Does preconditioning lower the rupture resistance of chorioamniotic membrane?

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Arash Dadkhah ◽  
Ata Hashemi
Keyword(s):  
Mechanical Properties ◽  
Cesarean Delivery ◽  
Fetal Membrane ◽  
Premature Rupture ◽  
Rupture Stress ◽  
Probe Diameter ◽  
Healthy Pregnancy ◽  
Probe Size ◽  
Puncture Force ◽  
The Mean

AbstractPremature rupture of fetal membrane occurs in about 3% of all pregnancies. The physical integrity of chorioamnion (CA) membrane should be retained until delivery for a healthy pregnancy. To explore the effect of pre-conditioning and probe size on the mechanical properties of human chorioamniotic sac, the mechanical properties of 17 human chorioamniotic membranes, collected from cesarean delivery, were examined using biaxial puncture tests with and without preconditioning by different probe sizes. For preconditioned samples, the mean ± std. of ultimate rupture stress was calculated to be 1.73 ± 0.13, 1.61 ± 0.29 and 1.78 ± 0.26 MPa for the probe sizes of 3, 5 and 7 mm, respectively. For samples with no preconditioning, these values were calculated to be 2.38 ± 0.29, 2.36 ± 0.37, and 2.59 ± 0.43 MPa for the above-mentioned probe sizes. The force to probe diameter for samples with no preconditioning was in the range of 1087–1301 N/m for the three probe diameters, well in the range of 850–1580 N/m reported by previous studies. Our results show that the preconditioned samples had significantly lower ultimate puncture force and ultimate stress compared to non-preconditioned samples. In addition, a correlation between the probe size and the magnitude of puncture force was observed, while the stress values were not significantly affected by changing probe size.

Visualisation of the insertion of a membrane for the treatment of preterm rupture of fetal membranes using a synthetic model of a pregnant uterus

2018 ◽  
Vol 33 (2) ◽  
pp. 234-244
Author(s):  
Sabiniano Roman ◽  
Christopher Hillary ◽  
Brenda Narice ◽  
Anthony J Bullock ◽  
Dilly OC Anumba ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Amniotic Fluid ◽  
Bilayer Membrane ◽  
Fetal Membrane ◽  
Fetal Membranes ◽  
Premature Rupture ◽  
Management Options ◽  
Pregnant Uterus ◽  
Fetal Survival ◽  
Preterm Premature Rupture

Preterm premature rupture of fetal membranes is a leading cause of preterm delivery. Preterm labour can compromise fetal survival, and even if a pregnancy affected by preterm premature rupture of fetal membrane continues, major complications associated with leakage of amniotic fluid and risk of infection can affect the normal development and survival of the baby. There are limited management options for preterm premature rupture of fetal membrane other than delivery of the baby if ascending infection (chorioamnionitis) is suspected. We have previously reported the development and characterisation of an implantable membrane with the aim of using it to occlude the internal os of the cervix, in order to prevent amniotic fluid loss, allow fluid reaccumulation and reduce the risk of chorioamnionitis. For this, an electrospun biocompatible and distensible bilayer membrane was designed with mechanical properties similar to the human amniotic membrane. In this study, we consider the effects of sterilization on the membrane, how to insert the membrane and visualise it using routine clinical methods. To do this, we used e-beam sterilisation and examined the ability of the membrane to adhere to ex vivo human cervical tissues. We also studied its insertion into a custom-synthesised model of a 20-week pregnant uterus and imaged the membrane using ultrasound. Sterilisation produced minor effects on physical and mechanical properties, but these did not affect the capacity of the membrane to be sutured or to provide a fluid barrier. We demonstrated that fibrin glue can successfully adhere the bilayer membrane to cervical tissues. Finally, we demonstrated that the membrane can be inserted through the cervix as well as visualized in place using ultrasound imaging and an endoscope. In summary, we suggest this membrane is a candidate for further development in an appropriate animal model, supported by appropriate imaging, to precede possible future human studies if judged to demonstrate satisfactory safety and efficacy profiles.

scholarly journals Fabrication of (SiC-AlN)/ZrB2 Composite with Nano-Micron Hybrid Microstructure via PCS-Derived Ceramics Route

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 334
Author(s):  
Aidong Xia ◽  
Jie Yin ◽  
Xiao Chen ◽  
Zhengren Huang ◽  
Xuejian Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Flexural Strength ◽  
Hot Pressing ◽  
Raw Materials ◽  
Secondary Phase ◽  
Pressing Temperature ◽  
Xrd Pattern ◽  
Mean Grain Size ◽  
The Mean

In this work, a (SiC-AlN)/ZrB2 composite with outstanding mechanical properties was prepared by using polymer-derived ceramics (PDCs) and hot-pressing technique. Flexural strength reached up to 460 ± 41 MPa, while AlN and ZrB2 contents were 10 wt%, and 15 wt%, respectively, under a hot-pressing temperature of 2000 °C. XRD pattern-evidenced SiC generated by pyrolysis of polycarbosilane (PCS) was mainly composed by 2H-SiC and 4H-SiC, both belonging to α-SiC. Micron-level ZrB2 secondary phase was observed inside the (SiC-AlN)/ZrB2 composite, while the mean grain size (MGS) of SiC-AlN matrix was approximately 97 nm. This unique nano-micron hybrid microstructure enhanced the mechanical properties. The present investigation provided a feasible tactic for strengthening ceramics from PDCs raw materials.

A multiscale topography analysis of ground stainless steel and titanium alloys

2007 ◽  
Vol 221 (9) ◽  
pp. 1407-1420 ◽  
Author(s):  
S Giljean ◽  
M Bigerelle ◽  
K Anselme
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Titanium Alloys ◽  
Roughness Parameter ◽  
Roughness Parameters ◽  
Observation Scale ◽  
316L Austenitic Stainless Steel ◽  
The Mean ◽  
Best Parameter

This study aims to perform a multiscale analysis of abraded surfaces of 316L austenitic stainless steel and titanium alloys (TiAl6V4) grinded at different paper grades. The authors propose to answer the following question: For a given distribution of silicon carbide grains of the paper, what is the best roughness parameter and at which scale must it be evaluated better to discriminate the effect of the mechanical properties of the materials? Paper grades from 80 to 4000 were used under identical pressure and erosion time. It can be concluded that the values of the amplitude roughness parameters depend on the observation scale. It is outlined that the abrasion process is very reproducible. A statistical analysis is then proposed, first, to define a classification of the relevance of the roughness parameters for each grain size distribution, and second, to determine at which scale the mechanical properties of the bulk are more influenced for all paper grades. Finally, at relevant scales, the Abbott amplitude parameters roughness kernel (RK) is the best parameter to discriminate the paper grade effect. The mean distance between asperities (SM) is the preferred method for determining the wear effect on materials and the linear mean normalizing autocorrelation (AMNLN) is the preferred method for determining the interaction between paper grade and materials.

scholarly journals Hubungan Ketuban Pecah dengan Kejadian Asfiksia Neonatorum di RSUD Kabupaten Kediri Tahun 2016

2017 ◽  
Vol 3 (2) ◽  
pp. 19
Author(s):  
Yanu Yufita Lestariningsih
Keyword(s):  
Public Hospital ◽  
Simple Random Sampling ◽  
Fetal Membrane ◽  
P Value ◽  
Premature Rupture Of Membranes ◽  
Premature Rupture ◽  
Chi Square ◽  
Asphyxia Neonatorum ◽  
Chi Square Test ◽  
Almost All

Premature rupture of  membranerevolves 5-10% from all birth. Impact a birth premature that espoused broken fetal membrane early causess 12-15% asphyxia neonatorum. The purpose of the study to determine the correlation between premature rupture of  membrane with the incidence of asphyxia neonatorum. The research method used is analytic with retrospective cohort approach with independent variable of premature rupture of membrane, dependent variable asphyxia neonatorum. The study was conducted on 7 June to 12 July 2017. The population of 1519 mothers inregional public hospital of Kediri regency 2016. Sample 139 respondents, taken by simple random sampling, was analyzed by Chi Square test with a significant of 0.05. Result of research most of respondent with rupture of membrane counted 46 respondents, almost all respondents that is 82.6% gave birth baby with asphyxia. From result of Chi Square test obtained by result of p-value equal to 0.000 (<0.05), result of coefficient of contingency (C) equal to 0.639 with closeness strong relation, so H1 received H0 rejected which means there is significant relation with closeness strong between premature rupture of membrane with asphyxia neonatorum inregional public hospital of Kediri regency 2016. Relative Risk (RR) 1.65 which means the possibility of a baby experiencing asphyxia neonatorum of 1.65 times in maternal who experience premature rupture of membranes compared to mothers who did not experience premature rupture of membranes.

scholarly journals Mechanical properties of microwave sintered Si3N4-based ceramics

2002 ◽  
Vol 34 (3) ◽  
pp. 223-229 ◽  
Author(s):  
O.I. Getman ◽  
V.V. Holoptsev ◽  
V.V. Panichkina ◽  
I.V. Plotnikov ◽  
V.K. Soolshenko
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bending Strength ◽  
Normal Pressure ◽  
Ceramic Materials ◽  
Particle Sizes ◽  
Phase Measurements ◽  
Ceramic Samples ◽  
Mean Size ◽  
The Mean

The mechanical properties and microstructure formation processes in Si3N4+3% AI2O3+5% Y2O3(Yb2O3) ceramic compacts sintered under microwave heating (MWH) and under traditional heating (TH) were investigated. The initial ceramic materials were powder blends of silicon nitride with oxides. The mean powder particle sizes were 0.5-1.0 mim. The content of alfa-phase in the Si3N4 powder was more than 95 %. The samples were sintered at 1800BC in nitrogen at normal pressure, the heating rate in all experiments was 60BC/min. The Vickers hardness (HV), fracture toughness (K1C) and bending strength (on) were determined. The microstructures of fracture surfaces of samples were studied by SEM. Quantitative microstructure analysis was carried out. It was shown that the values of HV and Kic of ceramic samples sintered under MWH at 1800BC rose steadily with the sintering time. This caused an increase in density, which reached maximum as fast as after 30 min of the MWH sintering; the mass loss at that time amounted to 3-4 %. The porosity of sintered samples with an addition of yttria was less than 1 %, that of ytterbia was greater, 2.4 %. For similar values of relative density, the hardness and fracture toughness of ceramic samples produced under MWH were higher as compared with those of samples sintered under TH. The microstructure of samples had the form of elongated grains in a matrix of polyhedral grains of the beta-Si3N4 phase. Measurements showed the mean size of grains in samples produced by MWH to be greater that in samples produced by TH. A larger number of elongated grains were formed. It was concluded that for sintering under MWH of Si3N4-based ceramics the growth of elongated beta-Si3N4 grains and formation of a "reinforced" microstructure were promoted and thereby improved the mechanical properties of such ceramics.

scholarly journals Longitudinal variation in mechanical competence of bone along the avian humerus.

1995 ◽  
Vol 198 (1) ◽  
pp. 209-212
Author(s):  
R H Bonser
Keyword(s):  
Mechanical Properties ◽  
Trabecular Bone ◽  
Cortical Bone ◽  
Vickers Microhardness ◽  
Bird Species ◽  
Longitudinal Variation ◽  
The Mean ◽  
Compressive Tests

Vickers microhardness tests were used to gauge the mechanical "competence" (ability to resist bending and failure) of cortical and trabecular bone along the humeri of three bird species. Hardness was greatest at the mid-length portion of the shaft. The mean hardness of trabeculae, where present, was between 78.7 and 90.9% of that of the adjacent cortical bone. The possible causes of this are briefly discussed. Microhardness tests offer the opportunity to gauge differences in mechanical properties over small distances and might usefully be applied to test the homogeneity of mechanical properties within specimens for tensile or compressive tests.

scholarly journals Risk Factors for Neonatal Bronchopulmonary Dysplasia in Extremely Preterm Premature Rupture of Membranes: A Retrospective Study

2020 ◽  
Author(s):  
Eishin Nakamura ◽  
Shigetaka Matsunaga ◽  
Yoshihisa Ono ◽  
Yasushi Takai ◽  
Hiroyuki Seki
Keyword(s):  
Risk Factors ◽  
Preterm Delivery ◽  
Bronchopulmonary Dysplasia ◽  
Roc Curve ◽  
Premature Rupture Of Membranes ◽  
Premature Rupture ◽  
Preterm Premature Rupture ◽  
Extremely Preterm ◽  
Gestational Week ◽  
The Mean

Abstract Background: Determination of the optimal timing for termination of pregnancy in cases of preterm premature rupture of membranes (pPROM) during the extremely preterm period is still difficult. Bronchopulmonary dysplasia (BPD) is a major disease widely taken into account when determining the prognosis of respiratory disorders in a neonate. Many aspects of this disease remain unclear. With the aim of further improving the prognosis of neonates born to mothers with pPROM, this study examined cases who were diagnosed with pPROM before 28 weeks of gestation. The study analysed risk factors for neonatal BPD. Methods: This study included 73 subjects with singleton pregnancy, diagnosed with pPROM during the gestational period from 22 weeks and 0 days to 27 weeks and 6 days. The following factors were retrospectively examined: the gestational week at which pPROM was diagnosed, the gestational week at which delivery occurred, the period for which the volume of amniotic fluid was maintained, and neonatal BPD as a complication. Receiver operating characteristic (ROC) curve analyses were conducted to analyse the relationship of the onset of BPD with the duration of oligohydramnios and the gestational weeks of delivery. Results: The mean gestational week at which a diagnosis of amniorrhexis was made was 24.5±1.9 weeks (mean±SD), and that at which delivery occurred was 27.0±3.0 weeks. Fifty-seven cases (78.1%) were diagnosed with oligohydramnios, the mean duration of which was 17.4±20.5 days. The mean birth weight of neonates was 1000±455 g, of which 49 (67.1%) were diagnosed with BPD following birth. No neonates died in this study. The ROC curve indicated that the cut-off values for the duration of oligohydramnios and gestational age at delivery were 4 days and 24.1 weeks, respectively. Multivariate analysis indicated that the duration of oligohydramnios for more than 4 days before delivery and preterm delivery at less than 24.1 weeks were risk factors for the onset of BPD. Conclusion: Our findings suggest that duration of oligohydramnios for more than 4 days before delivery and preterm delivery less than 24.1 weeks are risk factors for BPD in cases who are diagnosed with pPROM before 28 weeks of gestation.

scholarly journals Role of Chemical Biomarkers in Prediction of Intra-Amniotic Infection in Cases with Preterm Premature Rupture of Membrane, Observational Study

2019 ◽  
Vol 3 (2) ◽  
Keyword(s):  
Interleukin 6 ◽  
Mean Value ◽  
Maternal Serum ◽  
P Value ◽  
Subclinical Infection ◽  
Premature Rupture ◽  
Cutoff Value ◽  
The Mean ◽  
Sensitivity Specificity

Introduction: Early recognition of subclinical intra-amniotic infection before development of clinical Chorioamnionitis dramatically improve neonatal outcome before affection of fetal neurological function. Objective: this study was conducted to evaluate the role of procalcitonin and interleukin-6 in early prediction of intrauterine infection in pregnant women with premature rupture of membranes. Methods: This observational prospective cohort study was conducted on 100 pregnant women with preterm premature rupture of membrane (PPROM), Patients were divided into 2 groups: Group I: with normal CRP and WBCs level. Group2: with subclinical infection which was detected by elevated WBCs count >15,000 c/mm3 and / or positive CRP. This group was divided into two groups (Group (II) and Group (III) according to development of Chorioamnionitis. follow up of these patients was done to detect the cutoff value of procalcitonin and interleukin-6 as a predictive indicator of clinical intra-amniotic infection in patients with premature rupture of membrane. Results: This study showed that the mean value of maternal serum PCT concentration was higher in patients with clinical infection than its concentration in patients without infection or with subclinical infection with P-value 0.0001 which is highly significant between the studied cases and with cutoff value was >0.67ng/ml, sensitivity, specificity, PPV, NPV was 88.7%, 42.9%, 79.7% and 60% respectively and the mean value of maternal serum IL-6 concentration was also higher in patients with clinical infection than its concentration in patients without infection or with subclinical infection with P-value 0.001which is highly significant between the studied cases and with cutoff value was >11.1pg/ ml, sensitivity, specificity, PPV, NPV was 67.9%, 61.9%, 81.8% and 43.3% respectively. Conclusion: maternal serum procalcitonin is a good predictor of clinical intra-amniotic infection with good sensitivity, specificity, PPV, NPV which is nearly good as CRP which is better than serum interleukin-6 regarding sensitivity

scholarly journals Short Term Outcomes of Neonates Born after Prolonged Premature Rupture of Membranes < 34 Weeks Gestation

2019 ◽  
Vol 4 (2) ◽  
pp. 83
Author(s):  
Isam Bsisu ◽  
Alaa Aldalaeen ◽  
Rawan Elrajabi ◽  
Ala AlZaatreh ◽  
Rama Jadallah ◽  
...  
Keyword(s):  
Birth Weight ◽  
Gestational Age ◽  
Neonatal Intensive Care ◽  
Preterm Births ◽  
University Hospital ◽  
High Rate ◽  
Premature Rupture Of Membranes ◽  
Premature Rupture ◽  
Gestational Week ◽  
The Mean

<p><strong><em>Background:</em></strong><em> Preterm premature rupture of membranes (PPROM) is responsible for one?third of all preterm births worldwide. This aim of this study was to investigate the outcome of neonates born after prolonged PPROM with gestational age below 34 weeks. </em></p><p><strong><em>Materials and methods:</em></strong><em> This retrospective study included 65 patients who were born to mothers with Prolonged PPROM &lt;34 weeks gestation between January 2011 and December 2015 and admitted to the neonatal intensive care unit (NICU) at Jordan University Hospital. </em></p><p><strong><em>Results: </em></strong><em>The mean gestational age of included patients was (31.9 ± 2.5 weeks), mean birth weight was (1840 ± 583 g) and 43 (66.2%) were males. The mortality rate in those infants was 12.3 %. Gestational age, birth weight, and Apgar score were significantly lower among mortality cases compared to surviving cases (P &lt; 0.05). </em></p><p><strong><em>Conclusion:</em></strong><em> Prolonged PPROM before the 34<sup>th</sup> gestational week is associated with high rate of morbidity and mortality, for which early identification of risk factors for developing PPROM can help in reducing the risk for preterm labors and subsequent burden on healthcare system.</em></p>

Microstructure and Mechanical Performance of AZ31-1.7 Wt.% Si Alloy Processed by Cyclic Channel Die Compression

2010 ◽  
Vol 667-669 ◽  
pp. 457-461
Author(s):  
Wei Guo ◽  
Qu Dong Wang ◽  
Man Ping Liu ◽  
Tao Peng ◽  
Xin Tao Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Mechanical Performance ◽  
Chinese Script ◽  
Cast State ◽  
Microstructure And Mechanical Properties ◽  
Mean Grain Size ◽  
The Matrix ◽  
The Mean

Cyclic channel die compression (CCDC) of AZ31-1.7 wt.% Si alloy was performed up to 5 passes at 623 K in order to investigate the microstructure and mechanical properties of compressed alloys. The results show that multi-pass CCDC is very effective to refine the matrix grain and Mg2Si phases. After the alloy is processed for 5 passes, the mean grain size decreases from 300 μm of as-cast to 8 μm. Both dendritic and Chinese script type Mg2Si phases break into small polygonal pieces and distribute uniformly in the matrix. The tensile strength increases prominently from 118 MPa to 216 MPa, whereas the hardness of alloy deformed 5 passes only increase by 8.4% compared with as-cast state.

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