339 research outputs found
Very long optical path-length from a compact multi-pass cell
The multiple-pass optical cell is an important tool for laser absorption
spectroscopy and its many applications. For most practical applications, such
as trace-gas detection, a compact and robust design is essential. Here we
report an investigation into a multi-pass cell design based on a pair of
cylindrical mirrors, with a particular focus on achieving very long optical
paths. We demonstrate a path-length of 50.31 m in a cell with 40 mm diameter
mirrors spaced 88.9 mm apart - a 3-fold increase over the previously reported
longest path-length obtained with this type of cell configuration. We
characterize the mechanical stability of the cell and describe the practical
conditions necessary to achieve very long path-lengths
Exploring the Law of Detrital Zircon: LA-ICP-MS and CA-TIMS Geochronology of Jurassic Forearc Strata, Cook Inlet, Alaska, USA
Uranium-lead (U-Pb) geochronology studies commonly employ the law of detrital zircon: A sedimentary rock cannot be older than its youngest zircon. This premise permits maximum depositional ages (MDAs) to be applied in chronostratigraphy, but geochronologic dates are complicated by uncertainty. We conducted laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and chemical abrasion-thermal ionization mass spectrometry (CA-TIMS) of detrital zircon in forearc strata of southern Alaska (USA) to assess the accuracy of several MDA approaches. Six samples from MiddleâUpper Jurassic units are generally replete with youthful zircon and underwent three rounds of analysis: (1) LA-ICP-MS of âŒ115 grains, with one date per zircon; (2) LA-ICP-MS of the âŒ15 youngest grains identified in round 1, acquiring two additional dates per zircon; and (3) CA-TIMS of the âŒ5 youngest grains identified by LA-ICP-MS. The youngest single-grain LA-ICP-MS dates are all younger thanâand rarely overlap at 2Ï uncertainty withâthe CA-TIMS MDAs. The youngest kernel density estimation modes are typically several million years older than the CA-TIMS MDAs. Weighted means of round 1 dates that define the youngest statistical populations yield the best coincidence with CA-TIMS MDAs. CA-TIMS dating of the youngest zircon identified by LA-ICP-MS is indispensable for critical MDA applications, eliminating laser-induced matrix effects, mitigating and evaluating Pb loss, and resolving complexities of interpreting lower-precision, normally distributed LA-ICP-MS dates. Finally, numerous CA-TIMS MDAs in this study are younger than Bathonian(?)âCallovian and Oxfordian faunal correlations suggest, highlighting the need for additional radioisotopic constraintsâincluding CA-TIMS MDAsâfor the MiddleâLate Jurassic geologic time scale
Common cancer-associated imbalances in the DNA damage response confer sensitivity to single agent ATR inhibition
ATR is an attractive target in cancer therapy because it signals replication stress and DNA lesions for repair and to S/G2 checkpoints. Cancer-specific defects in the DNA damage response (DDR) may render cancer cells vulnerable to ATR inhibition alone. We determined the cytotoxicity of the ATR inhibitor VE-821 in isogenically matched cells with DDR imbalance. Cell cycle arrest, DNA damage accumulation and repair were determined following VE-821 exposure. Defects in homologous recombination repair (HRR: ATM, BRCA2 and XRCC3) and base excision repair (BER: XRCC1) conferred sensitivity to VE-821. Surprisingly, the loss of different components of the trimeric non-homologous end-joining (NHEJ) protein DNA-PK had opposing effects. Loss of the DNA-binding component, Ku80, caused hypersensitivity to VE-821, but loss of its partner catalytic subunit, DNA-PKcs, did not. Unexpectedly, VE-821 was particularly cytotoxic to human and hamster cells expressing high levels of DNA-PKcs. High DNA-PKcs was associated with replicative stress and activation of the DDR. VE-821 suppressed HRR, determined by RAD51 focus formation, to a greater extent in cells with high DNA-PKcs. Defects in HRR and BER and high DNA-PKcs expression, that are common in cancer, confer sensitivity to ATR inhibitor monotherapy and may be developed as predictive biomarkers for personalised medicine
Exploring the quality of social information disclosed in non-financial reports of Croatian companies
By enacting the provisions of Directive 2014/95/EU and the
Croatian Accounting Act on disclosing non-financial and diversity
information, companies of public interest registering 500 and
more employees are required to disclose non-financial information.
The purpose of this research is to assess the quality of disclosed
social information in non- financial/sustainability reports of
Croatian companies. The assessment of the social information was
grounded on the framework defined by globally accepted sustainability
reporting standards by assessing the quality of social subcategories
of human rights, labour practice, community/society
and product, measured by attributes of relevance, clarity, verifiability,
comparability and clarity. With the overall quality score of
13.16 (out of possible 36), the results prove that Croatian companies
do disclose certain social information, but the reliability of
this information for benchmarking and competitiveness assessment
is questionable, as a consensus on the minimum of information
to be disclosed as a fundamental requirement for
benchmarking has not yet been reached
Drivers and technology-related obstacles in moving to multichannel retailing
Today, multichannel retailing is a key strategic issue for most retailers. Yet, while there are many drivers associated with retailers going multichannel so too are there technology-related obstacles, however, few prior empirical studies explore these themes. In light of this, by using a multi-case approach to understand the key drivers and technology-related obstacles associated with retailers moving to multichannel retailing our study makes two key contributions. First, we extend prior theory by providing novel empirical insights into the main drivers underpinning retailers using a multichannel strategy. We find that meeting customer needs and increasing sales were the primary drivers behind retailers using the strategy, although there is diversity in the way retailers respond to these motives. Second, we provide empirical support for a proposed theoretical framework which summarises the key technology-related obstacles retailers encounter when going multichannel, by stage of implementation. The framework reveals that retailers face technology-related obstacles when implementing a multichannel strategy due to the need to switch/acquire resources and achieve channel integration. Furthermore, the framework highlights that these resource and channel integration issues are often interrelated with each other and with other staff engagement and cultural issues, vary by retailer and stage of implementation, and pose greater obstacles to retailers using new and multiple channels than the extant literature suggests
âBetter late than neverâ: the interplay between green technology and age for firm growth
This paper investigates the relationship between green/non-green technologies and firm growth. By combining the literature on eco-innovations, industrial organisation and entrepreneurial studies, we examine the dependence of this relationship on the pace at which firms grow and the age of the firm. From a dataset of 5498 manufacturing firms in Italy for the period of 2000â2008, longitudinal fixed effects quantile models are estimated, in which the firmâs age is set to moderate the effects of green and non-green patents on employment growth. We find that the positive effect of green technologies on growth is greater than that of non-green technologies. However, this result does not apply to struggling and rapidly growing firms. With fast-growing (above the median) firms, age moderates the growth effect of green technologies. Inconsistent with the extant literature, this moderation effect is positive: firm experience appears important for the growth benefits of green technologies, possibly relative to the complexity of their management
Molecular Basis of Increased Serum Resistance among Pulmonary Isolates of Non-typeable Haemophilus influenzae
Non-typeable Haemophilus influenzae (NTHi), a common commensal of the human pharynx, is also an opportunistic pathogen if it becomes established in the lower respiratory tract (LRT). In comparison to colonizing isolates from the upper airway, LRT isolates, especially those associated with exacerbations of chronic obstructive pulmonary disease, have increased resistance to the complement- and antibody-dependent, bactericidal effect of serum. To define the molecular basis of this resistance, mutants constructed in a serum resistant strain using the mariner transposon were screened for loss of survival in normal human serum. The loci required for serum resistance contribute to the structure of the exposed surface of the bacterial outer membrane. These included loci involved in biosynthesis of the oligosaccharide component of lipooligosaccharide (LOS), and vacJ, which functions with an ABC transporter encoded by yrb genes in retrograde trafficking of phospholipids from the outer to inner leaflet of the cell envelope. Mutations in vacJ and yrb genes reduced the stability of the outer membrane and were associated with increased cell surface hyrophobicity and phospholipid content. Loss of serum resistance in vacJ and yrb mutants correlated with increased binding of natural immunoglobulin M in serum as well as anti-oligosaccharide mAbs. Expression of vacJ and the yrb genes was positively correlated with serum resistance among clinical isolates. Our findings suggest that NTHi adapts to inflammation encountered during infection of the LRT by modulation of its outer leaflet through increased expression of vacJ and yrb genes to minimize recognition by bactericidal anti-oligosaccharide antibodies
The Emergence of Hospital Federations: An Integration of Perspectives from Organizational Theory
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68464/2/10.1177_107755878704400206.pd
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