Optical pumping effect in absorption imaging of F=1 atomic gases

We report our study of the optical pumping effect in absorption imaging of $^{23}$Na atoms in the $F=1$ hyperfine spin states. Solving a set of rate equations for the spin populations in the presence of a probe beam, we obtain an analytic expression for the optical signal of the $F=1$ absorption imaging. Furthermore, we verify the result by measuring the absorption spectra of $^{23}$Na Bose-Einstein condensates prepared in various spin states with different probe beam pulse durations. The analytic result can be used in the quantitative analysis of $F=1$ spinor condensate imaging and readily applied to other alkali atoms with $I=3/2$ nuclear spin such as $^{87}$Rb.Comment: 6 pages, 4 figure

Collisional Dynamics of Half-Quantum Vortices in a Spinor Bose-Einstein Condensate

We present an experimental study on the interaction and dynamics of half-quantum vortices (HQVs) in an antiferromagnetic spinor Bose-Einstein condensate. By exploiting the orbit motion of a vortex dipole in a trapped condensate, we perform a collision experiment of two HQV pairs, and observe that the scattering motions of the HQVs is consistent with the short-range vortex interaction that arises from nonsingular magnetized vortex cores. We also investigate the relaxation dynamics of turbulent condensates containing many HQVs, and demonstrate that spin wave excitations are generated by the collisional motions of the HQVs. The short-range vortex interaction and the HQV-magnon coupling represent two characteristics of the HQV dynamics in the spinor superfluid.Comment: 7 pages, 6 figure

Revealing the Charge Density Wave Proximity Effect in Graphene on 1T-TaS2_2

The proximity-effect, a phenomenon whereby materials in close contact appropriate each others electronic-properties, is widely used in nano-scale devices to induce electron-correlations at heterostructure interfaces. Layered group-V transition metal dichalcogenides host charge density waves and are expected to induce CDWs in a thin proximal 2D metal such as graphene. Thus far, however, the extremely large density of states of the TMDs compared to graphene have precluded efforts to unambiguously prove such proximity induced charge density waves (CDW). Here, using scanning tunneling microscopy (STM) and spectroscopy (STS), we report the first conclusive evidence of a CDW proximity effect between graphene and the commensurate CDW in 1T-TaS$_2$ (TaS$_2$ for brevity). We exploit the Mott gap of 1T-TaS$_2$ to scan the sample at bias voltages wherein only the graphene layer contributes to the STM topography scans. Furthermore, we observe that graphene modifies the band structure at the surface of TaS$_2$, by providing mid-gap carriers and reducing the strength of electron correlations there. We show that the mechanism underlying the proximity induced CDW is well-described by short-range exchange interactions that are distinctly different from previously observed proximity effects.Comment: 33 pages, 15 figures. arXiv admin note: text overlap with arXiv:2201.0919

Management of chest keloids

Keloid formation is one of the most challenging clinical problems in wound healing. With increasing frequency of open heart surgery, chest keloid formations are not infrequent in the clinical practice. The numerous treatment methods including surgical excision, intralesional steroid injection, radiation therapy, laser therapy, silicone gel sheeting, and pressure therapy underscore how little is understood about keloids. Keloids have a tendency to recur after surgical excision as a single treatment. Stretching tension is clearly associated with keloid generation, as keloids tend to occur on high tension sites such as chest region. The authors treated 58 chest keloid patients with surgical excision followed by intraoperative and postoperative intralesional steroid injection. Even with minor complications and recurrences, our protocol results in excellent outcomes in cases of chest keloids

Impact of Diabetes on Oncologic Outcome of Colorectal Cancer Patients: Colon vs. Rectal Cancer

Background: To evaluate the impact of diabetes on outcomes in colorectal cancer patients and to examine whether this association varies by the location of tumor (colon vs. rectum). Patients and methods This study includes 4,131 stage I-III colorectal cancer patients, treated between 1995 and 2007 (12.5% diabetic, 53% colon, 47% rectal) in South Korea. Cox proportional hazards modeling was used to determine the prognostic influence of DM on survival endpoints. Results: Colorectal cancer patients with DM had significantly worse disease-free survival (DFS) [hazard ratio (HR) 1.17, 95% confidence interval (CI): 1.00–1.37] compared with patients without DM. When considering colon and rectal cancer independently, DM was significantly associated with worse overall survival (OS) (HR: 1.46, 95% CI: 1.11–1.92), DFS (HR: 1.45, 95% CI: 1.15–1.84) and recurrence-free survival (RFS) (HR: 1.32, 95% CI: 0.98–1.76) in colon cancer patients. No association for OS, DFS or RFS was observed in rectal cancer patients. There was significant interaction of location of tumor (colon vs. rectal cancer) with DM on OS (P = 0.009) and DFS (P = 0.007). Conclusions: This study suggests that DM negatively impacts survival outcomes of patients with colon cancer but not rectal cancer

Rpgrip1 is required for rod outer segment development and ciliary protein trafficking in zebrafish

The authors would like to thank the Royal Society of London, the National Eye Research Centre, the Visual Research Trust, Fight for Sight, the W.H. Ross Foundation, the Rosetrees Trust, and the Glasgow Children’s Hospital Charity for supporting this work. This work was also supported by the Deanship of Scientific Research at King Saud University for funding this research (Research Project) grant number ‘RGP – VPP – 219’.Mutations in the RPGR-interacting protein 1 (RPGRIP1) gene cause recessive Leber congenital amaurosis (LCA), juvenile retinitis pigmentosa (RP) and cone-rod dystrophy. RPGRIP1 interacts with other retinal disease-causing proteins and has been proposed to have a role in ciliary protein transport; however, its function remains elusive. Here, we describe a new zebrafish model carrying a nonsense mutation in the rpgrip1 gene. Rpgrip1homozygous mutants do not form rod outer segments and display mislocalization of rhodopsin, suggesting a role for RPGRIP1 in rhodopsin-bearing vesicle trafficking. Furthermore, Rab8, the key regulator of rhodopsin ciliary trafficking, was mislocalized in photoreceptor cells of rpgrip1 mutants. The degeneration of rod cells is early onset, followed by the death of cone cells. These phenotypes are similar to that observed in LCA and juvenile RP patients. Our data indicate RPGRIP1 is necessary for rod outer segment development through regulating ciliary protein trafficking. The rpgrip1 mutant zebrafish may provide a platform for developing therapeutic treatments for RP patients.Publisher PDFPeer reviewe

Perpendicular Magnetic Anisotropy in FePt Patterned Media Employing a CrV Seed Layer

A thin FePt film was deposited onto a CrV seed layer at 400°C and showed a high coercivity (~3,400 Oe) and high magnetization (900–1,000 emu/cm3) characteristic of L10 phase. However, the magnetic properties of patterned media fabricated from the film stack were degraded due to the Ar-ion bombardment. We employed a deposition-last process, in which FePt film deposited at room temperature underwent lift-off and post-annealing processes, to avoid the exposure of FePt to Ar plasma. A patterned medium with 100-nm nano-columns showed an out-of-plane coercivity fivefold larger than its in-plane counterpart and a remanent magnetization comparable to saturation magnetization in the out-of-plane direction, indicating a high perpendicular anisotropy. These results demonstrate the high perpendicular anisotropy in FePt patterned media using a Cr-based compound seed layer for the first time and suggest that ultra-high-density magnetic recording media can be achieved using this optimized top-down approach