Phytoplankton blooms in the Barents Sea are highly sensitive to seasonal and interannual changes in sea ice extent, water mass distribution, and oceanic fronts. With the ongoing increase of Atlantic ...Water inflows, we expect an impact on these blooms. Here, we use a state‐of‐the‐art collection of in situ hydrogeochemical data for the period 1998–2014, which includes ocean color satellite‐derived proxies for the biomass of calcifying and noncalcifying phytoplankton. Over the last 17 years, sea ice extent anomalies were evidenced having direct consequences for the spatial extent of spring blooms in the Barents Sea. In years of minimal sea ice extent, two spatially distinct blooms were clearly observed: one along the ice edge and another in ice‐free water. These blooms are thought to be triggered by different stratification mechanisms: heating of the surface layers in ice‐free waters and melting of the sea ice along the ice edge. In years of maximal sea ice extent, no such spatial delimitation was observed. The spring bloom generally ended in June when nutrients in the surface layer were depleted. This was followed by a stratified and oligotrophic summer period. A coccolithophore bloom generally developed in August, but was confined only to Atlantic Waters. In these same waters, a late summer bloom of noncalcifying algae was observed in September, triggered by enhanced mixing, which replenishes surface waters with nutrients. Altogether, the 17 year time‐series revealed a northward and eastward shift of the spring and summer phytoplankton blooms.
Key Points
A 17 year time‐series of remotely sensed and in situ observations is used to describe the variability of phytoplankton blooms
At least three distinct blooms were revealed and are partly controlled by the position of the sea ice edge and the polar front
A north‐eastward shift of the spring and summer blooms was observed
Most satellite models of production have been designed and calibrated for use in the open ocean. Coastal waters are optically more complex, and the use of chlorophyll a (chl a) as a first-order ...predictor of primary production may lead to substantial errors due to significant quantities of coloured dissolved organic matter (CDOM) and total suspended material (TSM) within the first optical depth. We demonstrate the use of phytoplankton absorption as a proxy to estimate primary production in the coastal waters of the North Sea and Western English Channel for both total, micro- and nano+pico-phytoplankton production. The method is implemented to extrapolate the absorption coefficient of phytoplankton and production at the sea surface to depth to give integrated fields of total and micro- and nano+pico-phytoplankton primary production using the peak in absorption coefficient at red wavelengths. The model is accurate to 8% in the Western English Channel and 22% in this region and the North Sea. By comparison, the accuracy of similar chl a based production models was >250%. The applicability of the method to autonomous optical sensors and remotely sensed aircraft data in both coastal and estuarine environments is discussed.
We have examined the in vivo anti-inflammatory and analgesic activity of a new series of monocyclic β-lactams (azetidinones), similar to others which have been demonstrated to be inhibitors of human ...leukocyte elastase (HLE), an enzyme involved in degradation processes of connective tissue. Our new compounds have been administered orally (15 mg/kg) to albino rats 30 min before injecting carrageenin in the plantar aponeurosis. Tested compounds have demonstrated a certain activity and stability to gastric hydrolysis, in particular two of them markedly reduced paw efema formation, even if slightly less effectively than indomethacin (reference compound, 5 mg/kg). To eveluate the analgesic activity we carried out the acetic acid writhing test, pretreating rats orally with our compounds 30 min before injecting the acid solution i.p. Ths same two molecules which showed the anti-inflammatory activity demonstrated a very light analgesic activity. These results suggest the possibility of carrying out further studies, particularly in vitro, on the mechanism of action of our compounds, mechanism which could be the HLE inhibition.
This paper describes some methods for the synthesis and the isolation of novel 5 or 6-halopyridin-2-yl-boronic acids and esters
3
,
4
,
7
. These compounds are prepared via a regioselective ...halogen–metal exchange using
n-butyllithium and subsequent quenching with triisopropylborate starting from appropriate dihalopyridines. All substrates studied to date provided a single regioisomeric boronic acid or ester product. Additionally, these compounds have been found to undergo Pd-catalysed coupling with arylhalides and authorise a strategy to produce new pyridines libraries.
This paper describes a general method for the synthesis and isolation of stable 5, or 6-halopyridin-2-yl-boronic acids and esters. Two methods are carried out using Halogen–metal exchange (HMe) followed by either in situ transesterification, or isolation of the crude boronic acid followed by room temperature esterification.
The Ultra-Violet Imaging Telescope (UVIT) is one of the payloads in ASTROSAT, the first Indian Space Observatory. The UVIT instrument has two 375 mm telescopes: one for the far-ultraviolet (FUV) ...channel (1300-1800 ), and the other for the near-ultraviolet (NUV) channel (2000-3000 ) and the visible (VIS) channel (3200-5500 ). UVIT is primarily designed for simultaneous imaging in the two ultraviolet channels with spatial resolution better than 1 8, along with provisions for slit-less spectroscopy in the NUV and FUV channels. The results of in-orbit calibrations of UVIT are presented in this paper.
New drugs selective for histamine H3-receptors can be used to establish that these receptors are involved in the feedback control of histamine synthesis and release, and to demonstrate their ...distribution in the brain and peripheral tissues. These drugs provide new tools for affecting physiological and possibly pathological conditions in which histamine is involved.
In continuation of our previous work on piperazinopyrrolothienopyrazine derivatives, three series of piperazinopyridopyrrolopyrazines, piperazinopyrroloquinoxalines, and ...piperazinopyridopyrroloquinoxalines were prepared and evaluated as 5-HT3 receptor ligands. The chemical modifications performed within these new series led to structure−activity relationships regarding both high affinity and selectivity for the 5-HT3 receptors that are in agreement with those established previously for the pyrrolothienopyrazine series. The best compound (8a) obtained in these new series is in the picomolar range of affinity for 5-HT3 receptors with a selectivity higher than 106. Four of the high-affinity 5-HT3 ligands (8a, 15a,b, and 16d) were selected in both the pyridopyrrolopyrazine and the pyrroloquinoxaline series and were characterized in vitro and in vivo as agonists or partial agonists. Compound 8a was also evaluated in the light/dark test where it showed potential anxiolytic-like activity at very low doses per os.
This paper describes a general method for the synthesis and isolation of novel 6-halo-pyridin-3-yl-boronic acids and esters
2–
5
. These compounds are prepared taking in account a regioselective ...halogen–metal exchange with a trialkylborate starting from 2,5-dihalopyridines. All substrates studied to date provided a single regioisomeric boronic acid or ester product. Additionally, these compounds have been found to undergo Pd-catalysed coupling with a range of arylhalides and authorise a strategy to produce new pyridines libraries.
This paper describes a general method for the synthesis and isolation of novel 6-halo-pyridin-3-yl-boronic acids and esters.
NiW catalysts supported on γ-Al 2 O 3 (NiW/Al 2 O 3 ), commercial Beta (NiW/HB) and hierarchical Beta prepared by base–acid treatment (NiW/HB-M) were characterized by X-ray diffraction (XRD), N 2 ...sorption, infrared spectroscopy (IR), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The catalytic performance of these catalysts was evaluated in the hydrodesulfurization (HDS) of thiophene. The results indicate that NiW/HB as well as NiW/HB-M endured important and rapid deactivation showing that the introduction of additional mesopores/macropores in the support could not prevent the deactivation tendency. Interestingly, NiW/HB or NiW/HB-M mixed with NiW/Al 2 O 3 and the utilization of Na + -exchanged Beta as a support remarkably improved the anti-deactivation ability of the catalysts. As a result, the catalysts NiW/NaB-M (NiW catalyst supported on Na + -exchanged hierarchical Beta) and NiW/20HB-M (20% NiW/HB-M mixed with 80% NiW/Al 2 O 3 ) gave superior catalytic activity than NiW/Al 2 O 3 .
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