Description: Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1989

Description: This thesis studies mixing and convection in a rectangular basin driven by a specified heat flux at the surface. A numerical model is constructed for this purpose. The main focus of the study is on the density and circulation structure resulting from the thermal forcing. In chapter two, a simple vertical one-dimensional model is developed to examine the mixing processes under a given surface heat flux. In order to simulate strong vertical mixing in the region where stratification is unstable, turbulent processes are modeled by a convective overturning parameterization of eddy viscosity and diffusivity. The results show that the density structure is strongly affected by the convective overturning adjustment as surface cooling prevails, and the resulting density field is nearly depth independent. In chapter three, a more complicated two-dimensional model is constructed to simulate mixing and circulation in a vertical rectangular basin with rigid boundaries. The aspect ratio of the basin ranges from 1 to 0.001 and Rayleigh number from 104 to 2 x 1012. It is found that the circulation pattern is dominated by these two important numbers. The roles of density overturning and density-momentum overturning mixing are further investigated. The results show that the convective overturning not only homogenizes the density field in the unstably stratified region but also contributes to increase the circulation. A crude scale analysis of the system shows that the characteristics of the density and momentum fields from the analysis agree well with the numerical results.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1992

Description: This study concerns the barotropic interactions between a mesoscale eddy and a straight monotonic bottom topography. Through simple to relatively complicated modeling effort, some of the fundamental properties of the interaction are investigated. In chapter two, the fundamental aspects of the interaction are examined using a simple contour dynamics model. With the simplest model configuration of an ideal vortex and a step topography, the basic dynamical features of the observed oceanic eddy-topography interaction are qualitatively reproduced. The results consist of eddy-induced cross-topography exchange, formation of topographic eddies, eddy propagation and generation of topographic waves. In chapter three, a more complicated primitive equation model is used to investigate a mesoscale eddy interacting with an exponential continental shelf/slope topography on both f and β-planes. The f-plane model recasts the important features of chapter two. The roles of the eddy size and strength and the geometry of topography are studied. It is seen that the multiple anticyclonic eddy-slope interactions strongly affect the total cross-slope volume transport and the evolution of both the original anticyclone and the topographic eddy. Since a cyclone is trapped at the slope and eventually moves on to the slope, it is most effective in causing perturbation on the shelf and slope. The responses on the shelf and slope are mainly wavelike with dispersion relation obeying that of the free shelf-trapped wave modes. On the β-plane, the problem of an eddy colliding onto a continental shelf/slope from a distance with straight or oblique incident angles is investigated. It is found that the straight eddy incident is more effective in achieving large onslope eddy penetration distance than the oblique eddy incident. The formation of a dipole-like eddy pair consisting of the original anticyclone and the topographic cyclone acts to suppress the eddy decay due to long Rossby wave radiation. A weak along-slope current near the edge of the slope is found, which is part of a outer slope circulation cell originated from the Rossby wave wake trailing the propagating eddy. Model-observation comparisons in_chapter four show favorable qualitative agreement of the model results with some of the observed events in the eastern U.S. continental margins and in the Gulf of Mexico. The model results give dynamical interpretations to some observed features of the oceanic eddy-topography interactions and provide enlightening insight into the problem.

Description: Free nitrous acid (FNA), which is the protonated form of nitrite and inevitably produced during biological nitrogen removal, has been demonstrated to strongly inhibit the activity of polyphosphate accumulating organisms (PAOs). Herein we reported an efficient process for wastewater treatment, i.e., the oxic/anoxic/oxic/extended-idle process to mitigate the generation of FNA and its inhibition on PAOs. The results showed that this new process enriched more PAOs which thereby achieved higher phosphorus removal efficiency than the conventional four-step (i.e., anaerobic/oxic/anoxic/oxic) biological nutrient removal process (41 ± 7% versus 30 ± 5% in abundance of PAOs and 97 ± 0.73% versus 82 ± 1.2% in efficiency of phosphorus removal). It was found that this new process increased pH value but decreased nitrite accumulation, resulting in the decreased FNA generation. Further experiments showed that the new process could alleviate the inhibition of FNA on the metabolisms of PAOs even under the same FNA concentration. Scientific Reports 5 doi: 10.1038/srep08602

Description: Background: Necrosis of alveolar macrophages following Mycobacterium tuberculosis infection has been demonstrated to play a vital role in the pathogenesis of tuberculosis. Our previous study demonstrated that Wnt/β-catenin signaling was able to promote mycobacteria-infected cell apoptosis by a caspase-dependent pathway. However, the functionality of this signaling in the necrosis of macrophage following mycobacterial infection remains largely unknown. Methods: Murine macrophage RAW264.7 cells were infected with Bacillus Calmette-Guerin (BCG) in the presence of Wnt/β-catenin signaling. The necrotic cell death was determined by cytometric assay and electronic microscopy; the productions of reactive oxygen species (ROS) and reduced glutathione (GSH) were measured by a cytometric analysis and an enzyme-linked immunosorbent assay, respectively; and the activity of poly (ADP-ribose) polymerase 1 (PARP-1)/apoptosis inhibition factor (AIF) signaling was examined by an immunoblotting assay. Results: The BCG can induce RAW264.7 macrophage cells necrosis in a dose- and time-dependent manner along with an accumulation of reactive oxygen species (ROS). Intriguingly, an enhancement of Wnt/β-catenin signaling shows an ability to reduce the mycobacteria-induced macrophage necrosis. Mechanistically, the activation of Wnt/β-catenin signaling is capable of inhibiting the necrotic cell death in BCG-infected RAW264.7 cells through a mechanism by which the Wnt signaling scavenges intracellular ROS accumulation and increases cellular GSH concentration. In addition, immunoblotting analysis further reveals that Wnt/β-catenin signaling is capable of inhibiting the ROS-mediated cell necrosis in part through a PARP-1/AIF- dependent pathway. Conclusions: An activation of Wnt/β-catenin signaling can inhibit BCG-induced macrophage necrosis by increasing the production of GSH and scavenging ROS in part through a mechanism of repression of PARP-1/AIF signaling pathway. This finding may thus provide an insight into the underlying mechanism of alveolar macrophage cell death in response to mycobacterial infection.

Description: Article Psoriasis is a chronic inflammatory disease affecting up to 3% of the population. Here, Zuo et al. perform exome array analysis, identify single-nucleotide polymorphisms at 15 new loci, implicating several biological pathways in psoriasis risk and disease heritability. Nature Communications doi: 10.1038/ncomms7793 Authors: Xianbo Zuo, Liangdan Sun, Xianyong Yin, Jinping Gao, Yujun Sheng, Jinhua Xu, Jianzhong Zhang, Chundi He, Ying Qiu, Guangdong Wen, Hongqing Tian, Xiaodong Zheng, Shengxiu Liu, Wenjun Wang, Weiran Li, Yuyan Cheng, Longdan Liu, Yan Chang, Zaixing Wang, Zenggang Li, Longnian Li, Jianping Wu, Ling Fang, Changbing Shen, Fusheng Zhou, Bo Liang, Gang Chen, Hui Li, Yong Cui, Aie Xu, Xueqin Yang, Fei Hao, Limin Xu, Xing Fan, Yuzhen Li, Rina Wu, Xiuli Wang, Xiaoming Liu, Min Zheng, Shunpeng Song, Bihua Ji, Hong Fang, Jianbin Yu, Yongxin Sun, Yan Hui, Furen Zhang, Rongya Yang, Sen Yang, Xuejun Zhang

Description: The purpose of this study was to compare the efficacy and tolerability of the Ahmed glaucoma valve (AGV) implant and the Baerveldt implant for the treatment of refractory glaucoma.

Description: Article Whether microRNA processing mediated by Dicer is regulated in a cell-cycle-dependent manner is unknown. Here, Chen et al. show that Cyclin D1, which is important in the control of the cell cycle, regulates the expression of Dicer, and that Cyclin D1 and Dicer expression levels correlate in breast cancer. Nature Communications doi: 10.1038/ncomms3812 Authors: Zuoren Yu, Liping Wang, Chenguang Wang, Xiaoming Ju, Min Wang, Ke Chen, Emanuele Loro, Zhiping Li, Yuzhen Zhang, Kongming Wu, Mathew C. Casimiro, Michael Gormley, Adam Ertel, Paolo Fortina, Yihan Chen, Aydin Tozeren, Zhongmin Liu, Richard G. Pestell

Description: Water, Vol. 9, Pages 865: Cyanobacterial Nitrogen Fixation Influences the Nitrogen Removal Efficiency in a Constructed Wetland Water doi: 10.3390/w9110865 Authors: Xiaodong Zhang Xin Jia Liang Yan Jinzhi Wang Xiaoming Kang Lijuan Cui Nitrogen removal efficiency in constructed wetlands (CW) is influenced by multiple environmental factors. However, little is known about the role of cyanobacterial nitrogen fixation in affecting nitrogen removal efficiency. This study investigated how cyanobacterial nitrogen fixation affects the efficiency, at which a CW removes nitrogen from an associated artificial lake (AL) in Beijing. For this purpose, we measured cell densities of N-fixing and non-N-fixing cyanobacteria, the aquatic nitrogen fixation rate (RNfix), and the concentration of various nitrogen fractions over the growing season (April–November) of 2014 in both AL and CW. We found that the removal of particulate organic nitrogen (PON) contributed to >90% of the total nitrogen removal in the CW. The removal efficiency of PON was lower during August–October (55.45 ± 27.49%) than during April–July (68.86 ± 8.83%). Phytoplankton proliferation in summer, as one of the main sources of PON, may have exceeded the capacity of the CW and led to declines in PON removal efficiency. RNfix peaked in July–October (3–169 ng N·L−1·h−1) and was positively correlated with both PON concentration and the cell density of N-fixing Anabaena sp. over the growing season, suggesting that aquatic nitrogen fixation (primarily in the AL) may increase PON and thereby reduce the its removal efficiency in the CW.

Description: Universal salt iodization (USI) has been implemented for two decades in China. It is crucial to periodically monitor iodine status in the most vulnerable population, such as pregnant women. A cross-sectional study was carried out in an evidence-proved iodine-sufficient province to evaluate iodine intake in pregnancy. According to the WHO/UNICEF/ICCIDD recommendation criteria of adequate iodine intake in pregnancy (150–249 µg/L), the median urinary iodine concentration (UIC) of the total 8159 recruited pregnant women was 147.5 µg/L, which indicated pregnant women had iodine deficiency at the province level. Overall, 51.0% of the total study participants had iodine deficiency with a UIC 〈 150 µg/L and only 32.9% of them had adequate iodine. Participants living in coastal areas had iodine deficiency with a median UIC of 130.1 µg/L, while those in inland areas had marginally adequate iodine intake with a median UIC of 158.1 µg/L (p 〈 0.001). Among the total study participants, 450 pregnant women consuming non-iodized salt had mild-moderate iodine deficiency with a median UIC of 99.6 µg/L; 7363 pregnant women consuming adequately iodized salt had a lightly statistically higher median UIC of 151.9 µg/L, compared with the recommended adequate level by the WHO/UNICEF/ICCIDD (p 〈 0.001). Consuming adequately iodized salt seemed to lightly increase the median UIC level, but it may not be enough to correct iodine nutrition status to an optimum level as recommended by the WHO/UNICEF/ICCIDD. We therefore suggest that, besides strengthening USI policy, additional interventive measure may be needed to improve iodine intake in pregnancy.

Description: Heterozygous deletion of chromosome 17p renders prostate cancer vulnerable to inhibition of RNA polymerase II Heterozygous deletion of chromosome 17p renders prostate cancer vulnerable to inhibition of RNA polymerase II, Published online: 22 October 2018; doi:10.1038/s41467-018-06811-z Heterozygous loss of chromosome 17p is a common genomic event in castration-resistant prostate cancers (CRPC). Here, the authors use CRISPR-based screen to identify RBX1 as a target gene for CRPC with 17p loss and targeting RBX1 sensitizes CRPC to the treatment of α-amanitin antibody conjugates.