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Articles 1 - 30 of 37
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A Identification And Isolation Of Several Bacteria From Oral Cavity Among Human In Soran City, Holem Hashm Balaky, Alaa Taha Younis Al-Hammadi
A Identification And Isolation Of Several Bacteria From Oral Cavity Among Human In Soran City, Holem Hashm Balaky, Alaa Taha Younis Al-Hammadi
Al-Qadisiyah Journal of Pure Science
The aim of this study has been to estimate that the number of bacteria in the mouth exceeds the total number of people on the planet. In this context, scientists have discovered more than 700 different types of human oral bacteria. With such a large number of oral bacteria present, many diseases that may threaten health, especially oral health, can emerge. For this reason, this study was employed and conducted on 252 healthy people in the Soran area of the city of Erbil. Both sexes were involved and different ages were selected. Swabs taken from 226 participants gave positive growths …
Ectopic Expression Of Pericentric Hsatii Rna Results In Nuclear Rna Accumulation, Mecp2 Recruitment, And Cell Division Defects, C. C. Landers, C. A. Rabeler , '20, E. K. Ferrari, Lia R. D'Alessandro , '21, D. D. Kang, J. Malisa, Safia M. Bashir , '20, Dawn M. Carone
Ectopic Expression Of Pericentric Hsatii Rna Results In Nuclear Rna Accumulation, Mecp2 Recruitment, And Cell Division Defects, C. C. Landers, C. A. Rabeler , '20, E. K. Ferrari, Lia R. D'Alessandro , '21, D. D. Kang, J. Malisa, Safia M. Bashir , '20, Dawn M. Carone
Biology Faculty Works
Within the pericentric regions of human chromosomes reside large arrays of tandemly repeated satellite sequences. Expression of the human pericentric satellite HSATII is prevented by extensive heterochromatin silencing in normal cells, yet in many cancer cells, HSATII RNA is aberrantly expressed and accumulates in large nuclear foci in cis. Expression and aggregation of HSATII RNA in cancer cells is concomitant with recruitment of key chromatin regulatory proteins including methyl-CpG binding protein 2 (MeCP2). While HSATII expression has been observed in a wide variety of cancer cell lines and tissues, the effect of its expression is unknown. We tested the effect …
De-Coding The Impact Of Evolved Changes In Gene Expression And Cellular Phenotype On Primate Evolution, Trisha Zintel
De-Coding The Impact Of Evolved Changes In Gene Expression And Cellular Phenotype On Primate Evolution, Trisha Zintel
Doctoral Dissertations
The goal of the dissertation work outlined here was to investigate the influence of proximal processes contributing to evolutionary differences in phenotypes among primate species. There are numerous previous comparative analyses of gene expression between primate brain regions. However, primate brain tissue samples are relatively rare, and my results have contributed to the pre-existing data on more well-studied primates (i.e. humans, chimpanzees, macaques, marmosets) as well as produced information on more rarely-studied primates (i.e. patas monkey, siamang, spider monkey). Additionally, the primary visual cortex has not previously been as extensively studied at the level of gene expression as other brain …
Can Somatic Cell Nuclear Transfer Produce Human Pluripotent Stem Cells For Regenerative Medicine?, Alexandra Iskhakov
Can Somatic Cell Nuclear Transfer Produce Human Pluripotent Stem Cells For Regenerative Medicine?, Alexandra Iskhakov
The Science Journal of the Lander College of Arts and Sciences
In the last half a century, researchers and scientists discovered the application of somatic cell nuclear transfer (SCNT) to clone mammalian embryos to produce a line of pluripotent stem cells for medical and laboratory use. This is a breakthrough technology that is applied to stem cell research, regenerative medicine, and cloning. Somatic cells are non-germ cells that are differentiated but provide the nuclei that are transferred to enucleated oocytes. The replacement of the nuclei results in a developing embryo that contains the genetic information of the donated nucleus, which can either be transplanted into a surrogate mother to produce a …
Inferring Species Origin Through Virtual Histology: A Comparison Of Third Metapodials From Homo Sapiens And Ursus Americanus Using Micro-Computed Tomography, Hannah Stephen
Williams Honors College, Honors Research Projects
Human and black bear metacarpals and metatarsals, or the hand and foot bones and bear paws, are well documented on a gross anatomical level. The macrostructural data comparing the two species is useful in distinguishing the species unless fragmented bone is found. In this case, histological data is used for clearer and more accurate comparisons but, research that compares the metapodials of black bears and humans on a microstrutural level is scarce. This study aimed to aid in forensic science identification scenarios where fragmented bone is discovered by providing the differences between black bear and human metacarpals and metatarsals on …
Sf3b1 Is A Stress-Sensitive Splicing Factor That Regulates Both Hsf1 Concentration And Activity, Karen S. Kim Guisbert, Eric Guisbert
Sf3b1 Is A Stress-Sensitive Splicing Factor That Regulates Both Hsf1 Concentration And Activity, Karen S. Kim Guisbert, Eric Guisbert
Biomedical Engineering and Sciences Faculty Publications
The heat shock response (HSR) is a well-conserved, cytoprotective stress response that activates the HSF1 transcription factor. During severe stress, cells inhibit mRNA splicing which also serves a cytoprotective function via inhibition of gene expression. Despite their functional interconnectedness, there have not been any previous reports of crosstalk between these two pathways. In a genetic screen, we identified SF3B1, a core component of the U2 snRNP subunit of the spliceosome, as a regulator of the heat shock response in Caenorhabditis elegans. Here, we show that this regulatory connection is conserved in cultured human cells and that there are at least …
Winner's Curse Correction And Variable Thresholding Improve Performance Of Polygenic Risk Modeling Based On Genome-Wide Association Study Summary-Level Data, Jianxin Shi, Ju-Hyun Park, Jubao Duan, Sonja T. Berndt, Winton Moy, Kai Yu, Lei Song, William Wheeler, Xing Hua, Debra Silverman, Montserrat Garcia-Closas, Chao Agnes Hsiung, Jonine D. Figueroa, Victoria K. Cortessis, Nuria Malats, Margaret R. Karagas
Winner's Curse Correction And Variable Thresholding Improve Performance Of Polygenic Risk Modeling Based On Genome-Wide Association Study Summary-Level Data, Jianxin Shi, Ju-Hyun Park, Jubao Duan, Sonja T. Berndt, Winton Moy, Kai Yu, Lei Song, William Wheeler, Xing Hua, Debra Silverman, Montserrat Garcia-Closas, Chao Agnes Hsiung, Jonine D. Figueroa, Victoria K. Cortessis, Nuria Malats, Margaret R. Karagas
Dartmouth Scholarship
Recent heritability analyses have indicated that genome-wide association studies (GWAS) have the potential to improve genetic risk prediction for complex diseases based on polygenic risk score (PRS), a simple modelling technique that can be implemented using summary-level data from the discovery samples. We herein propose modifications to improve the performance of PRS. We introduce threshold-dependent winner’s-curse adjustments for marginal association coefficients that are used to weight the single-nucleotide polymorphisms (SNPs) in PRS. Further, as a way to incorporate external functional/annotation knowledge that could identify subsets of SNPs highly enriched for associations, we propose variable thresholds for SNPs selection. We applied …
Limited Trabecular Bone Density Heterogeneity In The Human Skeleton, Habiba Chirchir Phd
Limited Trabecular Bone Density Heterogeneity In The Human Skeleton, Habiba Chirchir Phd
Biological Sciences Faculty Research
There is evidence for variation in trabecular bone density and volume within an individual skeleton, albeit in a few anatomical sites, which is partly dependent on mechanical loading. However, little is known regarding the basic variation in trabecular bone density throughout the skeleton in healthy human adults. This is because research on bone density has been confined to a few skeletal elements, which can be readily measured using available imaging technology particularly in clinical settings. This study comprehensively investigates the distribution of trabecular bone density within the human skeleton in nine skeletal sites (femur, proximal and distal tibia, third metatarsal, …
Comparison Of The Osteogenic Differentiation Capacity Of Adipose Tissuederived Mesenchymal Stem Cells From Humans And Rats, Seçi̇l Erden Tayhan, Şeyma Taşdemi̇r, Sai̇me İsmet Deli̇loğlu Gürhan, Erol Mi̇r
Comparison Of The Osteogenic Differentiation Capacity Of Adipose Tissuederived Mesenchymal Stem Cells From Humans And Rats, Seçi̇l Erden Tayhan, Şeyma Taşdemi̇r, Sai̇me İsmet Deli̇loğlu Gürhan, Erol Mi̇r
Turkish Journal of Biology
Mesenchymal stem cells (MSCs) can be found in many types of adult tissues such as the bone marrow, adipose, placenta, liver, and periosteum. Recently, adipose tissue-derived MSCs (ADMSCs) have become one the most preferred MSC types because of their fast proliferation rate, abundance, and high plasticity for variable cell types. It is known that ADMSCs are able to differentiate into various cells, including osteoblasts, so they are quite promising for orthopedic clinical trials. The present study aimed to compare the osteogenic differentiation conditions of MSCs from human adipose tissue (hADMSC) and those of MSCs from rat adipose tissue (rADMSC). Therefore, …
A Mitochondria-Anchored Isoform Of The Actin-Nucleating Spire Protein Regulates Mitochondrial Division, Uri Manor, Sadie Bartholomew, Gonen Golani, Eric Christenson, Michael Kozlov, Henry Higgs, James Spudich, Jennifer Lippincott-Schwartz
A Mitochondria-Anchored Isoform Of The Actin-Nucleating Spire Protein Regulates Mitochondrial Division, Uri Manor, Sadie Bartholomew, Gonen Golani, Eric Christenson, Michael Kozlov, Henry Higgs, James Spudich, Jennifer Lippincott-Schwartz
Dartmouth Scholarship
Mitochondrial division, essential for survival in mammals, is enhanced by an inter-organellar process involving ER tubules encircling and constricting mitochondria. The force for constriction is thought to involve actin polymerization by the ER-anchored isoform of the formin protein inverted formin 2 (INF2). Unknown is the mechanism triggering INF2-mediated actin polymerization at ER-mitochondria intersections. We show that a novel isoform of the formin-binding, actin-nucleating protein Spire, Spire1C, localizes to mitochondria and directly links mitochondria to the actin cytoskeleton and the ER. Spire1C binds INF2 and promotes actin assembly on mitochondrial surfaces. Disrupting either Spire1C actin- or formin-binding activities reduces mitochondrial constriction …
Towards A New Measure For Human Visual Acuity, Andrew B. Wilson
Towards A New Measure For Human Visual Acuity, Andrew B. Wilson
Honors College
This prospective study investigates whether a newly modified software program can effectively substitute for clinical measures of visual acuity like the standard Landolt C, ETDRS (Early Treatment Diabetic Retinopathy Study) and Snellen charts. One goal of this study is to compare these different charts to the computerized experiment that we have created. Important differences between recognition versus resolution based visual acuity charts are discussed in light of these studies. The “open door” computerized acuity program displayed a black box on a white background (XoW) or a white box on a black background (WoX) that had an opening on one of …
Hormone Whodunit: Clues For Solving The Case Of Intratumor Androgen Production., Karen E Knudsen
Hormone Whodunit: Clues For Solving The Case Of Intratumor Androgen Production., Karen E Knudsen
Department of Cancer Biology Faculty Papers
One of the key mechanisms by which prostate cancer cells evade hormone therapy is through intratumor testosterone production. New evidence points toward androstenedione as a potential precursor of intratumor androgen production and furthers nomination of AKR1C3 as a therapeutic target in advanced disease. Clin Cancer Res; 20(21); 5343-5. ©2014 AACR.
Life Support: Long Term Storage Of Solid Waste In An Enclosed Membrane System, Emmy O. Trieu, Michael Flynn, Rocco Mancinelli
Life Support: Long Term Storage Of Solid Waste In An Enclosed Membrane System, Emmy O. Trieu, Michael Flynn, Rocco Mancinelli
STAR Program Research Presentations
In deep space missions, maintaining life support is of the utmost priority. In such a closed system, human waste must be stored and treated. Simulated feces (ersatz) will be inoculated with microbes representing normal fecal flora, mixed with urine brine and shredded refuse of products typically used in space missions. Composting methods often use alternating layers of waste with scraps of carboniferous materials (finely shredded refuse). By preparing membrane bags with a homogenized ersatz and carboniferous refuse mixture and membrane bags with alternating layers of ersatz and carboniferous refuse, it may be possible to monitor anaerobic thermophillic digestion of the …
Iqgap Family Members In Yeast, Dictyostelium, And Mammalian Cells, Katie Shannon
Iqgap Family Members In Yeast, Dictyostelium, And Mammalian Cells, Katie Shannon
Biological Sciences Faculty Research & Creative Works
IQGAPs are a family of scaffolding proteins with multiple domains, named for the IQ motifs and GTPase activating protein (GAP) related domains. Despite their GAP homology, IQGAP proteins act as effectors for GTP-bound GTPases of the Ras superfamily and do not stimulate GTP hydrolysis. IQGAPs are found in eukaryotic cells from yeast to human, and localize to actin-containing structures such as lamellipodia, membrane ruffles, cell-cell adhesions, phagocytic cups, and the actomyosin ring formed during cytokinesis. Mammalian IQGAPs also act as scaffolds for signaling pathways. IQGAPs perform their myriad functions through association with a large number of proteins including filamentous actin …
Remarkable Resilience Of Teeth (How Are Teeth So Brittle Yet So Resilient), Paul J. Constantino
Remarkable Resilience Of Teeth (How Are Teeth So Brittle Yet So Resilient), Paul J. Constantino
Biological Sciences Faculty Research
Tooth enamel is inherently weak, with fracture toughness comparable with glass, yet it is remarkably resilient, surviving millions of functional contacts over a lifetime. We propose a microstructural mechanism of damage resistance, based on observations from ex situ loading of human and sea otter molars (teeth with strikingly similar structural features). Section views of the enamel implicate tufts, hypomineralized crack-like defects at the enamel–dentin junction, as primary fracture sources. We report a stabilization in the evolution of these defects, by ‘‘stress shielding’’ from neighbors, by inhibition of ensuing crack extension from prism interweaving (decussation), and by self-healing. These factors, coupled …
Variation In The Branching Pattern Of The Four Major Caudal Vessels Emerging From The External Carotid Artery, Sara B. Heltzel
Variation In The Branching Pattern Of The Four Major Caudal Vessels Emerging From The External Carotid Artery, Sara B. Heltzel
Masters Theses, 2010-2019
The branching pattern of vessels emerging from the external carotid artery (ECA) displays considerable variation. Knowledge of this variation is of particular interest to clinicians. There are few reports in the literature assessing these differences with regard to sex and sidedness (i.e., branching patterns of the right vs. left neck). The objective of this study was to assess the origin of the four primary caudal branches of the external carotid artery: the superior thyroid (STA), lingual (LA), facial (FA), and occipital (OA) arteries, in addition to the level of common carotid artery bifurcation (CB), with regard to sex, and side. …
Nona-Arginine Facilitates Delivery Of Quantum Dots Into Cells Via Multiple Pathways, Yi Xu, Betty Revon Liu, Han Jung Lee, Katie Shannon, Jeffrey G. Winiarz, Tien-Chun Wang, Huey-Jenn Chiang, Yue-Wern Huang
Nona-Arginine Facilitates Delivery Of Quantum Dots Into Cells Via Multiple Pathways, Yi Xu, Betty Revon Liu, Han Jung Lee, Katie Shannon, Jeffrey G. Winiarz, Tien-Chun Wang, Huey-Jenn Chiang, Yue-Wern Huang
Biological Sciences Faculty Research & Creative Works
Semiconductor quantum dots (QDs) have recently been used to deliver and monitor biomolecules, such as drugs and proteins. However, QDs alone have a low efficiency of transport across the plasma membrane. In order to increase the efficiency, we used synthetic nona-arginine (SR9), a cell-penetrating peptide, to facilitate uptake. We found that SR9 increased the cellular uptake of QDs in a noncovalent binding manner between QDs and SR9. Further, we investigated mechanisms of QD/SR9 cellular internalization. Low temperature and metabolic inhibitors markedly inhibited the uptake of QD/SR9, indicating that internalization is an energy-dependent process. Results from both the pathway inhibitors and …
Identifying Sleep Regulatory Genes Using A Drosophila Model Of Insomnia, Laurent Seugnet, Yasuko Suzuki, Matthew S. Thimgan, Jeffrey Donlea, Sarah I. Gimbel, Laura Gottschalk, Stephen P. Duntley, Paul J. Shaw
Identifying Sleep Regulatory Genes Using A Drosophila Model Of Insomnia, Laurent Seugnet, Yasuko Suzuki, Matthew S. Thimgan, Jeffrey Donlea, Sarah I. Gimbel, Laura Gottschalk, Stephen P. Duntley, Paul J. Shaw
Biological Sciences Faculty Research & Creative Works
Although it is widely accepted that sleep must serve an essential biological function, little is known about molecules that underlie sleep regulation. Given that insomnia is a common sleep disorder that disrupts the ability to initiate and maintain restorative sleep, a better understanding of its molecular underpinning may provide crucial insights into sleep regulatory processes. Thus, we created a line of flies using laboratory selection that share traits with human insomnia. After 60 generations, insomnia-like (ins-l) flies sleep 60 min a day, exhibit difficulty initiating sleep, difficulty maintaining sleep, and show evidence of daytime cognitive impairment. ins-l flies …
Modulation Of Fast And Slow Inactivation In Two Cardiac Nav Channel Isoforms By Sdz 211-939, Tyce Jeffrey Kearl
Modulation Of Fast And Slow Inactivation In Two Cardiac Nav Channel Isoforms By Sdz 211-939, Tyce Jeffrey Kearl
Undergraduate Honors Capstone Projects
Here we report a hitherto unknown effect of a synthetic inactivation inhibitor on inactivation in cardiac sodium channels (Nav1.5) from two different species: human and bovine. SDZ 211-93 9 stabilized the slow inactivated-state in both channels as seen by an increased steady-state probability of slow inactivation. SDZ also destabilized the fast-inactivated state and increased the amplitude of persistent currents. SDZ modulated conductance parameters, open-state fast inactivation time constants, and activation kinetics of hNav1.5, but not bNav1.5. These findings will aid future studies designed to elucidate the binding site and molecular mechanisms of inactivation inhibitors …
Cytokine Expression By T. Helper Cells Responding To Stress, Dina Zanetti
Cytokine Expression By T. Helper Cells Responding To Stress, Dina Zanetti
Master's Theses
Stress causes alterations to the immune system. These alterations have lead to increased susceptibility to antigens. The present study explores shifts in T helper (TH) cell balance (TH1 and TH2), through their cytokine expression. This study was performed in three phases, and focused mainly on animals subjected to a 10 day a chronic unpredictable stress paradigm. Phase one used ELISAs to confirm the cytokine profile produced from TH 1 and TH2 murine cell-lines. Phase two used SDS PAGE and Western Immunoblotting to show that splenocytes from Long Evan's Hooded rats subjected to the stress paradigm, had decreased in intercellular in …
Mad2 And Bubr1 Function In A Single Checkpoint Pathway That Responds To A Loss Of Tension, Katie Shannon, Julie C. Canman, Edward D. Salmon
Mad2 And Bubr1 Function In A Single Checkpoint Pathway That Responds To A Loss Of Tension, Katie Shannon, Julie C. Canman, Edward D. Salmon
Biological Sciences Faculty Research & Creative Works
The spindle checkpoint monitors microtubule attachment and tension at kinetochores to ensure proper chromosome segregation. Previously, PtK1 cells in hypothermic conditions (23°C) were shown to have a pronounced mitotic delay, despite having normal numbers of kinetochore microtubules. At 23°C, we found that PtK1 cells remained in metaphase for an average of 101 min, compared with 21 min for cells at 37°C. The metaphase delay at 23°C was abrogated by injection of Mad2 inhibitors, showing that Mad2 and the spindle checkpoint were responsible for the prolonged metaphase. Live cell imaging showed that kinetochore Mad2 became undetectable soon after chromosome congression. Measurements …
Anaphase Onset Does Not Require The Microtubule-Dependent Depletion Of Kinetochore And Centromere-Binding Proteins, Julie C. Canman, Nitin Sharma, Aaron F. Straight, Katie Shannon, Guowei Fang, Edward D. Salmon
Anaphase Onset Does Not Require The Microtubule-Dependent Depletion Of Kinetochore And Centromere-Binding Proteins, Julie C. Canman, Nitin Sharma, Aaron F. Straight, Katie Shannon, Guowei Fang, Edward D. Salmon
Biological Sciences Faculty Research & Creative Works
Spindle checkpoint proteins, such as Mad2 and BubR1, and the motors dynein/dynactin and CENP-E usually leave kinetochores prior to anaphase onset by microtubule-dependent mechanisms. Likewise, 'chromosome passenger proteins' including INCENP are depleted from the centromeres after anaphase onset and then move to the midzone complex, an event that is essential for cytokinesis. Here we test whether the cell cycle changes that occur at anaphase onset require or contribute to the depletion of kinetochore and centromere proteins independent of microtubules. This required the development of a novel non-antibody method to induce precocious anaphase onset in vivo by using a bacterially expressed …
Interaction Of The Human Serine Protease Inhibitor Alpha-1-Antitrypsin With Cryptosporidium Parvum, John Russell Forney
Interaction Of The Human Serine Protease Inhibitor Alpha-1-Antitrypsin With Cryptosporidium Parvum, John Russell Forney
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The human serine protease inhibitor (serpin) alpha-1-antitrypsin (AAT) was studied for potential interaction with components of the protozoan parasite Cryptosporidium parvum. A homogenate prepared from C. parvum oocysts was incubated with purified human AAT, and complexes formed between the serpin and components of the homogenate were detected using an enzyme-linked immunosorbent assay (ELISA). Serpin:parasite infections were effectively blocked by preincubating AAT with a cognate target enzyme, porcine pancreatic elastase, prior to performing the ELISA on the homogenate. Incubation of a mixture of C. parvum oocysts and sporozoites with AAT demonstrated preferential fluorescence labeling of the sporozoite surface membrane by indirect …
Mutations In Two Ku Homologs Define A Dna End-Joining Repair Pathway In Saccharomyces Cerevisiae, George Todd Milne, Shengfang Jin, Katie Shannon, David T. Weaver
Mutations In Two Ku Homologs Define A Dna End-Joining Repair Pathway In Saccharomyces Cerevisiae, George Todd Milne, Shengfang Jin, Katie Shannon, David T. Weaver
Biological Sciences Faculty Research & Creative Works
DNA double-strand break (DSB) repair in mammalian cells is dependent on the Ku DNA binding protein complex. However, the mechanism of Ku-mediated repair is not understood. We discovered a Saccharomyces cerevisiae gene (KU80) that is structurally similar to the 80-kDa mammalian Ku subunit. Ku80 associates with the product of the HDF1 gene, forming the major DNA end-binding complex of yeast cells. DNA end binding was absent in ku80Δ, hdf1Δ, or ku80Δ hdf1Δ strains. Antisera specific for epitope tags on Ku80 and Hdf1 were used in supershift and immunodepletion experiments to show that both proteins …
Scanning Electron Microscopy Of Cyclosporine-Induced Gingival Overgrowth, Shahid H. Ashrafi, Krzysztof Slaski, Kyaw Thu, Eli S. Neiman, Michael P. Cunningham
Scanning Electron Microscopy Of Cyclosporine-Induced Gingival Overgrowth, Shahid H. Ashrafi, Krzysztof Slaski, Kyaw Thu, Eli S. Neiman, Michael P. Cunningham
Scanning Microscopy
Overgrown human gingival specimens were examined histologically and by scanning electron microscopy (SEM) to study structural changes caused by cyclosporine. The biopsy specimens were from organ transplant recipients receiving cyclosporine to suppress the rejection of the transplanted organ. The epithelium of the overgrown gingiva was thickened, acanthotic and parakeratotic. Retepegs were anastomosing and extending into connective tissue. The SEM examination of the outer surface of the attached gingival showed loss of cellular attachments and cells were exfoliating. The normal honeycomb structure formed by interconnecting microvilli surrounding the pits was distorted. Outer gingival cell surface showed numerous round, ovoid and dome-like …
The Effect Of Arf-Excimer Laser Irradiation Of The Human Enamel Surface On The Bond Strength Of Orthodontic Appliances, U. Stratmann, K. Schaarschmidt, M. Schürenberg, U. Ehmer
The Effect Of Arf-Excimer Laser Irradiation Of The Human Enamel Surface On The Bond Strength Of Orthodontic Appliances, U. Stratmann, K. Schaarschmidt, M. Schürenberg, U. Ehmer
Scanning Microscopy
This study investigated enamel laser conditioning as an alternative to acid etching in bracket therapy. In preliminary experiments optimal laser parameters for achieving a bond strength of 6-10 N/mm2 were defined. Enamel surface morphology was assessed and the ablation depth was measured on serial enamel sections. Thirty human molars were exposed to 193 nm ArF-excimer laser radiation (energy density: 260 mJ/cm2) by single pulse application of 23 nanoseconds. Thirty molars were etched with phosphoric acid (37%) for 60 seconds. The brackets from the treated molars and 30 untreated molars were debonded vertically for tensile bond strength measurement. …
An Experimental Scanning Electron Microscopic Study Of Human Cerebellar Cortex Using The T-Butyl Alcohol Freeze-Drying Device, Teruyuki Hojo
An Experimental Scanning Electron Microscopic Study Of Human Cerebellar Cortex Using The T-Butyl Alcohol Freeze-Drying Device, Teruyuki Hojo
Scanning Microscopy
Specimen preparation methods are very important in scanning electron microscopy (SEM) of nerve tissues. In the present study, a t-butyl alcohol freeze-drying device was used to prepare cerebellar cortex of the human and that of the rat at 15°C and 160 mm Hg. This method has been previously used with success in the preparation of other tissues, such as pancreas and trachea. Relatively large specimens (about 10 mm x 15 mm x 1 mm) of formalin-fixed human and glutaraldehyde-Millonig buffer perfused (1 hour) Wistar rat were rinsed in water, dehydrated in a series of ethanols, immersed in t-butyl …
Rabbit And Human Non-Keratinising Stratified Squamous Oesophageal Epithelium Displays Similar Microridge Structure By Scanning Electron Microscopy, S. Shasha'a, G. R. Dickson, R. St. C. Gilmore, G. C. Crean, M. M. Butt, K. E. Carr
Rabbit And Human Non-Keratinising Stratified Squamous Oesophageal Epithelium Displays Similar Microridge Structure By Scanning Electron Microscopy, S. Shasha'a, G. R. Dickson, R. St. C. Gilmore, G. C. Crean, M. M. Butt, K. E. Carr
Scanning Microscopy
Since the oesophageal epithelium of common laboratory animals, rats and mice, is keratinized it is unsuitable for comparison with typical non-keratinized stratified squamous human epithelium. It is thus important to find a suitable animal model for the study of human oesophageal tissue changes. This study investigated the microridge structure of immature and adult rabbit specimens, and adult human biopsies by scanning electron microscopy and morphometry. The investigation revealed a similarity between typical squamous human and adult rabbit oesophageal mucosal epithelium. While human epithelium specimens subdivided into two other groups (non-typical squamous and non-squamous); all typical squamous human biopsies were from …
Comparative Aspects Of Splenic Microcirculatory Pathways In Mammals: The Region Bordering The White Pulp, E. E. Schmidt, I. C. Macdonald, A. C. Groom
Comparative Aspects Of Splenic Microcirculatory Pathways In Mammals: The Region Bordering The White Pulp, E. E. Schmidt, I. C. Macdonald, A. C. Groom
Scanning Microscopy
Splenic microcorrosion casts prepared using minimal volumes of material show that most of the flow passes through the region bordering the white pulp. However, the nature of these microcirculatory pathways has received little attention. We have studied these in dog, cat, rat, mouse, and normal versus diseased human spleens. In all 5 species, a marginal sinus (MS) of anastomosing vascular spaces 5-10 μm thick lies between the white pulp and marginal zone (MZ). The morphology differs between species and the MS is absent in immune thrombocytopenia. The MS fills by circumferential flow before blood passes outward to the MZ. Many …
Scanning Electron Microscopy Of Styrene-Methylethylketone Casts Of The Airway And The Arterial System Of The Lung, Teruyuki Hojo
Scanning Electron Microscopy Of Styrene-Methylethylketone Casts Of The Airway And The Arterial System Of The Lung, Teruyuki Hojo
Scanning Microscopy
The method of making casts of airways and the pulmonary arterial system using a styrene polymer resin is described. A human and a dog were used as models. The viscosity of this resin ranges between 40 and 60 dPa/s at 24°C. The elastic rubber tube used for resin injection allows a constant perfusion pressure, i.e., 44 mm Hg and 110 mm Hg for airway and vascular filling, respectively. The casts obtained using this method are suitable both for macro- and microscopic analysis. Shrinkage during polymerization is minimal. Moreover, a preceding lavage is not necessary. Scanning electron microscopy (SEM) of cast …