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Quantum brachistochrone problem and the geometry of the state space in pseudo-hermitian quantum mechanics
No full textA non-Hermitian operator with a real spectrum and a complete set of eigenvectors may serve as the Hamiltonian operator for a unitary quantum system provided that one makes an appropriate choice for the defining the inner product of physical Hilbert state. We study the consequences of such a choice for the representation of states in terms of projection operators and the geometry of the state space. This allows for a careful treatment of the quantum Brachistochrone problem and shows that it is indeed impossible to achieve faster unitary evolutions using PT-symmetric or other non-Hermitian Hamiltonians than those given by Hermitian Hamiltonians
Indistinguishable photons from a single molecule
No full textWe report the results of coincidence counting experiments at the output, of a Michelson interferometer using the zero-phonon-line emission of a single molecule at 1.4 K. Under continuous wave excitation, we observe the absence of coincidence counts as an indication of two-photon interference. This corresponds to the observation of Hong-Ou-Mandel correlations and proves the suitability of the zero-phonon-line emission of single molecules for applications in linear optics quantum computation
Prediction of binding sites in receptor-ligand complexes with the Gaussian Network Model
No full textResidues at the binding sites of the ligand and receptor of several enzyme-inhibitor and antibody-antigen complexes are predicted from the slowest (for the ligand) and fastest (for the receptor) modes of motion by the Gaussian Network Model applied to unbound molecules
Biophotonic sensor applications based on photonic atoms - art. no. 60990Q
No full textMicrosphere resonators, i.e., photonic atoms, have found wide area of application in optical spectroscopy, quantum optics, cavity QED, switching, and sensing. Photonic atoms have unique optical properties such as high quality factor (Q-factor) morphology dependent resonances (MDR's), and relatively small volumes. High-Q MDR's are very sensitive to the refractive index change and microsphere uniformity. These tiny optical cavities, whose diameters vary from a few to several hundred micrometers, have resonances with reported Q-factors as large as 3x10(9). Due to their sensitivity, MDR's are also considered for biosensor applications. Binding of a protein or other biomolecules can be monitored by observing the wavelength shift of MDR's. A biosensor, based on this optical phenomenon, can even detect a single molecule, depending on the quality of the system. In this work, elastic scattering spectra from photonic atoms of different materials are experimentally obtained and MDR'S are observed. Preliminary results of unspecific binding of biomolecules are presented. Elastic light scattering spectra of MDR's for biosensor applications are calculated numerically for biomolecules such as Bovine Serum Albumin (BSA) and for Deoxyribo Nucleic Acid (DNA)
Human cancer protein-Protein ınteraction network: a structural perspective
No full textProtein-protein interaction networks provide a global picture of cellular function and biological processes. Some proteins act as hub proteins, highly connected to others, whereas some others have few interactions. The dysfunction of some interactions causes many diseases, including cancer. Proteins interact through their interfaces. Therefore, studying the interface properties of cancer-related proteins will help explain their role in the interaction networks. Similar or overlapping binding sites should be used repeatedly in single interface hub proteins, making them promiscuous. Alternatively, multi-interface hub proteins make use of several distinct binding sites to bind to different partners. We propose a methodology to integrate protein interfaces into cancer interaction networks (ciSPIN, cancer structural protein interface network). The interactions in the human protein interaction network are replaced by interfaces, coming from either known or predicted complexes. We provide a detailed analysis of cancer related human protein-protein interfaces and the topological properties of the cancer network. The results reveal that cancer-related proteins have smaller, more planar, more charged and less hydrophobic binding sites than non-cancer proteins, which may indicate low affinity and high specificity of the cancer-related interactions. We also classified the genes in ciSPIN according to phenotypes. Within phenotypes, for breast cancer, colorectal cancer and leukemia, interface properties were found to be discriminating from non-cancer interfaces with an accuracy of 71%, 67%, 61%, respectively. In addition, cancer-related proteins tend to interact with their partners through distinct interfaces, corresponding mostly to multi-interface hubs, which comprise 56% of cancer-related proteins, and constituting the nodes with higher essentiality in the network (76%). We illustrate the interface related affinity properties of two cancer-related hub proteins: Erbb3, a multi interface, and Raf1, a single interface hub. The results reveal that affinity of interactions of the multi-interface hub tends to be higher than that of the single-interface hub. These findings might be important in obtaining new targets in cancer as well as finding the details of specific binding regions of putative cancer drug candidates
Trading experience modulates anterior insula to reduce the endowment effect
No full textPeople often demand a greater price when selling goods that they own than they would pay to purchase the same goods-a well-known economic bias called the endowment effect. The endowment effect has been found to be muted among experienced traders, but little is known about how trading experience reduces the endowment effect. We show that when selling, experienced traders exhibit lower right anterior insula activity, but no differences in nucleus accumbens or orbitofrontal activation, compared with inexperienced traders. Furthermore, insula activation mediates the effect of experience on the endowment effect. Similar results are obtained for inexperienced traders who are incentivized to gain trading experience. This finding indicates that frequent trading likely mitigates the endowment effect indirectly by modifying negative affective responses in the context of selling
Bridging the gap between RF and optical patch antenna analysis via the cavity model
No full textAlthough optical antennas with a variety of shapes and for a variety of applications have been proposed and studied, they are still in their infancy compared to their radio frequency (rf) counterparts. Optical antennas have mainly utilized the geometrical attributes of rf antennas rather than the analysis tools that have been the source of intuition for antenna engineers in rf. This study intends to narrow the gap of experience and intuition in the design of optical patch antennas by introducing an easy-to-understand and easy-to-implement analysis tool in rf, namely, the cavity model, into the optical regime. The importance of this approach is not only its simplicity in understanding and implementation but also its applicability to a broad class of patch antennas and, more importantly, its ability to provide the intuition needed to predict the outcome without going through the trial-and-error simulations with no or little intuitive guidance by the user
Utilizing nonlinear ELF generation in modulated ionospheric heating experiments for communications applications
No full textModulated high-frequency heating of the D region ionosphere near the auroral electrojet can generate extremely low frequency (ELF; 3 Hz-3 kHz) radio waves. The modulated heating process is nonlinear and generates harmonics at integer multiples of the ELF modulation frequency. Quaternary phase shift keying, a digital modulation technique is applied to ELF waves to demonstrate transmission of digital data. Data were successfully decoded at a nearby receiver and the bit error rate computed. Square wave modulation of the high-frequency heater results in stronger signals and hence a smaller bit error rate. Simulations of the communication system using ELF waveforms and noise signals derived from ELF observations are also conducted. These simulations show that using higher harmonics of the ELF signal to improve the signal-to-noise ratio can reduce the bit error rate, although only when these harmonics are below similar to 4.5 kHz because of radio atmospherics (sferics) generating strong impulsive noise at higher frequencies. Citation: Jin, G., M. Spasojevic, M. B. Cohen, and U. S. Inan (2013), Utilizing nonlinear ELF generation in modulated ionospheric heating experiments for communications applications, Radio Sci., 48, 61-68, doi:10.1002/rds.20014
Nosocomial infections and associated risk factors in geriatric patients in the intensive care unit
No full textAim: The elderly population increases worldwide. The purpose of this study was to evaluate nosocomial infections (NI) detected in geriatric patients and to determine the risk factors leading to their development. Materials and Methods: Patients monitored in our hospital's Intensive Care Unit (ICU) were evaluated daily by intensive care and infectious disease specialists, including surveillance by our Infection Control Committee. We included the patients aged >= 65 years who were monitored in the adult ICU between January and December 2014, using the methods of retrospective file screening and computer record review. Patients were classified into two groups: patients with and without NI. Results: In total, 222 (38.07%) patients were >= 65 years old. 44 NI events were detected in 27 patients. Groups were compared with respect to age; sex; presence of mechanic ventilation (MV), central venous catheterization (CVC), cerebrovascular disease, chronic obstructive disease, diabetes mellitus; and mortality. The presence of MV, CVC, and mortality were seen to be significantly higher in patients with NI compared with those without. The most common NIs found were sepsis and pneumonia. The most common infectious agent was Acinetobacter. Conclusion: NIs observed in hospital ICUs are common, but largely preventable, conditions. A systematic approach and well-disciplined empiric therapy are very important. Our study revealed that the mortality rate is high in elderly patients who develop NI, and NI is more commonly seen in patients who undergo invasive interventions. We believe that using invasive interventions as little as possible in this group may improve their treatment success and outcome
Mediterranean spotted fever in the emergency department
No full textIntroduction: Mediterranean spotted fever (MSF) is one of the tick-borne rickettsial infections caused by Rickettsia conorii. In this case, we describe a patient who was admitted to the Emergency Department (ED) with persistent fever caused by MSF. Case Report: A 36-year-old male patient was admitted to the ED with persistent fever. Six days ago, antibacterial therapy had been started by his family practitioner; however, his fever continued. Upon admission on the seventh day of fever, the patient appeared ill. He had complaints such as malaise, myalgias, and nausea/vomiting. His fever was 38.6 degrees C, and other vital signs were normal. On physical examination, a single, crusted, ulcerated papule with a red halo resembling a cigarette burn was observed on the left leg. According to the diagnostic criteria for MSF, his score was 33, and he was admitted to the infectious disease department. Antibodies against Rickettsia were positive with the immunofluorescence assay. Fever after continuing for 24 hours reduced when a dose of 200 mg/daily doxycycline treatment was started. Conclusion: The aim of this presentation is to point out that MSF should be considered in the ED for the differential diagnosis of patient with a history of tick bite, persistent fever, maculopapular rash, headache, myalgia, arthralgia, and particularly with black eschar/tache noire