Drain-Source Voltage-Controllable Three-Switch Active-Clamp Forward Converter for Wide Input/Output Voltage Applications.

Active-clamp forward converters are applied to various medium-capacity power systems because they have a relatively simple structure and are capable of zero-voltage switching. In particular, there is the advantage that a stable output voltage can be obtained by controlling the duty ratio of the power semiconductor switch even in applications with wide input and output voltage ranges. However, the voltage stress on the power semiconductor switches due to the application of active clamp is higher than the input voltage, especially as the duty ratio increases. A three-switch active-clamp forward converter is proposed, which can overcome such shortcomings and can reduce the voltage stress of the power semiconductor switches, but it causes an increase in the DC bias of the magnetizing current and the additional conduction and switching losses. Therefore, in this paper, a voltage-stress-controllable three-switch active-clamp forward converter that can utilize both advantages of the conventional active-clamp forward converter and three-switch active clamp forward converter is proposed and verified through a prototype for 800 W battery charger.

Complete response in hepatocellular carcinoma with lymph node metastasis by combination therapy of atezolizumab and bevacizumab: a case report.

Sorafenib is the oldest first line systemic treatment in patients with advanced hepatocellular carcinoma (HCC) and has been used exclusively for nearly 10 years. The superiority of administering a combination of atezolizumab plus bevacizumab (AteBeva) compared to sorafenib as first line systemic treatment for unresectable HCC was recently proven during the IMbrave150 Phase III randomized trial. While clinicians can expect improved responses and treatment outcomes due to the good results of the IMbrave 150 trial, they must also consider that atezolizumab can cause various immune-related adverse events (IrAEs). Based on the above suggestions, we herein present a case of HCC with lymph node metastasis who achieved complete remission following treatment with AteBeva and developed an IrAE (adrenal insufficiency). Further study of real-life data regarding combination therapy with AteBeva is needed to manage patients with advanced HCC.

Enterovenous fistulization: a rare complication of Crohn's disease.

The presence of hepatic portal venous gas (HPVG) is associated with numerous diseases, and has been regarded as a serious, even catastrophic condition. However, anecdotal reports mention that some patients with inflammatory bowel disease (IBD), who developed HPVG after diagnostic examinations of the colon, were successfully managed with antibiotic therapy and have followed benign courses. In contrast, among IBD patients, the development of HPVG is rarely caused by enterovenous fistula. We describe a 32-year-old man with Crohn's ileocolitis who presented with hypotension and fever associated with HPVG, as well as superior mesenteric vein thrombosis, possibly caused by enterovenous fistula, who was successfully managed by surgery. We also review the literature concerning portal venous gas associated with Crohn's disease.

[Nine cases of sporadic acute hepatitis E in Korea].

Hepatitis E virus is an enterically transmitted virus that causes endemic cases of acute hepatitis in many countries in Africa, and Southeast and Central Asia. Sporadic cases of acute hepatitis E also have been reported in developed countries. In non-endemic areas, most of the sporadic cases of hepatitis E are introduced from the endemic areas. Until now, only three cases of acute hepatitis E have been reported in Korea. Recently, we experienced nine cases of acute hepatitis, in which serologic studies showed positive of IgM anti-HEV. We report these as cases of acute hepatitis E. These cases suggest that HEV infection occurs sporadically in Korea and should be considered as a cause of cryptogenic acute hepatitis.