Induction Chemotherapy Followed by Radiotherapy versus Concurrent Chemoradiotherapy in elderly patients with nasopharyngeal carcinoma: finding from a propensity-matched analysis.

BACKGROUND: To date, no guideline is proposed for elderly nasopharyngeal carcinoma (NPC) due to lack of prospective clinical trials. The present study comparing the survivals and toxicities in elderly NPC patients received either induction chemotherapy followed by radiotherapy(IC + RT) or concurrent chemoradiotherapy (CCRT) was therefore undertaken to provide a more accurate basis for future clinical practice. METHODS: The eligible elderly NPC patients were retrospectively enrolled. Propensity score matching generated a matched cohort (1:2) composed from CCRT and IC + RT groups. The survivals and treatment-induced toxicities were compared between two groups. Multivariable analysis was carried to identify significant prognostic factors. RESULTS: The 5-year overall survival, cancer-specific survival, locoregional failure-free survival, distant failure-free survival for all patients were 58.3 %, 62.7 %, 88.7 %, 83.0 %, respectively. No significant survival differences were found between CCRT and IC + RT groups in the propensity-matched cohort. In comparison with the patients who received IC + RT, patients who underwent CCRT were associated with more severe acute toxicities including leucopenia (30 % vs. 6.8 %, P = 0.005), anemia (20 % vs. 4.1 %, P = 0.027), mucositis (63.3 % vs. 34.2 %, P = 0.007), weight loss (23.4 % vs. 4.1 %, P = 0.009). Basicranial bone involvement was an independent prognostic factor that predicted all-cause death (HR = 0.553, 95 % CI 0.329-0.929; P = 0.025) and cancer specific death (HR = 0.558, 95 % CI 0.321-0.969; P = 0.038) in elderly patients. CONCLUSIONS: In the context of no guideline for elderly NPC, the present study suggested IC + RT should be a preferable modality compared with CCRT, with similar treatment outcomes but less acute toxicities.

Numerical simulation of heat transfer properties of large-sized biomass particles during pyrolysis process.

During the pyrolysis process of large particles, the conduction between particles cannot be ignored. In the present work, a numerical simulation model for the pyrolysis of biomass particles was established, which takes into account the conduction within the particles. Based on this model, the temperature distribution inside the particle during the pyrolysis process was determined and the effects of particle size, moisture content, and gas velocity on heat transfer characteristics were analyzed. The results showed that the temperatures at different positions of the particles along the inflow direction were quite different, and the maximum temperature difference inside the particles was about 146.7 K for a particle diameter of 10 mm and a velocity of 0.2 m/s. During the pyrolysis process of biomass particles, there were two peaks of Nusselt number. The increase of moisture content prolonged the pyrolysis time. The pyrolysis. time of particles with moisture content of 15 % was about 1.5 times longer than that of dry particles when the particle diameter was 10 mm. Increasing the particle size decreased the difference between the two peaks and increased the time interval between the two peaks. Increasing the gas velocity can improve the heat transfer, but the effect of too high gas velocity on improving the heat transfer is limited. The present study is of great importance for a detailed understanding of the pyrolysis process of biomass particles.

Social organization of white-headed langurs (Trachypithecus leucocephalus) in the Nongguan Karst Hills, Guangxi, China.

The number of males per group is the most variable aspect of primate social organization and is often related to the monopolizability of females, which is mainly determined by the number of females per group and their reproductive synchrony. Colobines show both inter-specific and intra-specific variations in the number of males per group. Compared with other colobine species, little is known about the social organization of white-headed langur (Trachypithecus leucocephalus), despite its endangered status and unusual limestone habitat. As a part of a long-term study of the white-headed langurs in the Nongguan Karst Hills, Guangxi, China, we quantitatively investigated their social organization by analyzing census data from 1998 to 2003. The population censuses revealed that the predominant social organization of bisexual groups was the one-male group, similar to a previous report on this species and many other Asian colobines. In such groups, one adult male associated with 5.1 adult females, 0.1 sub-adult males, 2.6 juveniles and 2.9 infants on average, with a mean group size of 11.7 individuals. In addition, three multi-male groups were recorded, consisting of 2-3 adult males, 1-5 adult females, 0-2 sub-adult males, 0-7 juveniles and 0-2 infants. They did not contain more adult females than the one-male groups and were unstable in group membership. The langurs outside bisexual groups were organized into small nonreproductive groups or lived as solitaries. The nonreproductive groups averaged 1.3 adult males, 1.3 sub-adult males and 2.6 juveniles. Juvenile females were present in such groups on 52.4% of all occasions. As predicted by the monopolization model, the prevalence of the one-male pattern in this species may mainly be attributed to the small number of females in the group. The possible reasons for the occurrence of multi-male groups and the presence of juvenile females in nonreproductive groups are also discussed.

Reproductive parameters of wild Trachypithecus leucocephalus: seasonality, infant mortality and interbirth interval.

Understanding the reproductive parameters of endangered primate species is vital for evaluating the status of populations and developing adequate conservation measures. This study provides the first detailed analysis of the reproductive parameters of wild white-headed langurs (Trachypithecus leucocephalus), based on demographic data collected over an 8-year period in the Nongguan Karst Hills in Chongzuo County, Guangxi, China. From 1998 to 2002, a total of 133 live births were recorded in the population based on systematic censuses. Births occurred throughout the year, but the temporal pattern was highly correlated with seasonal variation in temperature and rainfall, with the birth peak coinciding with the dry and cold months of November-March. The average birthrate was 0.47+/-0.13 births per female per year and mortality for infants younger than 20 months was 15.8%. From 1998 to 2006, 14 females gave birth to 41 infants in four focal groups. The average age at first birth for female langurs was 5-6 years (n = 5) and the interbirth interval (IBI) was 23.2+/-5.2 months (median = 24.5 months, n = 27). Infants are weaned at 19-21 months of age. The IBI for females with infant loss before weaning was significantly shorter than those for females whose infants survived. It appears that birth seasonality in the white-headed langurs is influenced by seasonal changes in food availability. The timing of conceptions was found to coincide with peak food availability. The reproductive parameters for white-headed langurs reported here are quite similar to those reported for other colobine species. One major difference is our observation of lower infant mortality in Trachypithecus.

AHP-based approach for optimization of waste disposal method in urban functional zone.

In this study, the municipal solid waste (MSW) is considered as one kind of energy source in urban planning scheme instead of a trash stream. Considering the characteristics of MSW from different urban functional zones and the current energy supply modes, an evaluation model for waste-to-energy (WtE) method was set up based on the analytical hierarchy process technique. The model consists of three layers: 15 fundamental indices, 4 influencing factors based on fundamental indices and the target functions supported by influencing factors. Taking an urban functional region of a city in north China as the research object, 4 alternatives are compared according to their weights and the sensitivities of the influencing factors are analyzed. The result will provide guide for the disposal method of WtE in new urban district planning and old urban redevelopment.

Utilization of PET-CT in target volume delineation for three-dimensional conformal radiotherapy in patients with non-small cell lung cancer and atelectasis.

BACKGROUND: To investigate the utilization of PET-CT in target volume delineation for three-dimensional conformal radiotherapy in patients with non-small cell lung cancer (NSCLC) and atelectasis. METHODS: Thirty NSCLC patients who underwent radical radiotherapy from August 2010 to March 2012 were included in this study. All patients were pathologically confirmed to have atelectasis by imaging examination. PET-CT scanning was performed in these patients. According to the PET-CT scan results, the gross tumor volume (GTV) and organs at risk (OARs, including the lungs, heart, esophagus and spinal cord) were delineated separately both on CT and PET-CT images. The clinical target volume (CTV) was defined as the GTV plus a margin of 6-8 mm, and the planning target volume (PTV) as the GTV plus a margin of 10-15mm. An experienced physician was responsible for designing treatment plans PlanCT and PlanPET-CT on CT image sets. 95% of the PTV was encompassed by the 90% isodose curve, and the two treatment plans kept the same beam direction, beam number, gantry angle, and position of the multi-leaf collimator as much as possible. The GTV was compared using a target delineation system, and doses distributions to OARs were compared on the basis of dose-volume histogram (DVH) parameters. RESULTS: The GTVCT and GTVPET-CT had varying degrees of change in all 30 patients, and the changes in the GTVCT and GTVPET-CT exceeded 25% in 12 (40%) patients. The GTVPET-CT decreased in varying degrees compared to the GTVCT in 22 patients. Their median GTVPET-CT and median GTVPET-CT were 111.4 cm3 (range, 37.8 cm3-188.7 cm3) and 155.1 cm3 (range, 76.2 cm3-301.0 cm3), respectively, and the former was 43.7 cm3 (28.2%) less than the latter. The GTVPET-CT increased in varying degrees compared to the GTVCT in 8 patients. Their median GTVPET-CT and median GTVPET-CT were 144.7 cm3 (range, 125.4 cm3-178.7 cm3) and 125.8 cm3 (range, 105.6 cm3-153.5 cm3), respectively, and the former was 18.9 cm3 (15.0%) greater than the latter. Compared to PlanCT parameters, PlanPET-CT parameters showed varying degrees of changes. The changes in lung V20, V30, esophageal V50 and V55 were statistically significant (Ps< 0.05 for all), while the differences in mean lung dose, lung V5, V10, V15, heart V30, mean esophageal dose, esophagus Dmax, and spinal cord Dmax were not significant (Ps> 0.05 for all). CONCLUSIONS: PET-CT allows a better distinction between the collapsed lung tissue and tumor tissue, improving the accuracy of radiotherapy target delineation, and reducing radiation damage to the surrounding OARs in NSCLC patients with atelectasis.