Exciton mediated one phonon resonant Raman scattering from one-dimensional systems

We use the Kramers-Heisenberg approach to derive a general expression for the resonant Raman scattering cross section from a one-dimensional (1D) system explicitly accounting for excitonic effects. The result should prove useful for analyzing the Raman resonance excitation profile lineshapes for a variety of 1D systems including carbon nanotubes and semiconductor quantum wires. We apply this formalism to a simple 1D model system to illustrate the similarities and differences between the free electron and correlated electron-hole theories.Comment: 10 pages, 6 figure

Chirality dependence of the radial breathing phonon mode density in single wall carbon nanotubes

A mass and spring model is used to calculate the phonon mode dispersion for single wall carbon nanotubes (SWNTs) of arbitrary chirality. The calculated dispersions are used to determine the chirality dependence of the radial breathing phonon mode (RBM) density. Van Hove singularities, usually discussed in the context of the single particle electronic excitation spectrum, are found in the RBM density of states with distinct qualitative differences for zig zag, armchair and chiral SWNTs. The influence the phonon mode density has on the two phonon resonant Raman scattering cross-section is discussed.Comment: 6 pages, 2 figures, submitted to Phys. Rev.

Tunable Resonant Raman Scattering from Singly Resonant Single Wall Carbon Nanotubes

We perform tunable resonant Raman scattering on 17 semiconducting and 7 metallic singly resonant single wall carbon nanotubes. The measured scattering cross-section as a function laser energy provides information about a tube's electronic structure, the lifetime of intermediate states involved in the scattering process and also energies of zone center optical phonons. Recording the scattered Raman signal as a function of tube location in the microscope focal plane allows us to construct two-dimensional spatial maps of singly resonant tubes. We also describe a spectral nanoscale artifact we have coined the "nano-slit effect"

Development of a Fiber Laser with Independently Adjustable Properties for Optical Resolution Photoacoustic Microscopy

Photoacoustic imaging is based on the detection of generated acoustic waves through thermal expansion of tissue illuminated by short laser pulses. Fiber lasers as an excitation source for photoacoustic imaging have recently been preferred for their high repetition frequencies. Here, we report a unique fiber laser developed specifically for multiwavelength photoacoustic microscopy system. The laser is custom-made for maximum flexibility in adjustment of its parameters; pulse duration (5–10 ns), pulse energy (up to 10 μJ) and repetition frequency (up to 1 MHz) independently from each other and covers a broad spectral region from 450 to 1100 nm and also can emit wavelengths of 532, 355, and 266 nm. The laser system consists of a master oscillator power amplifier, seeding two stages; supercontinuum and harmonic generation units. The laser is outstanding since the oscillator, amplifier and supercontinuum generation parts are all-fiber integrated with custom-developed electronics and software. To demonstrate the feasibility of the system, the images of several elements of standardized resolution test chart are acquired at multiple wavelengths. The lateral resolution of optical resolution photoacoustic microscopy system is determined as 2.68 μm. The developed system may pave the way for spectroscopic photoacoustic microscopy applications via widely tunable fiber laser technologies

Comparing Venous Reconstructions and Antimicrobial Graft Reconstructions in Mycotic Abdominal Aortic Aneurysms and Aortic Graft Infections

Background: The perioperative mortality and morbidity rates of surgical repair of mycotic abdominal aortic aneurysms and aortic graft infections are high, and the appropriate treatment is debated. This retrospective study compared venous and antimicrobial prosthetic aortic graft reconstructions. Methods: All patients of the Northwest Clinics and St. Antonius Hospital who were treated for mycotic abdominal aortic aneurysms or aortic graft infections between January 1, 2008, and January 1, 2018, were analyzed. Exclusion criterion was treatment other than venous or antimicrobial reconstructions. Primary end points were 30-day complications and mortality rates and 3-year overall survival. Secondary end points were reintervention-free survival, persistent infection and reinfection rates, and hospital length of stay. Results: Fifty-one patients met the inclusion criteria, of whom 32 underwent venous reconstructions and 19 antimicrobial prosthetic aortic graft reconstructions. Baseline characteristics did not differ significantly between these groups, except for duration of surgical repair, which was longer in the venous group. The 30-day and 1-year mortality rates, reinfection rates, complication rates, and hospital length of stay did not significantly differ between the groups. The 3-year overall survival was 77% for venous reconstruction compared with 66% for antimicrobial reconstruction (P = 0.781). The 30-day reintervention rate was 19% for the venous group compared with 42% for the prosthetic group (P = 0.071). Reintervention-free survival at 3 years was 46% for the venous group compared with 52% for the prosthetic group (P = 0.615). Conclusions: Venous reconstruction tends to have better 3-year overall survival and lower 30-day reintervention rates compared with antimicrobial prosthetic graft reconstruction in patients with mycotic abdominal aortic aneurysms or abdominal aortic graft infections. In the acute setting, antimicrobial prosthetic graft reconstruction is a valuable solution due to the shorter operation time and similar 30-day mortality and complication rates

Deformable Model for 3D Intramodal Nonrigid Breast Image Registration with Fiducial Skin Markers

We implemented a new approach to intramodal non-rigid 3D breast image registration. Our method uses fiducial skin markers (FSM) placed on the breast surface. After determining the displacements of FSM, finite element method (FEM) is used to distribute the markers’ displacements linearly over the entire breast volume using the analogy between the orthogonal components of the displacement field and a steady state heat transfer (SSHT). It is valid because the displacement field in x, y and z direction and a SSHT problem can both be modeled using LaPlace’s equation and the displacements are analogous to temperature differences in SSHT. It can be solved via standard heat conduction FEM software with arbitrary conductivity of surface elements significantly higher than that of volume elements. After determining the displacements of the mesh nodes over the entire breast volume, moving breast volume is registered to target breast volume using an image warping algorithm. Very good quality of the registration was obtained. Following similarity measurements were estimated: Normalized Mutual Information (NMI), Normalized Correlation Coefficient (NCC) and Sum of Absolute Valued Differences (SAVD). We also compared our method with rigid registration technique

Development of a Prediction Model for the Occurrence of Stenosis or Occlusion after Percutaneous Deep Venous Arterialization

Percutaneous deep venous arterialization (pDVA) is a promising treatment option in patients with chronic limb-threatening ischemia. Stenosis and occlusions, which are the Achilles' heel of every revascularization procedure, can be treated when detected early. However, frequent monitoring after pDVA is required because when stenosis or occlusions develop is unknown. Therefore, patients currently need to visit the hospital every 2 weeks for surveillance, which can be burdensome. Accordingly, we aimed to develop a model that can predict future stenosis or occlusions in patients after pDVA to be able to create tailor-made follow-up protocols. The data set included 343 peak systolic velocity and 335 volume flow measurements of 23 patients. A stenosis or occlusion developed in 17 patients, and 6 patients remained lesion-free. A statistically significant increase in the risk of stenosis or occlusion was found when duplex ultrasound values decreased 20% within 1 month. The prediction model was also able to estimate a patient-specific risk of future stenosis or occlusions. This is promising for the possibility of reducing the frequency of follow-up visits for low-risk patients and increasing the frequency for high-risk patients. These observations are the starting point for individual surveillance programs in post-pDVA patients. Future studies with a larger cohort are necessary for validation of this model

Robust Entanglement in Atomic Systems via Lambda-Type Processes

It is shown that the system of two three-level atoms in $\Lambda$ configuration in a cavity can evolve to a long-lived maximum entangled state if the Stokes photons vanish from the cavity by means of either leakage or damping. The difference in evolution picture corresponding to the general model and effective model with two-photon process in two-level system is discussed.Comment: 10 pages, 3 figure

Sex difference in alcohol withdrawal syndrome: a scoping review of clinical studies

BackgroundWe conducted a review of all studies comparing clinical aspects of alcohol withdrawal syndrome (AWS) between men and women.MethodsFive databases (PubMed, Cochrane, EMBASE, Scopus and Clinical Trials) were searched for clinical studies using the keywords “alcohol withdrawal syndrome” or “delirium tremens” limited to “sex” or “gender” or “sex difference” or “gender difference.” The search was conducted on May 19, 2023. Two reviewers selected studies including both male and female patients with AWS, and they compared males and females in type of AWS symptoms, clinical course, complications, and treatment outcome.ResultsThirty-five observational studies were included with a total of 318,730 participants of which 75,346 had AWS. In twenty of the studies, the number of patients presenting with or developing AWS was separated by sex, resulting in a total of 8,159 (12.5%) female patients and a total of 56,928 (87.5%) male patients. Despite inconsistent results, males were more likely than females to develop complicated AWS [delirium tremens (DT) and AW seizures, collective DT in Males vs. females: 1,792 (85.4%) vs. 307 (14.6%), and collective seizures in males vs. females: 294 (78%) vs. 82 (22%)]. The rates of ICU admissions and hospital length of stay did not show sex differences. Although variable across studies, compared to females, males received benzodiazepine treatment at higher frequency and dose. One study reported that the time from first hospitalization for AWS to death was approximately 1.5 years shorter for males and males had higher mortality rate [19.5% (197/1,016)] compared to females [16% (26/163)].ConclusionDespite the significant heterogeneity of the studies selected and the lack of a focus on investigating potential sex differences, this review of clinical studies on AWS suggests that men and women exhibit different AWS manifestations. Large-scale studies focusing specifically on investigating sex difference in AWS are needed