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Social Media (SM) has become a stage for people to share thoughts, emotions, opinions, and almost every other aspect of their daily lives. This abundance of human interaction makes SM particularly attractive for social sensing. Especially during polarizing events such as political elections or referendums, users post information and encourage others to support their side, using symbols such as hashtags to represent their attitudes. However, many users choose not to attach hashtags to their messages, use a different language, or show their position only indirectly. Thus, automatically identifying their opinions becomes a more challenging task. To uncover these implicit perspectives, we propose a collaborative filtering model based on Graph Convolutional Networks that exploits the textual content in messages and the rich connections between users and topics. Moreover, our approach only requires a small annotation effort compared to state-of-the-art solutions. Nevertheless, the proposed model achieves competitive performance in predicting individuals' stances. We analyze users' attitudes ahead of two constitutional referendums in Chile in 2020 and 2022. Using two large Twitter datasets, our model achieves improvements of 3.4% in recall and 3.6% in accuracy over the baselines.

Approximately 15% of US adults have circulating levels of uric acid above its solubility limit, which is causally linked to the disease gout. In most mammals, uric acid elimination is facilitated by the enzyme uricase. However, human uricase is a pseudogene, having been inactivated early in hominid evolution. Though it has long been known that uric acid is eliminated in the gut, the role of the gut microbiota in hyperuricemia has not been studied. Here, we identify a widely distributed bacterial gene cluster that encodes a pathway for uric acid degradation. Stable isotope tracing demonstrates that gut bacteria metabolize uric acid to xanthine or short chain fatty acids. Ablation of the microbiota in uricase-deficient mice causes severe hyperuricemia, and anaerobe-targeted antibiotics increase the risk of gout in humans. These data reveal a role for the gut microbiota in uric acid excretion and highlight the potential for microbiome-targeted therapeutics in hyperuricemia.

Social Media (SM) has become a stage for people to share thoughts, emotions, opinions, and almost every other aspect of their daily lives. This abundance of human interaction makes SM particularly attractive for social sensing. Especially during polarizing events such as political elections or referendums, users post information and encourage others to support their side, using symbols such as hashtags to represent their attitudes. However, many users choose not to attach hashtags to their messages, use a different language, or show their position only indirectly. Thus, automatically identifying their opinions becomes a more challenging task. To uncover these implicit perspectives, we propose a collaborative filtering model based on Graph Convolutional Networks that exploits the textual content in messages and the rich connections between users and topics. Moreover, our approach only requires a small annotation effort compared to state-of-the-art solutions. Nevertheless, the proposed model achieves competitive performance in predicting individuals' stances. We analyze users' attitudes ahead of two constitutional referendums in Chile in 2020 and 2022. Using two large Twitter datasets, our model achieves improvements of 3.4% in recall and 3.6% in accuracy over the baselines.

Approximately 15% of US adults have circulating levels of uric acid above its solubility limit, which is causally linked to the disease gout. In most mammals, uric acid elimination is facilitated by the enzyme uricase. However, human uricase is a pseudogene, having been inactivated early in hominid evolution. Though it has long been known that uric acid is eliminated in the gut, the role of the gut microbiota in hyperuricemia has not been studied. Here, we identify a widely distributed bacterial gene cluster that encodes a pathway for uric acid degradation. Stable isotope tracing demonstrates that gut bacteria metabolize uric acid to xanthine or short chain fatty acids. Ablation of the microbiota in uricase-deficient mice causes severe hyperuricemia, and anaerobe-targeted antibiotics increase the risk of gout in humans. These data reveal a role for the gut microbiota in uric acid excretion and highlight the potential for microbiome-targeted therapeutics in hyperuricemia.

Perovskite solar cells (PSCs) are known to be sensitive to the exposure to ambient humidity, which typically results in the degradation and deterioration of performance, although positive effects of exposure to moisture have also been reported, due to recrystallization of the perovskite. Common approach to improve stability is to use 3D/2D perovskite active layer, where 2D capping layer is prepared by spin coating the bulky organic cation halide. Herein, it is shown that optimizing the exposure of the capping layer prepared by spin coating phenylethylammonium iodide (PEAI) to ambient atmosphere results in substantial improvement of the PSC performance. Furthermore, the initial effects of PEAI treatment are dependent on the NiOx/perovskite interface, but in all cases except at very high humidity (80–85% RH) optimized exposure to ambient results in improved performance. The variations in device performance with PEAI treatment and ambient exposure can be attributed to defect passivation and changes in the charge extraction due to energy-level alignment at the interfaces. The best performing devices have passivation of NiOx/perovskite interface and PEAI treatment of top surface followed by exposure to ambient atmosphere at RH of 40–45%, which results in the power conversion efficiency increase from 20.3% to 22.4%.

Solid-state lithium metal batteries as promising energy storage devices have gathered many attentions for its appealing properties, such as improved safety and capacity density. Nevertheless, high interfacial resistance, uneven current density and severe Li dendrite growth caused by rigid contact at the cathode-electrolyte interface in solid-state batteries greatly restrict its electrochemical performance and further practical application. Herein, a cathode-electrolyte integrating strategy is proposed to achieve the soft interfacial contact through employing poly(vinylidene fluoride)-based composite electrolyte as the cathode binder and subsequent heat-pressing procedure. Due to the modification strategy, fabricated cells with integrated structure show lower resistance, faster Li-ion transport, enhanced capacity and improved cycle stability. The integrated LiFePO4/Li cell exhibits superior electrochemical performance, which present a capacity retention of 93.8% and 91.6% after 300 cycles at 0.5 C and 400 cycles at 1 C, respectively, being able to compare favorably with the conventional cells using liquid electrolyte. Overall, the study provides a solution for designing advanced solid-state lithium metal batteries.

Perovskite solar cells (PSCs) are known to be sensitive to the exposure to ambient humidity, which typically results in the degradation and deterioration of performance, although positive effects of exposure to moisture have also been reported, due to recrystallization of the perovskite. Common approach to improve stability is to use 3D/2D perovskite active layer, where 2D capping layer is prepared by spin coating the bulky organic cation halide. Herein, it is shown that optimizing the exposure of the capping layer prepared by spin coating phenylethylammonium iodide (PEAI) to ambient atmosphere results in substantial improvement of the PSC performance. Furthermore, the initial effects of PEAI treatment are dependent on the NiOx/perovskite interface, but in all cases except at very high humidity (80–85% RH) optimized exposure to ambient results in improved performance. The variations in device performance with PEAI treatment and ambient exposure can be attributed to defect passivation and changes in the charge extraction due to energy-level alignment at the interfaces. The best performing devices have passivation of NiOx/perovskite interface and PEAI treatment of top surface followed by exposure to ambient atmosphere at RH of 40–45%, which results in the power conversion efficiency increase from 20.3% to 22.4%.

Li-rich Mn-based-layered oxides are considered to be the most felicitous cathode material candidates for commercial application of lithium-ion batteries on account of high energy density. Nevertheless, defects containing an unsatisfactory initial Coulombic efficiency and rapid voltage decay seriously impede their practical utilization. Herein, a coating layer with three distinct crystalline states are employed as a coating layer to modify Li[Li0.2Mn0.54Ni0.13Co0.13]O2, respectively, and the effects of coating layers with distinct crystalline states on the crystal structure, diffusion kinetics, and cell performance of host materials are further explored. A coating layer with high crystallinity enables mitigatory voltage decay and better cyclic stability of materials, while a coating layer with planar defects facilitates Li+ transfer and enhances the rate performance of materials. Consequently, optimizing the crystalline state of coating substances is critical for preferable surface modification.

Sodium-ion batteries (SIBs) with huge cost advantages will show extraordinary talents in low-speed electric vehicles, energy storage, and base station communications. Manganese oxides are promising candidates for cathode materials, rapid capacity decay, and poor electrochemical performance that limit its commercial applications. Here, the nanosheets with exposed active crystal planes are prepared through a simple NH3∙H2O-assisted sol-gel process and subsequent high-temperature calcination. The unique structure considerably reduces the Na+ diffusion path for the excellent Na+ diffusion kinetics. The final results confirm that the NMO-pH6 sample, exposed to the active planes, has high energy density (557.9 Wh kg−1 at 0.1 C) and outstanding electrochemical performance, especially the rate performance (93.8 mAh g−1 at 5 C and 79.95 %, 100 cycles at 1 C). More importantly, it will facilitate the further construction of advanced cathode materials for high-performance SIBs.

Li-rich oxides are considered as the most commercial potential cathode materials due to the high theoretical specific discharge capacity. Here, ZrO2 in different crystalline states are applied as the coating layers to enhance the electrochemical performance of hollow Li[Li0.2Mn0.54Ni0.13Co0.13]O2 materials. Meanwhile, a series of characterizations (XRD, SEM, TEM, EDX etc.) are conducted to compare the effects of ZrO2 coating layer with different crystalline states on the host material. The results elucidate that the Li-rich Mn-based material with the polycrystal ZrO2 coating layer has a slight advantage in rate performance, while the host material with the single crystal ZrO2-coating layer has a better cycling performance and effectively suppresses voltage decay with the effect of excellently inhibiting layered to spinel-like phase transition and metal dissolution during charging and discharging process.

Timely and effective post-disaster assessment is of significance for the design of rescue plan, taking disaster mitigation measures and disaster analysis. Field investigation and remote sensing methods are the common ways to perform post-disaster assessment, which are usually limited by dense cloud coverage, potential risk, and tough transportation etc. in the mountainous area. In this paper, we employ the 2017 catastrophic Xinmo landslide (Sichuan, China) to demonstrate the feasibility of using spaceborne synthetic aperture radar (SAR) data to perform timely and effective post-disaster assessment. With C-band Sentinel-1 data, we propose to combine interferometric coherence to recognize the stable area, which helps us successfully identify landslide source area and boundaries in a space-based remote sensing way. Complementarily, X-band TanDEM-X SAR data allow us to generate a precise pre-failure high-resolution digital elevation model (DEM), which provides us the ability to accurately estimate the depletion volume and accumulation volume of Xinmo landslide. The results prove that spaceborne SAR can provide a quick, valuable, and unique assistance for post-disaster assessment of landslides from a space remote sensing way. At some conditions (bad weather, clouds, etc.), it can provide reliable alternative.

Timely and effective post-disaster assessment is of significance for the design of rescue plan, taking disaster mitigation measures and disaster analysis. Field investigation and remote sensing methods are the common ways to perform post-disaster assessment, which are usually limited by dense cloud coverage, potential risk, and tough transportation etc. in the mountainous area. In this paper, we employ the 2017 catastrophic Xinmo landslide (Sichuan, China) to demonstrate the feasibility of using spaceborne synthetic aperture radar (SAR) data to perform timely and effective post-disaster assessment. With C-band Sentinel-1 data, we propose to combine interferometric coherence to recognize the stable area, which helps us successfully identify landslide source area and boundaries in a space-based remote sensing way. Complementarily, X-band TanDEM-X SAR data allow us to generate a precise pre-failure high-resolution digital elevation model (DEM), which provides us the ability to accurately estimate the depletion volume and accumulation volume of Xinmo landslide. The results prove that spaceborne SAR can provide a quick, valuable, and unique assistance for post-disaster assessment of landslides from a space remote sensing way. At some conditions (bad weather, clouds, etc.), it can provide reliable alternative.

Xuechao Liu,1,2,* Haibo Qiu,1,2,* Pengfei Kong,1,2,* Zhiwei Zhou,1,2 Xiaowei Sun1,2 1State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 2Department of Gastric Surgery, Sun Yat-sen University Cancer Center, Guangzhou, People’s Republic of China *These authors contributed equally to this work Background: We aim to investigate the prognostic value of several nutrition-based indices, including the prognostic nutritional index (PNI), performance status, body mass index, serum albumin, and preoperative body weight loss in patients with gastric cancer (GC).Materials and methods: We retrospectively analyzed the records of 1,330 consecutive patients with GC undergoing curative surgery between October 2000 and September 2012. The relationship between nutrition-based indices and overall survival (OS) was examined using Kaplan–Meier analysis and Cox regression model.Results: Following multivariate analysis, the PNI and preoperative body weight loss were the only nutritional-based indices independently associated with OS (hazard ratio [HR]: 1.356, 95% confidence interval [CI]: 1.051–1.748, P=0.019; HR: 1.152, 95% CI: 1.014–1.310, P=0.030, retrospectively). In stage-stratified analysis, multivariate analysis revealed that preoperative body weight loss was identified as an independent prognostic factor only in patients with stage III GC (HR: 1.223, 95% CI: 1.065–1.405, P=0.004), while the prognostic significance of PNI was not significant (all P>0.05). In patients with stage III GC, preoperative body weight loss stratified 5-year OS from 41.1% to 26.5%. When stratified by adjuvant chemotherapy, the prognostic significance of preoperative body weight loss was maintained in patients treated with surgery plus adjuvant chemotherapy and in patients treated with surgery alone (P<0.001; P=0.003).Conclusion: Preoperative body weight loss is an independent prognostic factor fo

Shi-tong Yu,1,2,* Zhiwei Zhou,1,2,* Qian Cai,1,2 Faya Liang,1,2 Ping Han,1,2 Renhui Chen,1,2 Xiao-ming Huang1,2 1Department of Otolaryngology, Head and Neck Surgery, 2Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, People’s Republic of China *These authors contributed equally to this work Purpose: The present study was designed to retrospectively evaluate the prognostic value of the C-reactive protein/albumin (CRP/ALB) ratio in laryngeal squamous cell carcinoma (LSCC).Methods: One hundred and twenty-nine newly diagnosed LSCC patients admitted between May 2006 and October 2011 were retrospectively reviewed. Their serum CRP and ALB were quantified preoperatively. The relationship between the CRP/ALB ratio and the clinicopathologic features was analyzed. Receiver operating characteristic curve was used to calculate the prognostic value of the CRP/ALB ratio. Then, the Cox proportional hazards model was used in univariate and multivariate analyses to identify significant prognostic factors associated with disease-free survival and overall survival.Results: The cutoff value for CRP/ALB ratio was 0.047. An elevated CRP/ALB ratio was significantly associated with nodal metastasis, late disease stage, and recurrence. Also, high values of CRP/ALB ratio were significant predictors for poor overall survival and disease-free survival on multivariate analysis.Conclusion: Pretreatment CRP/ALB ratio may be a significant prognostic marker in LSCC. Keywords: C-reactive protein/albumin ratio, laryngeal squamous cell carcinoma, prognosis, survival

Xuechao Liu,1,2,* Pengfei Xu,1,3,* Haibo Qiu,1,2,* Jianjun Liu,1,2 Shangxiang Chen,1,2 Dazhi Xu,1,2 Wei Li,1,2 Youqing Zhan,1,2 Yuanfang Li,1,2 Yingbo Chen,1,2 Zhiwei Zhou,1,2 Xiaowei Sun1,2 1Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 2Department of Gastric and Pancreatic Surgery, 3Department of Thoracic Surgery, Sun Yat-sen University Cancer Center, Guangzhou, People’s Republic of China *These authors contributed equally to this work Purpose: We sought to determine whether human epidermal growth factor receptor 2 (HER2) and vascular endothelial growth factor (VEGF) expression were independent prognostic factors for gastric cancer (GC).Patients and methods: A total of 678 consecutive patients with GC undergoing curative surgery between October 2010 and December 2012 had resected tissue examined for HER2 and VEGF expression using immunohistochemistry. Immunohistochemical expression of HER2 was analyzed using the DAKO-HercepTest™ and scored according to published reports. VEGF expression was calculated by multiplying the score for the percentage of positive cells by the intensity score. We defined positive expression as a score of 1+, 2+, or 3+, and a score of 0 was defined as negative expression. We compared these results to clinicopathological characteristics, including overall survival (OS).Results: Multivariate analysis revealed that HER2 expression was independently associated with shorter OS (hazard ratio [HR], 1.55; 95% confidence interval [CI], 1.10–2.18; P=0.01) and with higher tumor–nodes–metastasis stage (HR, 3.88; 95% CI, 2.67–5.64; P<0.001) in patients with GC. VEGF expression was not associated with OS (HR, 1.25; 95% CI, 0.86–1.82; P=0.24). HER2 expression was still identified as an independent prognostic factor in Stage II–III p

A number of drugs and herbal compounds have been documented to cause hepatoxicity. Schisandrin B (Sch B) is an active dibenzocyclooctadiene isolated from Schisandrae fructus, with a wide array of pharmacological activities. However, the potential hepatotoxicity of Sch B is a major safety concern, and the underlying mechanism for Sch B-induced liver toxic effects is not fully elucidated. In the present study, we aimed to investigate the liver toxic effects and the molecular mechanisms of Sch B in mouse liver and macrophage cells. The results have shown that Sch B exhibits potent grow inhibitory, proapoptotic, and proautophagic effects in AML-12 and RAW 264.7 cells. Sch B markedly arrested cells in G1 phase in both cell lines, accompanied by the down-regulation of cyclin dependent kinase 2 (CDK2) and cyclin D1 and up-regulation of p27 Kip1 and checkpoint kinase 1. Furthermore, Sch B markedly increased the apoptosis of AML-12 and RAW 264.7 cells with a decrease in the expression of B-cell lymphoma-extra-large and (Bcl-xl) B-cell lymphoma 2 (Bcl-2), but an increase in the expression of B-cell lymphoma 2-associated X protein (Bax). Sch B promoted the cleavage of caspase 3 and poly-adenosine diphosphate-ribose polymerase (PARP) in both cell lines. Additionally, Sch B significantly induced autophagy of AML-12 and RAW 264.7 cells. Sch B inhibited the activation of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway, as indicated by their altered phosphorylation, contributing to the proautophagic effect of Sch B. Taken together, our findings show that the inducing effects of Sch B on cell cycle arrest, apoptosis, and autophagy may contribute to its liver toxic effects, which might provide a clue for the investigation of the molecular toxic targets and underlying mechanisms for Sch B-induced hepatotoxicity in herbal consumers. More studies are warranted to fully delineate the underlying mechanisms, effi

A number of drugs and herbal compounds have been documented to cause hepatoxicity. Schisandrin B (Sch B) is an active dibenzocyclooctadiene isolated from Schisandrae fructus, with a wide array of pharmacological activities. However, the potential hepatotoxicity of Sch B is a major safety concern, and the underlying mechanism for Sch B-induced liver toxic effects is not fully elucidated. In the present study, we aimed to investigate the liver toxic effects and the molecular mechanisms of Sch B in mouse liver and macrophage cells. The results have shown that Sch B exhibits potent grow inhibitory, proapoptotic, and proautophagic effects in AML-12 and RAW 264.7 cells. Sch B markedly arrested cells in G1 phase in both cell lines, accompanied by the down-regulation of cyclin dependent kinase 2 (CDK2) and cyclin D1 and up-regulation of p27 Kip1 and checkpoint kinase 1. Furthermore, Sch B markedly increased the apoptosis of AML-12 and RAW 264.7 cells with a decrease in the expression of B-cell lymphoma-extra-large and (Bcl-xl) B-cell lymphoma 2 (Bcl-2), but an increase in the expression of B-cell lymphoma 2-associated X protein (Bax). Sch B promoted the cleavage of caspase 3 and poly-adenosine diphosphate-ribose polymerase (PARP) in both cell lines. Additionally, Sch B significantly induced autophagy of AML-12 and RAW 264.7 cells. Sch B inhibited the activation of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway, as indicated by their altered phosphorylation, contributing to the proautophagic effect of Sch B. Taken together, our findings show that the inducing effects of Sch B on cell cycle arrest, apoptosis, and autophagy may contribute to its liver toxic effects, which might provide a clue for the investigation of the molecular toxic targets and underlying mechanisms for Sch B-induced hepatotoxicity in herbal consumers. More studies are warranted to fully delineate the underlying mechanisms, effi

A number of drugs and herbal compounds have been documented to cause hepatoxicity. Schisandrin B (Sch B) is an active dibenzocyclooctadiene isolated from Schisandrae fructus, with a wide array of pharmacological activities. However, the potential hepatotoxicity of Sch B is a major safety concern, and the underlying mechanism for Sch B-induced liver toxic effects is not fully elucidated. In the present study, we aimed to investigate the liver toxic effects and the molecular mechanisms of Sch B in mouse liver and macrophage cells. The results have shown that Sch B exhibits potent grow inhibitory, proapoptotic, and proautophagic effects in AML-12 and RAW 264.7 cells. Sch B markedly arrested cells in G1 phase in both cell lines, accompanied by the down-regulation of cyclin dependent kinase 2 (CDK2) and cyclin D1 and up-regulation of p27 Kip1 and checkpoint kinase 1. Furthermore, Sch B markedly increased the apoptosis of AML-12 and RAW 264.7 cells with a decrease in the expression of B-cell lymphoma-extra-large and (Bcl-xl) B-cell lymphoma 2 (Bcl-2), but an increase in the expression of B-cell lymphoma 2-associated X protein (Bax). Sch B promoted the cleavage of caspase 3 and poly-adenosine diphosphate-ribose polymerase (PARP) in both cell lines. Additionally, Sch B significantly induced autophagy of AML-12 and RAW 264.7 cells. Sch B inhibited the activation of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway, as indicated by their altered phosphorylation, contributing to the proautophagic effect of Sch B. Taken together, our findings show that the inducing effects of Sch B on cell cycle arrest, apoptosis, and autophagy may contribute to its liver toxic effects, which might provide a clue for the investigation of the molecular toxic targets and underlying mechanisms for Sch B-induced hepatotoxicity in herbal consumers. More studies are warranted to fully delineate the underlying mechanisms, effi

Guanghong Yang,1 Zhiwei Zhou,2 Yanli Cen,1 Xiaolin Gui,1 Qibing Zeng,1 Yunxia Ao,1 Qian Li,1 Shiran Wang,1 Jun Li,1 Aihua Zhang1 1Key Laboratory of Environment Pollution Monitoring and Disease Control, Ministry of Education, School of Public Health, Guiyang Medical University, 2Guizhou Provincial Key Laboratory for Regenerative Medicine, Stem Cell and Tissue Engineering Research Center and Sino-US Joint Laboratory for Medical Sciences, Guiyang Medical University, Guiyang, Guizhou, People’s Republic of China Abstract: Persistent organic pollutants in drinking water impose a substantial risk to the health of human beings, but the evidence for liver toxic effect and the underlying mechanism is scarce. This study aimed to examine the liver toxicity and elucidate the molecular mechanism of organic pollutants in drinking water in normal human liver cell line L02 cells and rats. The data showed that organic extraction from drinking water remarkably impaired rat liver function, evident from the increase in the serum level of alanine aminotransferase, aspartate aminotransferase, and cholinesterase, and decrease in the serum level of total protein and albumin. Organic extraction dose-dependently induced apoptotic cell death in rat liver and L02 cells. Administration of rats with organic extraction promoted death receptor signaling pathway through the increase in gene and protein expression level of Fas and FasL. Treatment of rats with organic extraction also induced mitochondria-mediated apoptosis via increasing the expression level of proapoptotic protein, Bax, but decreasing the expression level of antiapoptotic protein, Bcl-2, resulting in an upregulation of cytochrome c and activation of caspase cascade at both transcriptional and posttranscriptional levels. Moreover, organic extraction enhanced rat liver glutathione S-transferases activity and reactive oxygen species generation, and upregulated aryl hydrocarbon receptor and glutathione S-transferase A1

This thesis is devoted to the presentation of a simplified synthesis method and its application in the development of a computer program for the synthesis of LC ladder networks. The approach developed in the thesis is based on scattering transfer matrix theory which does not seem to have been applied directly to ladder synthesis before. The most important part of this thesis is the determination of a scattering sy thesis strategy for choosing the sequence of transmission zeros. A synthesis strategy was developed by W. F. Gottlicher for application to the traditional synthesis procedure. Gottlicher's method, presented in his thesis, is adapted as the basis of the scattering strategy. In addition, this thesis introduces a set of simplified scattering calculations by appropriately modifying the details of Gottlicher's strategy. The simplified scattering algorithm involves only calculation of the reflectance and the delay at a transmission zero and at zero or infinity. For multiple transmission zeros at zero orinfinity, the second and third derivatives of polynomials ' g' and 'h' at zero or infinity are required in addition. The main results are given in 'Chapter 3'. In that chapter, the derivation of the scattering characterization for all of the circuits and realization details of the modified strategy are presented. In ' Chapter 4', the flowgraph of the simplified scattering LC ladder filter synthesis program together with several design examples is presented. The thesis concludes with a summary and recommendations.

This thesis is devoted to the presentation of a simplified synthesis method and its application in the development of a computer program for the synthesis of LC ladder networks. The approach developed in the thesis is based on scattering transfer matrix theory which does not seem to have been applied directly to ladder synthesis before. The most important part of this thesis is the determination of a scattering sy thesis strategy for choosing the sequence of transmission zeros. A synthesis strategy was developed by W. F. Gottlicher for application to the traditional synthesis procedure. Gottlicher's method, presented in his thesis, is adapted as the basis of the scattering strategy. In addition, this thesis introduces a set of simplified scattering calculations by appropriately modifying the details of Gottlicher's strategy. The simplified scattering algorithm involves only calculation of the reflectance and the delay at a transmission zero and at zero or infinity. For multiple transmission zeros at zero orinfinity, the second and third derivatives of polynomials ' g' and 'h' at zero or infinity are required in addition. The main results are given in 'Chapter 3'. In that chapter, the derivation of the scattering characterization for all of the circuits and realization details of the modified strategy are presented. In ' Chapter 4', the flowgraph of the simplified scattering LC ladder filter synthesis program together with several design examples is presented. The thesis concludes with a summary and recommendations.

In the past three decades, peatlands all over the world such as upland bogs, tropical fens, have been undergoing significant and rapid degradations. These degradations cause carbon loss and CO2 emissions, and also fuel climate change. In this research, I present three case studies on how space geodetic tools, especially Radar Interferometry (InSAR), can be used to monitor and to advance our understanding of the long-term surface changes in peatlands. First, I investigate the eroding extent and severity of upland UK peatlands using InSAR. Both short wavelength C-band and long wavelength L-band data are explored in this study. I detect a long-term peat subsidence rate of about 0.3 cm/yr, and 2 cm of decrease in peat height between 2002 and 2010. I also examine the coherence performance of C- and L-band over upland bogs. I find L-band data provides better coherence than C-band in upland bogs. Second, I use InSAR time series generated by L-band images to map the spatial and temporal subsidence of drained tropical peatlands in Sumatra, Indonesia. And based on InSAR-derived subsidence rate data, I estimate carbon loss or CO2 emission. Third, I assess the effectiveness of peatland restoration work in in Central Kalimantan, Indonesia using InSAR (L-band images). Restoration effects and impact factors are investigated by the spatial and temporal changes of peat height, which also provide useful information for guiding future restoration activities in this region. Overall, this research suggests that InSAR time series is feasible to monitor long-term peat height change in peatlands, provides new insights into the dynamic surface changes in peatlands, and helps to study the carbon loss and CO2 emissions from peatlands, and understand restoration effects.

In the past three decades, peatlands all over the world such as upland bogs, tropical fens, have been undergoing significant and rapid degradations. These degradations cause carbon loss and CO2 emissions, and also fuel climate change. In this research, I present three case studies on how space geodetic tools, especially Radar Interferometry (InSAR), can be used to monitor and to advance our understanding of the long-term surface changes in peatlands. First, I investigate the eroding extent and severity of upland UK peatlands using InSAR. Both short wavelength C-band and long wavelength L-band data are explored in this study. I detect a long-term peat subsidence rate of about 0.3 cm/yr, and 2 cm of decrease in peat height between 2002 and 2010. I also examine the coherence performance of C- and L-band over upland bogs. I find L-band data provides better coherence than C-band in upland bogs. Second, I use InSAR time series generated by L-band images to map the spatial and temporal subsidence of drained tropical peatlands in Sumatra, Indonesia. And based on InSAR-derived subsidence rate data, I estimate carbon loss or CO2 emission. Third, I assess the effectiveness of peatland restoration work in in Central Kalimantan, Indonesia using InSAR (L-band images). Restoration effects and impact factors are investigated by the spatial and temporal changes of peat height, which also provide useful information for guiding future restoration activities in this region. Overall, this research suggests that InSAR time series is feasible to monitor long-term peat height change in peatlands, provides new insights into the dynamic surface changes in peatlands, and helps to study the carbon loss and CO2 emissions from peatlands, and understand restoration effects.