115 research outputs found
Singly generated quasivarieties and residuated structures
A quasivariety K of algebras has the joint embedding property (JEP) iff it is
generated by a single algebra A. It is structurally complete iff the free
countably generated algebra in K can serve as A. A consequence of this demand,
called "passive structural completeness" (PSC), is that the nontrivial members
of K all satisfy the same existential positive sentences. We prove that if K is
PSC then it still has the JEP, and if it has the JEP and its nontrivial members
lack trivial subalgebras, then its relatively simple members all belong to the
universal class generated by one of them. Under these conditions, if K is
relatively semisimple then it is generated by one K-simple algebra. It is a
minimal quasivariety if, moreover, it is PSC but fails to unify some finite set
of equations. We also prove that a quasivariety of finite type, with a finite
nontrivial member, is PSC iff its nontrivial members have a common retract. The
theory is then applied to the variety of De Morgan monoids, where we isolate
the sub(quasi)varieties that are PSC and those that have the JEP, while
throwing fresh light on those that are structurally complete. The results
illuminate the extension lattices of intuitionistic and relevance logics
-SDYM Fields and Heavenly Spaces. I. -SDYM equations as an integrable system
It is shown that the self-dual Yang-Mills (SDYM) equations for the
-bracket Lie algebra on a heavenly space can be reduced to one equation
(the \it master equation\rm). Two hierarchies of conservation laws for this
equation are constructed. Then the twistor transform and a solution to the
Riemann-Hilbert problem are given.Comment: 25 page
Mutations in Radial Spoke Head Genes and Ultrastructural Cilia Defects in East-European Cohort of Primary Ciliary Dyskinesia Patients
Primary ciliary dyskinesia (PCD) is a rare (1/20,000), multisystem disease with a complex phenotype caused by the impaired motility of cilia/flagella, usually related to ultrastructural defects of these organelles. Mutations in genes encoding radial spoke head (RSPH) proteins, elements of the ciliary ultrastructure, have been recently described. However, the relative involvement of RSPH genes in PCD pathogenesis remained unknown, due to a small number of PCD families examined for mutations in these genes. The purpose of this study was to estimate the involvement of RSPH4A and RSPH9 in PCD pathogenesis among East Europeans (West Slavs), and to shed more light on ultrastructural ciliary defects caused by mutations in these genes. The coding sequences of RSPH4A and RSPH9 were screened in PCD patients from 184 families, using single strand conformational polymorphism analysis and sequencing. Two previously described (Q109X; R490X) and two new RSPH4A mutations (W356X; IVS3_2–5del), in/around exons 1 and 3, were identified; no mutations were found in RSPH9. We estimate that mutations in RSPH4A, but not in RSPH9, are responsible for 2–3% of cases in the East European PCD population (4% in PCD families without situs inversus; 11% in families preselected for microtubular defects). Analysis of the SNP-haplotype background provided insight into the ancestry of repetitively found mutations (Q109X; R490X; IVS3_2–5del), but further studies involving other PCD cohorts are required to elucidate whether these mutations are specific for Slavic people or spread among other European populations. Ultrastructural defects associated with the mutations were analyzed in the transmission electron microscope images; almost half of the ciliary cross-sections examined in patients with RSPH4A mutations had the microtubule transposition phenotype (9+0 and 8+1 pattern). While microtubule transposition was a prevalent ultrastructural defect in cilia from patients with RSPH4A mutations, similar defects were also observed in PCD patients with mutations in other genes
Diagnosis and treatment of thyroid cancer in children in the multicenter analysis in Poland for PPGGL
Introduction: Differentiated thyroid carcinoma (DTC) in
children presents different biological behavior in comparison
to adults. Authors presents preliminary results of multicenter
analysis concerning incidence, diagnostics and treatment
of DTC in children.
Material and methods: The study is a retrospective analysis
of 107 pediatric patients from 14 academic centers based
on the data from 2000 to 2005 obtained by questionnaire in
hospitals involved in the treatment of DTC in children.
Results: Papillary thyroid cancer was diagnosed in 83 children,
follicular thyroid cancer in 10 children and medullary
thyroid cancer in 14 children. Incidence of DTC in children
was estimated between 18 and 23 cases per year. The biggest
group of patients consisted of children between 11 and
15 years of age, with girls to boys ratio 3.3 : 1. Clinically DTC
in children presented most often as solitary thyroid nodule.
Cervical lymphadenopathy was observed in 42% of patients.
Intraoperative verification indicated metastatic nodes
in 50% of children. Low stage DTC predominated (T1
in 36% and T2 in 26% of children). One step surgery was performed in 65% of children with DTC, two step surgery
in 25% of patients. I131 therapy was undertaken in 80% of
children. Lung metastases were indicated in post therapeutic
studies in 14% of children with DTC. Prophylactic thyroidectomies
were performed in 79% of children in the group
of patients with MTC and RET gene mutations.
Conclusions: The necessity of introduction of unified therapeutic
standard in children with DTC in Poland is underlined.Wstęp: Zróżnicowane raki tarczycy (DTC, differentiated thyroid
carcinoma) występują u dzieci rzadko. Większość przypadków
wykrywanych jest w wieku 11-17 lat. W odróżnieniu
od dorosłych DTC u dzieci prezentują odmienne zachowanie
biologiczne. Mała liczba przypadków DTC
w poszczególnych ośrodkach oraz względnie łagodny ich
przebieg utrudniają ocenę występowania i leczenia DTC
u dzieci w Polsce, uzależniając ją od wysiłków włożonych
w uzyskanie rzetelnych danych. Autorzy przedstawiają
wstępne wyniki analizy wieloośrodkowej dotyczące występowania,
diagnostyki i leczenia DTC u dzieci.
Materiał i metody: Podjęte badania są retrospektywną analizą
obejmującą lata 2000-2005, opartą na danych z historii
chorób uzyskanych z ankiet rozesłanych do ośrodków dla
dzieci i dorosłych podejmujących leczenie DTC. Do analizy
zgłoszono 107 pacjentów z 14 ośrodków akademickich
w Polsce. Analizie poddano wiek i płeć dzieci z DTC, wielkość
i lokalizację zmian w tarczycy, sposoby rozpoznawania
DTC, rodzaje i zakres wykonywanych zabiegów operacyjnych
oraz leczenie uzupełniające izotopem J131.
Wyniki: Raka brodawkowatego stwierdzono u 83 dzieci,
pęcherzykowego u 10 dzieci, a rdzeniastego u 14 dzieci. Częstość
występowania DTC u dzieci w Polsce wahała się między
18 a 23 przypadkami rocznie. W województwach: mazowieckim
i połączonych wielkopolskim i lubuskim wykazano
w okresie 2000-2005 wyższą (24 i 25) częstość występowania
DTC, w pozostałych województwach wykazywano
od 2 do 10 przypadków DTC. Największą grupę pacjentów
stanowiły dzieci w wieku 11-15 lat, a stosunek dziewcząt do chłopców wynosił 3,3 : 1. Klinicznie DTC prezentowały
się najczęściej jako pojedyncze guzki tarczycy. Limfadenopatię
szyjną w badaniu klinicznym stwierdzono
u 42% pacjentów, a śródoperacyjnie u 50% dzieci. U większości
pacjentów dominowały niższe stopnie zaawansowania
DTC (T1 u 36% i T2 u 26% dzieci). Operacje jednoetapowe
wykonano u 65% dzieci, operacje dwuetapowe u 25%
dzieci, a profilaktyczne tyreoidektomie u 79% dzieci z grupy
pacjentów z rakiem rdzeniastym tarczycy (MTC, medullary
thyroid cancinoma) i mutacją genu Ret. Leczenie izotopowe
J131 podjęto u 80% dzieci. Przerzuty do płuc w scyntygrafii
poterapeutycznej wykazano u 14% dzieci z DTC.
Wnioski: We wnioskach podkreśla się konieczność wdrożenia
na terenie całego kraju ujednoliconego i ocenianego
na podstawie obiektywnych przesłanek sposobu postępowania
z dziećmi z DTC
Correction to: Cluster identification, selection, and description in Cluster randomized crossover trials: the PREP-IT trials
An amendment to this paper has been published and can be accessed via the original article
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