514 research outputs found

    Resource allocation and feedback in wireless multiuser networks

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    This thesis focuses on the design of algorithms for resource allocation and feedback in wireless multiuser and heterogeneous networks. In particular, three key design challenges expected to have a major impact on future wireless networks are considered: cross-layer scheduling; structured quantization codebook design for MU-MIMO networks with limited feedback; and resource allocation to provide physical layer security. The first design challenge is cross-layer scheduling, where policies are proposed for two network architectures: user scheduling in single-cell multiuser networks aided by a relay; and base station (BS) scheduling in CoMP. These scheduling policies are then analyzed to guarantee satisfaction of three performance metrics: SEP; packet delay; and packet loss probability (PLP) due to buffer overflow. The concept of the τ-achievable PLP region is also introduced to explicitly describe the tradeoff in PLP between different users. The second design challenge is structured quantization codebook design in wireless networks with limited feedback, for both MU-MIMO and CoMP. In the MU-MIMO network, two codebook constructions are proposed, which are based on structured transformations of a base codebook. In the CoMP network, a low-complexity construction is proposed to solve the problem of variable codebook dimensions due to changes in the number of coordinated BSs. The proposed construction is shown to have comparable performance with the standard approach based on a random search, while only requiring linear instead of exponential complexity. The final design challenge is resource allocation for physical layer security in MU-MIMO. To guarantee physical layer security, the achievable secrecy sum-rate is explicitly derived for the regularized channel inversion (RCI) precoder. To improve performance, power allocation and precoder design are jointly optimized using a new algorithm based on convex optimization techniques

    ‘With Friends Like These’: Human Rights, Neoconservatism and U.S. Foreign Policy from Carter to Reagan.

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    This thesis engages with two emerging bodies of scholarship: the history of human rights and the history of U.S. neoconservatism. It begins with an exploration of the genesis of the contemporary international human rights movement, arguing that human rights as we know and understand them today were a product of the latter half of the twentieth century. Their path, however, was not a clear one. The emergence of neoconservative ideology in U.S. domestic politics would greatly impact upon the trajectory of the human rights movement under the presidencies of Jimmy Carter and Ronald Reagan. The latter period witnessed a conflict between America’s Watch and the Reagan administration over human rights as an ‘idea’ and as praxis, with U.S. policy towards Latin America as the primary battle field

    Impact of Increasing Level of Milk Production on Cow-Calf Performance in Nebraska Sandhills

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    In a 2-yr study, data were collected on 118 crossbred cow-calf pairs from March and May-calving herds. On approximately 30, 60, 90, 120, and 210 d postpartum, individual cow 24-h bilk yield was estimated through weigh-suckle weigh techniques. Cow body weight (BW) and body condition score (BCS) were collected weekly through breeding. Calf BW was recorded at each milking. Individual cow milk area under the curve (AUC) values were calculated and data were analyzed using linear regression analysis. Results from this study illustrate that increasing total milk produced throughout the lactation period had minimal influence on the cow production parameters assessed in the Nebraska Sandhills forage environment. However, the lack of differences found in this study may be due to years of selecting for low milk production genetics and the cowherd may not represent the US average for milk production

    68Ga-labelled exendin-3, a new agent for the detection of insulinomas with PET

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    Contains fulltext : 89596.pdf (publisher's version ) (Closed access)PURPOSE: Insulinomas are neuroendocrine tumours derived from pancreatic beta-cells. The glucagon-like peptide 1 receptor (GLP-1R) is expressed with a high incidence (>90%) and high density in insulinomas. Glucagon-like peptide 1 (GLP-1), the natural ligand of GLP-1R, is rapidly degraded in vivo. A more stable agonist of GLP-1R is exendin-3. We investigated imaging of insulinomas with DOTA-conjugated exendin-3 labelled with (68)Ga. METHODS: Targeting of insulinomas with [Lys(40)(DOTA)]exendin-3 labelled with either (111)In or (68)Ga was investigated in vitro using insulinoma tumour cells (INS-1). [Lys(40)((111)In-DTPA)]Exendin-3 was used as a reference in this study. In vivo targeting was investigated in BALB/c nude mice with subcutaneous INS-1 tumours. PET imaging was performed using a preclinical PET/CT scanner. RESULTS: In vitro exendin-3 specifically bound and was internalized by GLP-1R-positive cells. In BALB/c nude mice with subcutaneous INS-1 tumours a high uptake of [Lys(40)((111)In-DTPA)]exendin-3 in the tumour was observed (33.5 +/- 11.6%ID/g at 4 h after injection). Uptake was specific, as determined by coinjection of an excess of unlabelled [Lys(40)]exendin-3 (1.8 +/- 0.1%ID/g). The pancreas also exhibited high and specific uptake (11.3 +/- 1.0%ID/g). High uptake was also found in the kidneys (144 +/- 24%ID/g) and this uptake was not receptor-mediated. In this murine tumour model optimal targeting of the GLP-1R expressing tumour was obtained at exendin doses < or =0.1 microg. Remarkably, tumour uptake of (68)Ga-labelled [Lys(40)(DOTA)]exendin-3 was lower (8.9 +/- 3.1%ID/g) than tumour uptake of (111)In-labelled [Lys(40)(DTPA)]exendin-3 (25.4 +/- 7.2%ID/g). The subcutaneous tumours were clearly visualized by small-animal PET imaging after injection of 3 MBq of [Lys(40)((68)Ga-DOTA)]exendin-3. CONCLUSION: [Lys(40)((68)Ga-DOTA)]Exendin-3 specifically accumulates in insulinomas, although the uptake is lower than that of [Lys(40)((111)In-DTPA)]exendin-3. Therefore, [Lys(40)((68)Ga-DOTA)]exendin-3 is a promising tracer to visualize insulinomas with PET.01 juli 201

    Effect of Glucogenic Feed Additive on Reproductive Performance in Young Postpartum Range Cows

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    Performance of young March-Calving range cows receiving a protein supplement with the addition of either monensin or propionate salt were compared to evaluate the effect of feed additive on overall production in the postpartum stage. cow body weight and body condition were not impacted by postpartum supplementation throughout the study. Calf body weights were not impacted by type of feed additive at birth, weaning, or 205-d. Twenty-four-hour milk production was not impacted by the type of feed additive. Conception rates for cows receiving postpartum supplementation containing propionate salt were greater than cows receiving monsensin. This implies that the addition of propionate salt when supplementing young range cows in the postpartum period can increase pregnancy rate resulting in an increase in marginal revenue compared to cows fed monensin

    Long-term psychological distress in breast cancer survivors and their matched controls:A cross-sectional study

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    Introduction: Breast cancer survivors often experience psychological distress shortly after diagnosis. Long-term psychological effects, however, have not been clearly demonstrated. Methods: This cross-sectional cohort study included 350 breast cancer survivors and 350 age-matched and general-practitioner-matched women. The median follow-up was 10 years. Using logistic regression we compared breast cancer survivors with controls on having (severe) symptoms of depression and/or anxiety, as measured with the Hospital Anxiety and Depression Scale. In multivariable logistic regression, we adjusted the results for a history of depression or prescription of antidepressants. Results: Larger proportions of breast cancer survivors experienced symptoms of depression (10.6%) compared with controls (4.9%) and symptoms of anxiety (18.6%) compared with controls (16.3%). The odds of symptoms of depression (OR 2.3, 95%CI 1.3-4.2), severe symptoms of depression (OR 3.3, 95%CI 1.1-10.3) and severe symptoms of anxiety (OR 2.1, 95%CI, 1.1-4.0) were significantly higher for breast cancer survivors than for controls, even after adjusting for history of depression or prescription of antidepressants. No significant difference was seen for mild symptoms of anxiety. Conclusions: Breast cancer survivors have an increased risk of symptoms of depression, including severe symptoms, and severe symptoms of anxiety compared with controls, for up to at least 10 years after diagnosis

    Optimized labeling of NOTA-conjugated octreotide with F-18

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    We recently reported a facile method based on the chelation of [18F]aluminum fluoride (Al18F) by NOTA (1,4,7-triazacyclononane-1,4,7-triacetic acid). Here, we present a further optimization of the 18F labeling of NOTA-octreotide (IMP466). Octreotide was conjugated with the NOTA chelate and was labeled with 18F in a two-step, one-pot method. The labeling procedure was optimized with regard to the labeling buffer, ionic strength, peptide concentration, and temperature. Radiochemical yield, specific activity, in vitro stability, and receptor affinity were determined. Biodistribution of 18F-IMP466 was studied in AR42J tumor-bearing mice. In addition, microPET/CT images were acquired. IMP466 was labeled with Al18F in a single step with 97% yield in the presence of 80% (v/v) acetonitrile or ethanol. The labeled product was purified by HPLC to remove unlabeled peptide and unbound Al18F. The radiolabeling, including purification, was performed for 45 min. Specific activities of 48,000 GBq/mmol could be obtained. 18F-IMP466 showed a high tumor uptake and excellent tumor-to-blood ratios at 2 h post-injection. In addition, the low bone uptake indicated that the Al18F–NOTA complex was stable in vivo. PET/CT scans revealed excellent tumor delineation and specific accumulation in the tumor. Uptake in receptor-negative organs was low. NOTA-octreotide could be labeled with 18F in quantitative yields using a rapid two-step, one-pot, method. The compound was stable in vivo and showed rapid accretion in SSTR2-receptor-expressing AR42J tumors in nude mice. This method can be used to label other NOTA-conjugated compounds such as RGD peptides, GRPR-binding peptides, and Affibody molecules with 18F

    Diannexin Protects against Renal Ischemia Reperfusion Injury and Targets Phosphatidylserines in Ischemic Tissue

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    Renal ischemia/reperfusion injury (IRI) frequently complicates shock, renal transplantation and cardiac and aortic surgery, and has prognostic significance. The translocation of phosphatidylserines to cell surfaces is an important pro-inflammatory signal for cell-stress after IRI. We hypothesized that shielding of exposed phosphatidylserines by the annexin A5 (ANXA5) homodimer Diannexin protects against renal IRI. Protective effects of Diannexin on the kidney were studied in a mouse model of mild renal IRI. Diannexin treatment before renal IRI decreased proximal tubule damage and leukocyte influx, decreased transcription and expression of renal injury markers Neutrophil Gelatinase Associated Lipocalin and Kidney Injury Molecule-1 and improved renal function. A mouse model of ischemic hind limb exercise was used to assess Diannexin biodistribution and targeting. When comparing its biodistribution and elimination to ANXA5, Diannexin was found to have a distinct distribution pattern and longer blood half-life. Diannexin targeted specifically to the ischemic muscle and its affinity exceeded that of ANXA5. Targeting of both proteins was inhibited by pre-treatment with unlabeled ANXA5, suggesting that Diannexin targets specifically to ischemic tissues via phosphatidylserine-binding. This study emphasizes the importance of phosphatidylserine translocation in the pathophysiology of IRI. We show for the first time that Diannexin protects against renal IRI, making it a promising therapeutic tool to prevent IRI in a clinical setting. Our results indicate that Diannexin is a potential new imaging agent for the study of phosphatidylserine-exposing organs in vivo
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