| 1. |
- Arndt, D. S., et al.
(författare)
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State of the Climate in 2016
- 2017
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Ingår i: Bulletin of The American Meteorological Society - (BAMS). - 0003-0007 .- 1520-0477. ; 98:8, s. S1-S280
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Tidskriftsartikel (refereegranskat)abstract
- In 2016, the dominant greenhouse gases released into Earth's atmosphere-carbon dioxide, methane, and nitrous oxide-continued to increase and reach new record highs. The 3.5 +/- 0.1 ppm rise in global annual mean carbon dioxide from 2015 to 2016 was the largest annual increase observed in the 58-year measurement record. The annual global average carbon dioxide concentration at Earth's surface surpassed 400 ppm (402.9 +/- 0.1 ppm) for the first time in the modern atmospheric measurement record and in ice core records dating back as far as 800000 years. One of the strongest El Nino events since at least 1950 dissipated in spring, and a weak La Nina evolved later in the year. Owing at least in part to the combination of El Nino conditions early in the year and a long-term upward trend, Earth's surface observed record warmth for a third consecutive year, albeit by a much slimmer margin than by which that record was set in 2015. Above Earth's surface, the annual lower troposphere temperature was record high according to all datasets analyzed, while the lower stratospheric temperature was record low according to most of the in situ and satellite datasets. Several countries, including Mexico and India, reported record high annual temperatures while many others observed near-record highs. A week-long heat wave at the end of April over the northern and eastern Indian peninsula, with temperatures surpassing 44 degrees C, contributed to a water crisis for 330 million people and to 300 fatalities. In the Arctic the 2016 land surface temperature was 2.0 degrees C above the 1981-2010 average, breaking the previous record of 2007, 2011, and 2015 by 0.8 degrees C, representing a 3.5 degrees C increase since the record began in 1900. The increasing temperatures have led to decreasing Arctic sea ice extent and thickness. On 24 March, the sea ice extent at the end of the growth season saw its lowest maximum in the 37-year satellite record, tying with 2015 at 7.2% below the 1981-2010 average. The September 2016 Arctic sea ice minimum extent tied with 2007 for the second lowest value on record, 33% lower than the 1981-2010 average. Arctic sea ice cover remains relatively young and thin, making it vulnerable to continued extensive melt. The mass of the Greenland Ice Sheet, which has the capacity to contribute similar to 7 m to sea level rise, reached a record low value. The onset of its surface melt was the second earliest, after 2012, in the 37-year satellite record. Sea surface temperature was record high at the global scale, surpassing the previous record of 2015 by about 0.01 degrees C. The global sea surface temperature trend for the 21st century-to-date of +0.162 degrees C decade(-1) is much higher than the longer term 1950-2016 trend of +0.100 degrees C decade(-1). Global annual mean sea level also reached a new record high, marking the sixth consecutive year of increase. Global annual ocean heat content saw a slight drop compared to the record high in 2015. Alpine glacier retreat continued around the globe, and preliminary data indicate that 2016 is the 37th consecutive year of negative annual mass balance. Across the Northern Hemisphere, snow cover for each month from February to June was among its four least extensive in the 47-year satellite record. Continuing a pattern below the surface, record high temperatures at 20-m depth were measured at all permafrost observatories on the North Slope of Alaska and at the Canadian observatory on northernmost Ellesmere Island. In the Antarctic, record low monthly surface pressures were broken at many stations, with the southern annular mode setting record high index values in March and June. Monthly high surface pressure records for August and November were set at several stations. During this period, record low daily and monthly sea ice extents were observed, with the November mean sea ice extent more than 5 standard deviations below the 1981-2010 average. These record low sea ice values contrast sharply with the record high values observed during 2012-14. Over the region, springtime Antarctic stratospheric ozone depletion was less severe relative to the 1991-2006 average, but ozone levels were still low compared to pre-1990 levels. Closer to the equator, 93 named tropical storms were observed during 2016, above the 1981-2010 average of 82, but fewer than the 101 storms recorded in 2015. Three basins-the North Atlantic, and eastern and western North Pacific-experienced above-normal activity in 2016. The Australian basin recorded its least active season since the beginning of the satellite era in 1970. Overall, four tropical cyclones reached the Saffir-Simpson category 5 intensity level. The strong El Nino at the beginning of the year that transitioned to a weak La Nina contributed to enhanced precipitation variability around the world. Wet conditions were observed throughout the year across southern South America, causing repeated heavy flooding in Argentina, Paraguay, and Uruguay. Wetter-than-usual conditions were also observed for eastern Europe and central Asia, alleviating the drought conditions of 2014 and 2015 in southern Russia. In the United States, California had its first wetter-than-average year since 2012, after being plagued by drought for several years. Even so, the area covered by drought in 2016 at the global scale was among the largest in the post-1950 record. For each month, at least 12% of land surfaces experienced severe drought conditions or worse, the longest such stretch in the record. In northeastern Brazil, drought conditions were observed for the fifth consecutive year, making this the longest drought on record in the region. Dry conditions were also observed in western Bolivia and Peru; it was Bolivia's worst drought in the past 25 years. In May, with abnormally warm and dry conditions already prevailing over western Canada for about a year, the human-induced Fort McMurray wildfire burned nearly 590000 hectares and became the costliest disaster in Canadian history, with $3 billion (U.S. dollars) in insured losses.
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| 2. |
- Arndt, D. S., et al.
(författare)
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STATE OF THE CLIMATE IN 2017
- 2018
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Ingår i: Bulletin of The American Meteorological Society - (BAMS). - : American Meteorological Society. - 0003-0007 .- 1520-0477. ; 99:8, s. S1-S310
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Forskningsöversikt (refereegranskat)
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| 3. |
- Blunden, Jessica, et al.
(författare)
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State of the Climate in 2012
- 2013
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Ingår i: Bulletin of The American Meteorological Society - (BAMS). - 0003-0007 .- 1520-0477. ; 94:8, s. S1-S258
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Tidskriftsartikel (refereegranskat)abstract
- For the first time in serveral years, the El Nino-Southern Oscillation did not dominate regional climate conditions around the globe. A weak La Ni a dissipated to ENSOneutral conditions by spring, and while El Nino appeared to be emerging during summer, this phase never fully developed as sea surface temperatures in the eastern conditions. Nevertheless, other large-scale climate patterns and extreme weather events impacted various regions during the year. A negative phase of the Arctic Oscillation from mid-January to early February contributed to frigid conditions in parts of northern Africa, eastern Europe, and western Asia. A lack of rain during the 2012 wet season led to the worst drought in at least the past three decades for northeastern Brazil. Central North America also experienced one of its most severe droughts on record. The Caribbean observed a very wet dry season and it was the Sahel's wettest rainy season in 50 years. Overall, the 2012 average temperature across global land and ocean surfaces ranked among the 10 warmest years on record. The global land surface temperature alone was also among the 10 warmest on record. In the upper atmosphere, the average stratospheric temperature was record or near-record cold, depending on the dataset. After a 30-year warming trend from 1970 to 1999 for global sea surface temperatures, the period 2000-12 had little further trend. This may be linked to the prevalence of La Ni a-like conditions during the 21st century. Heat content in the upper 700 m of the ocean remained near record high levels in 2012. Net increases from 2011 to 2012 were observed at 700-m to 2000-m depth and even in the abyssal ocean below. Following sharp decreases in to the effects of La Ni a, sea levels rebounded to reach records highs in 2012. The increased hydrological cycle seen in recent years continued, with more evaporation in drier locations and more precipitation in rainy areas. In a pattern that has held since 2004, salty areas of the ocean surfaces and subsurfaces were anomalously salty on average, while fresher areas were anomalously fresh. Global tropical cyclone activity during 2012 was near average, with a total of 84 storms compared with the 1981-2010 average of 89. Similar to 2010 and 2011, the North Atlantic was the only hurricane basin that experienced above-normal activity. In this basin, Sandy brought devastation to Cuba and parts of the eastern North American seaboard. All other basins experienced either near-or below-normal tropical cyclone activity. Only three tropical cyclones reached Category 5 intensity-all in Bopha became the only storm in the historical record to produce winds greater than 130 kt south of 7 N. It was also the costliest storm to affect the Philippines and killed more than 1000 residents. Minimum Arctic sea ice extent in September and Northern Hemisphere snow cover extent in June both reached new record lows. June snow cover extent is now declining at a faster rate (-17.6% per decade) than September sea ice extent (-13.0% per decade). Permafrost temperatures reached record high values in northernmost Alaska. A new melt extent record occurred on 11-12 July on the Greenland ice sheet; 97% of the ice sheet showed some form of melt, four times greater than the average melt for this time of year. The climate in Antarctica was relatively stable overall. The largest maximum sea ice extent since records begain in 1978 was observed in September 2012. In the stratosphere, warm air led to the second smallest ozone hole in the past two decades. Even so, the springtime ozone layer above Antarctica likely will not return to its early 1980s state until about 2060. Following a slight decline associated with the global 2 emissions from fossil fuel combustion and cement production reached a record 9.5 +/- 0.5 Pg C in 2011 and a new record of 9.7 +/- 0.5 Pg C is estimated for 2012. Atmospheric CO2 concentrations increased by 2.1 ppm in 2012, to 392.6 ppm. In spring 2012, 2 concentration exceeded 400 ppm at 7 of the 13 Arctic observation sites. Globally, other greenhouse gases including methane and nitrous oxide also continued to rise in concentration and the combined effect now represents a 32% increase in radiative forcing over a 1990 baseline. Concentrations of most ozone depleting substances continued to fall.
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| 4. |
- Batool, Tahira, et al.
(författare)
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Upregulated BMP-Smad signaling activity in the glucuronyl C5-epimerase knock out MEF cells
- 2019
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Ingår i: Cellular Signalling. - : Elsevier. - 0898-6568 .- 1873-3913. ; 54, s. 122-129
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Tidskriftsartikel (refereegranskat)abstract
- Glucuronyl C5-epimerase (Hsepi) catalyzes the conversion of glucuronic acid to iduronic acid in the process of heparan sulfate biosynthesis. Targeted interruption of the gene, Glce,in mice resulted in neonatal lethality with varied defects in organ development. To understand the molecular mechanisms of the phenotypes, we used mouse embryonic fibroblasts (MEF) as a model to examine selected signaling pathways. Our earlier studies found reduced activities of FGF-2, GDNF, but increased activity of sonic hedgehog in the mutant cells. In this study, we focused on the bone morphogenetic protein (BMP) signaling pathway. Western blotting detected substantially elevated endogenous Smad1/5/8 phosphorylation in the Hsepi mutant (KO) MEF cells, which is reverted by re-expression of the enzyme in the KO cells. The mutant cells displayed an enhanced proliferation and elevated alkaline phosphatase activity, marking higher differentiation, when cultured in osteogenic medium. The high level of Smad1/5/8 phosphorylation was also found in primary calvarial cells isolated from the KO mice. Analysis of the genes involved in the BMP signaling pathway revealed upregulation of a number of BMP ligands, but reduced expression of several Smads and BMP antagonist (Grem1) in the KO MEF cells. The results suggest that Hsepi expression modulates BMP signaling activity, which, at least partially, is associated with defected molecular structure of heparan sulfate expressed in the cells.
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| 5. |
- Bian, F., et al.
(författare)
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Ultrasmall Silver Nanopores Fabricated by Femtosecond Laser Pulses
- 2011
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 11:8, s. 3251-3257
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Tidskriftsartikel (refereegranskat)abstract
- Ultrasmall nanopores in silver thin films with a diameter of about 2 nm have been fabricated using femtosecond laser ablation in liquid. Ultrafast laser pulse ablation generates highly nonequilibrium excitated states, from which silver thin films emerge and progressively grow with the assistance of capping agent molecules. During this growth process, capping agent molecules are enclaved within the film, leaving individual ultrasmall pores in the thin film. Our first-principles calculations show that the pore size is critically determined by the dimension of the confined molecules. Our approach advances the capability of optical methods in making nanoscale structures with potential applications in areas such as near-field aperture probes, imaging masks, magnetic plasmonic resonances, and biosensing with individual nanopores.
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| 6. |
- Chen, Moashan, et al.
(författare)
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Data on the expression of cellular lncRNAs in human adenovirus infected cells
- 2016
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Ingår i: Data in Brief. - Elsevier : Elsevier BV. - 2352-3409. ; 8, s. 1263-1279
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Tidskriftsartikel (refereegranskat)abstract
- Expression of cellular long non-coding RNAs (lncRNAs) in human primary lung fibroblasts (IMR-90) during the course of adenovirus type 2 (Ad2) infection was studied by strand-specific whole transcriptome sequencing. In total, 645 cellular lncRNAs were expressed at a significant level and 398 of them were changed more than 2-fold. The changes in expression followed a distinct temporal pattern. Significantly, 80% of the changes occurred at the late phase and 80% of the de-regulated lncRNAs were up-regulated. The three largest groups of deregulated lncRNAs were 125 antisense RNAs, 111 pseudogenes and 85 long intergenic non-coding RNAs (lincRNAs). Lastly, more than 36% of lncRNAs have been shown to interact with RNA binding proteins.
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| 7. |
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| 8. |
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| 9. |
- Granberg, Fredrik, et al.
(författare)
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Adenovirus-induced alterations in host cell gene expression prior to the onset of viral gene expression
- 2006
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Ingår i: Virology. - : Elsevier BV. - 0042-6822 .- 1096-0341. ; 353:1, s. 1-5
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Tidskriftsartikel (refereegranskat)abstract
- In this report, we have studied gene expression profiles in human primary lung fibroblasts (IMR-90) during the very early phase of an adenovirus infection. Eight out of twelve genes with known functions encoded transcription factors linked to two major cellular processes; inhibition of cell growth (ATF3, ATF4, KLF4, KLF6 and ELK3) and immune response (NR4A1 and CEBPB), indicating that the earliest consequences of an adenovirus infection are growth arrest and induction of an immune response. A time course analysis showed that the induction of these immediate-early response genes was transient and suppressed after the onset of the adenovirus early gene expression.
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| 10. |
- Granberg, Fredrik, 1975-
(författare)
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Global Profiling of Host Cell Gene Expression During Adenovirus Infection
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- To investigate mechanisms involved in virus-host interactions, global changes in host gene expression were examined during infection with adenovirus type 2 (Ad2) using cDNA microarray technology. In paper I and II, transcriptional changes in HeLa cells were investigated during the early and late phase of infection, respectively. A limited number of genes, mainly implicated in cell growth and antiviral defence, were found to be differentially expressed in the early phase, whereas modulation of host cell gene expression during the late phase was augmented and mainly focused on growth inhibition and cell architecture. The experimental set-up was then redesigned to follow transcriptional regulatory events in growth synchronised, human primary lung fibroblasts. The immediate response of the host cell within two hours of infection was investigated in paper III, revealing a transient induction of a small number of cellular alert genes. This was followed by an expanded time course presented in paper IV, which included gene expression profiling at eight consecutive time points throughout the infectious cycle. The results indicated that specific sets of cellular genes were targeted at different stages of the infection, and four distinct periods were identified. In summary, the studies presented in this thesis demonstrate that adenovirus interferes with many cellular processes during the progression of infection to optimize the cellular environment for viral replication. These include cell cycle control, cell growth and growth inhibition, as well as DNA, RNA and protein metabolism. However, a transient induction of cellular genes involved in immune response and growth inhibition was observed before the onset of viral gene expression. During the very late stages of infection, the expression of a large number of genes involved in maintaining the cell structure was down-regulated, presumably to facilitate the spread of progeny virus.
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