197,585 research outputs found
How aligned are we? Assessment procedures and practices between early childhood and early intervention
No full textEarly intervention and early childhood share a unique space in our early years education in Aotearoa/New Zealand. The assessment practices of the two are distinctively different and specific to each discipline. As assessment is a powerful agent for change and responsiveness to learners this article will unpack the reasoning behind these differences and consider the possibility of addressing a possible alignment through the early childhood curriculum Te Whariki (Ministry of Education, 1996)
Boosting Static and Dynamic Performance of Integrated Solid-State Diodes By Peripheral Integration of Nanostructured Porous Silicon
No full textOver the past two decades, different nanomaterials have been proposed for the design of novel silicon-based electronic devices or to push the performance of existing ones, leveraging the unique properties of charge carriers traveling in meso-to-nano scale structures.
Porous silicon (PSi) is the nano- (n-PSi) to micro- (m-Psi) structured form of silicon achieved by anodic etching of a silicon wafer in acidic HF-based electrolytes. However, the low mobility and reduced lifetime of charge carriers traveling in n-PSi have been mainly perceived such as a deterioration the bulk silicon properties, thus hampering the use of n-PSi in micro and nano electronics to date.
Here, we show that the integration of n-PSi in specific regions of a solid-state diode significantly improves both static and dynamic electrical performance of the diode, with respect to the unmodified device. Specifically, leveraging the unique mobility and lifetime of charge carriers traveling in the n-PSi layer, we achieve a significant increase of the breakdown voltage (>2x) and reduction of the turn-off time (about 30%). This improvement is shown to be robust with respect to n-PSi preparation conditions and diode typologies. Two dimensional (2D) TCAD simulations further corroborate that the improvement of the electrical performance of n-PSi modified diodes is related to the strong mobility and lifetime reduction of carriers in the nanostructured porous silicon layer. Remarkably, no significant drawbacks are observed after the peripheral integration of n-PSi in solid-state diodes, thus confirming the beneficial effect of n-PSi when employed for the modification of micro and nano electronic devices.
A. Paghi, L. M. Strambini, F. F. Toia, M. Sambi, M. Marchesi, R. Depetro, M. Morelli, G. Barillaro, Peripheral Nanostructured Porous Silicon Boosts Static and Dynamic Performance Of Integrated Electronic Devices, Advanced Electronic Materials 6, 2000615 (2020)
Free or Perforator-Pedicled Propeller Flaps in Lower Extremity Reconstruction: Defining the Coverage Failure: Response
No full textDesigning Assessment Tools in a Service Oriented Architecture
No full textAssessment is an important component of formal learning, and Computer Assisted Assessment (CAA) is a well established component of most online learning. However, technical issues such as interoperability and security, and pedagogic reservations as to its effectiveness still remain barriers to the uptake of CAA. In this paper we examine a number of current assessment projects, predominantly emanating from the UK, to consider how a service oriented architecture can facilitate the implementation of tailored assessment environments, providing improved assessments within an interoperable and secure framework
Injectable hydrogel formulations to host adipose stem cell spheroids for stemness maintenance and bone and cartilage regeneration
No full textAdipose-derived mesenchymal stem cells (ASCs) represent a great promise for tissue regeneration as fat is a very abundant source of stem cells (1) and owing to their ability to self-renew and differentiate into specific tissue types (2). In general, they are usually cultured as two-dimensional (2D) adherent monolayers, not representative of the in vivo condition, often entailing lower cell viability and, more in general, a lower “cell quality” in terms of regenerative potential (3, 4). When ASCs are cultured in low adhesion flasks and with a suitable culture medium, they aggregate in the form of three-dimensional spheroids (SASCs). The incorporation of these spheroids into injectable, in-situ gelling, polymer solutions can preserve the 3D structure of the cells from extraction to administration, avoid uncontrolled cell spreading, poor interaction and integration with the surrounding tissue. Moreover, in the presence of the right signaling molecules, SASCs are ready to differentiate in osteogenic (5) and chondrogenic (6) tissue, therefore, incorporated in the right scaffold, they can be very useful in the repair of both cartilage and bone defects that are still a challenge for modern medicine (7). As scaffold, hydrogels can meticulously look like the native ECM, due to their interconnected pore architecture, high water content and amenability to incorporate biomolecules or to provide specific biomechanical cues (8, 9). Therefore, hydrogels can be a fundamental element for tissue regeneration, maintenance of stem cell viability and stemess potential, induction of differentiation, support for cell proliferation and spreading with minimally invasive procedures.
Our work explores the suitability of hydrogels obtained by temperature-triggered self-assembly of partially degalactosylated xyloglucan aqueous dispersions (dXGaq) as SASCs niches for stemness considtions maintenance or for their differentiation in either osteogenic or chondrogenic lineages. The influence of the different culture media mixed with dXGaq and the presence of cell spheroids in the mixtures on the flow properties before gelation of all the above and the extrusion process with a syringe on the formed physical networks were investigated by shear viscosity and small amplitude oscillatory rheological analyses.
(1) Cheng, N. C., Wang, S., & Young, T. H. (2012). The influence of spheroid formation of human adipose-derived stem cells on chitosan films on stemness and differentiation capabilities. Biomaterials, 33(6), 1748-1758.
(2) Nii, M., Lai, J. H., Keeney, M., Han, L. H., Behn, A., Imanbayev, G., & Yang, F. (2013). The effects of interactive mechanical and biochemical niche signaling on osteogenic differentiation of adipose-derived stem cells using combinatorial hydrogels. Acta Biomaterialia, 9(3), 5475-5483.
(3) Di Stefano, A. B., Montesano, L., Belmonte, B., Gulino, A., Gagliardo, C., Florena, A. M., ... & Toia, F. (2020). Human Spheroids from Adipose-Derived Stem Cells Induce Calvarial Bone Production in a Xenogeneic Rabbit Model. Annals of Plastic Surgery.
(4)Di Stefano, A. B., Grisafi, F., Perez-Alea, M., Castiglia, M., Di Simone, M., Meraviglia, S., ... & Toia, F. (2020). Cell quality evaluation with gene expression analysis of spheroids (3D) and adherent (2D) adipose stem cells. Gene, 145269.
(5) Li, W., Liu, Y., Zhang, P., Tang, Y., Zhou, M., Jiang, W., ... & Zhou, Y. (2018). Tissue-engineered bone immobilized with human adipose stem cells-derived exosomes promotes bone regeneration. ACS applied materials & interfaces, 10(6), 5240-5254.
(6) Ansari, S., Diniz, I. M., Chen, C., Aghaloo, T., Wu, B. M., Shi, S., & Moshaverinia, A. (2017). Alginate/hyaluronic acid hydrogel delivery system characteristics regulate the differentiation of periodontal ligament stem cells toward chondrogenic lineage. Journal of Materials Science: Materials in Medicine, 28(10), 162.
(7) Kwon, H., Brown, W. E., Lee, C. A., Wang, D., Paschos, N., Hu, J. C., & Athanasiou, K. A. (2019). Surgical and tissue engineering strategies for articular cartilage and meniscus repair. Nature Reviews Rheumatology, 15(9), 550-570.
(8) Geckil, H., Xu, F., Zhang, X., Moon, S., & Demirci, U. (2010). Engineering hydrogels as extracellular matrix mimics. Nanomedicine, 5(3), 469-484.
(9) Hong, K. H., Kim, Y. M., & Song, S. C. (2019). Fine‐Tunable and Injectable 3D Hydrogel for On‐Demand Stem Cell Niche. Advanced Science, 6(17), 1900597
Axial propeller flaps: A proposal for update of the "Tokyo consensus on propeller flaps"
No full textCarico immediato su 108 impianti : follow-up a tre anni
No full textIl presente lavoro valuta la stabilità ossea perimplantare in un gruppo di pazienti sottoposto a carico immediato della arcata mandibolare con follow-up di tre anni. 20 pazienti, 12 maschi 8 femmine, età media 63 anni, sono stati sottoposti a carico immediato. 14 pazienti presentavano edentulia totale, 4 edentulia parziale, e 2 arcate con restaurazioni fisse. Ai pazienti sono stati inseriti impianti Astra TiO -Blasted osseospeed (Astra-Tech AB, Molndal Sweden). Il numero medio degli impianti era di 5.4 in un range tra 4 e 6. Tutti gli impianti mostravano stabilità primaria. Una protesi fissa avvitata su monconi provvisori in titanio viene applicata immediatamente. Dopo 4 mesi dalla chirurgia viene consegnata una protesi avvitata definitiva usando come framework una travata in titanio fabbricata secondo la metodica cresco Ti (Astra-Tech AB, Molndal Sweden). I pazienti sono stati sottoposti a controlli radiografici dall’inserimento degli impianti fino a 3 anni. Due impianti in due pazienti sono falliti dopo i tre mesi di guarigione, mentre nessun impianto è fallito nei successivi periodi. Il livello di osso marginale attorno al colletto perimplantare mostra in tre anni una perdita media nei 106 impianti caricati di 0.3mm. Il Periotest risulta simile ai dati convenzionali. Con le limitazioni di questo studio, i dati ottenuti risultano simili con quelli riportati in letteratura, inoltre il riassorbimento osseo è molto limitato concentrato soprattutto in impianti caricati immediatamente in siti post estrattivi mostrando la complessità nell’associare carico immediato e siti post estrattivi
The little finger ulnar palmar digital artery perforator flap: anatomical basis
No full textPURPOSE:
The aim of this study was to explore the cutaneous vascularization of the hypothenar region and investigate the anatomical basis for perforator propeller flaps for coverage of the flexor aspect of the little finger.
METHODS:
The area between the pisiform and the base of the little finger was studied in 14 hands of fresh cadavers injected with red latex. An oval flap 1.5 cm large was raised along the axis between these two points. Perforators going into the flap were dissected up to their origin from the ulnar palmar digital artery of the little finger, and their distance from the proximal edge of the A1 pulley was recorded.
RESULTS:
The mean number of perforator arteries entering the flap was 5.8 (range 4-8). A constant sizeable perforator was identified within 0.7 cm from the proximal margin of the A1 pulley in all 14 specimens. In the majority of cases (64 %), the most distal perforator was located at this level. Dissection of the flap was carried out suprafascially on the most distal perforator and 180° rotation allowed the flap to reach the flexor surface of the fifth finger. The donor site was closed primarily.
CONCLUSION:
Distal perforators of the ulnar palmar digital artery of the little finger are constantly found. Our anatomical findings support the possibility of raising a propeller perforator flap from the hypothenar region for coverage of the flexor aspect of the little finger. Its clinical application could provide a quick and straightforward single-stage option with a negligible donor-site morbidity for reconstruction of such defects
Free flaps for anterior chest wall reconstruction
No full textReconstruction of full-thickness chest wall defects usually entails the use of regional pedicled myocutaneous flaps as first-choice option. As defect complexity increases and local options are not available, microsurgical reconstruction is required to transfer reliable and well-vascularized tissues from distant sites. Size, anatomic location, presence of dead spaces, and extent of eventual bone defect should be assessed for proper selection of the flap. Regional recipient vessels should be previously identified and checked in order to consider alternatively the need of extension of distant recipient vessels through arteriovenous (AV) loops or vein graft interposition
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
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