407 research outputs found
Nonaqueous Emulsion Polymerization: A Practical Synthetic Route for the Production of Molecularly Imprinted Nanospheres
No full textMonodisperse, molecularly imprinted nanospheres
were synthesized by nonaqueous (mini)emulsion polymerization
using a standard monomer mixture of methacrylic acid
and ethylene dimethacrylate containing the drug propranolol
as a template. The preparation conditions (solvent, amount of
surfactant, and amount of employed template) were extensively
varied in order to assess their effect on the properties of
the resulting polymer nanoparticles. The molecular recognition
capability of the nanospheres was evaluated in batch rebinding
experiments, and the effect of the nanosphere preparation conditions as well as of the reaction conditions was investigated.
In this way, optimal preparation protocols for molecularly
imprinted nanoparticles under nonaqueous conditions with the
use of a nonionic emulsifier were identified, which lead to
nanospheres with a diameter of around 100 nm having an
enhanced capacity of specific template rebinding compared to
both nonimprinted nanospheres and to particles obtained by
emulsion polymerization in water. Best results were obtained
with nanospheres prepared in N,N-dimethylformamide/
n-hexane with a high functional monomer to template ratio.
The enantioselectivity of the rebinding process was also demonstrated
Follicular lymphoma: still six characters in search of an author?
No full textFollicular lymphoma (FL) is regarded as a distinct entity in the literature as well as in the 2008 edition of the WHO classification of tumours of haematopoietic and lymphoid tissues.Nevertheless, there are still several issues that are matters of controversy such as the grading system or the exact biological location of grade 3B FL. This makes FL somewhat like the Six characters in search of an author of Pirandello's comedy. Here, we revise the morphology and pathobiology of FL by highlighting both the areas remaining critical and future perspectives. This review was inspired by the reappraisal of Professor Lennert's personal archive that represents a unique legacy for the entire scientific community
The role of factoring for financing small and medium enterprises
No full textAround the world, factoring is a growing source of external financing for corporations and small and medium-size enterprises (SMEs). What is unique about factoring is that the credit provided by a lender is explicitly linked to the value of a supplier's accounts receivable and not the supplier's overall creditworthiness. Therefore, factoring allows high-risk suppliers to transfer their credit risk to their high-quality buyers. Factoring may be particularly useful in countries with weak judicial enforcement and imperfect records of upholding seniority claims because receivables are sold, rather than collateralized, and factored receivables are not part of the estate of a bankrupt SME. Empirical tests find that factoring is larger in countries with greater economic development and growth and developed credit information bureaus. In addition, the author finds that creditor rights are not related to factoring. The author also discusses reverse factoring, which is a technology that can mitigate the problem of borrowers'informational opacity in business environments with weak information infrastructures if only receivables from high-quality buyers are factored. She illustrates the case of the Nafin reverse factoring program in Mexico and highlights how the use of electronic channels and a supportive legal and regulatory environment can cut costs and provide greater SME services in emerging markets.Banks&Banking Reform,Banking Law,Financial Intermediation,Environmental Economics&Policies,Economic Theory&Research
Los efectos de la comunicación de masas de Joseph T. Klapper
No full textIn this paper we review the Joseph T. Klapper (1960) book's The effects of mass communication. The paper begin with a context from the author and his work. Following we present the contents, on the one hand the effects of persuasive communication and the influence of certain specific types of media material, and on the other the generalizations which are capable of relating these findings. The article ends with reflection about the impact of the work in the history of the research. We suggest that the Klapper's book is the last legacy of the empirical sociology of the Columbia¿s Bureau led by Paul F. Lazarsfeld into the communication research.Ciencias de la Comunicación I
Characterization of genomic imbalances in diffuse large B-cell lymphoma by detailed SNP-chip analysis
No full textThe pathogenesis of diffuse large B-cell lymphomas (DLBCL) is only partly understood. We analyzed 148 DLBCL by single nucleotide polymorphism (SNP)-chips to characterize genomic imbalances. Seventy-nine cases were of the germinal center B-cell like (GCB) type of DLBCL, 49 of the activated B-cell like (ABC) subtype and 20 were unclassified DLBCL. Twenty-four regions of recurrent genomic gains and 38 regions of recurrent genomic losses were identified over the whole cohort, with a median of 25 imbalances per case for ABC-DLBCL and 19 per case for GCB-DLBCL. Several recurrent copy number changes showed differential frequencies in the GCB- and ABC-DLBCL subgroups, including gains of HDAC7A predominantly in GCB-DLBCL (38% of cases) and losses of BACH2 and CASP8AP2 predominantly in ABC-DLBCL (35%), hinting at disparate pathogenetic mechanisms in these entities. Correlating gene expression and copy number revealed a strong gene dosage effect in all tumors, with 34% of probesets showing a concordant expression change in affected regions. Two new potential tumor suppressor genes emerging from the analysis, CASP3 and IL5RA, were sequenced in ten and 16 candidate cases, respectively. However, no mutations were found, pointing to a potential haploinsufficiency effect of these genes, considering their reduced expression in cases with deletions. Our study thus describes differences and similarities in the landscape of genomic aberrations in the DLBCL subgroups in a large collection of cases, confirming already known targets, but also discovering novel copy number changes with possible pathogenetic relevance. What's new? In their quest to uncover new genes involved in diffuse large B-cell lymphoma (DLBCL), these authors searched for changes in copy number using an array of small nucleotide polymorphisms - a SNP-chip. They found a number of recurrent copy number changes across the entire sample of 148 tumors, and when they separated the samples by lymphoma subtype, they found some of these changes were common to the various subtypes, but some were specific to a single subtype. They also found that a third of the copy number changes did correspond to changes in gene expression. This is the first analysis to investigate subtype-specific changes in copy number, and reveal similarities and differences between the two main types
Gene expression profiling reveals a close relationship between follicular lymphoma grade 3A and 3B, but distinct profiles of follicular lymphoma grade 1 and 2
No full textA linear progression model of follicular lymphomas (FL) FL1, FL2 and FL3A has been favored, since FL3A often co-exist with an FL1/2 component. FL3B, in contrast, is thought to be more closely related to diffuse large B-cell lymphoma (DLBCL), and both are often simultaneously present in one tumor (DLBCL/FL3B). To obtain more detailed insights into follicular lymphoma progression, a comprehensive analysis of a well-defined set of FL1/2 (n=22), FL3A (n=16), FL3B (n=6), DLBCL/FL3B (n=9), and germinal center B-cell-type diffuse large B-cell lymphoma (n=45) was undertaken using gene expression profiling, immunohistochemical stainings and genetic analyses by fluorescence in situ hybridization. While immunohistochemical (CD10, IRF4/MUM1, Ki67, BCL2, BCL6) and genetic profiles (translocations of BCL2, BCL6 and MYC) delineate FL1-3A from FL3B and DLBCL/FL3B, significant differences were observed between FL1/2 and FL3A upon gene expression profiling. Interestingly, FL3B turned out to be closely related to FL3A, not categorizing within a separate gene expression cluster, and both FL3A and FL3B showed overlapping profiles in between FL1/2 and diffuse large B-cell lymphoma. Finally, based upon their gene expression pattern, DLBCL/FL3B represent a composite form of FL3B and DLBCL, with the majority of samples more closely resembling the latter. The fact that gene expression profiling clearly separated FL1/2 from both FL3A and FL3B suggests a closer biological relationship between the latter. This notion, however, is in contrast to immunohistochemical and genetic profiles of the different histological FL subtypes that point to a closer relationship between FL1/2 and FL3A, and separates them from FL3B
Automated macrophage counting in DLBCL tissue samples: a ROF filter based approach
No full textBackgroundFor analysis of the tumor microenvironment in diffuse large B-cell lymphoma (DLBCL) tissue samples, it is desirable to obtain information about counts and distribution of different macrophage subtypes. Until now, macrophage counts are mostly inferred from gene expression analysis of whole tissue sections, providing only indirect information. Direct analysis of immunohistochemically (IHC) fluorescence stained tissue samples is confronted with several difficulties, e.g. high variability of shape and size of target macrophages and strongly inhomogeneous intensity of staining. Consequently, application of commercial software is largely restricted to very rough analysis modes, and most macrophage counts are still obtained by manual counting in microarrays or high power fields, thus failing to represent the heterogeneity of tumor microenvironment adequately.MethodsWe describe a Rudin-Osher-Fatemi (ROF) filter based segmentation approach for whole tissue samples, combining floating intensity thresholding and rule-based feature detection. Method is validated against manual counts and compared with two commercial software kits (Tissue Studio 64, Definiens AG, and Halo, Indica Labs) and a straightforward machine-learning approach in a set of 50 test images. Further, the novel method and both commercial packages are applied to a set of 44 whole tissue sections. Outputs are compared with gene expression data available for the same tissue samples. Finally, the ROF based method is applied to 44 expert-specified tumor subregions for testing selection and subsampling strategies.ResultsAmong all tested methods, the novel approach is best correlated with manual count (0.9297). Automated detection of evaluation subregions proved to be fully reliable. Comparison with gene expression data obtained for the same tissue samples reveals only moderate to low correlation levels. Subsampling within tumor subregions is possible with results almost identical to full sampling. Mean macrophage size in tumor subregions is 152.5111.3 m(2).ConclusionsROF based approach is successfully applied to detection of IHC stained macrophages in DLBCL tissue samples. The method competes well with existing commercial software kits. In difference to them, it is fully automated, externally repeatable, independent on training data and completely documented. Comparison with gene expression data indicates that image morphometry constitutes an independent source of information about antibody-polarized macrophage occurence and distribution
Molecularly Imprinted Nanospheres by Nonaqueous Emulsion Polymerization
No full textThe preparation of nanosized, molecularly imprinted polymer particles by nonaqueous emulsion polymerization is presented. Monodisperse cross-linked polymer nanospheres with a diameter of around 100 nm were synthesized using a standard monomer mixture of methacrylic acid and ethylene dimethacrylate, containing (+/-)-propranolol as a template. The rebinding efficiency of the resulting particles was determined by batch rebinding tests and isothermal titration calorimetry (ITC). The results indicate that the proposed imprinting process under nonaqueous conditions lead to particles with an enhanced capacity of template rebinding compared to both nonimprinted ones and to particles obtained by more conventional emulsion polymerization in water
Does strict employment protection discourage job creation? Evidence from Croatia
No full textEmployment protection legislation in Croatia is among the most strict in Europe. Firing is difficult and costly, and flexible forms of employment are limited. Is this apparent rigidity reflected-as one would expect based on standard economic theory-in low labor market dynamics? Is job creation low and hiring limited? Is the job security of insiders achieved at the cost of outsiders not being able to enter thelabor market? The author attempts to answer these questions by examining job flows. If the employment protection legislation is binding, then job and worker turnover should be low. He shows that this is indeed the case. Hiring is limited and the average job tenure is very long in Croatia. Job destruction is low, however job creation is still lower. The result is accumulation of unemployment, in large part due to new labor market entrants not being able to find a job. The high degree of job protection also seems to strengthen the bargaining position of insiders and results in relatively high wages. So, wages in Croatia are higher than among its competitors, even after adjusting for productivity. These high labor costs are likely to contribute to limited job creation in existing firms, but also are likely to discourage the entry of-and thus job creation in-new firms. The author presents evidence that firm growth has been indeed limited in Croatia, contributing to the low employment level. The author examines other potential causes of high unemployment in Croatia (the unemployment benefit system, labor taxation, the wage structure, and skill and spatial mismatches). He argues that they do not play a substantial part in accounting for poor labor market outcomes in Croatia. The author concludes that the stringent employment protection legislation is the key labor market institution behind low job creation and high unemployment. Based on this he recommends specific measures aimed at liberalizing the labor market to foster job creation and employment.Labor Management and Relations,Labor Policies,Labor Markets,Environmental Economics&Policies,Trade Finance and Investment,Labor Markets,Labor Management and Relations,Labor Standards,Banks&Banking Reform,Environmental Economics&Policies
ANALYSIS OF MECHANISMS OF MALIGNANT TRANSFORMATION IN TP53 WILD-TYPE BURKITT'S LYMPHOMA BY INTEGRATION OF MOLECULAR AND FUNCTIONAL GENOMICS DATA
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