topology was chosen. Each state of the HMM represented a phase of the gait cycle. The different states were equipped with Gaussian distributions and transition probabilities to model the run of the angles observed. The HMM modelling human gait best was selected and trained with data of 17 double gait cycles for each data sequence of every test person. RESULTS: The trained HMMs showed recognition rates from 63% to 100% for the observed data sequences for five male test persons. Highest rates could be obtained with Centre of Mass and head angles. For some test person recognition rates decreased with data of gait cycles that were captured towards the end of one run. DISCUSSION: The high recognition rates based on kinematic data of Centre of Mass were expected due to the different mean values of the test persons according to their body height. The decrease of recognition rates that could be observed at some of the test person on late data of one run seems to be caused by acclimatisation to treadmill running. The achieved recognition rates exceed rates typical for speech recognition (Rabiner 1989). A combination of different angle data seems to promise increasing recognition rates. CONCLUSION: The study showed that HMMs seem to be suitable to identify humans based on their kinematic gait data satisfyingly stable. According to dislocation of the Gaussian distributions it could be possible to suggest on systematic changes on patterns over changes in walking-/running speed. REFERENCES: Bilmes, J. (2002). What HMMs Can Do. UWEE Technical Report, No UWEETR-2002-2003, University of Washington, Dept. of EE. Rabiner, L. R. (1989). A Tutorial on Hidden Markov Models and Selected Applications in Speech Recognition. Proceedings of the IEEE, 77 (2), 257-286 Acknowledgement V. Wank, Institute of Sport Science, University of Tübingen German Research Foundation – CRC 588 Humanoid Robot

Environmental Processing in Meiothermus ruber: the Inorganic Phosphate ABC Transporter

Bioinformatics analysis of M. rube

Parallel pathways in the folding of a short-term denatured scFv fragment of an antibody

Background: Antibodies are prototypes of multimeric proteins and consist of structurally similar domains. The two variable domains of an antibody (VH and VL) interact through a large hydrophobic interface and can be expressed as covalently linked single-chain Fv (scFv) fragments. The in vitro folding of scFv fragments after long-term denaturation in guanidinium chloride is known to be slow. In order to delineate the nature of the rate-limiting step, the folding of the scFv fragment of an antibody after short-term denaturation has been investigated.Results: Secondary structure formation, measured by H/D-exchange protection, of a mutant scFv fragment of an antibody after short incubation in 6 M guanidinium chloride was shown to be multiphasic. NMR analysis shows that an intermediate with significant proton protection is observed within the dead time of the manual mixing experiments. Subsequently, the folding reaction proceeds via a biphasic reaction and mass spectrometry analyses of the exchange experiments confirm the existence of two parallel pathways. In the presence of cyclophilin, however, the faster of the two phases vanishes (when followed by intrinsic tryptophan fluorescence), while the slower phase is not significantly enhanced by equimolar cyclophilin.Conclusions: The formation of an early intermediate, which shows amide-proton exchange protection, is independent of proline isomerization. Subsequently, a proline cis–trans isomerization reaction in the rapidly formed intermediate, producing ‘non-native’ isomers, competes with the fast formation of native species. Interface formation in a folding intermediate of the scFv fragment is proposed to prevent the back-isomerization of these prolines from being efficiently catalyzed by cyclophilin

De novo undifferentiated pleomorphic sarcoma arising from a renal allograft: A case report

To the best of our knowledge, this is the first report of an undifferentiated pleomorphic sarcoma arising from a renal graft. Transplantectomy was performed in a 47-year old woman presenting to the emergency room because of general weakness. Preoperative workup revealed a 5.5 cm malignant mass of the graft which was not present on routine ultrasound performed 12 months earlier. Following transplantectomy, local recurrence developed despite complete tumor resection and interruption of immunosuppression. Despite radiation therapy, the outcome was ultimately fatal. Genetic analysis revealed that the tumor had arisen from donor tissue. Annual ultrasound surveillance might not be enough effective to screen for these rare high grade neoplasms

Cervical Cancer in Women Aged 35 Years and Younger

AbstractPurposeAge has been evaluated as a prognostic factor in cervical cancer in both hospital- and population-based studies. Results regarding the relation of age and cervical cancer prognosis are conflicting. This study pursued a contemporary assessment of the association of extreme young age at the time of a cervical cancer diagnosis on survival.MethodsInstitutional review board approval was obtained, and retrospective data collection at 2 academic institutions was performed. Inclusion criteria involved women ≤35 years diagnosed with cervical cancer between 1990 and 2012. Data included demographic and prognostic information pertinent to survival and progression. Characteristics of very young (≤25 years) and young (>25–35 years) women were compared. Kaplan-Meier estimates, the log-rank test, and Cox proportional hazards modeling were used to assess the association of age, tumor histology, grade, stage, and parametrial involvement with progression-free survival (PFS) and overall survival (OS).FindingsIncident cases (n = 126) of cervical cancer in patients ≤35 years of age were identified of which complete clinical information was available for 114 women. Fifteen percent (17 of 114) were ≤25 years, with the remaining 85% (97 of 114) being 26 to 35 years of age. Race, smoking status, and marital status were comparable between the 2 groups. Squamous histology dominated overall (77 of 114; 68%) with adenocarcinoma contributing ~25% (30 of 114; 26%) of cases. The majority (96 of 114, 84%) had either stage 1A (31 of 114, 27%) or 1B (65 of 114, 57%) disease. A log-rank test revealed no evidence to infer a difference in either PFS or OS among the age groups (P = 0.511 and P = 0.340). In a univariate analysis, grade and stage significantly affected OS (P < 0.0001, P = 0.045), and stage significantly affected PFS (P < 0.0001). In multivariate modeling, presence of parametrial involvement and histologic cancer type significantly affected both PFS (P = 0.002, P = 0.001) and OS (P = 0.001, P = 0.001).ImplicationsTumor histology, parametrial involvement, and stage continue to be strong prognosticators for PFS and OS. Progression and survival outcomes are age independent in women with cervical cancer ≤35 years of age. Further study of a larger young cohort may potentially yield different outcomes