Enhanced Nonlinear Response by Manipulating the Dirac Point at the (111) LaTiO_{3}/SrTiO_{3} Interface.

Tunable spin-orbit interaction (SOI) is an important feature for future spin-based devices. In the presence of a magnetic field, SOI induces an asymmetry in the energy bands, which can produce nonlinear transport effects (V∼I^{2}). Here, we focus on such effects to study the role of SOI in the (111) LaTiO_{3}/SrTiO_{3} interface. This system is a convenient platform for understanding the role of SOI since it exhibits a single-band Hall response through the entire gate-voltage range studied. We report a pronounced rise in the nonlinear longitudinal resistance at a critical in-plane field H_{cr}. This rise disappears when a small out-of-plane field component is present. We explain these results by considering the location of the Dirac point formed at the crossing of the spin-split energy bands. An in-plane magnetic field pushes this point outside of the Fermi contour, and consequently changes the symmetry of the Fermi contours and intensifies the nonlinear transport. An out-of-plane magnetic field opens a gap at the Dirac point, thereby significantly diminishing the nonlinear effects. We propose that magnetoresistance effects previously reported in interfaces with SOI could be comprehended within our suggested scenario.

Two-component nematic superconductivity in 4Hb-TaS2.

Most superconductors have an isotropic, single component order parameter and are well described by the standard (BCS) theory for superconductivity. Unconventional, multiple-component superconductors are exceptionally rare and are much less understood. Here, we combine scanning tunneling microscopy and angle-resolved macroscopic transport for studying the candidate chiral superconductor, 4Hb-TaS2. We reveal quasi-periodic one-dimensional modulations in the tunneling conductance accompanied by two-fold symmetric superconducting critical field. The strong modulation of the in-plane critical field, Hc2, points to a nematic, unconventional order parameter. However, the imaged vortex core is isotropic at low temperatures. We suggest a model that reconciles this apparent discrepancy and takes into account previously observed spontaneous time-reversal symmetry breaking at low temperatures. The model describes a competition between a dominating chiral superconducting order parameter and a nematic one. The latter emerges close to the normal phase. Our results strongly support the existence of two-component superconductivity in 4Hb-TaS2 and can provide valuable insights into other systems with coexistent charge order and superconductivity.

Production of fibrogenic cytokines by interleukin-2-treated peripheral blood leukocytes: expression of transforming growth factor-beta and platelet-derived growth factor B chain genes.

OBJECTIVE: To assess the production of fibrogenic cytokines by interleukin-2 (IL-2)-stimulated peripheral blood leukocytes and to examine their ability to stimulate the production of connective tissue. METHODS: Culture medium from human peripheral blood leukocytes incubated with or without IL-2 was tested for induction of fibroblast proliferation, collagen synthesis, and expression of cytokine genes. RESULTS: Supernatants from IL-2-treated peripheral blood leukocytes induced six times more fibroblast proliferation than medium from leukocytes cultured without IL-2. The expression of type I procollagen and fibronectin messenger RNAs was increased in human fibroblasts in response to leukocyte supernatants. Unstimulated leukocytes expressed minimal levels of transforming growth factor-beta or platelet-derived growth factor B chain messenger RNAs, but could be greatly enhanced by IL-2 treatment. CONCLUSION: Mediators that induce connective tissue production are secreted by IL-2-treated peripheral blood leukocytes. These cytokines may be responsible, in part, for the stimulation of abdominal adhesions in patients receiving intraperitoneal immunotherapy.

Prepubertal yolk sac testicular tumors--report of the testicular tumor registry.

In 1980 the Section on Urology of the American Academy of Pediatrics established a registry of prepubertal testicular tumors. A total of 181 yolk sac tumors has been reported to the registry. Complete followup is available for 154 of these 181 patients. Most of the patients presented with low stage disease. Radical orchiectomy without adjunctive retroperitoneal lymphadenectomy, chemotherapy or radiotherapy was sufficient therapy for most stage 1 cancer patients. alpha-Fetoprotein is a reliable marker for this tumor. Chest x-rays and abdominal computerized tomography are reliable for staging. When metastases appeared they did so within 14 months of presentation so that 2 years of followup after any evidence of disease seems to be adequate. Approximately two-thirds of the patients with metastases were salvaged by chemotherapy, radiotherapy and/or an operation.

Gonadal stromal tumors: a report of the Prepubertal Testicular Tumor Registry.

A total of 15 gonadal stromal tumors in prepubertal boys has been reported to the Prepubertal Testicular Tumor Registry of the Section on Urology of the American Academy of Pediatrics. Leydig cell tumors invariably are benign and patients usually present with precocious puberty when they are 5 to 9 years old. Other gonadal stromal tumors either present in infancy as a scrotal mass and exhibit a benign behavior or occur later in childhood and may be malignant.

Retroperitoneal fibrosis with hydronephrosis as a complication of the Dwyer procedure.

The first reported urological complication of Dwyer Instrumentation for scoliosis is presented. This patient demonstrated ureteral obstruction secondary to retroperitoneal fibrosis temporally associated with this procedure. Routine IVP following surgery is recommended for early detection of urinary complication.

Penile metastases from bronchogenic carcinoma.

A case of secondary penile carcinoma originating in the lung is reported. Modes of metastases to the penis, treatment, prognosis, and a brief review of the literature are given.

Bedside sphincterometry.

We describe the use of a simple bedside sphinctermometer which has proved valuable and reliable in the practical evaluation and management of those patients with neurogenic bladder dysfunction.