We prospectively investigated the association between gastric cancer screening and subsequent risk of gastric cancer in a large-scale population-based prospective cohort study, with a 13-year follow-up in Japan. Data were analyzed from a population-based cohort of 42,150 (20,326 men and 21,824 women) subjects. Approximately 36% of subjects reported that they had undergone screening photofluorography during the preceding 12 months, and were regarded as the screened group. A total of 179 gastric cancer deaths and 636 incident gastric cancers were identified during the follow-up period. We observed a 2-fold decrease in gastric cancer mortality in screened versus unscreened subjects (RR 5 0.52; 95% CI 5 0.36-0.74). The extent of the reduction in mortality for gastric cancer was greater than in death from all causes excluding gastric cancer (RR 5 0.71; 95% CI 5 0.65-0.78). A significant decrease in the incidence of advanced gastric cancer was observed in screened subjects (RR 5 0.75; 95% CI 5 0.58-0.96), although the overall incidence rate did not differ significantly between the screened and unscreened subjects (RR 5 1.06; 95% CI 5 0.90-1.25). In age-stratified analyses, a significant reduction in gastric cancer mortality was seen in screened subjects aged 40-49 years at baseline, compared with a lesser reduction in screened subjects aged 50-59 (RR 5 0.30, 95% CI 5 0.13-0.72; and RR 5 0.60, 95% CI 5 0.40-0.88, respectively). These findings suggest that gastric cancer screening may be associated with a reduced risk of mortality from gastric cancer. ' 2005 Wiley-Liss, Inc.Key words: gastric cancer; gastric cancer screening; prospective study; Japan Although the incidence and mortality of gastric cancer in Japan is falling, in line with a worldwide decrease in this condition, 1,2 it remains the second most frequent cause of cancer death among Japanese men and women, with an estimated 50,000 deaths from gastric cancer in 2000.2 The prevention of gastric cancer is therefore still one of the most important cancer control strategies.In Japan, gastric cancer screening by photofluorography began in Miyagi Prefecture, around 1960.3 It was subsequently expanded through implementation of the National Health and Medical Services Law for the Aged in 1983, and is now an established cancer control strategy nationwide. National statistics indicate that 4.3 million inhabitants (13% of those aged 40 years and over) participated in gastric cancer screening organized by local governments in 2002. 4 Although randomized controlled trials represent the most reliable method for evaluating the impact of screening on cancer risk, no such intervention studies are available in Japan. The efficacy of gastric cancer screening has instead been assessed using other epidemiological methods 5-12 over the last 20 years, but results have been controversial (Table I). Although most case-control studies 5-7 suggested a 40-60% decrease in gastric cancer mortality in screened versus unscreened subjects, previous prospective studies have shown inconsisten...

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Summary: This paper describes a simple and facile approach to fabricate well dispersed silver nanoparticles (AgNPs) in poly[N‐isopropylacrylamide‐co‐(sodium acrylate)] hydrogels. The silver nanoparticles formed are spherical in shape with a narrow size distribution in the hydrogel networks in which the nanoparticles are stabilized by the polymer network. Uniformly dispersed silver nanoparticles were obtained with poly[N‐isopropylacrylamide‐co‐[sodium acrylate)] hydrogels, whereas a poly(N‐isopropylacrylamide)/poly(sodium acrylate) IPN gel showed aggregated nanoparticles. It is demonstrated that the hydrogel network structure determines the size and shape of the nanoparticles. These particles are more stable in the gel networks compared to other reduction methods. The hydrogel/silver nanohybrids were well characterized by XRD, UV‐vis spectrometry, scanning electron microscopy and transmission electron microscopy.

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Because there is no consensus regarding the factors predicting femoral head collapse in asymptomatic osteonecrosis of the hip, we studied the risk factors for collapse. Between 1990 and 2000, we used MRI to confirm asymptomatic osteonecrosis of the femoral head in 81 patients (81 hips) whose other hip had nontraumatic symptomatic osteonecrosis and we monitored them prospectively. The minimum followup was 5 years (mean, 8.3 years; range, 5-16 years). At the latest followup, 31 hips (38%) were symptomatic and 26 hips (32%) had collapsed. The mean interval between diagnosis and collapse was 4.1 years. We observed no correlation between femoral head collapse and patients' age, gender, weight, presumed cause of osteonecrosis, or length of followup. With combined factors, only extent of large necrotic lesion (hazard ratio, 4.06; 95% confidence interval, 1.29-12.77) and location of Type C2 necrotic lesion (hazard ratio, 6.35; 95% confidence interval, 1.18-34.11) predicted collapse.

In this paper, a sparse Markov decision process (MDP) with novel causal sparse Tsallis entropy regularization is proposed. The proposed policy regularization induces a sparse and multi-modal optimal policy distribution of a sparse MDP. The full mathematical analysis of the proposed sparse MDP is provided. We first analyze the optimality condition of a sparse MDP. Then, we propose a sparse value iteration method which solves a sparse MDP and then prove the convergence and optimality of sparse value iteration using the Banach fixed point theorem. The proposed sparse MDP is compared to soft MDPs which utilize causal entropy regularization. We show that the performance error of a sparse MDP has a constant bound, while the error of a soft MDP increases logarithmically with respect to the number of actions, where this performance error is caused by the introduced regularization term. In experiments, we apply sparse MDPs to reinforcement learning problems. The proposed method outperforms existing methods in terms of the convergence speed and performance.

These findings suggest that physical activity may prevent colon cancer among Japanese men.

We prospectively examined the association between coffee consumption and the risk of developing colorectal cancer in a large population-based cohort study (the JPHC Study) of Japanese men and women. Data were analyzed from a population-based cohort of 96,162 subjects (46,023 men and 50,139 women). A total of 1,163 incident colorectal cancers were identified during the followup period, including 763 cases of colon cancer and 400 of rectal cancer. We observed a significant inverse association between coffee consumption and the risk of developing invasive colon cancer among women. Compared with those who almost never consumed coffee, women who regularly consumed 3 or more cups of coffee per day had a RR of 0.44 (95% CI 5 0.19-1.04; p for trend 5 0.04) after adjustment for potential confounding factors. However, no significant association was found for rectal cancer in women. In men, no significant decrease was observed in any colorectal cancer site. Further, additional analyses on the association of green tea consumption with colorectal cancer risk found no significant association in men or women. These findings suggest that coffee consumption may lower the risk of colon cancer among Japanese women. ' 2007 Wiley-Liss, Inc.Key words: colorectal cancer; coffee; prospective study; Japan Colorectal cancer is one of the most common cancers in more developed countries, with nearly 945,000 new cases diagnosed worldwide each year and 492,000 deaths. 1 In Japan, the incidence and mortality of colorectal cancer has recently increased, and it is now a leading cause of morbidity and mortality, with about 36,000 deaths in 2000.2 This recent increase in Japan may be associated with changes in environmental factors such as dietary habits or lifestyle factors.Coffee drinking is popular in many parts of the world. In Japan, coffee has been popularly consumed since its initial introduction, although coffee consumption is relatively new in comparison to green tea consumption. Given the widespread consumption of coffee and high incidence of colorectal cancer in developed countries, the possible role of coffee consumption in the etiology of colorectal carcinogenesis has drawn interest, 3 and the relation between coffee consumption and colorectal cancer risk has been investigated over the last 4 decades. However, results from epidemiological studies have been inconsistent.3,4 A meta-analysis showed a lower risk of colorectal cancer associated with substantial consumption of coffee, 3 but the results were inconclusive owing to inconsistencies between case-control and prospective studies. Case-control studies have tended to support an inverse association between coffee consumption and risk of colorectal cancer, [5][6][7][8][9][10][11][12][13][14][15] whereas the albeit limited number of prospective cohort studies have not supported any significant reduction in risk. [16][17][18][19][20][21][22][23][24][25] Moreover, most previous studies have been conducted in Western countries. 16-24Here, we prospectively examined the association between...