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Elucidating the seasonal patterns of water sources for dominant species in the sub-tropical humid mountainous forest, analyzing the eco-hydrological complementarity and competition mechanisms among coexisting species, investigating the responses of plant water utilization to precipitation, could provide a theoretical basis for vegetation restoration and management. Based on the stable hydrogen and oxygen isotope technique, we analyzed the δ 2 H and δ 18 O characteristics of precipitation, xylem water from Pinus massoniana and Quercus variabilis , and soil water from 0-100 cm depth in Mount Lushan, China. The MixSIAR model, Levins index, and PS index were used to calculate the relative contribution rate of each water source, the hydrological niche breadth, and niche overlap of P. massoniana and Q. variabilis . The results showed that, in the wet season (March to July), P. massoniana primarily utilized soil water from the 0-20 cm and 20-40 cm depths, while Q. variabilis primarily utilized that from the 20-40 cm and 40-60 cm depths. During the dry season (August to September), P. massoniana and Q. variabilis utilized 40-60 cm and 60-80 cm of soil water, respectively, resulting in an increase in the depth of water absorption. In the early growing season (March to April) and the late growing season (September), there was a high hydrological niche overlap between P. massoniana and Q. variabilis , resulting in intensitive water competition. In the middle of the growing season (May to August), the water source was adequately allocated, and the hydrolo-gical niche was segregated to meet the high transpiration demand. Q. variabilis primarily utilized soil water from a depth of 60-80 cm and 60-80 cm before a precipitation event, and from a depth of 0-20 cm and 20-40 cm after the event. In contrast, P. massoniana primarily utilized soil water from a depth of 0-20 cm and 20-40 cm both before and after a precipitation event. In conclusion, water utilization patterns of P. massoniana and Q. variabilis exhibited a seasonal trend, with shallow water uptake during the rainy season and deep water uptake during the dry season. These species are capable of efficiently allocating water resources during the peak growth season, and their root systems actively respond to change in soil moisture level. They have strong adaptability to extreme precipitation events and exhibit remarkable water conservation capabilities.

The ecological environment along the Qinghai-Xizang highway is an important part of the construction of the ecological civilization in the Xizang region, and current research generally suffers from difficulties in data acquisition, low timeliness, and failure to consider the unique "alpine saline" environmental conditions in the study area due to the unique geographical environment of the Qinghai-Xizang plateau. Based on the GEE platform and the unique geographical environment of the study area, the remote sensing ecological index (RSEI) was improved, and a new saline remote sensing ecological index (SRSEI) applicable to the alpine saline region was constructed by using principal component analysis as an ecological environment quality evaluation index. The spatial distribution pattern and temporal variation trend of ecological environment quality along the Qinghai-Xizang Highway Nagqu-Amdo section were analyzed at multiple spatial and temporal scales using the ArcGIS 10.3 platform and geographic probes, and the driving mechanisms of eight control factors, including natural and human-made, on the spatial and temporal changes in SRSEI were investigated. The results showed that:① compared with RSEI, SRSEI was more sensitive to vegetation and had a stronger discriminatory ability in areas with sparse vegetation and severe salinization, which is suitable for ecological quality evaluation in alpine saline areas. ② The spatial scale of ecological environment quality in the study area had obvious geographical differentiation, and the areas with poor ecological quality were mainly concentrated in the northern Amdo County, whereas the areas with excellent and good quality grades were mainly distributed in the central-western and southeastern Nagqu areas. On the temporal scale, the ecological environment of the study area as a whole showed an improvement trend over 32 years, and the vegetation cover in the central-western and southeastern areas increased significantly, which had a strong improvement effect on the ecological environment. The improvement area was 1 425.98 km 2 , accounting for 99.82%. The mean value of SRSEI was 0.49, with an overall fluctuating upward trend and an average increase of 0.015 7 a -1 . ③ The land use pattern was the most driving influence factor in the change of ecological environment quality in the study area, with an average q value of 0.157 6 over multiple years, and the influence of environmental factors was low. The multi-factor interaction results showed that the ecological environment in the study area was the result of multiple factors acting together, all factors had synergistic enhancement under the interaction, the influence of human factors was gradually increasing, and the interaction of the net primary productivity (NPP) of vegetation and land use pattern was the main interactive control factor of ecological environment quality in the study area. This study can provide a theoretical basis for ecological environmental protection and sustainable development along the Nagqu to Amdo section.

Purpose: To explore the effect of extracting the completely impacted teeth by minimally invasive surgery with preserving the buccal bone plate., Methods: Eighty-six cases were selected and randomly divided into 2 groups. In the experimental group, a fenestration was made with a ball drill to expose the buccal and lingual margin of crown, and the buccal bone plate was preserved. T-shaped crown cuttings were performed, minimally invasive extraction was conducted.In the control group, the distal and buccal bone plates were removed with a ball drill, the distal and buccal crowns were exposed, and T-shaped crown was cut. The other procedures were the same. The degree of swelling, restricted mouth opening and VAS pain score after operation were observed, the levels of C-reactive protein and anti-hemolytic streptoglobulin were detected by laboratory tests, and the periodontal probing depth(PD), bleeding index (BI), and clinical attachment loss(CAL) of the adjacent second molar were examined 1 month after surgery. SPSS 25.0 software package was used for data analysis., Results: The swelling degree of the two groups was significantly relieved in the experimental group than in the control group (P＜0.05), and there was no significant difference in the degree of mouth opening limitation and pain (P＞0.05). The level of C-reactive protein in the control group was significantly higher than that in the observation group (P＜0.05). There was no significantly difference in the level of anti-hemolytic streptococcus between the 2 groups (P＞0.05). One month after operation, the PD and CAL in the control group were significantly higher than those in the experimental group(P＜0.05). There was no significant difference between the 2 groups in BI(P＞0.05)., Conclusions: The patients who preserve the buccal bone plate by minimally invasive extraction of impacted mandibular teeth have less reaction and better wound healing.

Background: Radiotherapy-related toxicities of nasopharyngeal carcinoma (NPC) caused by a standard dose of 70 Gy remain a critical issue. Therefore, we assessed whether a radiotherapy dose of 60 Gy was non-inferior to the standard dose in patients with low-risk stage III NPC with a favourable response to induction chemotherapy (IC)., Patients and Methods: We did a single-arm, single-centre, phase II clinical trial in China. Patients with low-risk (Epstein-Barr virus [EBV] DNA level <4000 copies/ml) stage III NPC were treated with two cycles IC. Patients with complete/partial response and undetectable EBV DNA level were assigned 60 Gy intensity-modulated radiotherapy concurrently with three cycles of cisplatin. The primary end-point was 2-year progression-free survival (PFS). This trial is registered with ClinicalTrials.gov, number NCT03668730., Results: One patient quit because of withdrawal of informed consent after IC. In total, 215 patients completed two cycles of IC, after which 116 (54.0%) and 99 (46.0%) patients were assigned 60 and 70 Gy radiotherapy, respectively. For 215 patients, the 2-year PFS was 90.7% (95% CI, 86.8%-94.6%) with a median follow-up of 43.9 months (interquartile range [IQR], 39.8-46.2). For patients treated with 60 Gy radiotherapy, the 2-year PFS rate was 94.8% (95%CI 90.7%-98.9%) with a median follow-up of 43.9 months (IQR 40.2-46.2). The most common late toxicity was grade 1-2 dry mouth (incidence rate: 54.3%). No grade 3+ long-term adverse event was observed, and most quality-of-life items, domains, and symptom scores returned to baseline by 6 months., Conclusion: Reduced-dose radiation (60 Gy) is associated with favourable survival outcomes and limited treatment-related toxicities in patients with low-risk stage III NPC sensitive to IC., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Immunotherapy combined with antiangiogenic targeted therapy has improved the treatment of certain solid tumors, but effective regimens remain elusive for refractory recurrent/metastatic nasopharyngeal carcinoma (RM-NPC). We conducted a phase 2 trial to evaluate the safety and activity of camrelizumab plus apatinib in platinum-resistant (cohort 1, NCT04547088) and PD-1 inhibitor resistant NPC (cohort 2, NCT04548271). Here we report on the primary outcome of objective response rate (ORR) and secondary endpoints of safety, duration of response, disease control rate, progression-free survival, and overall survival. The primary endpoint of ORR was met for cohort 1 (65%, 95% CI, 49.6-80.4, n = 40) and cohort 2 (34.3%; 95% CI, 17.0-51.8, n = 32). Grade ≥ 3 treatment-related adverse events (TRAE) were reported in 47 (65.3%) of 72 patients. Results of our predefined exploratory investigation of predictive biomarkers show: B cell markers are the most differentially expressed genes in the tumors of responders versus non-responders in cohort 1 and that tertiary lymphoid structure is associated with higher ORR; Angiogenesis gene expression signatures are strongly associated with ORR in cohort 2. Camrelizumab plus apatinib combination effectiveness is associated with high expression of PD-L1, VEGF Receptor 2 and B-cell-related genes signatures. Camrelizumab plus apatinib shows promising efficacy with a measurable safety profile in RM-NPC patients., (© 2023. Springer Nature Limited.)

Background: Patients with N2-3 nasopharyngeal carcinoma have a high risk of treatment being unsuccessful despite the current practice of using a concurrent adjuvant cisplatin-fluorouracil regimen. We aimed to compare the efficacy and safety of concurrent adjuvant cisplatin-gemcitabine with cisplatin-fluorouracil in N2-3 nasopharyngeal carcinoma., Methods: We conducted an open-label, randomised, controlled, phase 3 trial at four cancer centres in China. Eligible patients were aged 18-65 years with untreated, non-keratinising, stage T1-4 N2-3 M0 nasopharyngeal carcinoma, an Eastern Cooperative Oncology Group performance status score of 0-1, and adequate bone marrow, liver, and renal function. Eligible patients were randomly assigned (1:1) to receive concurrent cisplatin (100 mg/m 2 intravenously) on days 1, 22, and 43 of intensity-modulated radiotherapy followed by either gemcitabine (1 g/m 2 intravenously on days 1 and 8) and cisplatin (80 mg/m 2 intravenously for 4 h on day 1) once every 3 weeks or fluorouracil (4 g/m 2 in continuous intravenous infusion for 96 h) and cisplatin (80 mg/m 2 intravenously for 4 h on day 1) once every 4 weeks, for three cycles. Randomisation was done using a computer-generated random number code with a block size of six, stratified by treatment centre and nodal category. The primary endpoint was 3-year progression-free survival in the intention-to-treat population (ie, all patients randomly assigned to treatment). Safety was assessed in all participants who received at least one dose of chemoradiotherapy. This study was registered at ClinicalTrials.gov, NCT03321539, and patients are currently under follow-up., Findings: From Oct 30, 2017, to July 9, 2020, 240 patients (median age 44 years [IQR 36-52]; 175 [73%] male and 65 [27%] female) were randomly assigned to the cisplatin-fluorouracil group (n=120) or cisplatin-gemcitabine group (n=120). As of data cutoff (Dec 25, 2022), median follow-up was 40 months (IQR 32-48). 3-year progression-free survival was 83·9% (95% CI 75·9-89·4; 19 disease progressions and 11 deaths) in the cisplatin-gemcitabine group and 71·5% (62·5-78·7; 34 disease progressions and seven deaths) in the cisplatin-fluorouracil group (stratified hazard ratio 0·54 [95% CI 0·32-0·93]; log rank p=0·023). The most common grade 3 or worse adverse events that occurred during treatment were leukopenia (61 [52%] of 117 in the cisplatin-gemcitabine group vs 34 [29%] of 116 in the cisplatin-fluorouracil group; p=0·00039), neutropenia (37 [32%] vs 19 [16%]; p=0·010), and mucositis (27 [23%] vs 32 [28%]; p=0·43). The most common grade 3 or worse late adverse event (occurring from 3 months after completion of radiotherapy) was auditory or hearing loss (six [5%] vs ten [9%]). One (1%) patient in the cisplatin-gemcitabine group died due to treatment-related complications (septic shock caused by neutropenic infection). No patients in the cisplatin-fluorouracil group had treatment-related deaths., Interpretation: Our findings suggest that concurrent adjuvant cisplatin-gemcitabine could be used as an adjuvant therapy in the treatment of patients with N2-3 nasopharyngeal carcinoma, although long-term follow-up is required to confirm the optimal therapeutic ratio., Funding: National Key Research and Development Program of China, National Natural Science Foundation of China, Guangdong Major Project of Basic and Applied Basic Research, Sci-Tech Project Foundation of Guangzhou City, Sun Yat-sen University Clinical Research 5010 Program, Innovative Research Team of High-level Local Universities in Shanghai, Natural Science Foundation of Guangdong Province for Distinguished Young Scholar, Natural Science Foundation of Guangdong Province, Postdoctoral Innovative Talent Support Program, Pearl River S&T Nova Program of Guangzhou, Planned Science and Technology Project of Guangdong Province, Key Youth Teacher Cultivating Program of Sun Yat-sen University, the Rural Science and Technology Commissioner Program of Guangdong Province, and Fundamental Research Funds for the Central Universities., Competing Interests: Declaration of interests We declare no competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Objective: We compared the clinical characteristics and survival outcomes after radical radiotherapy between nasopharyngeal carcinoma (NPC) with early and late metastases based on a relatively large cohort, which provides valuable data for the planning of clinical surveillance strategies., Methods: This was a single-center retrospective analysis of 10,566 patients who received radical radiotherapy in China from January 2000 to December 2016. Overall survival was the primary endpoint. Kaplan-Meier survival analysis and log-rank tests were applied to investigate the association between early or late metastasis and the endpoints. The prognostic value of clinicopathological features was identified using univariate and multivariate Cox proportional hazards models., Results: The cutoff value for time to metastasis was based on ROC analysis. A total of 559 (5.3%) patients developed distant metastases, 297 (53.1%) of which developed early metastatic disease, with the rest (46.9%) developing late metastatic disease. The K-M analysis showed that the patients with late metastatic foci had significantly better post-metastatic OS (P = 0.0056). Multivariate analysis indicated that age, liver metastasis, the number of metastatic foci and time to metastasis (P = 0.013) are independent prognostic factors for OS. After analyzing the impact of different treatment methods, we found that local treatment was an independent protective factor for LM, while local treatment was not associated with a survival benefit for EM disease., Conclusions: The time to metastasis after radical radiotherapy affected the prognosis of NPC patients and local treatment was an independent protective factor that could improve the survival of late metastatic NPC patients., (© 2023. The Author(s).)

Objective: Apolipoprotein E (APOE) loci, including rs429358 (Ɛ4) and rs7412 (Ɛ2), are involved in cardiovascular (CV) health. However, their effect on the CV-protective effect of aspirin remains unknown., Methods: A total of 515 aspirin-treated individuals with existing CV diseases were recruited, and their APOE genotypes, platelet functions and other routine laboratory parameters were assessed when they enrolled. The first major CV events (myocardial infarction, stroke, revascularisation and CV death) and all CV events (major CV events plus unstable angina and transient ischaemic attack) during a mean 5.2-year follow-up period were recorded., Results: After adjusting for age, gender, BMI, lifestyle, lipid profiles and other CV drugs and comorbidities, Ɛ2 carriers were found to exhibit ~80% lower risk of major CV and 60% lower risk of all CV (HR = 0.186, CI: 0.048-0.715, P = 0.014; HR = 0.435, CI: 0.234-0.812, P = 0.009, respectively) than Ɛ2 noncarriers. Furthermore, high incidence of high platelet reactivity assessed by arachidonic acid-induced light transmission aggregometry (23.4 vs. 13.7%, P = 0.038), triglyceride and haemoglobin and low low-density lipoprotein were observed. Ɛ4 carriers had slightly increased cholesterol and hypercholesterolemia incidence relative to Ɛ4 noncarriers., Conclusions: Our results demonstrated that APOE*Ɛ2 carriers can derive additional CV benefit from long-term aspirin treatment. Moreover, it was observed that APOE2 interacts with cyclooxygenase-1 (COX-1) and upregulates its activity. The CV-protective effect of aspirin in Ɛ2 carriers is likely attributed to APOE2 upregulating vascular COX-1-mediated CV protective pathway, together with aspirin partially inhibiting platelet COX-1-mediated platelet aggregation., (© The Author(s) 2022. Published by Oxford University Press on behalf of the British Geriatrics Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Purpose: Cumulative doses of 200 mg/m 2 for concurrent cisplatin (DDP) were indicated by retrospective studies as sufficient in conferring survival benefit for locoregionally advanced nasopharyngeal carcinoma (LA-NPC). We performed an open-label, phase II, randomized, controlled trial to test the noninferiority of a two-cycle 100 mg/m 2 concurrent DDP regimen over three-cycle in patients with low-risk LA-NPC with pretreatment Epstein-Barr virus DNA levels < 4,000 copies/mL., Patients and Methods: Eligible patients were randomly assigned 1:1 to receive two cycles or three cycles concurrent DDP-based chemoradiotherapy. The primary end point was 3-year progression-free survival (PFS). The secondary end points included overall survival, distant metastasis-free survival, locoregional relapse-free survival, etc., Results: Between September 2016 and October 2018, 332 patients were enrolled, with 166 in each arm. After a median follow-up of 37.7 months, the estimated 3-year PFS rates were 88.0% in the two-cycle group and 90.4% in the three-cycle group, with a difference of 2.4% (95% CI, -4.3 to 9.1, P noninferiority = .014). No differences were observed between groups in terms of PFS, overall survival, and the cumulative incidences of locoregional relapse and distant metastasis. Patients in the three-cycle group developed significantly more grade 3-4 mucositis (41 [24.8%] v 25 [15.1%]), hyponatremia (26 [15.8%] v 14 [8.4%]), and dermatitis (9 [5.5%] v 2 [1.2%]). The overall all-grade and grade 3-4 toxicity burdens were heavier in three-cycle group (T-scores, 12.33 v 10.57, P < .001 for all grades; 1.76 v 1.44, P = .05 for grade 3-4). Patients in the three-cycle group also showed more all-grade hearing impairment, dry mouth and skin fibrosis, and impaired long-term quality of life., Conclusion: Intensity-modulated radiotherapy plus two cycles of concurrent 100 mg/m 2 DDP could be an alternative treatment option for patients with low-risk LA-NPC.

Background: To evaluate the prognostic value of the dynamic change in absolute lymphocyte counts (ALCs) and absolute monocyte counts (AMCs) and identify patients with N stage and plasma Epstein-Barr virus (EBV) DNA levels in nasopharyngeal carcinoma (NPC) who are at risk of treatment failure., Methods: A total of 1124 eligible patients with Stage II-IVb NPC treated with concurrent chemoradiotherapy (CCRT) were enrolled. Percentage changes in the ALC (ΔALC%) and AMC (ΔAMC%) were calculated., Results: Patients with high ΔALC% were correlated with poorer 5-year overall survival (OS), progression-free survival (PFS), and distant metastasis-free survival (DMFS) rates than those with low ΔALC%. Likewise, high ΔAMC% was significantly associated with worse outcome than low ΔAMC% (OS, p = 0.001; PFS, p = 0.001; DMFS, p = 0.034). Multivariate analyses revealed that ΔALC% (p = 0.046), ΔAMC% (p = 0.019), and EBV DNA level (p < 0.001) were independent prognostic factors for OS. With respect to PFS, ΔALC% (p = 0.036), ΔAMC% (p = 0.011), N classification (p = 0.016), and EBV DNA level (p < 0.001) were also independent prognosticators. Based on the aforementioned independent risk factors (ΔALC% ≥ 83.33%, ΔAMC% ≥ 40.00%, Stage N2-3, EBV DNA ≥ 4000 copies/ml), patients were divided into three different risk groups (low-risk group [with <1 risk factor], intermediate risk group [with 1-3 risk factors], and high-risk group [with 4 risk factors]) that correlated with disparate risks of death (p < 0.001), disease progression (p < 0.001), and distant metastasis (p < 0.001)., Conclusions: High ΔALC% and ΔAMC% were correlated with poor prognosis in patients with NPC. Risk stratification based on ΔALC%, ΔAMC%, N classification, and plasma EBV DNA levels could provide potential utility for risk-adapted therapeutic strategies for NPC., (© 2021 Wiley Periodicals LLC.)

Rainfall intensity, slope length, and slope gradient are the important factors affecting runoff and sediment yield. In order to quantitatively analyze the effects of rainfall intensity, slope length, and slope gradient on the erosion process of Ansai loess slope in loess hilly and gully region, we analyzed the variation of runoff and sediment yield on Ansai loess with two slope lengths (5, 10 m), three slopes (5°, 10°, 15°) and two rainfall intensities (60, 90 mm·h -1 ) in an indoor simulated rainfall experiment. The results showed that the initial runoff generation time decreased with the increases of slope length, though the overall change was not significant. The initial runoff generation time decreased with the increases of rainfall intensity. Compared with the intensity of 60 mm·h -1 , the initial runoff generation time decreased by 5.7-18 min under the intensity of 90 mm·h -1 . Among them, the runoff initiation time on the slope of 10° was the fastest. With the duration of rainfall, runoff yield rate increased rapidly at first, and then gradually fluctuated around a certain value. The sediment yield rate increased rapidly in a short period of time at the initial stage of runoff generation, and then decreased after reaching the maximum, and being gradua-lly stable. The rates of runoff and sediment yield increased with the increases of slope length and rainfall intensity, but the law of change with slope was not obvious. With the increases of rainfall intensity, slope length and gradient, the total sediment yield increased accordingly. Under the rainfall intensity of 90 mm·h -1 , the slope surface with the length of 10 m and slope of 15° generated rill, leading to the highest total erosion amount (11885.66 g). Under the rainfall intensity of 60 mm·h -1 , the erosion amount per unit area decreased with the increases of slope length, and there was a critical erosion slope length in 5-10 m slope section. Slope length, slope and rainfall intensity all played a promoting role in runoff process. Rainfall intensity, slope length, and their interaction contributed more to runoff yield rate and total erosion amount. Rainfall intensity contributed the most to runoff yield rate, with a contribution rate of 49.8%. The contribution rate of slope length to the total erosion was the largest, which reached 37.8%.

The complex terrain and poor climatic conditions in Bashang area of Hebei Province result in water and soil loss and geological disasters, which pose a serious threat to ecological safety in North China. In order to improve local environmental quality, barren-resistant and fast-growing tree species such as Pinus sylvestris var. mongolica and Larix gmelinii are planted with large areas. However, unreasonable plantation density will lead to inefficient utilization of rainfall and intensify the conflict between forest and water. In this study, we analyzed the effects of five thinning intensities (0, 20%, 40%, 60%, 80%) of P. sylvestris var. mongolica plantation on herbs, litter, soil and overall water-holding capacity, with the aim to provide scientific basis for management of P. sylvestris var. mongolica. The results showed that water-holding rate of herb varied from 47.7% to 90.7%, and that the water-holding capacity of herb decreased with increasing thinning intensity. When the thinning intensity was less than 40%, water-holding capacity decreased slowly, and then decreased rapidly. With the increase of thinning intensity, natural water-holding rate and maximum water-holding rate of undecomposed layer and semi-decomposed layer decreased gradually, with the effective water-holding rate being 60%>40%>20%>80%>0, and the water-holding capacity of semi-decomposed layer being better than that of undecomposed layer. The water-holding capacity of soil decreased gradually with the increases of thinning intensity. Thinning intensity less than 40% promoted water holding capacity. Under different thinning intensities, the total water-holding rate of understory was 8.3%-14.3%, with an order of 20%>0>40%>60%>80%. In view of understory all layers and overall changes, the thinning intensity at 20% in the study area could effectively improve the understory water-holding capacity and achieve better ecological benefits.

To fully understand the changes in the evapotranspiration components in forest ecosystem and their contribution to evapotranspiration at daily scale, we used the hypothesis theory of isotopic steady state and non-steady state combined with the water isotope analyzer system to quantitatively split and compare the evapotranspiration components of Platycladus orientalis ecosystem during the growing season. Results showed that the 18 O of water from different sources during the four mea-surement days (August 5, 8, 10, 11, 2016) all showed surface soil water and oxygen isotope composition (δ S ) > branch water and oxygen isotope composition (δ X ) > atmospheric water vapor oxygen isotopes composition (δ V ), with obvious differences due to the isotope fractionation. Oxygen isotopes composition of soil evaporated water vapor (δ E ) was between -26.89‰～-59.68‰ at the daily scale, showing a pattern of first rising and then decreasing. The oxygen isotopic composition of evapotranspiration water vapor in forest ecosystem (δ ET ) was between -15.99‰～-10.04‰. The oxygen isotopic composition of transpired water vapor under steady state(δ T-ISS ) was between -12.10‰～-9.51‰. The oxygen isotopic composition of transpired water vapor under non-steady state (δ T-NSS ) was between -13.02‰～-7.23‰. δ ET and δ T-NSS had the same changing trend throughout the day at the daily scale, while the trend of δ ET , δ T-ISS and δ T-NSS was approximately the same during 11:00-17:00. In general, the contribution rate of plant transpiration to total evapotranspiration showed that F T-ISS was between 79.1%-98.7%, and F T-NSS was between 88.7%-93.7%. Our results suggested that water consumption through soil evaporation was far less than that of vegetation transpiration in the study area, and that vegetation transpiration dominated forest evapotranspiration.

In the areas with seasonal drought, water is the key factor affecting plant growth and development. Based on long-term continuous observation data, it is of great significance to explore plant water use patterns for vegetation construction in areas with seasonal drought. Taking Platycladus orientalis in Beijing mountainous area as the research object, stable hydrogen and oxygen isotope technique was applied to measure the isotopic composition of water from the soil, plant branches, and precipitation from 2012 to 2017. The relative contribution of soil water from different soil layers to P. orientalis was quantified by the MixSIAR model. The results showed that soil water in the deep layer (40-100 cm) was more stable than that in the shallow layer (0-40 cm). The variation of soil water content and water isotope values in the shallow layer were more obvious due to the effects of evaporation and precipitation. P. orientalis mainly absorbed stable deep soil water, with a relative contribution rate of 55.7%. In the dry season, with the decreases of soil water content, the absorption depth of plants to soil water gradually shifted to the shallow layer. Under conditions of moist, natural condition, mild drought and moderate drought, the relative contribution rates of deep soil water were 59.8%, 57.9%, 54.6%, 52.7%, respectively. To maintain higher transpiration in the wet season, P. orientalis relied more on deep soil water under mild and moderate drought conditions than in the dry season. Under the conditions of moist, natural condition, mild drought and moderate drought, the relative contribution rates of deep soil water were 58.9%, 57.6%, 56.4%, and 57.1%, respectively. The adaptive characteristic of P. orientalis , which adjusts the depth of root water absorption according to soil moisture condition, is of great significance for tree species selection in ecological afforestation and long-term management planning in areas with seasonal drought.

Background: Nasopharyngeal carcinoma (NPC) is a malignancy predominantly associated with infection by the Epstein-Barr virus (EBV). Approximately 12,900 new cases of NPC occur each year, with more than 70% of cases occurring in the east and southeast Asia. NPC is different from ordinary head and neck squamous cell carcinoma due to its particular biological properties and it is highly sensitive to radiotherapy. With the development of RT technology, the 3-year local control rate and survival rates of non-metastatic NPC reached 80-90% in the intensity-modulated RT (IMRT) era. However, whether distant metastatic NPC (de novo mNPC, dmNPC) should receive locoregional RT (LRRT) needs to be clarified., Results: Multivariate analysis identified three independent prognostic factors: Epstein-Barr virus (EBV) DNA, number of metastatic lesions, and number of metastatic organs. Through these factors, all patients were successfully divided into 3 subgroups: low-risk (single metastatic organ, EBV DNA ≤ 25,000 copies/ml, and ≤ 5 metastatic lesions), intermediate-risk (single metastatic organ, EBV DNA > 25,000 copies/ml, and ≤ 5 metastatic lesions), and high-risk (multiple metastatic organs or > 5 metastatic lesions or both). By comparing LRRT and non-LRRT groups, statistical differences were found in OS in the low-risk and intermediate-risk subgroups (p = 0.039 and p = 0.010, respectively) but no significant difference was found in OS in the high-risk subgroup (p = 0.076). Further multivariate analysis of different risk stratifications revealed that LRRT can improve OS of low- and intermediate-risk subgroups., Conclusions: The risk stratification of dmNPC may be used as a new prognostic factor to help clinicians organize individualized LRRT treatment to improve the survival outcomes of dmNPC patients.

Objective: This study aimed to select optimal candidates benefiting from the addition of induction chemotherapy (IC) to concurrent chemoradiotherapy (CCRT) in stage II-IVa nasopharyngeal carcinoma (NPC) based on Epstein-Barr virus (EBV) DNA and nodal maximal standardized uptake values (SUVmax-N) of [ 18 F]-fluorodeoxyglucose positron emission tomography., Patients and Materials: A total of 679 patients diagnosed with stage II-IVa (except N0) NPC were retrospectively included in this study. Overall survival was the primary endpoint. Survival differences between different groups were compared using the log-rank test. The hazard ratio (HR) and 95% confidence interval (CI) were calculated using a multivariable Cox proportional hazards model., Results: Both high levels of EBV DNA (>1500 copies/mL) and SUVmax-N (>12.3) indicated worse survival conditions. All patients were divided into low- and high-risk groups based on these two biomarkers. The risk group was an independent prognostic factor in OS, progression-free survival (PFS), and distant metastasis-free survival (DMFS) (all p-values<0.05). The addition of IC to CCRT was associated with survival improvement in OS, PFS, and DMFS in high-risk patients, while no survival difference was found between CCRT and IC+CCRT in low-risk patients., Conclusions: Our study can help clinicians select stage II-IVa NPC patients who benefit from IC, which is important in guiding individual treatment., (© 2020 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

A water-controlled experiment with four treatments (no rain, half raining, natural raining and double raining) was carried out in a Platycladus orientalis forest. The factors including soil water content (SWC), precipitation, sap flow density ( J s ), leaf area index (LAI), vapor pressure deficit (VPD) were monitored during August 2016 to August 2017. We further analyzed the response of canopy stomatal conductance ( g s ) to changes of SWC. The results showed that the SWC of plots (half, natural and double raining) showed a positive correlation with precipitation, and the range of SWC was 4.9%-16.0%, 7.2%-22.9%, 7.4%-29.6%, respectively. The SWC in the plot with no rain decreased by 50% from August to October. The daily g s reached a peak of 166.64 mmol·m -2 ·s -1 at 14:00 in July, which was significantly higher than other months. A bimodal phenomenon occurred. The daily g s reached a peak of 54.1 mmol·m -2 ·s -1 at 12:00 in January. Under the three rain plots, diurnal variation of g s and SWC showed a negative quadratic correlation. The SWC corresponding to the peak of g s was 8.5%, 12.5% and 18.5%, respectively, close to the annual average SWC. Sensitivity ( δ ) of g s to VPD /reference canopy stomatal conductance ( g sref ) was more than or equal to 0.6 in different water-controlled plots, indicating that soil water condition was more suitable for water demand of P. orientalis . When SWC was between 3.7% and 7.5%, the δ and g sref increased rapidly, indicating that stomata had better regulation ability, and that plant stomata was more sensitive to VPD. When SWC increased to 11%, SWC alteration did not affect the response sensitivity of g sref and g s to VPD. There might be a SWC threshold value for the adaptation of P. orientalis . By closing or reducing stomatal aperture, leaf water potential decreased, P. orientalis could adapt to excessive VPD and avoid excessive transpiration, which was more effective in regulating transpiration.

Objective: Thus far, there is no final conclusion on the treatment of local recurrent nasopharyngeal carcinoma (lrNPC) patients. Herein, we developed a nomogram which combined prognostic biomarkers to predict clinical outcome and guide individual treatment., Materials and Methods: From 2006 to 2016, 303 patients with lrNPC were retrospectively reviewed. Overall survival (OS) was the primary endpoint. The nomogram was established with the significant prognostic factors (P < 0.05) selected by multivariate analysis using Cox regression model. Harrell Concordance Index (C-index), calibration curves, and decision curve analysis (DCA) were applied to evaluate this model., Results: Four independent prognostic factors (age, hypertension, relapsed T (rT) stage, and Epstein-Barr virus DNA) identified from multivariable analysis were included into the nomogram. The C-index of the nomogram was 0.687. The calibration curves for 1-, 3-, and 5-year OS rate showed satisfactory agreements between the predicted and actual values. The decision curve analysis also exhibited a preferable net benefit of this model. All patients were subdivided into three risk groups based on the nomogram. Local treatment was associated with higher OS than palliative chemotherapy alone in the low (P < 0.001) and intermediate-risk groups (P = 0.001). However, no significant difference was observed between different treatment methods in the high-risk group (P = 0.176)., Conclusion: We established the nomogram for patients with lrNPC to predict OS and guide individual treatment, which showed satisfactory performance in accuracy, discrimination capability, and clinical utility., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Plants could maintain growth by foliar water uptake and reverse sap flow under certain conditions, particularly in regions with seasonal drought. This physiological activity is often overlooked, however, leaving a gap in quantitatively understanding the processes and mechanisms underlying water utilization of forest vegetation under drought stress. In this study, with both field comparison experiments and pot experiments, we used heat ratio method with stable isotope technique to monitor a typical plantation tree species, Platycladus orientalis, in the Beijing mountainous area. We aimed to analyze the patterns and the influencing factors of the reverse sap flow occurrence in P. orientalis, to quantify the amount and the replenishment rate of reverse sap flow, and to examine the characteristics and processes of reverse sap flow at different parts of plants. In the field comparison experiment, reverse sap flow was detected at the breast height of stem and in the root in the controlled plot (drought plot) after rainfall. The reverse sap flow of root system was detected later than that in the stem. By contrast, no reverse sap flow was observed in the natural plot. In the pot experiments, the recharge rate of all the groups reached the peak value two hours after the rainfall treatment. Except for the groups of severe and moderate drought, recovery of δD to the original level was observed eight hours after rainfall, and the reverse sap flow on plants generally lasted no more than 24 h. The amount of foliar water uptake and the reverse sap flow to the branches and rhizosphere soil had a negative relationship with the initial soil moisture. The maximum recharge rates for leaves, branches, and rhizosphere soil were (9.5±0.1)%, (5.9±0.3)% and (5.7%±0.6)%, respectively. Different rates and timing of the reverse sap flow were observed at different parts of P. orientalis. Under complex and variable conditions of water supply, it is of great significance to examine the process and mechanism of reverse water movement of plants to better understand its survival and competitive strategies.

Clarifying 18 O isotope composition of leaf water (δ L,b ) would provide theoretical refe-rence for the study of leaf physiology and forest hydrology. We continuously monitored the concentration of atmospheric water vapor (W a ) and 18 O isotope composition of atmospheric water vapor (δ v ) at the canopy of Platycladus lateralis plantation in the mountain area of Beijing. We analyzed the effects of kinetic fractionation coefficients Δ k1 (32%) and Δ k2 (28%) on the prediction of δ L,b by combining the measured leaf water 18 O isotope (δ x ) and δ L,b of P. lateralis. The results showed that the diurnal variation of W a was irregular. Atmospheric relative humidity (RH) showed a "V" shape of diurnal variation, and stomatal conductance (g s ) increased first and then decreased at the diurnal scale. W a , RH, and g s showed a significant negative correlation with δ L,b when isotopes approached a steady-state equilibrium around noon. The kinetic fractionation coefficient Δ k1 and Δ k2 were applied to the Craig-Gordon model to predict δ L,b under the isotopic quasi-steady-state condition. The results showed that the predicted values of Δ k2 approached the observed values of δ L,b . This result indicated that the application of Δ k2 to the model was more consistent with the change of water isotope concentration in the leaves of P. lateralis in the mountain area of Beijing. These results would improve our understanding of water isotope enrichment model and evapotranspiration resolution model in leaves.

Water availability is the key factor limiting plant growth in arid regions. Populus simonii is a typical shelterbelt tree species in Zhangbei County, Hebei Province, with an important role in constructing ecological barrier. With stable isotope technique, graphical method, and multiple linear mixing model, we analyzed water sources and water use strategies of P. simonii in different growth periods with four different degrees of degradation (non-degraded, slightly degraded, modera-tely degraded and severely degraded) in Zhangbei County. Results would help improve our understanding on the cause and mechanism of the large-scale degradation of P. simonii in this area. The results showed that water sources of P. simonii in the early growth stage (May-June) from all four degradation degrees were relatively simple. P. simonii mainly used soil water in 0-40 cm, with the utilization rates being 34.2%, 50.1%, 41.6%, and 55.7% for the four degradation degrees, respectively. At the middle growth stage (July-August), non-degraded P. simonii utilized soil water from layers of 200-280 cm and 280-400 cm, with utilization rates of 20.2% and 30.9%, respectively. Soil water at 200-280 cm and 280-400 cm layers was utilized by slightly degraded poplar, with the contribution rates of each layer being 33.2% and 27.9%, respectively. Moderately degraded P. simonii utilized soil water from the depths of 0-40 cm and 40-120 cm, with the rates of 30% and 26.9%, respectively. Water utilization rate of severely degraded P. simonii to 0-40 cm depth was 55.4%. At the late growth stage (September-October), water sources of non-degraded P. simonii transferred to the upper-middle soil layers, with the utilization rate of 0-40 cm, 40-80 cm, and 80-120 cm being 23.3%, 17.2%, and 16.5%, respectively. The utilization rate of the slightly degraded P. simonii was 35.7% at 0-40 cm and 20.6% at 80-200 cm. The moderately and severely degraded P. simonii mainly utilized soil water at 0-40 cm layer, with the contribution rates of soil water being 43.7% and 51.8%, respectively. With the exacerbation of degradation, the main water source of P. simonii gradually transferred from deep to surface soil water.

Analysis of plant photosynthesis and post-photosynthetic fractionation can improve our understanding of plant physiology and water management. By measuring δ 13 C in the atmosphere, and δ 13 C of soluble compounds in leaves and branch phloem of Platycladus orientalis, we examined discrimination pattern, including atmosphere-leaf discrimination during photosynthesis (ΔC a-leaf ) and leaf-twig discrimination during post-photosynthesis (ΔC leaf-phlo ), in response to changes of soil water content (SWC) and atmospheric CO 2 concentration (C a ). The results showed that ΔC a-leaf reached a maximum of 13.06‰ at 95%-100% field water-holding capacity (FC) and C a 400 μmol·mol -1 , and a minimum of 8.63‰ at 35%-45% FC and C a 800 μmol·mol -1 . Both stomatal conductance and mesophyll cell conductance showed a significant linear positive correlation with ΔC a-leaf , with a correlation coefficient of 0.43 and 0.44, respectively. ΔC leaf-phlo was not affected by SWC and C a . Our results provide mechanism of carbon isotopes fractionation and a theoretical basis for plant survival strategies in response to future climate change.

Based on stable carbon isotope, we quantitatively partitioned ecosystem respiration in a Platycladus orientalis forest in the west mountainous area of Beijing. Results from this study could lay the foundation for carbon exchange research in forest ecosystems of this region. The spectroscopy technique was used to continuously measure CO 2 concentrations and δ 13 C values at different height of the forest. Soil and branch chambers were used for measuring nighttime δ 13 C values in underground and aboveground respiration, and then the proportions of respiration components were calculated. Combined with soil respiration efflux measurement, ecosystem respiration was then quantitatively partitioned. The results showed that δ 13 C values of respiratory components fluctuated, which ranged from -31.74‰ to -23.33‰ in aboveground respiration of plants and from -32.11‰ to -27.74‰ in soil respiration. The δ 13 C values of ecosystem respiration was at the middle of those ranges. Soil respiration averaged 1.70 μmol·m -2 ·s -1 at night, accounting for 47%-91% of ecosystem respiration. Aboveground respiration averaged 0.72 μmol·m -2 ·s -1 , contributing less to ecosystem respiration. Daytime respiration based on isotope mixing model calculation had greater variability than that based on temperature response model, with a mean value of 2.31 μmol·m -2 ·s -1 and 2.28 μmol·m -2 ·s -1 , respectively.

Objective: To compare the survival outcomes brought by different radiation dose schedules to bone lesions and different chemotherapy regimens in bone metastatic nasopharyngeal carcinoma (NPC). Background: The current treatment strategy for bone metastatic NPC patients was empirically given and poorly studied before. It is of necessity to optimize the treatment for bone metastasis to enhance the therapeutic effect and increase the proportion of long-term survived patients. Methods: Three hundred patients who received chemoradiotherapy from 2002 to 2018 were involved in the study. Demographics, laboratory results, and detailed treatment plans were recorded. Radiotherapy plans were classified into three categories based on the intensity, and the survival analysis was performed using log-rank test. Multivariable analysis was made by the Cox proportional regression model. Results: Patients who received 60-75 Gy/30-35 fractions of radiation to the metastatic bones had significantly longer bone relapse-free survival (BRFS) (HR, 0.53, 95% CI, 0.37-0.78, P = 0.003), overall survival (OS) (HR, 0.63, 95% CI, 0.46-0.84, P = 0.007), and progression-free survival (PFS) (HR, 0.80, 95% CI, 0.67-0.95, P = 0.041). The administration of paclitaxel, cisplatin and 5-fluorouracil regimen was also associated with better BRFS (HR, 0.27, 95% CI, 0.10-0.75, P = 0.007), PFS (HR, 0.60, 95% CI, 0.42-0.87, P = 0.007), and OS with borderline significance (HR, 0.54, 95% CI, 0.29-1.03, P = 0.058). In multivariable analysis, the post-treatment EBV DNA level and radical radiation dose were proved as independent prognostic factors for both BRFS and OS. Conclusions: Radiotherapy to metastatic bones with palliative dose prescription should not be considered in bone metastatic NPC patients. TPF chemotherapy regimen might help to improve the survivals in NPC patients but failed to be an independent protective factor., (Copyright © 2020 Li, Jia, Sun, Guo, Liu, Liu, Yan, Luo, Sun, Guo, Mo, Tang, Chen and Mai.)

As an important component of terrestrial ecosystem carbon cycle, soil respiration is a hot topic in the studies of carbon cycle. The temperature sensitivity (Q 10 ) of soil respiration is a critical index to estimate the effects of global warming on soil respiration. Understanding Q 10 of different vegetation types is of important significance for assessing the carbon budget of forest ecosystems. We examined soil respiration and its temperature sensitivity in three typical forests (Pinus tabuliformis, Platycladus orientalis, and Quercus variabilis) in the Beijing mountainous area by measuring the soil physical and chemical properties, soil temperature, soil moisture, and soil respiration rate (R s ) during the growing season. The results showed that R s of three typical vegetation types showed a similar trend with changes of soil temperature and humidity, which showed a unimodal pattern, with minimum value (0.45 μmol·m -2 ·s -1 ) in early April and maximum value (3.95 μmol·m -2 ·s -1 ) in early July. There were significant differences in R s and Q 10 values among the three vegetation types. Soil temperature and humidity were the important factors affecting soil respiration, together they could explain the seasonal variation of soil respiration rate from 48.1% to 56.7%. The range of Q 10 value was between 2.05 and 3.19. There was a significant negative correlation between soil organic carbon content and Q 10 under each vegetation type (R 2 >0.9). Vegetation type, elevation, and soil organic carbon content were important drivers for the variation of Q 10 .

Water use efficiency (WUE) is an important index to evaluate plant drought resistance. Studying the dynamics of WUE and its influencing factors can provide reference for the vegetation restoration in Beijing mountainous area. We measured WUE of Platycladus orientalis in growing season and investigated the influence of meteorological factors, soil factors, and atmospheric CO 2 concentration on WUE, based on the stable carbon isotope techniques. The results showed that: 1) The short-term WUE decreased and then increased in the growing season, with minimum value (2.69 mmol·mol -1 ) in July and maximum value (13.88 mmol·mol -1 ) in October. 2) The vapor pressure deficit (VPD) had the most significant impacts on WUE, followed by air temperature (T a ), soil moisture (M s ), relative humidity (RH), and atmospheric CO 2 concentration (C a ), explaining 89.7% of the total variance. Solar radiation (R a ) and wind speed (W s ) had no impacts on WUE. 3) VPD and T a are the most two important factors influencing short-term WUE, explaining 53.9% of the total variance. The effects of VPD on short-term WUE was higher than that of T a . M s and RH were the second important factors of the short-term WUE, explaining 25.4% of the total variance. The effects of M s on short-term WUE was higher than that of RH. C a had little effect on the short-term WUE and could explain 10.3% of the total variance.

In Zhangbei County, Hebei Province, poplar-dominated shelterbelts are degraded to different extents. Water availability is the main limiting factor for plant survival in arid areas. The purpose of this study was to reveal the relationship between water availability and poplar degradation. Based on the hydrogen and oxygen stable isotope techniques, we explored the water sources of Populus simonii under different degradation degrees by comparing the isotopic values of P. simonii xylem water with that in potential water source, and calculated the utilization ratio of each water source. The results showed that the water sources of poplar trees varied with degradation degree. The water sources of P. simonii gradually transferred from the deep layer to the surface layer with the increases of degradation. P. simonii with no degradation mainly absorbed soil water in the range of 320-400 cm, with the utilization rate being 25.1%. P. simonii with slight degradation mainly used soil water at depth of 120-180, 180-240 and 240-320 cm. The total utilization rate of three layers was close to 50.0%, with less utilization of water from other layers. The moderately degraded P. simonii mainly used soil water at depth of 20-40, 40-60 and 60-80 cm. The utilization rate of each layer was 17.5%-20.9%, and the contribution rate of soil water under 120 cm was less than 10.0%. The severely degraded P. simonii mainly used water from surface soil layer (0-20 cm), with the utilization rate being 30.4%, which was significantly higher than that of other water sources. The water sources of poplar shelter forests were gradually shallower during the process of degradation. However, the low soil water content in the shallow layer could not meet the normal water demand of poplar, which would accelerate the degradation and even decline of poplar.

This research investigated shelterbelt structure indices using the standard sampling method, to study the dynamic changes of different tree species including Ulmus pumila, Populus simonii and Pinus tabuliformis in the depression area in Xiaobazi Township of Fengning County, Hebei Province, China. The results showed that the average age of U. pumila, P. simonii and P. tabuliformis pure forests was 10 years in this area. The average DBH and tree height of P. simonii pure forest were 2.3 times and 3.8 times as those of U. pumila pure forest, as well as, 2.3 times and 3.0 times as those of P. tabuliformis pure forest, respectively. The average DBH, tree height, LAI and height of first live branch of P. simonii pure forest were significantly larger than those of U. pumila pure forest and P. tabuliformis pure forest. Compared with P. simonii mixed forest, the stand density of P. simonii pure forest was 10.8% higher, average DBH of pure forest was 5.2% lower, and average tree height was 11.3% lower. Compared with U. pumila mixed forest, the stand density of U. pumila pure forest was 6.6% higher, average DBH and tree height of pure forest were 7.8% and 14.2% lower. Compared with P. tabuliformis mixed forest, the stand density of P. tabuliformis pure forest was 4.9% larger, but average DBH and tree height were 29.3% and 31.8% lower, respectively. The average DBH, tree height of different forest types showed significant negative correlation with the stand density. Average LAI showed significant positive correlation with density and height of first live branch, and significant negative correlation with the DBH, tree height. There was a significant positive relationship between the average height of first live branch and stand density. The increments of DBH and tree height of coniferous and broad-leaved mixed forest were significantly higher than those of coniferous pure forest. The comprehensive growth potential of the shelterbelts tended to increase, and the lateral growth potential on the whole exhibited a declining trend.

Canopy stomatal conductance (g s ) is an important biological parameter to measure water vapor flux in canopy atmosphere interface. Exploring characteristics of canopy stomatal conductance and its responses to environmental factors can offer theoretical evidence for conducting mechanism based study of vapor exchange process in forest canopy. SF-L thermal dissipation probe was adopted to measure sap flow density (J s ) of Platycladus orientalis in 2014. The environmental factors including photosynthetically active radiation (PAR), vapor pressure deficit (VPD) and air temperature (T) were simultaneously observed. The canopy stomatal conductance was calculated, and the responses of g s to environmental factors were analyzed. The results showed that the daily variation of sap flow density was of two peak pattern curve, and the J s in growing season was higher than in non-growing season. And the bigger DBH was, the higher J s would be. The daily variation of canopy stomatal conductance was similar to the canopy transpiration of per leaf area (E L ), which was of two peak pattern curve. The g s and E L in growing season were higher than those in non growing season. The canopy stomatal conductance and air temperature presented parabolic relation, and g s reached peak valley at around 10 ℃. Taking the value of 400 μmol·m -2 ·s -1 as the PAR thre shold, when PAR was under this threshold, g s was positively correlated with PAR. When PAR was beyond this threshold, the correlation between g s and PAR would be small. The relationship between canopy stomatal conductance and vapor pressure deficit was negative logarithmic function. As VPD increasing, g s decreased gradually. Higher air temperature and photosynthetically active radiation, and lower vapor pressure deficit contributed to higher canopy stomatal conductance of P. orientalis and could promote greater canopy transpiration.

In this study, we focused on Platycladus orientalis, a widely distributed tree species in Beijing western mountains area, and precisely determined its foliar water use efficiency (including instantaneous water use efficiency derived from gas exchange and short-term water use efficiency obtained on carbon isotope model) by carefully considering the discrepancies of meteorological factors and atmosphere CO 2 concentration and δ 13 C among different canopy heights, hoping to provide theoretical basis for carbon sequestration and water loss in regional forest ecosystem, and offer technical support for regional forest management and maintenance. The results showed that the foliar instan-taneous water use efficiency tended to increase with the increasing canopy height, following the order of the upper canopy > the middle canopy > the lower canopy. A variety of meteorological factors synergistically influenced stomatal movement, and stomatal conductance would in turn have an effect on foliar instantaneous water use efficiency. Foliar short-term water use efficiency also increased with increasing canopy height, following the order of the upper canopy > the middle canopy > the lower canopy. The differences of foliar short-term water use efficiency among different heights could be explained by discrepancies of environmental drivers and atmosphere CO 2 concentration and δ 13 C. Platycladus orientalis leaves in upper canopy adapted to ambient condition by improving water use efficiency.

Soil-vegetation-atmosphere continuum (SPAC) is one of the important research objects in the field of terrestrial hydrology, ecology and global change. The process of water and carbon cycling, and their coupling mechanism are frontier issues. With characteristics of tracing, integration and indication, stable isotope techniques contribute to the estimation of the relationship between carbon sequestration and water consumption in ecosystems. In this review, based on a brief introduction of stable isotope principles and techniques, the applications of stable isotope techniques to water and carbon exchange in SPAC using optical stable isotope techniques were mainly explained, including: partitioning of net carbon exchange into photosynthesis and respiration; partitioning of evapotranspiration into transpiration and evaporation; coupling of water and carbon cycle at the ecosystem scale. Advanced techniques and methods provided long-term and high frequency measurements for isotope signals at the ecosystem scale, but the issues about the precision and accuracy for measurements, partitioning of ecosystem respiration, adaptability for models under non-steady state, scaling up, coupling mechanism of water and carbon cycles, were challenging. The main existing research findings, limitations and future research prospects were discussed, which might help new research and technology development in the field of stable isotope ecology.

This research employed off-axis integrated cavity output spectroscopy technique to observe CO 2 concentration and δ 13 C values of planted Platycladus orientalis in Beijing mountainous area. We compared the variation between CO 2 concentration and δ 13 C values in the plantation at different heights observed by every 0.5 h to explore how the CO 2 concentration and δ 13 C values responded to the meteorological factors. The results showed that the CO 2 concentration showed the pattern of "first decreased and then increased" after sunrise. The lowest value (352.5 μmol·mol -1 ) appeared at 16:00-16:30, while the maximum value (402.0 μmol·mol -1 ) was observed at about 5:00. However, the change of δ 13 C value was not significant and regular, which increased firstly and then decreased in the surface layer while opposite for the canopy. Atmospheric CO 2 concentration decreased with the increasing height. In the height of 0, 2, 5, 8, 12.5 and 18 m, the average daily value was 386.5, 369.9, 368.2, 367.8, 367.9 and 367.9 μmol·mol -1 , respectively. In contrast, the δ 13 C values tended to rise correspondingly with height with the average daily value being -16.0‰, -13.7‰, -13.5‰, -13.5‰, -13.1‰ and -13.3% at 0, 2, 5, 8, 12.5 and 18 m, respectively. The stepwise regression analysis showed that temperature and humidity were the main factors for the changes of atmospheric CO 2 concentration and δ 13 C values. The saturated vapor pressure difference (VPD) affected the concentration of CO 2 in the forest and wind speed could affect it on the canopy. However, soil moisture, soil electric conductivity and net solar radiation affected the CO 2 concentration and δ 13 C values in surface layer. All these environmental factors influenced CO 2 concentration and δ 13 C values through their influences on the photosynthesis and respiration.

Water is the key factor limiting plant growth in seasonal arid area. In order to analyze the water sources of community plant (Platycladus orientalis, Vitex negundo var. heterophylla, Broussonetia papyrifera and Lespedeza bicolor) in Beijing mountainous area, we measured hydrogen and oxygen stable isotope ratio (δD and δ 18 O) values of their xylem water and potential water sources. The results showed the four species had different water sources. P. orientalis mainly absorbed water from 40-60, 60-80 and 80-100 cm soil layers, and the utilization ratio of the three layers was 23.3%-25.9%. It still grabbed water from 0-20 and 20-40 cm soil layers with the utilization ratio of 12.3% and 13.0%, respectively. V. negundo var. heterophylla mainly absorbed 60-80 and 80-100 cm depth soil water, and the utilization rate was 51.9% and 25.2%, respectively, while it barely absorbed water in other soil layers. B. papyrifera mainly absorbed 0-20 and 20-40 cm depth soil water, and the utilization rate was 47.5% and 36.8%, respectively. L. bicolor used the water from five layers, and the utilization ratio of 0-20, 20-40 and 40-60 cm layer was 21.4%-22.8%, and that of 60-80 and 80-100 cm layer was 15.2%-18.3%, respectively. The competition was higher in mixed forest of P. orientalis and L. bicolor because they had similar water sources. It was better to mix V. negundo var. heterophylla and B. papyrifera because their water sources were complementary. The results could provide reference for the best combination of plant species to restore the damaged ecological environment.

The determination of plant foliar water use efficiency will be of great value to improve our understanding about mechanism of plant water consumption and provide important basis of regional forest ecosystem management and maintenance, thus, laboratory controlled experiments were carried out to obtain Platycladus orientalis sapling foliar water use efficiency under five different soil water contents, including instantaneous water use efficiency (WUE gs ) derived from gas exchange and short-term water use efficiency (WUE cp ) caculated using carbon isotope model. The results showed that, controlled by stomatal conductance (g s ), foliar net photosynthesis rate (P n ) and transpiration rate (T r ) increased as soil water content increased, which both reached maximum va-lues at soil water content of 70%-80% field capacity (FC), while WUE gs reached a maximum of 7.26 mmol·m -2 ·s -1 at the lowest soil water content (35%-45% FC). Both δ 13 C of water-soluble leaf and twig phloem material achieved maximum values at the lowest soil water content (35%-45% FC). Besides, δ 13 C values of leaf water-soluble compounds were significantly greater than that of phloem exudates, indicating that there was depletion in 13 C in twig phloem compared with leaf water-soluble compounds and no obvious fractionation in the process of water-soluble material transportation from leaf to twig. Foliar WUE cp also reached a maximum of 7.26 mmol·m -2 ·s -1 at the lowest soil water content (35%-45% FC). There was some difference between foliar WUE gs and WUE cp under the same condition, and the average difference was 0.52 mmol·m -2 ·s -1 . The WUE gs had great space-time variability, by contrast, WUE cp was more representative. It was concluded that P. orientalis sapling adapted to drought condition by increasing water use efficiency and decreasing physiological activity.

Water use efficiency (WUE) is different among species and regions. Few literatures have been reviewed related to long-term WUE of Platycladus orientalis in mountainous areas of Beijing, China. Tree-ring δ 13 C of P. orientalis was used to determine the long-term variation of annual intrinsic water use efficiency (WUE i ) and its response to environmental change. Combining with quantification of tree-ring width, the relationship between net carbon sequestration and WUE i of P. orientalis was eventually explored. The results showed that mean annual temperature increased with the increase of time from 1918 to 2013, whereas annual precipitation fiercely fluctuated. Tree-ring δ 13 C decreased and WUE i increased over time. WUE i was positively related and more sensitive to air temperature increasing than temperature decreasing. Correlation between WUE i and fluctuated annualprecipitation was ambiguous, which indicated the precipitation was not the main factor affecting WUE i . The de-trend tree-ring width of P. orientalis increased initially and then decreased, especially in recent 20 years. According to the correlation between WUE i and environmental factors, temperature resulted in stomatal conductance (g s ) decreasing, which caused a reduction in evapotranspiration and an increase in respiratory loss, leading to the increase of WUE i and a down trend in net carbon sequestration and tree growth.

In order to explore the variation of CO2 concentration and soil respiration in soil profile, the nondispersive infrared (NDIR) spectroscopy technique was applied to continually estimate the soil CO2 concentration in different soil layers (the humus horizon, A-, B-, C-horizon) in situ. The main instrument used in this experiment was silicon-based nondispersive infrared sensor, which could work in severe environment. We collected the Measurement value by NDIR spectroscopy technique throughout 2013. The values of soil carbon flux in different soil layers were calculated based on the model of gradient method and calibrated by measuring with an automated soil CO2 efflux system (LI-8100). The results showed that: a vertical gradient for the carbon dioxide concentration in soil profile was found, and the concentration was highest in the deepest soil horizon. Moreover, A linear correlation between the soil CO2 effluxes was calculated based on model and measurement, and the model prediction correlation coefficient was 0.9069, 0.7185, 0.8382, and 0.9030 in the H-, A-, B-, and C-horizon, respectively. The roots of mean square error (RMSE) were 0.2067, 0.1041, 0.0156, and 0.0096 in the H-, A-, B-, and C-horizon, respectively. These results suggest that the gradient method based on the NDIR spectroscopy technique can be successfully used to measure soil CO2 efflux in different soil layers, which reveal that diffusion and convection transport CO2 between the soil layers. It is a promising sensor for detecting CO2 concentration in soil profile, providing the basic data for calculating the global carbon in soil profile.

In this study, a novel column design with a round cross-section was proposed to be suitable for a transverse electric field (EF). Additionally, two beads for entropic interaction chromatography (EIC) were prepared by grafting glycidyl methacrylate onto Toyopearl HW-65F (T65F) beads. Solute partitioning was then investigated to elucidate the role of graft polymerization with and without an EF. In a T65F column, solute partitioning was attributed to the distinct pore structure in the beads and was governed by pore flow. Under EF, partition coefficients (Kp) for solutes decreased with increasing EF strength. In the two EIC columns, a decrease of Kp was also observed without an EF while the fractionation windows were extended. It was more pronounced in the EIC column with a high grafting density (T65F-H). This was explained by the decrease in the effective pore size of solutes caused by the steric hindrance of polymer chains. Under an EF, the solutes showed different partitioning behaviours in the T65F-H column. With increasing EF strength, Kp for vitamin B12 and myoglobin was decreased. In contrast, Kp for large solutes increased as a result of concentration polarization on the bead surface. Both behaviors were related to the modulation of graft polymerization to residual charge on the matrix and the pore size of the solutes., (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A novel chromatographic medium for high-capacity protein adsorption was fabricated by grafting dextran (40kDa) onto the pore surfaces of superporous agarose (SA) beads. The bead was denoted as D-SA. D-SA, SA and homogeneous agarose (HA) beads were modified with sulfopropyl (SP) group to prepare cation exchangers, and the adsorption and uptake of lysozyme on all three cation-exchange chromatographic beads (SP-HA, SP-SA and SP-D-SA) were investigated at salt concentrations of 6-50mmol/L. Static adsorption experiments showed that the adsorption capacity of SP-D-SA (2.24mmol/g) was 78% higher than that of SP-SA (1.26mmol/g) and 54% higher than that of SP-HA (1.45mmol/g) at a salt concentration of 6mmol/L. Moreover, salt concentration had less influence on the adsorption capacity and dissociation constant of SP-D-SA than it did on SP-HA, suggesting that dextran-grafted superporous bead is a more potent architecture for chromatographic beads. In the dynamic uptake of lysozyme to the three cation-exchange beads, the D(e)/D(0) (the ratio of effective pore diffusivity to free solution diffusivity) values of 1.6-2.0 were obtained in SA-D-SA, indicating that effective pore diffusivities of SP-D-SA were about two times higher than free solution diffusivity for lysozyme. At 6mmol/L NaCl, the D(e) value in SA-D-SA (22.0x10(-11)m(2)/s) was 14.4-fold greater than that in SP-HA. Due to the superior uptake kinetics in SA-D-SA, the highest dynamic binding capacity (DBC) and adsorption efficiency (the ratio of DBC to static adsorption capacity) was likewise found in SP-D-SA. It is thus confirmed that SP-D-SA has combined the advantages of superporous matrix structure and drafted ligand chemistry in mass transport and offers a new opportunity for the development of high-performance protein chromatography.

Aim: To compare the differences of pharmacological characteristics of the endothelial target for acetylcholine (ETA) between rat aorta and tail artery., Methods: Differences in the endothelium-dependent relaxation induced by acetylcholine (ACh: 10(-8) - 10(-4) mol/L) were studied using isolated rat tail artery helical strips and aortic rings, so that the pharmacological characteristics of ETA in small artery can be observed., Results: ACh-induced endothelium-dependent relaxation was observed both in rat tail artery strips and in aortic rings precontracted with potassium chloride (60 mmol/L) in a concentration-dependent manner. In tail artery this effect was partially blocked by L-N(omega)-Nitro-arginine methyl ester (L-NAME: 10(-4) mol/L) or methylene blue (MB: 10(-5) mol/L), together with indomethacin (Indo: 10(-4) mol/L), but in aorta it was completely blocked by L-NAME or MB., Conclusion: It is different of the pharmacological characteristics of ETA between big artery and small artery. A non-NO and non-PGI2 relaxing factor, together with nitric oxide (NO) and prostacyclin (PGI2), mediates endothelium-dependent vasorelaxation induced by ACh in small artery, but NO may be the principal endothelial vasodilator substance in big artery.