title: Bayesian evaluation of the southern hemisphere radiocarbon offset during the holocene

authors: Hogg, Alan G.

subjects: radiocarbon

abstract: While an interhemispheric offset in atmospheric radiocarbon levels from AD 1950–950 is now well established, its existence earlier in the Holocene is less clear, with some studies reporting globally uniform 14C levels while others finding Southern Hemisphere samples older by a few decades. In this paper, we present a method for wiggle-matching Southern Hemisphere data sets against Northern Hemisphere curves, using the Bayesian calibration program OxCal 4.1 with the Reservoir Offset function accommodating a potential interhemispheric offset. The accuracy and robustness of this approach is confirmed by wiggle-matching known-calendar age sequences of the Southern Hemisphere calibration curve SHCal04 against the Northern Hemisphere curve IntCal04. We also show that 5 of 9 Holocene Southern Hemisphere data sets are capable of yielding reliable offset information. Those data sets that are accurate and precise show that interhemispheric offset levels in the Early Holocene are similar to modern levels, confirming SHCal04 as the curve of choice for calibrating Southern Hemisphere samples.

text: Bayesian evaluation of the southern hemisphere radiocarbon offset during the holocene While an interhemispheric offset in atmospheric radiocarbon levels from AD 1950–950 is now well established, its existence earlier in the Holocene is less clear, with some studies reporting globally uniform 14C levels while others finding Southern Hemisphere samples older by a few decades. In this paper, we present a method for wiggle-matching Southern Hemisphere data sets against Northern Hemisphere curves, using the Bayesian calibration program OxCal 4.1 with the Reservoir Offset function accommodating a potential interhemispheric offset. The accuracy and robustness of this approach is confirmed by wiggle-matching known-calendar age sequences of the Southern Hemisphere calibration curve SHCal04 against the Northern Hemisphere curve IntCal04. We also show that 5 of 9 Holocene Southern Hemisphere data sets are capable of yielding reliable offset information. Those data sets that are accurate and precise show that interhemispheric offset levels in the Early Holocene are similar to modern levels, confirming SHCal04 as the curve of choice for calibrating Southern Hemisphere samples.

year: 2009

title: Effects of metformin on human monocytic THP-1 cells - Implications for type 2 diabetes mellitus

authors: Tsuei, An-Chi

subjects: Metformin

abstract: Metformin is an anti-hyperglycaemic agent widely prescribed for type 2 diabetes (T2D). Despite decades of clinical use, its exact pharmacological mechanism(s) is yet to be definitively determined. Accumulative data have shown its mild inhibitory effect on the complex 1 of the mitochondrial respiratory chain, which is thought to contribute to its anti-hyperglycaemic effect. Metformin is also thought to have a protective effect on cardiovascular disease (CVD), the most common complication in T2D. It is widely accepted that T2D is an inflammatory state thus it is not surprising that T2D patients have 2-4 times higher risk in developing CVD. Furthermore, the pathology of T2D has been proposed to involve dysfunctioning mitochondria, the organelle of energy sensing and production. The use of metformin, a mitochondria inhibitor, in cells under mitochondrial stress led us to speculate the physiological responses that ensue.
To understand metformin‟s mode of action and its involvement in inflammation processes the human monocytic leukemia THP-1 cells were used in this study. Since studies of metformin on this cell type is scarce if not non-existence the first task was to determine its cytoxicity in this cell line. Next the mRNA and protein expressions of heat shock protein 60 (Hsp60), a mitochondrial stress marker, was determined in metformin-treated THP-1 cells. Further, various cell types have shown surface expressed Hsp60 under stress conditions. Thus the study here attempted to optimise the detection of surface Hsp60 in THP-1 cells, as human Hsp60 has been shown to induce innate immune response. Localisation of Hsp60 on the cell surface in metformin-treated cells may exacerbate the already-inflammed state of T2D. Lastly, metformin‟s effect on PMA-stimulated monocyte differentiation was determined by the mRNA expression of CD14, a surface receptor on macrophages.
The results here agreed with published data that metformin at therapeutic concentrations are not cytotoxic and is a mild inhibitor of mitochondrial respiration. We also provide evidence that metformin up-regulated the mitochondria stress protein, Hsp60, in a time- and dose-dependent manner. In addition, live cell Hsp60 immunocytochemistry proved to be a promising method for surface Hsp60 detection in THP-1 cells. Finally, at the therapeutic concentration metformin caused a significant up-regulation in cd14 expression, which contradicts with much acclaimed protective effect of metformin in the literature.

text: Effects of metformin on human monocytic THP-1 cells - Implications for type 2 diabetes mellitus Metformin is an anti-hyperglycaemic agent widely prescribed for type 2 diabetes (T2D). Despite decades of clinical use, its exact pharmacological mechanism(s) is yet to be definitively determined. Accumulative data have shown its mild inhibitory effect on the complex 1 of the mitochondrial respiratory chain, which is thought to contribute to its anti-hyperglycaemic effect. Metformin is also thought to have a protective effect on cardiovascular disease (CVD), the most common complication in T2D. It is widely accepted that T2D is an inflammatory state thus it is not surprising that T2D patients have 2-4 times higher risk in developing CVD. Furthermore, the pathology of T2D has been proposed to involve dysfunctioning mitochondria, the organelle of energy sensing and production. The use of metformin, a mitochondria inhibitor, in cells under mitochondrial stress led us to speculate the physiological responses that ensue.
To understand metformin‟s mode of action and its involvement in inflammation processes the human monocytic leukemia THP-1 cells were used in this study. Since studies of metformin on this cell type is scarce if not non-existence the first task was to determine its cytoxicity in this cell line. Next the mRNA and protein expressions of heat shock protein 60 (Hsp60), a mitochondrial stress marker, was determined in metformin-treated THP-1 cells. Further, various cell types have shown surface expressed Hsp60 under stress conditions. Thus the study here attempted to optimise the detection of surface Hsp60 in THP-1 cells, as human Hsp60 has been shown to induce innate immune response. Localisation of Hsp60 on the cell surface in metformin-treated cells may exacerbate the already-inflammed state of T2D. Lastly, metformin‟s effect on PMA-stimulated monocyte differentiation was determined by the mRNA expression of CD14, a surface receptor on macrophages.
The results here agreed with published data that metformin at therapeutic concentrations are not cytotoxic and is a mild inhibitor of mitochondrial respiration. We also provide evidence that metformin up-regulated the mitochondria stress protein, Hsp60, in a time- and dose-dependent manner. In addition, live cell Hsp60 immunocytochemistry proved to be a promising method for surface Hsp60 detection in THP-1 cells. Finally, at the therapeutic concentration metformin caused a significant up-regulation in cd14 expression, which contradicts with much acclaimed protective effect of metformin in the literature.

year: 2010

title: A Critical Tiriti Analysis of the Treaty Statement From a University in Aotearoa New Zealand

authors: Hamley, Logan

abstract: Universities in Aotearoa New Zealand have been placed under the spotlight for claims of systemic racism. Following the claims made in relation to the University of Waikato in 2020 and University of Otago in 2022, universities have the responsibility to create an inclusive environment where systemic racism is dismantled, to meaningfully partner with Māori to construct a model for decolonisation, and to enhance the academic experience of Māori staff and students by weaving in mātauranga Māori into existing teaching and research practices. The University of Waikato progresses ahead of other universities in its attempt to fulfil Te Tiriti o Waitangi commitment through the introduction of the Treaty Statement. In this paper, the Treaty Statement is used as a case study to identify how universities articulate bicultural commitments. To do so, our team (consisting of Māori and tauiwi scholars) performed a critical Tiriti analysis comprising five phases to investigate the degree of alignment of the statement with Te Tiriti. The desktop analysis showed poor engagement with most Te Tiriti elements. The analysis evaluation of “good” (more than satisfactory) was measured for the consideration of “Māori exercising equitable citizenship”. This article concludes with recommendations of how universities can strengthen their practices to live up to Te Tiriti aspirations.

text: A Critical Tiriti Analysis of the Treaty Statement From a University in Aotearoa New Zealand Universities in Aotearoa New Zealand have been placed under the spotlight for claims of systemic racism. Following the claims made in relation to the University of Waikato in 2020 and University of Otago in 2022, universities have the responsibility to create an inclusive environment where systemic racism is dismantled, to meaningfully partner with Māori to construct a model for decolonisation, and to enhance the academic experience of Māori staff and students by weaving in mātauranga Māori into existing teaching and research practices. The University of Waikato progresses ahead of other universities in its attempt to fulfil Te Tiriti o Waitangi commitment through the introduction of the Treaty Statement. In this paper, the Treaty Statement is used as a case study to identify how universities articulate bicultural commitments. To do so, our team (consisting of Māori and tauiwi scholars) performed a critical Tiriti analysis comprising five phases to investigate the degree of alignment of the statement with Te Tiriti. The desktop analysis showed poor engagement with most Te Tiriti elements. The analysis evaluation of “good” (more than satisfactory) was measured for the consideration of “Māori exercising equitable citizenship”. This article concludes with recommendations of how universities can strengthen their practices to live up to Te Tiriti aspirations.

year: 2024-02-21