Thermophotovoltaic efficiency of 40.

Thermophotovoltaics (TPVs) convert predominantly infrared wavelength light to electricity via the photovoltaic effect, and can enable approaches to energy storage1,2 and conversion3-9 that use higher temperature heat sources than the turbines that are ubiquitous in electricity production today. Since the first demonstration of 29% efficient TPVs (Fig. 1a) using an integrated back surface reflector and a tungsten emitter at 2,000 °C (ref. 10), TPV fabrication and performance have improved11,12. However, despite predictions that TPV efficiencies can exceed 50% (refs. 11,13,14), the demonstrated efficiencies are still only as high as 32%, albeit at much lower temperatures below 1,300 °C (refs. 13-15). Here we report the fabrication and measurement of TPV cells with efficiencies of more than 40% and experimentally demonstrate the efficiency of high-bandgap tandem TPV cells. The TPV cells are two-junction devices comprising III-V materials with bandgaps between 1.0 and 1.4 eV that are optimized for emitter temperatures of 1,900-2,400 °C. The cells exploit the concept of band-edge spectral filtering to obtain high efficiency, using highly reflective back surface reflectors to reject unusable sub-bandgap radiation back to the emitter. A 1.4/1.2 eV device reached a maximum efficiency of (41.1 ± 1)% operating at a power density of 2.39 W cm-2 and an emitter temperature of 2,400 °C. A 1.2/1.0 eV device reached a maximum efficiency of (39.3 ± 1)% operating at a power density of 1.8 W cm-2 and an emitter temperature of 2,127 °C. These cells can be integrated into a TPV system for thermal energy grid storage to enable dispatchable renewable energy. This creates a pathway for thermal energy grid storage to reach sufficiently high efficiency and sufficiently low cost to enable decarbonization of the electricity grid.

Gamma-delta T-cell lymphoma arising in a long-standing cutaneous plaque.

The precise classification and characterization of primary cutaneous gamma-delta T-cell lymphoma (PCGD-TCL) has been hindered by clinical and morphologic features that overlap with other lymphomas, especially subcutaneous panniculitis-like T cell lymphoma (SPTCL). The recent World Health Organization/European Organization for Research and Treatment of Cancer (WHO/EORTC) classification distinguishes the more aggressive PCGD-TCL from the usually indolent SPTCL, however. We report a 30-year-old woman with an indurated violaceous plaque on the left cheek that had been present for several years. Biopsies showed a dense lymphocytic infiltrate involving the subcutis and dermis that consisted mostly of small and medium-sized lymphocytes, some with irregular nuclear contours and dense chromatin. These cells were positive for TIA-1, TCR-gamma and CD8, but negative for beta-F1 and granzyme-B. Staging with positron emission tomography-computed tomography (PET/CT), CBC and bone marrow with flow cytometry identified lymphadenopathy as well as blood and marrow involvement by an abnormal TCRgd-positive T-cell proliferation (Ann Arbor Stage IV). The patient's history of a long-standing lesion in this case is unusual, in that gamma-delta T-cell lymphomas are typically rapidly progressive neoplasms. As such, it raises the possibility of 'transformation' of a long-standing inflammatory process into an overt lymphoma.

Complications are increased with the need for an abdominal-assisted Kraske procedure.

The Kraske procedure offers a sphincter-saving alternative for surgical correction of rectal disease. This study was performed to investigate the complication rate with the traditional (transsacral) Kraske procedure versus an abdominal-assisted Kraske approach (laparoscopic or open). We conducted a retrospective review of all patients undergoing the Kraske procedure at Harper University Hospital over a 10-year period. A total of 54 patients were identified. Indications for surgery included rectal carcinoma (43), large villous adenomas (6), and other (5). Average post-operative follow-up was 40 +/- 25 months (mean +/- SD). Complications included rectocutaneous fistulae (9), perineal infections (13), and incontinence (8). In patients requiring an abdominal-assisted approach for colorectal mobilization, the fistula rate was significantly higher (33% vs 3%; P = 0.007), as were the rates of perineal infections (33% vs 17%) and of initial incontinence (25% vs 7%). The laparoscopic-assisted approach significantly reduced the operating time (272 +/- 72 minutes) compared to the open-assisted approach (498 +/- 138 minutes) (P < 0.001). The traditional Kraske procedure can be utilized in a safe, effective manner for treatment of rectal disease. Knowledge of the increased rate of complications with the abdominal-assisted Kraske approach can guide the patient and physician considering sphincter salvage.