Centromeres are essential chromosomal structures that mediate accurate chromosome segregation during cell division. Centromeres are specified epigenetically by the heritable incorporation of the ...centromeric histone H3 variant CENP-A. While many of the primary factors that mediate centromeric deposition of CENP-A are known, the chromatin and DNA requirements of this process have remained elusive. Here, we uncover a role for transcription in Drosophila CENP-A deposition. Using an inducible ectopic centromere system that uncouples CENP-A deposition from endogenous centromere function and cell-cycle progression, we demonstrate that CENP-A assembly by its loading factor, CAL1, requires RNAPII-mediated transcription of the underlying DNA. This transcription depends on the CAL1 binding partner FACT, but not on CENP-A incorporation. Our work establishes RNAPII passage as a key step in chaperone-mediated CENP-A chromatin establishment and propagation.
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•CENP-A deposition is coupled with transcription•CAL1 recruits RNAPII onto DNA during CENP-A deposition•CAL1 interacts directly with the histone chaperone FACT•FACT depletion causes loss of transcription and defective CENP-A deposition
Centromeres are specified epigenetically by chromatin containing the histone H3 variant CENP-A. Chen et al. shed light on CENP-A deposition mechanisms, showing that the CENP-A chaperone CAL1 recruits FACT and RNAPII to CENP-A assembly sites, where they trigger transcription. In the absence of FACT, transcription ceases and CENP-A deposition is defective.
Collagen represents one of the most widely used biomaterial for scaffolds fabrication in tissue engineering as it represents the mechanical support of natural tissues. It also provides physical ...scaffolding for cells and it influences their attachment, growth, and tissue regeneration. Among all fibrillary collagens, type I is considered one of the gold standard for scaffolds fabrication, thanks to its high biocompatibility, biodegradability, and hemostatic properties. It can be extracted by chemical and enzymatic protocols from several collagen‐rich tissues, such as tendon and skin, of different animal species. Both the extraction processes and the manufacturing protocols for scaffolds fabrication provide structural and mechanical changes that can be tuned in order to deeply impact the properties of the final biomaterial. The aim of this review is to discuss the role of X‐rays to study structural changes of type I collagen from fresh collagen‐rich tissues (bovine, equine, fish) to the final scaffolds, with the aim to screen across available collagen sources and scaffolds fabrication protocols to be used in tissue regeneration.
Bovine, equine, tilapia fish type I collagen are studied by wide and small angle X‐ray scattering to evaluate the multilevel structure of raw materials and final scaffolds, and to screen across collagen sources and scaffolds fabrication protocols available for tissue engineering.
Squamous cell carcinoma is the most common malignant oral tumor in cats. The late presentation is one of the factors contributing to the detrimental prognosis of this disease. The immunohistochemical ...expression of the p53 tumor suppressor protein has been reported in 24% to 65% of feline oral squamous cell carcinomas, but no study has systematically evaluated in this tumor the presence of p53 encoding gene (TP53) mutations. The aim of this retrospective study was to determine whether p53 immunohistochemistry accurately reflects the mutational status of the TP53 gene in feline oral squamous cell carcinoma. Additionally, the prevalence of p53 dysregulation in feline oral squamous cell carcinoma was compared with that of feline non-neoplastic oral mucosa, in order to investigate the relevance of these dysregulations in cancer development. The association between p53 dysregulations and exposure to environmental tobacco smoke and tumor characteristics was further assessed. Twenty-six incisional biopsies of oral squamous cell carcinomas and 10 cases each of lingual eosinophilic granuloma, chronic gingivostomatitis and normal oral mucosa were included in the study. Eighteen squamous cell carcinomas (69%) expressed p53 and 18 had mutations in exons 5-8 of TP53. The agreement between immunohistochemistry and mutation analysis was 77%. None of non-neoplastic oral mucosa samples had a positive immunohistochemical staining, while one case each of eosinophilic granuloma and chronic gingivostomatitis harbored TP53 mutations. Unlike previously hypothesized, p53 dysregulations were not associated with exposure to environmental tobacco smoke. These results suggest an important role of p53 in feline oral tumorigenesis. Additionally, the immunohistochemical detection of p53 expression appears to reflect the presence of TP53 mutations in the majority of cases. It remains to be determined if the screening for p53 dysregulations, alone or in association with other markers, can eventually contribute to the early detection of this devastating disease.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Integral formulations can be convenient for computing eddy currents in complicated electromagnetic systems. However, large-scale problems may quickly exceed the memory capacity even of very large ...machines, since the matrices are fully populated. We aim at illustrating how ℌ-matrices with adaptive cross approximation can provide an effective method to increase the size of the largest solvable problems by means of boundary element methods based on stream functions with modest implementation effort. The method is first validated on a benchmark problem for which an analytical solution is available and then applied to a complex problem of engineering interest related to the computation of the currents induced in the stabilizing shell of a nuclear fusion device.
This study evaluated the efficacy of buccal fat pad (BFP) as a natural barrier to cover nonresorbable devices for vertical ridge augmentation (VRA). Twelve consecutive patients with 14 vertical bone ...defects in need of bone augmentation for implantprosthetic rehabilitation were treated according to the described protocol. VRA was performed by means of customized titanium meshes, titanium-reinforced d-PTFE membranes, or resorbable membranes and titanium plates. After buccal flap release, the BFP was identified and isolated, then mesially and coronally advanced to cover the whole augmented area. BFP was used as a pedicle flap in 11 cases and as a free graft in 3 cases. The mean BFP surface area was 13.5 ± 5.5 cm
. Healing was uneventful in all 14 augmented sites. No patients reported healing complications or facial volumetric changes. The mean vertical bone gain (VBG) was 4.2 ± 1.8 mm. In this limited number of cases, using the BFP as a natural barrier has proven to be efficient in bone augmentation, as it improved the healing process while reducing the risk of complications. Int J Periodontics Restorative Dent 2023;43:e99-e109. doi: 10.11607/prd.5473.
Adaptive capacity is widely held as a key property of resilient and transformative social-ecological systems. However, current knowledge of the term does not yet address key questions of how to ...operationalize this system condition to address sustainability challenges through research and policy. This paper explores temporal and agency dimensions of adaptive capacity in practice to better understand how system conditions and attributes enable adaptation. An institutional dynamics lens is employed to systemically examine empirical cases of change in urban water management. Comparative analysis of two Australian cities' drought response is conducted using institutional analysis and qualitative system dynamics mapping techniques. The study finds that three forms of adaptive capacity appear critical: the ability to learn, decide, and act. The analytical approach developed provides insight into change dynamics and the agency mechanisms that generate them. The paper proposes a typology of adaptive capacity by characterizing these change dynamics and mechanisms for locked-in, crisis, reorganizing, and stabilizing systems. This set of propositions on institutional conditions and forms of adaptive capacity is offered to further advance research on the topic and help to operationalize adaptive capacity in practice.
In questo articolo è descritto l’uso intenzionale di più strumenti (orchestrazione strumentale) quali un pantografo, un software di geometria dinamica e una lavagna interattiva multimediale (LIM), ...per introdurre studenti di seconda media all’idea di simmetria assiale come corrispondenza biunivoca tra punti del piano, superando quella più ingenua di trasformazione di figure. Si è fatto riferimento alla teoria della mediazione semiotica (Bartolini Bussi & Mariotti, 2009) e alla struttura didattica in essa proposta: attività con artefatto a piccolo gruppo, attività individuale e discussione collettiva. Inoltre ci si è riferiti all’approccio strumentale (Rabardel, 1995) basato sulla distinzione fra artefatto e strumento. La LIM è stata utilizzata come spazio d’azione (Didoni & Di Palma, 2009) per rendere visibili all’intera classe azioni individuali.
Cosmic-ray muon flux at Canfranc Underground Laboratory Trzaska, Wladyslaw Henryk; Slupecki, Maciej; Bandac, Iulian ...
The European physical journal. C, Particles and fields,
08/2019, Letnik:
79, Številka:
8
Journal Article
Recenzirano
Odprti dostop
Residual flux and angular distribution of high-energy cosmic muons have been measured in two underground locations at the Canfranc Underground Laboratory (LSC) using a dedicated Muon Monitor. The ...instrument consists of three layers of fast scintillation detector modules operating as 352 independent pixels. The monitor has a flux-defining area of
1
m
2
and covers all azimuth angles, and zenith angles up to
80
∘
. The measured integrated muon flux is
(
5.26
±
0.21
)
×
10
-
3
m
-
2
s
-
1
in the Hall A of the LAB2400 and
(
4.29
±
0.17
)
×
10
-
3
m
-
2
s
-
1
in LAB2500. The angular dependence is consistent with the known profile and rock density of the surrounding mountains. In particular, there is a clear maximum in the flux coming from the direction of the Rioseta valley.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
One of the main drawbacks of welding dissimilar metal alloys is the potential massive precipitation of deleterious intermetallic compounds that occurs at the interface joint. Solid-state welding ...processes are therefore attractive, given the lower temperatures involved. In this work, dissimilar high strength aluminum and titanium alloys were friction-stir-welded using the spindle power control mode to reduce the heat input at the joint as much as possible. A microstructural characterization indicated that the chosen parameters (heat input of ~0.5 kJ/mm) produced welded joints without spatially continuous layers of deleterious intermetallic compounds.
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Location-Related Privacy in Geo-Social Networks Ruiz Vicente, C; Freni, D; Bettini, C ...
IEEE internet computing,
2011-May-June, 2011-05-00, 20110501, Letnik:
15, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Geo-social networks (GeoSNs) provide context-aware services that help associate location with users and content. The proliferation of GeoSNs indicates that they're rapidly attracting users. GeoSNs ...currently offer different types of services, including photo sharing, friend tracking, and "check-ins." However, this ability to reveal users' locations causes new privacy threats, which in turn call for new privacy-protection methods. The authors study four privacy aspects central to these social networks - location, absence, co-location, and identity privacy - and describe possible means of protecting privacy in these circumstances.
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