441 research outputs found
Electrochemical approach for isolation of chitin from the skeleton of the black coral cirrhipathes sp. (Antipatharia)
The development of novel and effective methods for the isolation of chitin, which remains one of the fundamental aminopolysaccharides within skeletal structures of diverse marine invertebrates, is still relevant. In contrast to numerous studies on chitin extraction from crustaceans, mollusks and sponges, there are only a few reports concerning its isolation from corals, and especially black corals (Antipatharia). In this work, we report the stepwise isolation and identification of chitin from Cirrhipathes sp. (Antipatharia, Antipathidae) for the first time. The proposed method, aiming at the extraction of the chitinous scaffold from the skeleton of black coral species, combined a well-known chemical treatment with in situ electrolysis, using a concentrated Na2SO4 aqueous solution as the electrolyte. This novel method allows the isolation of a-chitin in the form of a microporous membrane-like material. Moreover, the extracted chitinous scaffold, with a well-preserved, unique pore distribution, has been extracted in an astoundingly short time (12 h) compared to the earlier reported attempts at chitin isolation from Antipatharia corals. © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)
Effect of natalizumab on disease progression in secondary progressive multiple sclerosis (ASCEND). a phase 3, randomised, double-blind, placebo-controlled trial with an open-label extension
Background: Although several disease-modifying treatments are available for relapsing multiple sclerosis, treatment effects have been more modest in progressive multiple sclerosis and have been observed particularly in actively relapsing subgroups or those with lesion activity on imaging. We sought to assess whether natalizumab slows disease progression in secondary progressive multiple sclerosis, independent of relapses. Methods: ASCEND was a phase 3, randomised, double-blind, placebo-controlled trial (part 1) with an optional 2 year open-label extension (part 2). Enrolled patients aged 18–58 years were natalizumab-naive and had secondary progressive multiple sclerosis for 2 years or more, disability progression unrelated to relapses in the previous year, and Expanded Disability Status Scale (EDSS) scores of 3·0–6·5. In part 1, patients from 163 sites in 17 countries were randomly assigned (1:1) to receive 300 mg intravenous natalizumab or placebo every 4 weeks for 2 years. Patients were stratified by site and by EDSS score (3·0–5·5 vs 6·0–6·5). Patients completing part 1 could enrol in part 2, in which all patients received natalizumab every 4 weeks until the end of the study. Throughout both parts, patients and staff were masked to the treatment received in part 1. The primary outcome in part 1 was the proportion of patients with sustained disability progression, assessed by one or more of three measures: the EDSS, Timed 25-Foot Walk (T25FW), and 9-Hole Peg Test (9HPT). The primary outcome in part 2 was the incidence of adverse events and serious adverse events. Efficacy and safety analyses were done in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT01416181. Findings: Between Sept 13, 2011, and July 16, 2015, 889 patients were randomly assigned (n=440 to the natalizumab group, n=449 to the placebo group). In part 1, 195 (44%) of 439 natalizumab-treated patients and 214 (48%) of 448 placebo-treated patients had confirmed disability progression (odds ratio [OR] 0·86; 95% CI 0·66–1·13; p=0·287). No treatment effect was observed on the EDSS (OR 1·06, 95% CI 0·74–1·53; nominal p=0·753) or the T25FW (0·98, 0·74–1·30; nominal p=0·914) components of the primary outcome. However, natalizumab treatment reduced 9HPT progression (OR 0·56, 95% CI 0·40–0·80; nominal p=0·001). In part 1, 100 (22%) placebo-treated and 90 (20%) natalizumab-treated patients had serious adverse events. In part 2, 291 natalizumab-continuing patients and 274 natalizumab-naive patients received natalizumab (median follow-up 160 weeks [range 108–221]). Serious adverse events occurred in 39 (13%) patients continuing natalizumab and in 24 (9%) patients initiating natalizumab. Two deaths occurred in part 1, neither of which was considered related to study treatment. No progressive multifocal leukoencephalopathy occurred. Interpretation: Natalizumab treatment for secondary progressive multiple sclerosis did not reduce progression on the primary multicomponent disability endpoint in part 1, but it did reduce progression on its upper-limb component. Longer-term trials are needed to assess whether treatment of secondary progressive multiple sclerosis might produce benefits on additional disability components. Funding: Biogen
Multidifferential study of identified charged hadron distributions in -tagged jets in proton-proton collisions at 13 TeV
Jet fragmentation functions are measured for the first time in proton-proton
collisions for charged pions, kaons, and protons within jets recoiling against
a boson. The charged-hadron distributions are studied longitudinally and
transversely to the jet direction for jets with transverse momentum 20 GeV and in the pseudorapidity range . The
data sample was collected with the LHCb experiment at a center-of-mass energy
of 13 TeV, corresponding to an integrated luminosity of 1.64 fb. Triple
differential distributions as a function of the hadron longitudinal momentum
fraction, hadron transverse momentum, and jet transverse momentum are also
measured for the first time. This helps constrain transverse-momentum-dependent
fragmentation functions. Differences in the shapes and magnitudes of the
measured distributions for the different hadron species provide insights into
the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any
supplementary material and additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb
public pages
Study of the decay
The decay is studied
in proton-proton collisions at a center-of-mass energy of TeV
using data corresponding to an integrated luminosity of 5
collected by the LHCb experiment. In the system, the
state observed at the BaBar and Belle experiments is
resolved into two narrower states, and ,
whose masses and widths are measured to be where the first uncertainties are statistical and the second
systematic. The results are consistent with a previous LHCb measurement using a
prompt sample. Evidence of a new
state is found with a local significance of , whose mass and width
are measured to be and , respectively. In addition, evidence of a new decay mode
is found with a significance of
. The relative branching fraction of with respect to the
decay is measured to be , where the first
uncertainty is statistical, the second systematic and the third originates from
the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb
public pages
Measurement of the ratios of branching fractions and
The ratios of branching fractions
and are measured, assuming isospin symmetry, using a
sample of proton-proton collision data corresponding to 3.0 fb of
integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The
tau lepton is identified in the decay mode
. The measured values are
and
, where the first uncertainty is
statistical and the second is systematic. The correlation between these
measurements is . Results are consistent with the current average
of these quantities and are at a combined 1.9 standard deviations from the
predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb
public pages
Cisplatin and fluorouracil with or without panitumumab in patients with recurrent or metastatic squamous-cell carcinoma of the head and neck (SPECTRUM): an open-label phase 3 randomised trial
Polyaniline nanobiodetector - detection and characterization of microorganisms
Wydział ChemiiCelem niniejszej pracy była próba zastosowania
nanomateriałów i nanotechnologii przy konstrukcji
układów detekcyjnych do szybkiego wykrywania i
identyfikacji żywych komórek, mikroorganizmów.
W oparciu o skonstruowany przez autora niniejszej
pracy nanobiodetektor, opracowano dwa systemy
pomiarowe - stacjonarny system nanobiodetekcyjny,
który umożliwiał monitoring zmian zachodzących w
płynnej hodowli bakterii oraz układ przepływowy,
który pozwalał na wielokrotne - następujące jeden
po drugim - badania próbek bakteryjnych.
W przypadku przepływowego układu
nanobiodetekcyjnego, możliwe było wykrycie od
kilkuset do kilku miliardów komórek bakterii w
mililitrze badanej próbki.
W trakcie badań ustalono, że różnice w uzyskanej
odpowiedzi zmian elektrycznych polianilinowej
nanosieci detektora zależną od ilości komórek, jak
również od gatunku bakterii oraz typu komórki -
formy przetrwalnikowej, wegetatywnej - i jej kształtu
i wielkości (np. ziarniak, pałeczka, przecinkowiec)
oraz możliwości ruchu (rzęski, wić).
Nanobiodetekcyjny układ przepływowy pozwala
określić przynależność badanych bakterii do grupy
bakterii Gram ujemnych czy też Gram dodatnich, a
rejestrowane zmiany odpowiedzi elektrycznej
polianilinowej sieci są gatunkowo zależne.
Polianilinowy nanobiodetektor może służyć do
określania przybliżonej liczby badanych
drobnoustrojów, jak również wstępnej identyfikacji
rodzajowej i gatunkowej analizowanych próbek.The aim of this study was to use nanomaterials and
nanotechnology in the construction of the sensing
systems for the rapid detection and identification of
microorganisms.
Polyaniline-based nanobiodetector was applied in
the construction of two basic sensing systems:
stationary and continuous flow nanobiodetecting
system (CFNBD), including a microfluidic version
(microCFNBD).
Stationary nanobiodetecting system was
used to monitor changes in liquid bacterial culture. It
enabled performing multiple bacteriological
analyses - one after another. CFNBD allows to
detect from few hundreds up to over a billion of cells
per one millilitre of analysed colony.
It was found, that the changes in electrical
response of detecting element depend on the
number of cells, including bacterial species, but also
the type of cells - spores or vegetative cells, on their
size, shape (e.g. coccus, bacilli) and motility (cilia,
flagellum) and are species dependent.
With the use of a continuous flow nanobiodetecting
system (CFNBD) it was possible to determine if
tested bacteria belongs to the group of Gramnegative
or Gram positive bacteria.
Thus, it has been proved that the polyaniline
nanobiodetector can be used to determine the
approximate number of microorganisms, as well as
a method of preliminary identification of genus and
species of bacteria in the analysed samples.
The CFNBD system also enabled to determine the
composition of the mixture of bacteria, which contain
varying proportions of dead and living cells or
spores and vegetative species of bacteria of the
genus Bacillus
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Is Silent R&D Productive?
In competitive markets where ideas are getting harder to find, firms have strong incentives to keep their ideas quiet. For this reason, many innovative firms do not disclose research and development (R&D) expenses even if their research efforts are very productive. I identify “silent R&D” firms as firms that operate in an innovative industry and choose not to disclose R&D as a separate line item but instead pool R&D with sales, general, and administrative (SG&A) expenses. I document that there is a significant proportion of silent R&D firms in the sample of the U.S.-listed stocks and that this proportion is stable over time at 13% on average. I show that silent R&D firms are different from missing R&D or trade secrecy firms identified in prior research and are not associated with poor disclosure quality. Finally, I find that silent R&D firms have higher future profitability at the magnitude of about 3 to 4.5 percent accumulated over the next three years. This higher future profitability is primarily due to the higher productivity of their intangible capital. This evidence suggests strongly that silence enshrouds better ideas. Using the findings from this paper, I also provide initial estimates of SG&A reclassification rates for silent R&D firms
An efficient 3D cell culture method on biomimetic nanostructured grids.
Current techniques of in vitro cell cultures are able to mimic the in vivo environment only to a limited extent, as they enable cells to grow only in two dimensions. Therefore cell culture approaches should rely on scaffolds that provide support comparable to the extracellular matrix. Here we demonstrate the advantages of novel nanostructured three-dimensional grids fabricated using electro-spinning technique, as scaffolds for cultures of neoplastic cells. The results of the study show that the fibers allow for a dynamic growth of HeLa cells, which form multi-layer structures of symmetrical and spherical character. This indicates that the applied scaffolds are nontoxic and allow proper flow of oxygen, nutrients, and growth factors. In addition, grids have been proven to be useful in in situ examination of cells ultrastructure
HeLa cells stained with Hoechst 33342 and propidium iodide after 24 (A), 48 (B) and 72 (C) hours of 3D culture on the nanostructure grids.
<p>Original magnification x200. A fragment of the spherical 3D structure of cell growing on nanostructured grids visualized after 48 hours. Original magnification x400 (D).</p
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