36 research outputs found
College of Engineering Drexel E-Repository and Archive (iDEA)
No full textwww.library.drexel.edu The following item is made available as a courtesy to scholars by the author(s) and Drexel University Library and may contain materials and content, including computer code and tags, artwork, text, graphics, images, and illustrations (Material) which may be protected by copyright law. Unless otherwise noted, the Material is made available for non profit and educational purposes, such as research, teaching and private study. For these limited purposes, you may reproduce (print, download or make copies) the Material without prior permission. All copies must include any copyright notice originally included with the Material. You must seek permission from the authors or copyright owners for all uses that are not allowed by fair use and other provisions of the U.S. Copyright Law. The responsibility for making an independent legal assessment and securing any necessary permission rests with persons desiring to reproduce or use the Material. Please direct questions to [email protected] F M Sasoglu, A J Bohl and B E Layton Microbeam array for nN force measurement Design and microfabrication a high-aspect-ratio PDMS microbeam array for parallel nanonewton force measurement and protein printin
Towards a method for printing a network of chick forebrain neurons for biosensor applications
No full textPaper presented at the 29th Annual International Conference of IEEE-EMBS, Engineering in Medicine and Biology Society, EMBC'07, Lyon, France.The primary goal of this work is to establish a
robust, repeatable method for printing arrays of neurons. This
work has two endpoints. One is to use a neural array as an
experimental testbed for investigating neuronal cell growth
hypotheses. The other endpoint is to enable the next generation
of cell-based sensors. Herein we compare microcontact printing
results previously published by our group with a new method
of dip-pen printing. We present preliminary results for neurons
growing on these microprinted arrays, assessing contact
frequencies and growth characteristics
Microfabrication procedure of PDMS microbeam array using photolithography for laminin printing and piconewton force transduction on axons
No full textMicrofabrication procedure of PDMS microbeam array using photolithography for laminin printing and piconewton force transduction on axons
No full textPaper presented at 28th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBS), New York, NY: Aug 30 - Sept 3, 2006.The purpose of this paper is to introduce our
design for transducing forces on the order of tens of
piconewtons by optically measuring deflection of a
microfabricated beam tip as it pulls on an array of
flexible structures such as axons in an array of lamininprinted
neurons. To achieve this we have designed
polymeric beams with spring constants on the order of
10pN/μm. We have fabricated circular microbeams with
Sylgard® polydimethylsiloxane (PDMS). The elastic
modulus of PDMS was determined experimentally using
a microscale and a micrometer at different
concentrations of curing agent and base agent and found
to be on the order of 100kPa. The designed geometry is a
100x100 tapered microcone array with each beam
having a length of 100μm, and a base diameter of 10 μm.
A SU-8 negative photoresist is etched using
photolithography and used as a mold for PDMS soft
lithography. PDMS was injected into the mold and the
array peeled from the mold
Design and microfabrication of a high-aspect-ratio PDMS microbeam array for parallel nanonewton force measurement and protein printing
No full textJournal of Micromechanics and Microengineering, 17(3): pp. 623-632.Cell and protein mechanics has applications ranging from cellular development
to tissue engineering. Techniques such as magnetic tweezers, optic tweezers, and atomic
force microscopy have been used to measure cell deformation forces on the order of
piconewtons to nanonewtons. In this study, an array of polymeric polydimethylsiloxane
(PDMS) microbeams with diameters of 10-40μm and lengths of 118μm was fabricated
from Sylgard® with curing agent concentrations ranging from 5% to 20%. Resulting
spring constants were 100-300nN/μm. The elastic modulus of PDMS was determined
experimentally at different curing agent concentrations and found to be 346kPa to 704kPa
in a millimeter-scale array and ~1MPa in a microbeam array. Additionally, the
microbeam array was used to print laminin for the purpose of cell adhesion. Linear and
non-linear finite element analyses are presented and compared to the closed-from
solution. Conclusion: The highly compliant, transparent, biocompatible PDMS may offer
a method for more rapid throughput in cell and protein mechanics force measurement
experiments with sensitivities necessary for highly compliant structures such as axons
In vitro evaluation of the apoptotic, autophagic, and necrotic molecular pathways of fluoride
No full textTaşpınar, Mehmet ( Aksaray, Yazar )The original version of this article unfortunately contained
mistakes. The complete list of corrections is given below.
& The author’s affiliations in now corrected in the author
group.
& The correct order of the keywords should be: Apoptosis,
Autophagy, In vitro, Naf, Necrosis, NRK-52E cell line
& p.2, fourth sentence of the last paragraph under the header
“Total RNA Isolation and Quantitative Real-Time PCR”,
BCt should be CT
& p.3, second sentence of the first paragraph under the
Results section, results should be PCR results
& The correct bibliographic information for reference [1]
should be Yur F, Mert N, Dede S, Değer Y, Ertekin A,
Mert H, Yaşar S, Doğan I, Işık A (2013) Evaluation of
serum lipid fractions and tissue antioxidant levels in sheep
with fluorosis. Fluoride 46(2):90–9
Discrete-item inventory control involving fixed setup costs, demand censoring, and ambiguity
No full textWe investigate a dynamic inventory control problem involving fixed setup costs and lost sales. Considering ambiguity, even the demand distribution itself, out of which random realizations are sampled, can come from a vast and definitely non-singleton set. Lost sales and demand ambiguity would together complicate the problem through censoring, namely, the inability of the firm to observe the lost portion of the demand. Our main policy idea advocates periodically ordering up to seemingly inadvisable high levels just to learn and in intervening periods, cleverly exploiting the information gained in these learning periods. By regret, we mean the price paid for ambiguity in long-run average performances. %The bulk of our efforts are devoted to the case where no known bound is known for realized demand levels. When demand has finite support, we can accomplish a regret bound in the order of which almost matches a known lower bound as long as inventory costs are genuinely convex. Major policy adjustments are warranted for the more complex case involving unbounded demand support, for which our regret bound is in the order of . We find it necessary to separately treat the situation where gets arbitrarily close to one, and can be established if the firm is allowed to remove items --with immediate cost-- from the inventory. We also propose other policies based on the general learning-while-doing idea using the Kaplan-Meier (KM) estimator.
Our simulation demonstrates the merits of the various policy ideas and the hurdles posed by the prospect of .Ph.D.Includes bibliographical reference
Clinical predictors of incipient vertebral fractures and bone mineral density in kidney transplant patients
No full text© 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Purpose: Kidney transplant recipients are prone to metabolic bone diseases and consequent fractures. This study aimed to evaluate the incidence of incipient vertebral fractures, osteopenia, osteoporosis, and the clinical factors associated with incipient vertebral fractures in a group of kidney transplant patients. Methods: Two hundred sixty-four patients (F/M 124/140, 45.3 ± 13 years) who had undergone kidney transplantation in tertiary care centers were included. Vertebral fractures were assessed semiquantitatively using conventional thoracolumbar lateral radiography in 202 of the patients. Results: Vertebral fractures were observed in 56.4% (n = 114) of the study group. The frequency of osteoporosis was 20.0% (53 of 264 patients), and osteopenia was 35.6% (94 of 264 patients). Bone mineral density (BMD) levels were in the normal range in 40.3% (n = 46) of the subjects with vertebral fractures. It was in the osteoporotic range in 20.1% (n = 23) and the osteopenic range in 40.3% (n = 46). Vertebral fractures were associated with age, duration of hemodialysis, BMI, and femoral neck Z score (R2 37.8%, p = 0.027). Conclusion: As incipient vertebral fractures can be observed in patients with normal BMD levels in kidney transplant recipients, conventional X-ray screening for vertebral fractures may be beneficial for a proper therapy decision of metabolic bone disease in kidney transplant recipients
The association of CMV infection with bacterial and fungal infections in hematopoietic stem cell transplant recipients: A retrospective single center study
No full textThis study aims to evaluate the probable association between CMV infection and bacterial or fungal infections in 91 consecutive adult patients who underwent autologous or allogeneic HSCT within a period of two years.Medical records of the patients were retrospectively reviewed. Blood cultures were evaluated by automated blood culture system. A quantitative real-time polymerase chain reaction was performed to detect CMV DNA.CMV infection and CMV disease were detected in 42 (46%) ADDIN EN.CITE <EndNote><Cite><Author>Ng</Author><Year>2005</Year><RecNum>191</RecNum><DisplayText>(Ng<style face="italic"> et al., </style>2005)</DisplayText><record><rec-number>191</rec-number><foreign-keys><key app="EN" db-id="a20etv5e6ade0berxf1vw5vp0apvfptetwwd" timestamp="1639991687">191</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Ng, A. P.</author><author>Worth, L.</author><author>Chen, L.</author><author>Seymour, J. F.</author><author>Prince, H. M.</author><author>Slavin, M.</author><author>Thursky, K.</author></authors></contributors><titles><title>Cytomegalovirus DNAemia and disease: incidence, natural history and management in settings other than allogeneic stem cell transplantation</title><secondary-title>Haematologica</secondary-title></titles><periodical><full-title>Haematologica</full-title></periodical><pages>1672-1679</pages><volume>90</volume><number>12</number><dates><year>2005</year><pub-dates><date>Dec</date></pub-dates></dates><isbn>0390-6078</isbn><accession-num>WOS:000506833800012</accession-num><urls><related-urls><url>&lt;Go to ISI&gt;://WOS:000506833800012</url></related-urls></urls></record></Cite></EndNote>(Ng et al., 2005) and six (6.6%) patients, respectively. Of the 158 microorganisms isolated, 115 (73%) were Gram-positive bacteria. Bacteremia and fungemia developed in 55 (60%) and eight (8%) patients, respectively. Concurrent CMV infection and bacteremia were detected in 17 (18.7%) patients and concurrent CMV infection and fungal infection were detected in five (5.5%) patients. Graft versus host disease (GVHD) developed in 15 (50%) allogeneic HSCT recipients and two (2.2%) autologous HSCT recipients. Twenty-one (23%) patients including 13 (43%) allogeneic and eight (13%) autologous HSCT recipients died.The most common infection is bacteremia, and it develops concurrently with CMV infection in approximately one-fifth of HSCT recipients. Gram-positive bacteria are more common in bacteremia. Further studies on the follow-up and treatment of infections after HSCT will improve survival rates post-HSCT
