Let
C
0
(
G
)
denote the near-ring of congruence preserving functions of the group
G
. We investigate the question “When is
C
0
(
G
)
a ring?”. We obtain information externally via the lattice ...structure of the normal subgroups of
G
and internally via structural properties of the group
G
.
The increased production of ethylene during carnation petal senescence regulates the transcription of the GST1 gene encoding a subunit of glutathione-S-transferase. We have investigated the molecular ...basis for this ethylene-responsive transcription by examining the cis elements and trans-acting factors involved in the expression of the GST1 gene. Transient expression assays following delivery of GST1 5' flanking DNA fused to a beta-glucuronidase reporter gene were used to functionally define sequences responsible for ethylene-responsive expression. Deletion analysis of the 5' flanking sequences of GST1 identified a single positive regulatory element of 197 bp between -667 and -470 necessary for ethylene-responsive expression. The sequences within this ethylene-responsive region were further localized to 126 bp between -596 and -470. The ethylene-responsive element (ERE) within this region conferred ethylene-regulated expression upon a minimal cauliflower mosaic virus-35S TATA-box promoter in an orientation-independent manner. Gel electrophoresis mobility-shift assays and DNase I footprinting were used to identify proteins that bind to sequences within the ERE. Nuclear proteins from carnation petals were shown to specifically interact with the 126-bp ERE and the presence and binding of these proteins were independent of ethylene or petal senescence. DNase I footprinting defined DNA sequences between -510 and -488 within the ERE specifically protected by bound protein. An 8-bp sequence (ATTTCAAA) within the protected region shares significant homology with promoter sequences required for ethylene responsiveness from the tomato fruit-ripening E4 gene
Intestinal epithelial cells derive from stem cells at the base of the crypt and migrate along the crypt-lumen axis. Their life is terminated as they reach the luminal surface where they detach and ...are shed. Intestinal epithelial cells show evidence of apoptosis in the region of shedding, and cell death is thought to resemble a form of apoptosis called detachment-induced cell death, or anoikis. Human intestinal epithelial cells die rapidly
in vitro due to loss of anchorage during isolation, making primary culture of these cells a goal that has not yet been reached. However, the molecular mechanisms underlying this process of anoikis are largely unknown. In this study, a novel protocol for the rapid, temperature-controlled isolation of highly purified human colonic epithelial cells from surgical specimens is described. Using this method, early molecular events of anoikis in nontransformed epithelial cells were studied. Intestinal epithelial cells were isolated at the beginning of the apoptotic cascade, before the activation of caspase 3 family members and cleavage of poly(ADP-ribose) polymerase and DNA fragmentation. Elucidating the molecular mechanisms of detachment-induced cell death may facilitate the establishment of long-term primary cultures of human intestinal epithelial cells and enhance our understanding of homeostasis in the intestinal epithelium.
The cell injury caused by oxidized lipoproteins was among the first findings that led to the theory that it is the oxidation of low-density lipoprotein (LDL), not just LDL concentration, that leads ...to arterial disease. Voluminous studies have now revealed that oxidized lipoproteins and their constituents can induce numerous effects on cells that can be construed to be atherogenic. Cell injury is but one of these, and it is these injurious effects that are the focus of this brief review. Cell injury and death appear to play multiple roles in lesion development and the toxic lipid constituents of oxidized lipoproteins, including a variety of oxysterols, are candidates for the in vivo effectors of this cytotoxicity. Recent studies have focused on the mechanisms of oxidized lipoprotein-induced cell death, whether the cells die by apoptosis or necrosis, and the identities of the toxins that induce injury. Understanding the roles of these agents in lesion development could lead to therapies that modulate cell death and inhibit lesion formation.
Unique maximal rings of functions Maxson, C. J.; Meyer, J. H.
Communications in algebra,
01/2017, Letnik:
45, Številka:
1
Journal Article
Recenzirano
For several classes of groups G, we characterize when the near-ring M
0
(G) of 0-preserving selfmaps on G contains a unique maximal ring. Definitive results are obtained for finite Abelian, finite ...nilpotent, and finite permutation groups. As an application, we determine those finite groups G such that all rings in M
0
(G) are commutative.
In this paper we study in detail the design of a novel S-band radiofrequency photogun structure to maximize the accelerating field experienced by the particles at injection. This is a critical ...quantity for electron sources as it has a direct impact on the maximum brightness achievable. The proposed design is based on a modification of the latest generation of S-band RF photoinjectors to include novel fabrication approaches. The gun is designed to operate at a 120MV/m gradient and at an optimal injection phase of 70° providing the beam quality required to enable novel electron beam applications such as single shot time-resolved transmission electron microscopy and ultrafast electron nanodiffraction.
Purpose. The aim of this study was to evaluate the relative activity and tolerance of liposomal doxorubicin in recurrent ovarian, peritoneal, and tubal carcinoma at an initial dose of 40 or 50 mg/m2 ...every 4 weeks.
Methods. A retrospective single-institution study was performed on patients who received liposomal doxorubicin from 1/97 to 12/00. Demographic data, liposomal doxorubicin dose, dose reductions, response, and progression-free and overall survival were recorded.
Results. Seventy-eight patients, 38 treated at 40 mg/m2 and 40 treated at 50 mg/m2, were identified. There was no difference with respect to patient age, performance status, percentage of patients who were platinum resistant or paclitaxel resistant, or tumor bulk. The response rate in this highly resistant population was 13.5 and 7.7% for liposomal doxorubicin at 40 and 50 mg/m2 every 4 weeks, respectively. Stable disease was observed in 49 and 51% of patients treated with liposomal doxorubicin at a dose of 40 and 50 mg/m2 every 4 weeks, respectively. The progression-free survival for patients with responding and stable disease was similar. Dose reductions were required in 27.5% of patients treated at 50 mg/m2 versus no patients treated at 40 mg/m2 (P < 0.001). Treatment delays due to toxicity were required in 32.5% of patients treated at 50 mg/m2 versus 16% of patients treated at 40 mg/m2 (P = 0.14).
Conclusion. Liposomal doxorubicin at a dose of 40 mg/m2 appears to be as active as liposomal doxorubicin at a dose of 50 mg/m2 in ovarian, peritoneal, and tubal carcinoma and is better tolerated based on the frequency of dose reductions and treatment delays.
We present a methodology for designing and measuring pulse front tilt in an ultrafast laser for use in dielectric laser acceleration. Previous research into dielectric laser accelerating modules has ...focused on measuring high accelerating gradients in novel structures, but has done so only for short electron–laser coupling lengths. Here we demonstrate an optical design to extend the laser–electroninteraction to 1 mm.
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