The Role of Metallurgy in Transforming Global Forests.

Forest degradation—both past and present—has been a significant research focus of many disciplines in recent decades, and it is an area in which the multidisciplinarity and long-term perspectives of archaeological endeavour has the potential to make a particularly valuable contribution. One of the past craft activities that has long been linked to significant socio-economic change and associated accelerations in forest cover reduction and environmental decline is the intensification of early iron production—an industry reliant on the consumption of charcoal as fuel for much of its history. However, the impact of iron production on the transformation of woodlands is dependent on a suite of interrelated factors—climatic, ecological, technological and cultural—only some of which have so far been adequately scrutinised. This paper explores the theoretical context that links iron production with deforestation in academic and popular cultures, examining the role that archaeology can play in investigating this association, before reviewing recent methodological approaches that aim to interrogate the relationship between metallurgy and the environment in archaeological settings

The exploitation of manganese-rich ‘ore’ to smelt iron in Mwenge, western Uganda, from the mid second millennium AD

By the later second millennium AD, iron production was a key economic industry in western Uganda, and Mwenge was a prominent centre of production, highly regarded for the quality of the iron it produced. Between 2007 and 2011, excavation and analysis of iron production remains from six smelting sites in Mwenge enabled the reconstruction of local smelting technologies in operation there from the fourteenth century AD onwards. Chemical and microstructural analysis of approximately 100 samples revealed that slag from some of these sites is typically characterised by a bulk chemistry high in manganese oxide (up to 12 wt%) and knebelitic olivines. Slag samples from the remainder of the sites contain low levels of manganese oxide (below 4 wt%) and fayalitic olivines. The majority of the slag samples also contain notable levels of phosphorous (1–2 wt%). This sample set provided an opportunity to discuss the impacts of manganese and phosphorous on the smelting systems in operation in Mwenge. Principal component analysis suggests that smelters in this region were deliberately combining an iron ore with a separate manganese-rich flux, rather than using a naturally manganiferous iron ore. This use of two ‘ores’ has parallels with ethnographic literature from the region, which link the use of a second ore to the production of a harder metal. It is believed that this is the first analytically documented example of the use of a manganese-rich flux in sub-Saharan Africa. In the absence of analyses of surviving iron artefacts, the data also provides an opportunity to consider the quality of the iron metal that would have been produced

Exploring the impact of iron production on forest and woodland resources : estimating fuel consumption from slag

Reconstructing past anthropogenic influences on forest and woodland resources is an important tool to understand the development of present patterns of land use, and their long-term impacts. Past metallurgical activity undoubtedly consumed significant charcoal, exploiting forest resources for fuel at various stages of metal extraction and processing. This study aimed to quantify this fuel consumption from archaeometallurgical remains, with North Pare as a case study – a prominent centre of precolonial iron production activity in north Tanzania, and a mountainous region subject to considerable erosion processes attributed to changes in forest cover. Archaeometallurgical remains from Pare were examined with bulk chemical analysis, optical microscopy and elemental analysis to reconstruct Pare’s past iron production technologies. The data was interrogated to distinguish the contribution of the fuel ash to the smelting system, with implications for our understanding of past forest degradation processes in relation to metallurgy, reducing reliance on potentially problematic analogy

Recent advances in GaAs/Ge solar cells

By growing the GaAs cell on a Ge substrate, the advantages of GaAs cells can be retained and the higher mechanical strength of the Ge makes larger, thinner GaAs cells possible. To conform to immediate user requirements, GaAs growth conditions were modified to eliminate the additional PV output at GaAs/Ge interface. To demonstrate acceptable cell manufacturing technology, the major areas in cell manufacture were analyzed and developed, and efficiency combined. Also the cells were successfully assembled on current lightweight arrays. The main areas of effort are discussed

Radiation resistance of Ge, Ge0.93Si0.07, GaAs and Al0.08Ga0.92 as solar cells

Solar cells made of Ge, Ge(0.93)Si(0.07) alloys, GaAs and Al(0.08)Ga(0.92)As were irradiated in two experiments with 1-meV electrons at fluences as great as 1 x 10(exp 16) cm(exp-2). Several general trends have emerged. Low-band-gap Ge and Ge(0.93)Si(0.07) cells show substantial resistance to radiation-induced damage. The two experiments showed that degradation is less for Al(0.08)Ga(0.92)As cells than for similarly irradiated GaAs cells. Compared to homojunctions, cells with graded-band-gap emitters did not show the additional resistance to damage in the second experiment that had been seen in the first. The thickness of the emitter is a key parameter to limit the degradation in GaAs devices

APLF (C2orf13) is a novel component of poly(ADP-ribose) signaling in mammalian cells

APLF is a novel protein of unknown function that accumulates at sites of chromosomal DNA strand breakage via forkhead-associated (FHA) domain-mediated interactions with XRCC1 and XRCC4. APLF can also accumulate at sites of chromosomal DNA strand breaks independently of the FHA domain via an unidentified mechanism that requires a highly conserved C-terminal tandem zinc finger domain. Here, we show that the zinc finger domain binds tightly to poly(ADP-ribose), a polymeric posttranslational modification synthesized transiently at sites of chromosomal damage to accelerate DNA strand break repair reactions. Protein poly(ADP-ribosyl)ation is tightly regulated and defects in either its synthesis or degradation slow global rates of chromosomal single-strand break repair. Interestingly, APLF negatively affects poly(ADP-ribosyl)ation in vitro, and this activity is dependent on its capacity to bind the polymer. In addition, transient overexpression in human A549 cells of full-length APLF or a C-terminal fragment encoding the tandem zinc finger domain greatly suppresses the appearance of poly(ADP-ribose), in a zinc finger-dependent manner. We conclude that APLF can accumulate at sites of chromosomal damage via zinc finger-mediated binding to poly(ADP-ribose) and is a novel component of poly(ADP-ribose) signaling in mammalian cells

Development of a Clinical MALDI-ToF Mass Spectrometry Assay for SARS-CoV-2: Rational Design and Multi-Disciplinary Team Work.

The COVID-19 pandemic caused by the SARS-CoV-2 coronavirus has stretched national testing capacities to breaking points in almost all countries of the world. The need to rapidly screen vast numbers of a country's population in order to control the spread of the infection is paramount. However, the logistical requirement for reagent supply (and associated cost) of RT-PCR based testing (the current front-line test) have been hugely problematic. Mass spectrometry-based methods using swab and gargle samples have been reported with promise, but have not approached the task from a systematic analysis of the entire diagnostic process. Here, the pipeline from sample processing, the biological characteristics of the pathogen in human biofluid, the downstream bio- and physical-chemistry and the all-important data processing with clinical interpretation and reporting, are carefully compiled into a single high-throughput and reproducible rapid process. Utilizing MALDI-ToF mass spectrometric detection to viral envelope glycoproteins in a systems biology-multidisciplinary team approach, we have achieved a multifaceted clinical MALDI ToF MS screening test, primarily (but not limited to) SARS-CoV-2, with direct application to other future epidemics/pandemics that may arise. The clinical information generated not only includes SARS-CoV-2 coronavirus detection-(Spike protein fragments S1, S2b, S2a peaks), but other respiratory viral infections detected as well as an assessment of generalised oral upper respiratory immune response (elevated total Ig light chain peak) and a measure of the viral immune response (elevated intensity of IgA heavy chain peak). The advantages of the method include; (1) ease of sampling, (2) speed of analysis, and much reduced cost of testing. These features reveal the diagnostic utility of MALDI-ToF mass spectrometry as a powerful and economically attractive global solution

Novel insights into the expression of CGB1 & 2 genes by epithelial cancer cell lines secreting ectopic free hCGβ

BACKGROUND Ectopic secretion of human chorionic gonadotrophin free beta (hCGβ) by epithelial cancer is associated with aggressive tumors which more readily metastasize, possibly by acting as an autocrine anti-apoptotic agent. hCGβ is encoded by six homologous CGB genes, with poorly-understood variable transcriptionally active expression profiles; CGB1 and CGB2 have always been considered pseudogenes. However, transcripts from CGB1 and -2 can be detected in placental, testicular and pituitary tissues. The expression and function of these genes in cancer is less well-known. MATERIALS AND METHODS Expression profiles of CGB genes in epithelial cancer cells by quantitative polymerase chain reaction (qPCR) were explored, along with the consequence of specific siRNA silencing of CGB1 and 2. Immunohistochemical and immunoassay techniques were used to detect the translation and secretion of hCGβ in these cells. RESULTS CGB1 and -2 gene transcripts were only detected in cells which secreted hCGβ. siRNA-mediated silencing of CGB1 and -2 transcripts significantly reduced secreted protein in concordance with a reduction in cell survival to a greater degree than that of other CGB genes. CONCLUSION CGB genes 1 and 2, previously considered as pseudogenes, are notably expressed by epithelial cancer cell lines. The transcription of these genes, but not other CGB genes, correlates with a functionally expressed protein and propensity for cancer growth