149 research outputs found
BIOMETRIC AND MORHOLOGIC OBSERVATIONS ON SALIX FRAGILIS (SALICACEAE) LEAVES
The paper discloses a research model of leaf investigation, based on biometric measurements and morphologic observations. There are only a few examples of this type of biometric investigation model applied on spontaneous plants leaves in literature. The article comprises biometrical and morphologic investigations on 40 leaves of Salix fragilis L. The measurements and observations were performed on 40 mature leaves collected from the apex, middle and base of the crown, including linear measurements, percentage ratio, angular measurements and other measurements such as the number semi-sum of secondary pairs of veins (Np), the teeth number/cm and the lamina surface as well. The biometric measurements were the basis of a mathematical calculation of the average values on the studied species leaves
ANATOMICAL ASPECTS OF BEGONIAHYDROCOTYLIFOLIAOTTO EX HOOK. (BEGONIACEAE) LEAF
The paper presents anatomical aspects concerning the leaf structure of Begonia hydrocotylifolia Otto ex Hook. belonging to Begoniaceae family. Anatomically, the petiole has a unistratous epidermis and a differentiated mesophyll. The vascular system is fascicular type with a large number of collateral bundles placed into a basic tissue. The blade consits of an upper epidermis with a many-layerd hypodermis, a lower epidermis and the mesophyll. The mesophyll is differentiated into palisade and spongy tissue with the same vascular bundle structure such as those of the petiole but with foliar arrangement of the conductive tissues. Stomata are present to the lower epidermis. Remarkable are the cytological elements represented by prismatic oxalate crystals, druses, crystalline sand and tannin cells. The mechanical tissue is represented by collencyma cellls, presented in the petiole and blade structure
STRUCTURAL ASPECTS OF THE VEGETATIVE OEGANS OF CRYPTOCORYNE WENDTII DE WIT. (ARACEAE)
The paper presents structural aspects of the vegetative organs (adventitious root, stem and leaf) of a monocot herb, native to Sri Lanka and Thailand, namely Cryptocorynewendtii de Wit. It is a green variety of Cryptocorynewendtii, growing both submerged and emerged in its native regions. In our country the plant is known as an aquarium plant. The material fixation and processing was done according to the usual protocol of the Vegetal Morphology and Anatomy Laboratory belonging to the Natural Sciences Department of the our faculty. The adventitious root has a primary monocot structure with small intercellular spaces. The short stem vascular system consists of amphivasal bundles to the center and fewcollateral bundles to periphery.The petiole exhibits epidermis with regularlly arranged cutinized cells, without intercellular spaces, covered by a thik cuticle and poor developed stele vascular system. The leaf mesophyll is homogenous (isobilateral) type, with small intercellular spaces and a poor developed midrib collateral bundle with few conductive elements. The mechanical tissues almost lack. The petiole and blade have sclerenchyma groups of cells bellow the epidermis and for the blade to the lower epidermis
Lipids induce expression of serum-responsive transmembrane kinase EhTMKB1-9 in an early branching eukaryote Entamoeba histolytica
Mechanisms underlying the initiation of proliferative response are known only for a few organisms, and are not understood for the medically important organisms including Entamoeba histolytica. The trans membrane kinase EhTMKB1-9 of E. histolytica is one of the early indicators of proliferation and its' expression is regulated by serum, one of the components necessary for cellular proliferation in vitro. In this study we show that bovine serum albumin (BSA) can induce EhTMKB1-9 expression in place of serum, and that both follow the same mechanism. Both serum and BSA use the same promoter element and the activation process is initiated through a PI3 kinase-mediated pathway. We further show that BSA activates EhTMKB1-9 due to the lipids associated with it and that unsaturated fatty acids are responsible for activation. These results suggest that lipid molecules are ligand(s) for initiation of a signaling system that stimulates EhTMKB1-9 expression
Skin sensitization in silico protocol
The assessment of skin sensitization has evolved over the past few years to include in vitro assessments of key events along the adverse outcome pathway and opportunistically capitalize on the strengths of in silico methods to support a weight of evidence assessment without conducting a test in animals. While in silico methods vary greatly in their purpose and format; there is a need to standardize the underlying principles on which such models are developed and to make transparent the implications for the uncertainty in the overall assessment. In this contribution, the relationship of skin sensitization relevant effects, mechanisms, and endpoints are built into a hazard assessment framework. Based on the relevance of the mechanisms and effects as well as the strengths and limitations of the experimental systems used to identify them, rules and principles are defined for deriving skin sensitization in silico assessments. Further, the assignments of reliability and confidence scores that reflect the overall strength of the assessment are discussed. This skin sensitization protocol supports the implementation and acceptance of in silico approaches for the prediction of skin sensitization
Lectures on Gaussian approximations with Malliavin calculus
In a seminal paper of 2005, Nualart and Peccati discovered a surprising
central limit theorem (called the "Fourth Moment Theorem" in the sequel) for
sequences of multiple stochastic integrals of a fixed order: in this context,
convergence in distribution to the standard normal law is equivalent to
convergence of just the fourth moment. Shortly afterwards, Peccati and Tudor
gave a multidimensional version of this characterization. Since the publication
of these two beautiful papers, many improvements and developments on this theme
have been considered. Among them is the work by Nualart and Ortiz-Latorre,
giving a new proof only based on Malliavin calculus and the use of integration
by parts on Wiener space. A second step is my joint paper "Stein's method on
Wiener chaos" (written in collaboration with Peccati) in which, by bringing
together Stein's method with Malliavin calculus, we have been able (among other
things) to associate quantitative bounds to the Fourth Moment Theorem. It turns
out that Stein's method and Malliavin calculus fit together admirably well.
Their interaction has led to some remarkable new results involving central and
non-central limit theorems for functionals of infinite-dimensional Gaussian
fields. The current survey aims to introduce the main features of this recent
theory. It originates from a series of lectures I delivered at the Coll\`ege de
France between January and March 2012, within the framework of the annual prize
of the Fondation des Sciences Math\'ematiques de Paris. It may be seen as a
teaser for the book "Normal Approximations Using Malliavin Calculus: from
Stein's Method to Universality" (jointly written with Peccati), in which the
interested reader will find much more than in this short survey.Comment: 72 pages. To be published in the S\'eminaire de Probabilit\'es. Mild
update: typos, referee comment
Space Charge at Nanoscale: Probing Injection and Dynamic Phenomena Under Dark/Light Configurations by Using KPFM and C-AFM
International audienc
Thresholds of Toxicological Concern for Cosmetics-Related Substances: New Database, Thresholds, and Enrichment of Chemical Space
A new dataset of cosmetics-related chemicals for the Threshold of Toxicological Concern (TTC) approach has been compiled, comprising 552 chemicals with 219, 40, and 293 chemicals in Cramer Classes I, II, and III, respectively. Data were integrated and curated to create a database of No-/Lowest-Observed-Adverse-Effect Level (NOAEL/LOAEL) values, from which the final COSMOS TTC dataset was developed. Criteria for study inclusion and NOAEL decisions were defined, and rigorous quality control was performed for study details and assignment of Cramer classes. From the final COSMOS TTC dataset, human exposure thresholds of 42 and 7.9 μg/kg-bw/day were derived for Cramer Classes I and III, respectively. The size of Cramer Class II was insufficient for derivation of a TTC value. The COSMOS TTC dataset was then federated with the dataset of Munro and colleagues, previously published in 1996, after updating the latter using the quality control processes for this project. This federated dataset expands the chemical space and provides more robust thresholds. The 966 substances in the federated database comprise 245, 49 and 672 chemicals in Cramer Classes I, II and III, respectively. The corresponding TTC values of 46, 6.2 and 2.3 μg/kg-bw/day are broadly similar to those of the original Munro dataset
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