6 research outputs found
Longhorn beetles fauna (Coleoptera: Cerambycidae) of Puszcza Pilicka
On the basis of the material collected from 1981-1995 in Pilica F orest and analysis
of published data 76 species of Cerambycidae were recorded. Twenty nine of them have for
the first time been recorded from the mentioned area.Zadanie pt. „Digitalizacja i udostępnienie w Cyfrowym Repozytorium Uniwersytetu Łódzkiego kolekcji czasopism naukowych wydawanych przez Uniwersytet Łódzki” nr 885/P-DUN/2014 dofinansowane zostało ze środków MNiSW w ramach działalności upowszechniającej naukę
The microstructure of composite materials in the EN AW-2024 alloy matrix reinforced by α-Al<sub>2</sub>O<sub>3</sub> particles
W pracy zostały przedstawione wyniki badań mikrostruktur
materiałów kompozytowych wytwarzanych metodą
infiltracji ciśnieniowej preform z cząstek ceramicznych
α-Al2O3 stopem aluminium EN AW-2024. W badaniach mikroskopowych
w szczególności oceniano jakość połączeń
na granicach międzyfazowych osnowa-cząstki ceramiczne.
Stwierdzono, że krzemionka (SiO2) stosowana do łączenia
cząstek tlenku glinu w preformie powoduje wzbogacenie
osnowy w krzem (Si), w części dyfundujący do stopu aluminium,
który jednak pozostaje w osnowie w postaci skupisk
SiO2, szczególnie w obrębie cząstek ceramicznych o dużym
stopniu aglomeracji. Infiltracja porów otwartych preformy
ceramicznej stopem EN AW-2024 o ograniczonej rzadkopłynności
utrudnia proces infiltracji, pozostawiając lokalnie
występującą porowatość. Propagacja pęknięć w materiale
kompozytowym po badaniach właściwości mechanicznych
następuje głównie po granicach międzyfazowych osnowa-
-cząstka, szczególnie w miejscach o zwiększonej ilości rezydualnej
krzemionki (SiO2) w osnowie. Na powierzchniach
przełomów obserwuje się cząstki ceramiczne umocnienia
α-Al2O3 o mocnym adhezyjnym połączeniu z osnową, które
podczas tworzenia złomu ulegają pęknięciom.The paper presents the results of investigations into the
microstructures of composite materials produced by pressure
infiltration of preforms of ceramic α-Al2O3 particles with
aluminium alloy EN AW-2024. In particular, the quality of the
bonds at the interphase boundaries of matrix-ceramic particles
was evaluated using microscopy investigations. It was
found that silica (SiO2) used for bonding alumina particles
in the preform causes an enrichment of the matrix in silicon
(Si), which partly diffuses to aluminium alloy, yet remains
in the matrix in the form of SiO2 concentrations, especially
within ceramic particles with a high degree of agglomeration.
The infiltration of open pores of ceramic preforms with
EN AW-2024 alloy of limited flowing power hinders the
infiltration process, resulting in local porosity. The propagation
of cracks in the composite material after tests for
mechanical properties occurs mainly along the interphase
boundaries of the matrix-particle, especially in places with
an increased residual amount of silica (SiO2) in the matrix.
On the surfaces of the fractures ceramic particles of the
α-Al2O3 reinforcement are observed, they form a strong adhesive
bond with the matrix and crack during the formation
of scrap metal
Clinical characteristics and treatment outcomes of myeloid sarcoma in children : the experience of the Polish Pediatric Leukemia and Lymphoma Study Group
INTRODUCTION: Myeloid sarcoma (MS) is an extramedullary malignant tumor composed of immature myeloid cells. It occurs in patients with acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), or chronic myeloid leukemia (CML). MS may coincide with disease diagnosis or precede bone marrow involvement by months or even years; it can also represent the extramedullary manifestation of a relapse (1, 2). AIM: The aim of this study is to describe clinical characteristics of children diagnosed with MS in Poland as well as to analyze diagnostic methods, treatment, and outcomes including overall survival (OS), relapse-free survival (RFS), and event-free survival (EFS). The study also attempted to identify factors determining treatment outcomes. PATIENTS: The study group comprised 43 patients (F=18, M=25) aged 0-18 years (median age, 10.0 years; mean age, 8.8 years) diagnosed with MS based on tumor biopsy and immunohistochemistry or identification of underlying bone marrow disease and extramedullary tumor according to imaging findings. METHODS: The clinical data and diagnostic and therapeutic methods used in the study group were analyzed. A statistical analysis of the treatment outcomes was conducted with STATISTICA v. 13 (StatSoft, Inc., Tulsa, OK, USA) and analysis of survival curves was conducted with MedCalc 11.5.1 (MedCalc Software, Ostend, Belgium). Statistical significance was considered at p<0.05. RESULTS: In the study group, MS was most frequently accompanied by AML. The most common site of involvement was skin, followed by orbital region. Skin manifestation of MS was more common in the age group <10 years. The most frequent genetic abnormality was the t(8;21)(q22;q22) translocation. The 5-year OS probability (pOS), 5-year RFS probability (pRFS), and 5-year EFS probability (pEFS) were 0.67 ± 0.08, 0.79 ± 0.07, and 0.65 ± 0.08, respectively. In patients with isolated MS and those with concurrent bone marrow involvement by AML/MDS, pOS values were 0.56 ± 0.12 and 0.84 ± 0.09 (p=0.0251), respectively, and pEFS values were 0.56 ± 0.12 and 0.82 ± 0.08 (p=0.0247), respectively. In patients with and without the t(8;21)(q22;q22) translocation, pEFS values were 0.90 ± 0.09 and 0.51 ± 0.14 (p=0.0490), respectively. CONCLUSIONS: MS is a disease with a highly variable clinical course. Worse treatment outcomes were observed in patients with isolated MS compared to those with concurrent bone marrow involvement by AML/MDS. Patients with the t(8;21)(q22;q22) translocation were found to have significantly higher pEFS. MS location, age group, chemotherapy regimen, surgery, and/or radiotherapy did not have a significant influence on treatment outcomes. Further exploration of prognostic factors in children with MS is indicated