scholarly journals Stress Distribution in Co-Cr Implant Frameworks after Laser or TIG Welding

2013 ◽  
Vol 24 (2) ◽  
pp. 147-151 ◽  
Author(s):  
Gabriela Cassaro de Castro ◽  
Cleudmar Amaral de Araújo ◽  
Marcelo Ferraz Mesquita ◽  
Rafael Leonardo Xediek Consani ◽  
Mauro Antônio de Arruda Nóbilo
Keyword(s):  
Shear Stress ◽  
Maximum Shear Stress ◽  
Tig Welding ◽  
Edentulous Mandible ◽  
Significant Difference ◽  
Photoelastic Model ◽  
Group A ◽  
Photoelastic Analysis ◽  
The Right ◽  
Control Laser

Lack of passivity has been associated with biomechanical problems in implant-supported prosthesis. The aim of this study was to evaluate the passivity of three techniques to fabricate an implant framework from a Co-Cr alloy by photoelasticity. The model was obtained from a steel die simulating an edentulous mandible with 4 external hexagon analog implants with a standard platform. On this model, five frameworks were fabricated for each group: a monoblock framework (control), laser and TIG welding frameworks. The photoelastic model was made from a flexible epoxy resin. On the photoelastic analysis, the frameworks were bolted onto the model for the verification of maximum shear stress at 34 selected points around the implants and 5 points in the middle of the model. The stresses were compared all over the photoelastic model, between the right, left, and center regions and between the cervical and apical regions. The values were subjected to two-way ANOVA, and Tukey's test (α=0.05). There was no significant difference among the groups and studied areas (p>0.05). It was concluded that the stresses generated around the implants were similar for all techniques.

DeVega versus ring annuloplasty in severe functional tricuspid insufficiency and their impact on the right ventricle

2019 ◽  
Vol 1 (4) ◽  
pp. 133-139
Author(s):  
Yasser Hamdy ◽  
Mohammed Mahmoud Mostafa ◽  
Ahmed Elminshawy
Keyword(s):  
Right Ventricular ◽  
Tricuspid Valve ◽  
Tricuspid Regurgitation ◽  
Early Postoperative Period ◽  
Tricuspid Valve Repair ◽  
Ring Annuloplasty ◽  
Significant Difference ◽  
Group A ◽  
Group B ◽  
The Right

Background: Functional tricuspid valve regurgitation secondary to left-sided valve disease is common. DeVega repair is simple, but residual regurgitation with subsequent impairment of the right ventricular function is a concern. This study aims to compare tricuspid valve repair using DeVega vs. ring annuloplasty and their impact on the right ventricle in the early postoperative period and after six months. Methods: This is a prospective cohort study of 51 patients with rheumatic heart disease who underwent tricuspid valve repair for secondary severe tricuspid regurgitation. Patients were divided into two groups: group A; DeVega repair (n=34) and group B; ring annuloplasty repair (n=17). Patients were assessed clinically and by echocardiography before discharge and after six months for the degree of tricuspid regurgitation, right ventricular diameter and tricuspid annular plane systolic excursion (TAPSE). Results: Preoperative echocardiographic assessment showed no difference in left ventricular end-systolic diameter, end-diastolic diameter, ejection fraction and right ventricular diameter, however; group A had significantly better preoperative right ventricular function measured by TAPSE (1.96 ± 0.27 vs1.75 ± 0.31 cm; p=0.02). Group B had significantly longer cardiopulmonary bypass time (127.65 ± 13.56 vs. 111.74 ± 18.74 minutes; p= 0.003) and ischemic time (99.06 ± 11.80 vs. 87.15 ± 16.01 minutes; p= 0.009). Pre-discharge, there was no statistically significant difference in the degree of tricuspid regurgitation, but the right ventricular diameter was significantly lower in group B (2.66 ± 0.41 and 2.40 ± 0.48 cm; p=0.049). After six months of follow up, the degree of tricuspid regurgitation (p= 0.029) and the right ventricular diameter were significantly lower in the ring annuloplasty group (2.56 ± 0.39 and 2.29 ± 0.44 cm; p=0.029). Although there was a statistically significant difference in preoperative TAPSE, this difference disappeared after six months. Conclusion: Both DeVega and ring annuloplasty techniques were effective in the early postoperative period, ring annuloplasty was associated with lesser residual regurgitation and better right ventricular remodeling in severe functional tricuspid regurgitation than DeVega procedure after 6-months of follow up.

Different selective dry cow therapy concepts compared to blanket antibiotic dry cow treatment

2017 ◽  
Vol 45 (06) ◽  
pp. 343-349 ◽  
Author(s):  
Nicole Wente ◽  
Jan-Hendrik Paduch ◽  
Doris Klocke ◽  
Elisabeth Mansion-de Vries ◽  
Martina Hoedemaker ◽  
...  
Keyword(s):  
Rapid Test ◽  
Study Groups ◽  
Test Methods ◽  
Farm Animals ◽  
Control Group ◽  
Dry Period ◽  
Udder Health ◽  
Significant Difference ◽  
Group A ◽  
The Right

SummaryObjective: The aim of the study was to investigate the use of somatic cell count (SCC) and aerobic bacterial counts as possible tools to choose animals for selective dry cow treatment (DCT) on cow level. Blanket antibiotic DCT is an approved and common method in Germany aimed at increasing the cure rate of existing intramammary infections (IMI) at the time of drying off and decreasing the risk of new infections during the dry period. However, not all animals benefit equally from an antibiotic DCT. Moreover, dairies, consumers and politicians demand a reduction in the use of antibiotics in farm animals. Several criteria for identifying animals which would benefit from antibiotic DCT have been described in the literature. Material and methods: Animals chosen for this investigation were divided into three study groups: Aerobic Count Petrifilm® group A (153 cows), SCC group S (160 cows) and control group C (169 cows). All quarters were treated with an internal teat sealant (ITS) no matter which group the cows belonged to. Results: Group C, in which all cows received an antibiotic DCT, achieved the best results referred to udder health, particularly regarding bacteriological dry period cure. However, the results of the two study groups A and S, in which the animals were dried off selectively, were only marginally worse. A significant difference regarding bacterial dry period cure was revealed between group S and group C (p = 0.039), whereas no significant difference concerning new IMI risk could be detected between the three study groups. Compared to a blanket antibiotic DCT of all cows in the corresponding study group, a reduction of the usage of antibiotics of 23.5 % (A) and 55 % (S) was noticed, respectively. Furthermore, it could be shown that the lactation number as well as the microorganisms present at the time of drying off influence udder health. Conclusion: Selective DCT is an alternative method to the widespread blanket antibiotic DCT. However, it has to be mentioned that selective DCT involves the described marginal decline in udder health and the additional amount of time, which might arise from the procedure of choosing the right animals and performing the applied rapid test methods.

scholarly journals Shear Stress Distribution in the Opening Chords of Hybrid R/C T-Beams with Opening

2018 ◽  
Vol 147 ◽  
pp. 01005
Author(s):  
Jonie Tanijaya
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Shear Force ◽  
Maximum Shear Stress ◽  
Shear Stress Distribution ◽  
Shear Stresses ◽  
Web Openings ◽  
The Right ◽  
Lower Corner ◽  
T Beam

This study is carried out to evaluate the potential of three hybrid T-beams with web openings theoretical shear stresses distribution. The shear stresses at the opening edges were plotted at the working stage, yielding stage and collapse stage for these three tested beams. The available experimental results from the previous research was compared to the finite element results as well as the developed analytical. The shear stress distribution at the middle of the top and bottom chords of the opening in pure bending region are zero. At the upper and lower corners of the opening occurs the maximum shear stresses. The maximum shear stress occurs at the right lower corner chord at the high moment edge and at the left upper corner chord at the low moment edge in beams with openings at high shear and high flexural – shear region. Furthermore, an extensive parametric study is performed on these beams to find the distributing ratio of the shear force between the opening chords. The shear force at an opening in hybrid R/C T-beam is carried by the top and bottom chords of the opening according to the area – moment of inertia root ratio with the correction factor 0.70.

Prevention of Capsular Contracture with Montelukast After Insertion of Silicone Implants in Rabbits

2016 ◽  
Vol 13 (10) ◽  
pp. 7623-7627
Author(s):  
Zhenyu Jin ◽  
Ki Yong Hong ◽  
Kyung Won Minn ◽  
Hak Chang ◽  
Ung Sik Jin
Keyword(s):  
Breast Implant ◽  
Capsular Contracture ◽  
White Female ◽  
Silicone Implants ◽  
Control Group ◽  
Tissue Samples ◽  
Significant Difference ◽  
Group A ◽  
The Right ◽  
Experimental Group

Capsular contracture is the most common complication after insertion of silicone implants during breast implant surgery. The discovery that myofibroblasts play an important role in the formation of hypertrophic scars led to the development of pharmacological drugs such as zafirlukast, which prevents capsular contracture by resisting the above mechanism. As a result, the author sought to investigate the effect of the anti-leukotriene montelukast on capsular contracture. Ten white female New Zealand rabbits, each weighing approximately 3 kg, were used as subjects. Through bilateral incision of the midback area, the prostheses were inserted on the subpanniculus carnosus plane. Once the silicone prostheses had been inserted, the right implant was injected with 10 mL of montelukast (10 µg/mL), and the left implant was injected with 10 mL of normal saline. Eight weeks after the procedure, the capsular pressure was measured via tonometry using a circular glass piece weighing 42.7 g. The tissue samples were then extracted, and their thicknesses were measured using hematoxylin-eosin stain and Masson trichrome stain. The average pressure was 4.23±0.99 mmHg in the control group and 3.71±0.51 mmHg in the experimental group, a statistically significant difference (p = 0.02). The average capsular thickness was 947.938±300 µm in the control group and 709.672±274 µm in the experimental group, a statistically significant difference (p = 0.028). The author confirmed that montelukast injections during silicone prosthesis insertion decreased the formation of capsular contracture.

Effect of Hemiovariectomy on reproductive performance in Chinchila Rabbits.

2021 ◽  
Vol 36 (1) ◽  
pp. 167-174
Author(s):  
C. A. Eze ◽  
C. P. Nwodo ◽  
E. O. Ogbu
Keyword(s):  
Birth Weight ◽  
Litter Size ◽  
Conception Rate ◽  
Control Group ◽  
Significant Difference ◽  
Negative Effect ◽  
Group A ◽  
Group B ◽  
The Right ◽  
Reproductive Indices

This work evaluates the effects of hemiovariectomi (37 some reproductive indices such as conception rate, birth weight and birth litter size in Chinchilla breed of rabbits. Thirty females and six males were used for the experiment. The males were examined for breeding soundness before using them to cross the females. The experiment was replicated in two batches of three groups of five females and a male each at different periods. Hemi-ovariectomy was carried out in the right ovary of 10 does (Group A) and left ovary of another 10 does (Group B). Ten females in Group C were not ovariectomised and served as the control group. All groups were served at reproductive maturity by rotating the bucks. Pregnancy was diagnosed using a standard method. The reproductive indices evaluated included conception rate, birth weight and birth litter size. Data were analyzed using percentages, ratios, and analysis of variance (ANOVA) was computed where necessary. Results showed that hemi ovariectomy significantly (P<0.01) reduced the mean litter size, Group A (2.50+58), Group B (3.00+0.71), control (Group C) (6.20+0.84). However, there was increased mean litter birth weight which, differed significantly (P<0.01) from that of the control (27.06), Group A (33.64+1.86) and Group B (33.93=1.75). Also, the conception rate in the treated groups averaged 65% while the control was 80%. There was no significant difference (P>0.05) between the groups in the interval from the introduction of the huck to the does to the time of conception. It is concluded thai hemiovariectomy has negative effect on the conception rate and birth litter size but has positive effect on birth litter weight. The procedure has shown that in highly priced breed of animal with unilateral ovarian uilments such an animal can still be used for breeding using the healthy ovary: The procedure could also be a more reliable method of birth control in pet animals as well as a means of producing heavy weight offspring.

Stress distribution analysis of novel dental mini-implant designs to support overdenture prosthesis

2021 ◽  
Author(s):  
Mariana Lima da Costa Valente ◽  
Ana Paula Macedo ◽  
Andréa Reis
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Axial Load ◽  
Static Load ◽  
Maximum Shear Stress ◽  
Load Application ◽  
Distribution Analysis ◽  
Mini Implants ◽  
Photoelastic Analysis

This study aimed to test and compare two novel dental mini-implant designs to support overdentures with a commercial model, regarding the stress distribution, by photoelastic analysis. Three different mini-implant designs (Ø 2.0 mm × 10 mm) were tested: G1—experimental threaded (design with threads and 3 longitudinal and equidistant self-cutting chamfers), G2—experimental helical (design with 2 long self-cutting chamfers in the helical arrangement), and G3—Intra-Lock® System. After including the mini-implants in a photoelastic resin, they were subjected to a static load of 100 N under two situations: axial and inclined model (30°). The fringe orders (n), that represents the intensity of stresses were analyzed around the mini-implants body and quantified using Tardy's method that calculates the maximum shear stress (τ) value in each point selected. In axial models, less stress was observed in the cervical third mini-implants, mainly in G1 and G2. In inclined models (30°), higher stresses were generated on the opposite side of the load application, mainly in the cervical third of G2 and G3. All mini-implant models presented lower tensions in the cervical third compared with the middle and apical third. The new mini-implants tested (G1 and G2) showed lower stresses than the G3 in the cervical third under axial load, while loading in the inclined model generated greater stresses in the cervical of G2.

scholarly journals Length and Depth of the Central Sulcus: A Postmortem Study

2014 ◽  
Vol 11 (1) ◽  
pp. 19-24
Author(s):  
Kanij Fatema ◽  
Shamim Ara ◽  
Mushfika Rahman ◽  
Halima Afroz ◽  
Anjuman Ara Sultana ◽  
...  
Keyword(s):  
Right Hemisphere ◽  
Age Groups ◽  
Central Sulcus ◽  
Cross Sectional ◽  
Male And Female ◽  
Significant Difference ◽  
Group A ◽  
The Difference ◽  
Group B ◽  
The Right

Context: The central sulcus, which is located between the primary motor and primary somatic sensory cortex is an important structure and landmark of the cerebral hemisphere. Morphology of the central sulcus varies with age, sex, manual skill, handedness and in many diseases. This study is carried out to establish a normal standard in different age groups in length and depth of the central sulcus. Materials and Methods: A cross-sectional, analytical type of study was conducted in the department of Anatomy, Dhaka Medical College, on one hundred and forty (140) on human cerebral hemispheres. The samples were divided into four different age groups i.e. Group A (20-29 years), Group B (30-39 years), Group C (40-49 years) and Group D (50-59 years). All the samples were studied morphologically. Results: The mean length of central sulcus was 102.89±3.55 mm to 96.83±3.92 mm in male and 98.00±5.17 mm to 96.29±2.56 mm in female. Depth of the central sulcus was 20.02±2.41 mm to 21.50±2.21 mm in male and 20.50±2.57 mm to 21.36±1.87 mm in female. The difference in mean length of the right central sulcus between male and female was statistically significant in group A (p<0.05) and B (p<0.05). The difference in mean depth of the central sulcus between male and female was not statistically significant in any age groups. No significant difference was found between right and left hemisphere for both length and depth of the central sulcus. The difference in mean length and depth of the central sulcus between different age groups for both left and right hemisphere was not statistically significant in any age group. Conclusion: The length and depth of the central sulcus showed gradual decreasing values with advancing age. DOI: http://dx.doi.org/10.3329/bja.v11i1.20504 Bangladesh Journal of Anatomy, January 2013, Vol. 11 No. 1 pp 19-24

Early Closure of Growth Plate Due to Avascular Necrosis of the Femoral Head After Displaced Fracture of the Femoral Neck in Children

2020 ◽  
Vol 12 (1) ◽  
pp. 34-38
Author(s):  
Fei Jiang ◽  
Fei Qiao ◽  
He Hu ◽  
Limin Hou ◽  
Dongpo Lv
Keyword(s):  
Tissue Engineering ◽  
Growth Plate ◽  
Immunohistochemical Staining ◽  
Type Ii ◽  
Limb Deformity ◽  
Significant Difference ◽  
Group A ◽  
Group B ◽  
Growth Plate Injury ◽  
The Right

To investigate the effect of autogenous tissue engineering of growth plates in the treatment of growth plate injury. The growth plate chondrocytes were cultured from the iliac crest of 3-week-old rabbits by mechanical shearing and type II collagenase digestion. After in vitro development, the chondrocytes were seeded on the allogeneic decalcified bone matrix. After being mixed in culture for one week, the chondrocytes were implanted into the defects of the medial growth plate at the upper end of the right tibia; the left tibia was not treated. Dynamic X-ray photography was used to measure the shortening and angular changes in the lower extremity. The H & E and collagen1 immunohistochemical staining were used to observe the in vivo outcomes of the growth plate. There was a slight deformity in the right tibia of group A and group B on the 2nd and 3rd week after the operation, however, there was no significant difference between the three groups (P > 0.05). After that, the right tibia of group B and group C had progressive severe shortening and angulation deformity, while the right tibia of group A had no significant increase in deformity. There was a significant difference between group A, B and C at each time point (P < 0.05). In group A, the normal growth plate structure from collagen-1 immunohistochemical staining was recovered, while in group B and C the damaged area was repaired by new bone tissue. Autogenous tissue engineering of the growth plate can effectively prevent limb deformity after acute growth plate injury. The implanted tissue engineered growth plate can produce a columnar structure; cells can express type II collagen.

scholarly journals Histological Assessment of the Effect of α-Tocopherol on Fracture Healing in Rabbits

2003 ◽  
Vol 31 (1) ◽  
pp. 26-30 ◽  
Author(s):  
K Durak ◽  
G Sonmez ◽  
B Sarisozen ◽  
S Ozkan ◽  
M Kaya ◽  
...  
Keyword(s):  
Fracture Healing ◽  
Treated Group ◽  
Control Group ◽  
Free Oxygen Radicals ◽  
Free Oxygen ◽  
Fracture Management ◽  
Significant Difference ◽  
Fracture Area ◽  
Group A ◽  
The Right

To investigate the effect of α-tocopherol (vitamin E) on fracture healing in rabbits, two groups of 10 rabbits were either injected with α-tocopherol (treated) or untreated (controls). The right femurs of both groups were fractured, and the treated group were injected intramuscularly with 20 mg/kg α-tocopherol daily for 5 days starting on the day of fracture. After 21 days, histological sections of the fractured region were examined and scored. Fracture healing had progressed further in the α-tocopherol group than in the control group. A statistically significant difference between the histological grading of fracture healing in the two groups was found. This difference may result from an antioxidant (α-tocopherol) effect on free oxygen radicals in the fracture area. We conclude that α-tocopherol may affect fracture healing favourably and might be useful as a therapeutic agent in clinical fracture management.

Suicidal Ideation and Self-Determination in Institutionalized Elderly

Crisis ◽  
2001 ◽  
Vol 22 (1) ◽  
pp. 15-19 ◽  
Author(s):  
Andrée Fortin ◽  
Sylvie Lapierre ◽  
Jacques Baillargeon ◽  
Réal Labelle ◽  
Micheline Dubé ◽  
...  
Keyword(s):  
Self Determination ◽  
Current Debate ◽  
Elderly Persons ◽  
Rational Suicide ◽  
Institutionalized Elderly ◽  
Significant Difference ◽  
Social Subscale ◽  
Civil Status ◽  
The Right ◽  
Taking Action

The right to self-determination is central to the current debate on rational suicide in old age. The goal of this exploratory study was to assess the presence of self-determination in suicidal institutionalized elderly persons. Eleven elderly persons with serious suicidal ideations were matched according to age, sex, and civil status with 11 nonsuicidal persons. The results indicated that suicidal persons did not differ from nonsuicidal persons in level of self-determination. There was, however, a significant difference between groups on the social subscale. Suicidal elderly persons did not seem to take others into account when making a decision or taking action. The results are discussed from a suicide-prevention perspective.

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