Endoscopic submucosal dissection for small submucosal tumors of the rectum compared with endoscopic submucosal resection with a ligation device

AIM To evaluate the efficacy and safety of endoscopic submucosal dissection(ESD) for small rectal submucosal tumors(SMTs).METHODS Between August 2008 and March 2016, 39 patients were treated with endoscopic submucosal resection with a ligation device(ESMR-L)(n = 21) or ESD(n = 18) for small rectal SMTs in this study. Twenty-five lesions were confirmed by histological evaluation of endoscopic biopsy prior to the procedure, and 14 lesions were not evaluated by endoscopic biopsy. The results for the ESMR-L group and the ESD group were retrospectively compared, including baseline characteristics and therapeutic outcomes.RESULTS The rate of en bloc resection was 100% in both groups. Although the rate of complete endoscopic resectionwas higher in the ESD group than in the ESMR-L group(100% vs 95.2%), there were no significant differences between the two groups(P = 0.462). In one patient in the ESMR-L group with a previously biopsied tumor, histological complete resection with a vertical margin involvement of carcinoid tumor could not be achieved, whereas there was no incomplete resection in the ESD group. The mean length of the procedure was significantly greater in the ESD group than in the ESMR-L group(14.7 ± 6.4 min vs 5.4 ± 1.7 min, P < 0.05). The mean period of the hospitalization was also significantly longer in the ESD group than in the ESMR-L group(3.7 ± 0.9 d vs 2.8 ± 1.5 d, P < 0.05). Postoperative bleeding was occurred in one patient in the ESMR-L group.CONCLUSION Both ESMR-L and ESD were effective for treatment of small rectal SMTs. ESMR-L was simpler to perform than ESD and took less time.

Evapotranspiration Characteristics of a Lowland Dry Evergreen Forest in Central Cambodia Examined Using a Multilayer Model

Development pressure has led to serious deforestation on the Indochina Peninsula. Particularly rapid defor-estation has occurred in easily accessible lowland areas, and it is thus important to accumulate knowledge about these forests immediately. We measured evapotranspiration rates for a lowland dry evergreen forest in Kampong Thom Province, central Cambodia, using the energy balance Bowen ratio (EBBR) method based on meteorological data collected from a 60-m-high observation tower. Daily evapotranspiration was higher during the dry season than during the rainy season of the Asian monsoon climate. The seasonal variation in evapotranspiration generally corresponded to the seasonal difference in the vapor pressure deficit. A multi-layer model was used to simulate the seasonal variation in evapotranspiration. The multilayer model also reproduced the larger evapotranspiration rate in the dry season than in the rainy season. However, observed values substantially exceeded model-calculated results during certain periods at the beginning of the dry season and in the late dry season. Moreover, during the rainy season, the model tended to overestimate evapotranspiration. The differences between these observed and simulated values may have been caused by seasonal characteristics of photosynthesis and transpiration in the lowland dry evergreen forest that were not considered in the model simulation.

Rainfall and Runoff Observations in the Subtropical Forest of Okinawa Island, Japan

We set up two experimental catchments to provide an improved understanding of hydrological processes in a subtropical forested area in the northern part of Okinawa Island, Japan. We calculated runoff using water level data (recorded by a pressure-type water level gauge installed in a box culvert) and a discharge rating curve (derived from in situ observations). Water balance calculations for 2010 showed that the rainfall, runoff and evapotranspiration losses (= rainfall – runoff) were 3403.6 mm, 2285.7 mm and 1117.4 mm, respectively. This result was in agreement with previous results from other forested experimental catchments in this region. Direct runoff, as a proportion of event total rainfall, can be expressed by the empirical equation (Qdirect = 0.0048, Pevent 1.7971, R2 = 0.9599). When Pevent was 100 mm or less, the ratios of Qdirect to Pevent were less than 15% in general. When Pevent exceeded 100 mm, the ratios were 20% - 30%.

Calculation of Forest Potential Evapotranspiration of Okinawa in Japan Using the Penman Equation

The northern area of Okinawa Island is a unique forest area in Japan, with a distinctive ecosystem and subtropical climate. The area is a central region of forestry in Okinawa Prefecture. However, quantitative evaluation of the effects of the forest environment is inadequate. The authors began meteorological observation of this forested area to address this situation by setting up a weather station in 2009. In this study, we performed research on one of the major factors of the water cycle in forest ecosystems, evapotranspiration. We calculate seasonal changes in potential evapotranspiration through analysis of data from our weather station in 2013, because all measurement elements were assembled. To calculate potential evapotranspiration, we used the Penman equation. We found that the potential evapotranspiration in this forest area was 1170.5 mm in 2013. The mean temperature in 2013 was 20.7°C, yearly average relative humidity was 84.7%, and average wind speed was 1.40 m/s. Regarding the amount of evapotranspiration in the forests of northern Okinawa Island, which has not been previously obtained, it has become possible to calculate the amount of potential evapotranspiration using the Penman equation.

Multichannel and high-density hybrid integrated light source with a laser diode array on a silicon optical waveguide platform for interchip optical interconnection

A hybrid integrated light source was developed with a configuration in which a laser diode(LD)array was mounted on a silicon optical waveguide platform for interchip optical interconnection.This integrated light source is composed of 13-channel stripes with a pitch of 20 or 30μm.The output power of each LD in the 400 or 600-μm long LD array was over 40 mW at room temperature without cooling.An output power uniformity was 1.3 dB including an LD array power uniformity.The use of a SiON waveguide with a spot size converter resulted in an optical coupling loss of 1 dB between an LD and SiON waveguide.The integrated light source including 52 output ports demonstrated a reduction in the footprint per channel.We also demonstrated a light source with over 100 output ports in which the number of output ports is increased by using a waveguide splitter and multichip bonding.These integrated light sources are practical candidates for use with photonic integrated circuits for high-density optical interconnection.