169,720 research outputs found
Incidence and outcome of prenatal brain abnormality in twin-to-twin transfusion syndrome: systematic review and meta-analysis
No full textOBJECTIVES: to ascertain the incidence of antenatally diagnosed brain injuries in twin pregnancies complicated by twin to twin transfusion syndrome (TTTS) and to quantify the perinatal mortality, morbidity and long-term neurodevelopmental outcomes of these fetuses. METHODS: Medline, Embase, Clinicaltrials.gov and Cochrane Library databases were searched. Inclusion criteria were studies reporting on brain abnormalities diagnosed antenatally in twin pregnancies complicated by TTTS. The primary outcome was the incidence of prenatal brain abnormalities. The secondary outcomes were intrauterine demise (IUD), neonatal death, termination of pregnancy (TOP) and long-term morbidity. All these outcomes were explored in the overall population of fetuses with antenatal diagnosis of brain abnormalities. Sub-group analysis according to: type of treatment, gestational age and Quintero stage at diagnosis and/or treatment, co-twin death was planned. Meta-analyses of proportions were used to combine data and reported pooled proportion and their 95% confidence intervals (CI). RESULTS: Thirteen studies including 1573 cases of TTTS and 88 fetuses with an antenatal diagnosis of brain abnormalities were included in the systematic review. The meta-analysis included only studies reporting on brain abnormalities in twin pregnancies complicated by TTTS cases and treated with laser. Overall, brain injuries occurred in 2.2% of fetuses (eight studies (52/2410 fetuses)). These brain abnormalities were reported in 1.03% and 0.82% of recipients or donors, respectively. These abnormalities were mainly ischemic lesions (30.4%, 95%CI 19.1-43), followed by destructive lesions (23.9%, 95%CI 13.7-35.9), ventriculomegaly (19.9%, 95% CI 10.6-31.3) and hemorrhagic (15.3%, 95%CI 7.1-25.8). Spontaneous IUD occurred in 13.4% (95%CI 5.1-24.8) of fetuses, while TOP was chosen by parents in 53.5% (95%CI 38.9-67.8) cases. Neonatal death was reported only by three studies with an incidence of 15.4% (95%CI 2.8-35.4). Finally, only two studies reported on composite morbidity with 20.4% of morbidity reported overall (95%CI 2.5-49.4) which occurred in 29.7% and 20.4% of the recipient and donor fetuses, respectively. Due to the small numbers, only composite morbidity was analyzed and no information on neonatal intensive care unit admission, respiratory distress syndrome or other long-term outcomes such as neurodevelopmental delay or cerebral palsy could be reliably retrieved. CONCLUSIONS: The overall incidence of antenatally diagnosed fetal brain abnormalities in fetuses from twin pregnancies complicated by TTTS treated with laser is around 2%, mainly ischemic (30.4%) in nature. TOP was chosen by parents in almost half of the cases (53.5%). No information could be retrieved on morbidity outcomes, highlighting the urgent need for long-term follow up studies of these children
Perinatal outcomes of twin pregnancies complicated by late twin‐twin transfusion syndrome: A systematic review and meta‐analysis
No full textIntroduction
Untreated twin‐to‐twin transfusion syndrome (TTTS) is associated with a high risk of perinatal mortality and morbidity. Laser surgery is recommended before 26 weeks of gestation. However, the optimal management in case of late TTTS (occurring after 26 weeks of gestation) is yet to be established.
Material and methods
We conducted a systematic review and meta‐analysis to evaluate the outcomes of monochorionic‐diamniotic twin pregnancies complicated by late TTTS according to different management options (expectant, laser therapy, amnioreduction, or delivery). The primary outcome was mortality, including single and double intrauterine, neonatal, and perinatal death. Secondary outcomes were composite morbidity, neuromorbidity, respiratory distress syndrome, admission to neonatal intensive care unit, intact survival (ie, free from neurological complications), and preterm birth before <32 weeks of gestation. Outcomes were reviewed according to the management and reported for the overall population of twins and disease status (ie, donor and recipient separately). Random‐effect meta‐analyses of proportions were used to analyze the data.
Results
Nine studies including 796 twin pregnancies affected by TTTS were included. No randomized controlled trials were available for inclusion. TTTS occurred at ≥26 weeks of gestation in 8.7% (95% CI 6.9%‐10.9%; 67/769) of cases reporting TTTS at all gestations. Intrauterine death occurred in 17.7% (95% CI 4.9%‐36.2%) of pregnancies managed expectantly, 5.3% (95% CI 0.9%‐12.9%) of pregnancies treated with laser, and 0% (95% CI 0%‐9%) after amnioreduction. Neonatal death occurred in 42.5% (95% CI 17.5%‐69.7%) of pregnancies managed expectantly, in 2.8% (95% CI 0.3%‐7.7%) of cases treated with laser, and in 20.2% (95% CI 6%‐40%) after amnioreduction. Only one study (10 cases) reported data on immediate delivery after diagnosis with no perinatal deaths. Perinatal death incidence was 55.7% (95% CI 31.4%‐78.6%) in twin pregnancies managed expectantly, 5.6% (95% CI 0.5%‐15.3%) in those treated with laser, and 20.2% (95% CI 6%‐40%) in those after amnioreduction. Intact survival was reported in 44.4%, 96.4%, and 78% of fetuses managed expectantly, with laser or amnioreduction, respectively.
Conclusions
Evidence regarding perinatal mortality and morbidity in twin pregnancies complicated by late TTTS according to the different managements was of very low quality. Therefore further high‐quality research in this field is needed to elucidate the optimal management of these pregnancies
Perinatal outcomes of twin pregnancies affected by early twin‐twin transfusion syndrome: A systematic review and meta‐analysis
No full textIntroduction
Twin‐to‐twin transfusion syndrome (TTTS) is associated with a high risk of perinatal mortality and morbidity if not treated. However, the optimal timing and management in case of early (occurring < 18 weeks) TTTS has not been established yet.
Material and methods
This is a systematic review and meta‐analysis aiming at evaluating the outcomes of monochorionic diamniotic twin pregnancies complicated by early (ie before 18 weeks) TTTS according to different management options (expectant, laser therapy, amnioreduction or cord occlusion). The primary outcome was mortality, including single and double intrauterine, neonatal and perinatal death. Secondary outcomes were: composite morbidity, neuromorbidity, respiratory distress syndrome, admission to neonatal intensive care unit, intact survival (defined as survival free from neurological complications) and preterm birth < 32 weeks of gestation. All outcomes were reviewed according to the different management options (expectant, laser therapy, amnioreduction or cord occlusion) and reported FOR the overall population of twins, and for the donor and recipient separately. Subgroup analysis for TTTS occurring before 16 weeks of gestation was performed. Random‐effect meta‐analyses of proportions were used to analyse the data.
Results
Thirteen studies were included. Early TTTS occurred in 14.3% (95% confidence interval [CI] 11.9‐17.0) of cases. The incidence of intrauterine death was 19.0% (95% CI 2.6‐45.5) in twins managed expectantly, 32.4% (95% CI 16.5‐50.7) in those who received laser treatment and 12.5% (95% CI 4.8‐23.0) in those treated with amnioreduction. The incidence of neonatal death was 22.6% (95% CI 4.2‐49.8) in twins managed expectantly, 24.7% (95% CI 0.5‐80.3) in those who received laser and 20.2 (95% CI 5.8‐43.4) in those who had amnioreduction; it was not possible to compute the incidence of these outcomes in twins undergoing cord occlusion because of insufficient sample and lack of reporting of most of the observed outcomes. Overall, the incidence of perinatal death was 43.9% (95% CI 5.9‐87.7) in twins managed expectantly, 47.3% (95% CI 21.4‐70.0) in those treated with laser and 28.5% in those who had amnioreduction.
Conclusions
Twin pregnancies affected by early TTTS are at substantial risk of perinatal mortality and morbidity; however, the data come from very small studies with a high risk of selection bias
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Mitomycin C in highly myopic eyes - Author reply
No full textOphthalmology. 2005 Feb;112(2):208-18; discussion 219.
Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes.
Gambato C, Ghirlando A, Moretto E, Busato F, Midena E.
SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy.
Abstract
PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes.
DESIGN: Prospective, double-masked, randomized clinical trial.
PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia.
METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months).
MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH.
RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively).
CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK.
Comment in
Ophthalmology. 2006 Feb;113(2):357; author reply 357-8
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
A Multi-Language Comparison of Influences on Author Verification using Character N-Grams
No full textWe create a new multi-language corpus for author verification based on Wikipedia talkpages, and evaluate the influence that differences in topic and time have on character n-gram author profiles. Topic alignment between two texts is found to increase author verification precision, and an authors writing style is found to change over time, but not more significantly after 3 years than after 1 year.Information ArchitectureWISElectrical Engineering, Mathematics and Computer Scienc
A 0.12mm<sup>2</sup> Wien-Bridge Temperature Sensor with 0.1°C (3σ) Inaccuracy from -40°C to 180°C
No full text Resistor-based temperature sensors can achieve much higher resolution and energy efficiency than conventional BJT-based sensors [1], but they typically occupy more area (> 0.25 mm 2 ) and have lower operating temperatures (le 125 {circ} {C}) [2]-[4]. This work describes a 0.12mm 2 resistor-based sensor that uses a Wien-bridge (WB) filter to achieve 0.1 {circ} {C} (3 sigma) inaccuracy from - 40 {circ} {C} to 180 {circ} {C}. Compared to a state-of-the-art WB sensor [4], it occupies 6 × less area and achieves comparable relative accuracy over a 76% wider operating range. Session 10.3 Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
A ±25A Versatile Shunt-Based Current Sensor with 10kHz Bandwidth and ±0.25% Gain Error from -40°C to 85°C Using 2-Current Calibration
No full textAccurate current sensing is critical in many industrial applications, such as battery management and motor control. Precise shunt-based current sensors have been reported with gain errors of less than 1% over the industrial temperature range (-40°C to 85°C) [1]–[4]. However, since they are intended for coulomb counting, their bandwidth is limited to a few tens of Hz, making them unsuitable for battery impedance or motor-current sensing. This paper presents a current sensor with a wide (10kHz) bandwidth and a tunable temperature compensation scheme (TCS), which allows it to be flexibly used with different types of shunts while maintaining high accuracy. A low-cost room-temperature calibration scheme is proposed to optimize gain flatness over temperature by exploiting the shunt's self-heating at large currents. Over the industrial temperature range and a ±25A current range, it achieves state-of-the-art gain error (±0.25%) with both low-cost PCB and stable metal-alloy shunts.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
An Article About Albertus C. Van Raalte, Author Unknown, Except for Parts Taken from an Article by Anna C. Post
No full textAn article about Albertus C. Van Raalte, author unknown, except for parts taken from an article by Anna C. Post. The author knew first generation persons in the Holland settlement and therefore, the article has some value.https://digitalcommons.hope.edu/vrp_1890s/1012/thumbnail.jp
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