Thanh Thuong Huynh¹, Tien V. T. Nguyen^2,3, Quoc Manh Nguyen⁴, Trieu Khoa Nguyen^2,*

CMC-Computers, Materials & Continua, Vol.68, No.3, pp. 2913-2923, 2021, DOI:10.32604/cmc.2021.016064

Abstract In this study, we investigated warpage and corner lifting minimization for three-dimensional printed parts generated by macro-size fused deposition modeling (FDM). First, the reasons for warpage were theoretically elucidated. This approach revealed that the thermal deformation and differential volumetric shrinkage of the extruded molten plastic resulted in warpage of FDM parts. In addition, low adhesion between the deposited model and the heated or non-heated printing bed may intensify warpage further. As a next step, initial small-size and medium-size models were used to identify parameters to manage and minimize warpage in a way that would reduce material consumption and running time.… More >

Matea Perić^1,*, Robert Putz¹, Christian Paulik²

Journal of Renewable Materials, Vol.8, No.7, pp. 759-772, 2020, DOI:10.32604/jrm.2020.09284

Abstract In the current study poly(lactic acid) PLA composites with a 3 wt% and 5 wt% of nanofibrillated cellulose (NFC) were produced by 3D-printing method. An enzymatic pretreatment coupled with mechanical fibrillation in a twin screw extruder was used to produce high consistency NFC. Scanning electron microscopy (SEM) equipped with Fibermetric software, FASEP fiber length distribution analysis, Furrier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), tensile tests, impact tests and differential scanning calorimetry were used to characterize NFC and PLA/NFC composites. The results of the fiber length and width measurements together with the results of the SEM analysis showed that enzymatic… More >

FRANCISCO CAPANI¹, EZEQUIEL SARACENO¹, VALERIA ROMINA BOTI¹, LAURA AON-BERTOLINO¹, JUAN CARLOS FERNÁNDEZ¹, FERNANDO GATO¹, MARIA SOL KRAUSE², LISANDRO GIRALDEZ³, MARK H. ELLISMAN⁴, HÉCTOR COIRINI^1,2

BIOCELL, Vol.32, No.1, pp. 1-8, 2008, DOI:10.32604/biocell.2008.32.001

Abstract Cellular and subcellular organization and distribution of actin filaments have been studied with various techniques. The use of fluorescence photo-oxidation combined with phalloidin conjugates with eosin has allowed the examination of the precise cellular and subcellular location of F-actin. Correlative fluorescence light microscopy and transmission electron microscopy studies of F-actin distribution are facilitated with this method for morphological and physiological studies. Because phalloidin-eosin is smaller than other markers, this method allows the analysis of the three-dimensional location of F-actin with high-resolution light microscopy, three-d serial sections reconstructions, and electron tomography. The combination of selective staining and three-dimensional reconstructions provide a… More >

JUAN CARLOS CAVICCHIA^1*, MABEL FÓSCOLO¹ , JORGE IBAÑEZ¹, CHRISTOPHER LILLIG², FRANCISCO CAPANI³

BIOCELL, Vol.35, No.3, pp. 81-90, 2011, DOI:10.32604/biocell.2011.35.081

Abstract Junctional devices in Sertoli cells conform the blood-testis barrier and play a key role in maturation and differentiation of germ cells. The spacial distribution of ectoplasmic specializations of Sertoli cells was studied by β-actin immunolabelling, using laser confocal and transmission electron microscopy. For confocal microscopy, β-actin immunolabelling of ectoplasmic specializations was studied over the background of either prosaposin or glutaredoxin immunolabelling of the Sertoli cytoplasm. Labelling was found near the basal lamina, surrounding early spermatocytes (presumably in leptotene-zygotene) or at one of two levels in the seminiferous epithelium: (1) around deep infoldings of the Sertoli cell cytoplasm, in tubular stages… More >

ROMINA J. BEVACQUA, RAFAEL FERNANDEZ-MARTIN, DANIEL F. SALAMONE

BIOCELL, Vol.35, No.1, pp. 1-7, 2011, DOI:10.32604/biocell.2011.35.001

Abstract Parthenogenetic embryos are an ethically acceptable alternative for the derivation of human embryonic stem cells. In this work, we propose a new strategy to produce bovine parthenogenetic embryos inhibiting the emission of the first polar body during in vitro maturation, and allowing the extrusion of the second polar body during oocyte activation. Cytochalasin B, an inhibitor of actin microfilaments, was employed during in vitro maturation to inhibit first polar body emission or during parthenogenetic activation to block second polar body emission. Only one polar body was inhibited in each strategy in order to keep the diploid chromosome set. In experiment… More >

Nan Shen^1,2, Dabajyoti Datta¹, Chris B. Schaffer^1,3,4,5, Eric Mazur^1,6

Molecular & Cellular Biomechanics, Vol.2, No.1, pp. 17-26, 2005, DOI:10.3970/mcb.2005.002.017

Abstract Analysis of cell regulation requires methods for perturbing molecular processes within living cells with spatial discrimination on the nanometer-scale. We present a technique for ablating molecular structures in living cells using low-repetition rate, low-energy femtosecond laser pulses. By tightly focusing these pulses beneath the cell membrane, we ablate cellular material inside the cell through nonlinear processes. We selectively removed sub-micrometer regions of the cytoskeleton and individual mitochondria without altering neighboring structures or compromising cell viability. This nanoscissor technique enables non-invasive manipulation of the structural machinery of living cells with several-hundred-nanometer resolution. Using this approach, we unequivocally demonstrate that mitochondria are… More >

JongWon Kim^1,2, Ning Li², Ramana Pidaparti^2,*, Xianqiao Wang^2,*

Molecular & Cellular Biomechanics, Vol.15, No.3, pp. 127-141, 2018, DOI: 10.3970/mcb.2018.02669

Abstract Nonlinear microstructure of the microtubules (MTs) plays an important role in their mechanical properties. Despite the extensive efforts into the development of continuum models for microtubules, a mesoscale finite element model that can link the molecular level information to the overall performance of microtubules is still missing. The aim of this study is to develop a molecular dynamics model (MDM), finite element model (FEM) and structural mechanics beam model (SMBM) for tubulins of protofilament (PF). In MDM, the backbone atoms of α-tubulin were fixed while the backbone atoms of β-tubulin were attached to a molecular dynamics (MD) atom through a… More >

Tong Li^∗, Prasad KDV Yarlagadda^∗, Adekunle Oloyede^∗, Namal Thibbotuwawa^∗, YuanTong Gu^∗,†

Molecular & Cellular Biomechanics, Vol.12, No.1, pp. 17-35, 2015, DOI:10.3970/mcb.2015.012.017

Abstract Living cells are the functional unit of organs that controls reactions to their exterior. However, the mechanics of living cells can be difficult to characterize due to the crypticity of their microscale structures and associated dynamic cellular processes. Fortunately, multiscale modelling provides a powerful simulation tool that can be used to study the mechanical properties of these soft hierarchical, biological systems. This paper reviews recent developments in hierarchical multiscale modeling technique that aimed at understanding cytoskeleton mechanics. Discussions are expanded with respects to cytoskeletal components including: intermediate filaments, microtubules and microfilament networks. The mechanical performance of difference cytoskeleton components are… More >

JA. Herzog^∗, TR. Leonard^†, A. Jinha^†, W. Herzog^†,‡

Molecular & Cellular Biomechanics, Vol.11, No.1, pp. 1-17, 2014, DOI:10.3970/mcb.2014.011.001

Abstract Titin is the third most abundant protein in sarcomeres and fulfills a number of mechanical and signaling functions. Specifically, titin is responsible for most of the passive forces in sarcomeres and the passive visco-elastic behaviour of myofibrils and muscles. It has been suggested, based on mechanical testing of isolated titin molecules, that titin is an essentially elastic spring if Ig domain un/refolding is prevented either by working at short titin lengths, prior to any unfolding of Ig domains, or at long sarcomere (and titin) lengths when Ig domain un/refolding is effectively prevented. However, these properties of titin, and by extension… More >

Walter Herzog^∗, Tim Leonard^†, Venus Joumaa^‡, Michael DuVall^§, Appaji Panchangam^¶

Molecular & Cellular Biomechanics, Vol.9, No.3, pp. 175-192, 2012, DOI:10.3970/mcb.2012.009.175

Abstract Ever since the 1950s, muscle force regulation has been associated with the cross-bridge interactions between the two contractile filaments, actin and myosin. This gave rise to what is referred to as the "two-filament sarcomere model". This model does not predict eccentric muscle contractions well, produces instability of myosin alignment and force production on the descending limb of the force-length relationship, and cannot account for the vastly decreased ATP requirements of actively stretched muscles. Over the past decade, we and others, identified that a third myofilament, titin, plays an important role in stabilizing the sarcomere and the myosin filament. Here, we… More >