75 research outputs found
Positron collisions with alkali-metal atoms
The total cross sections for positron and electron collisions with potassium, sodium, lithium and rubidium are calculated, employing the modified Glauber approximation. The Modified Glauber cross sections for positron collision with potassium and sodium at low intermediate energies are found to agree reasonably well with existing experimental data
The Emerging Role of PARP Inhibitors in the Treatment of Epithelial Ovarian Cancer
Poly(ADP-ribose) polymerase-1 (PARP-1) is an important novel target in cancer therapy. This enzyme is essential in the repair of single-stranded breaks in DNA via the base excision repair pathway. Drugs which inhibit PARP are emerging as a promising new class of anticancer agents particularly effective against tumors which have lost homologous recombination (HR) through loss of functional BRCA1 and BRCA2. PARP inhibitors potentially represent a major breakthrough for patients with hereditary BRCA-associated cancers. Furthermore their role in sporadic epithelial ovarian cancer is emerging with identification of additional subpopulations of women who may benefit a priority. This paper will summarize the mechanism of action of PARP inhibition and its role in the treatment of BRCA1- and 2-associated cancers. We will then expand on the broader relevance and future directions for PARP inhibition in the clinical setting
Photoelectron Angular Distributions for Two-photon Ionization of Helium by Ultrashort Extreme Ultraviolet Free Electron Laser Pulses
Phase-shift differences and amplitude ratios of the outgoing and
continuum wave packets generated by two-photon ionization of helium atoms are
determined from the photoelectron angular distributions obtained using velocity
map imaging. Helium atoms are ionized with ultrashort extreme-ultraviolet
free-electron laser pulses with a photon energy of 20.3, 21.3, 23.0, and 24.3
eV, produced by the SPring-8 Compact SASE Source test accelerator. The measured
values of the phase-shift differences are distinct from scattering phase-shift
differences when the photon energy is tuned to an excited level or Rydberg
manifold. The difference stems from the competition between resonant and
non-resonant paths in two-photon ionization by ultrashort pulses. Since the
competition can be controlled in principle by the pulse shape, the present
results illustrate a new way to tailor the continuum wave packet.Comment: 5 pages, 1 table, 3 figure
Risk factors for acute kidney injury in neonates with congenital diaphragmatic hernia
This article is made available for unrestricted research re-use and secondary analysis in any form or be any means with acknowledgement of the original source. These permissions are granted for the duration of the World Health Organization (WHO) declaration of COVID-19 as a global pandemic.Objective: To examine incidence of acute kidney injury (AKI), antenatal and postnatal predictors, and impact of AKI on outcomes in infants with congenital diaphragmatic hernia (CDH).
Study design: Single center retrospective study of 90 CDH infants from 2009-2017. Baseline characteristics, CDH severity, possible AKI predictors, and clinical outcomes were compared between infants with and without AKI.
Result: In total, 38% of infants developed AKI, 44% stage 1, 29% stage 2, 27% stage 3. Lower antenatal lung volumes and liver herniation were associated with AKI. Extracorporeal life support (ECLS), diuretics, abdominal closure surgery, hypotension, and elevated plasma free hemoglobin were associated with AKI. Overall survival was 79%, 47% with AKI, and 35% with AKI on ECLS. AKI is associated with increased mechanical ventilation duration and length of stay.
Conclusion: AKI is common among CDH infants and associated with adverse outcomes. Standardized care bundles addressing AKI risk factors may reduce AKI incidence and severity
Braneworld dynamics with the BraneCode
We give a full nonlinear numerical treatment of time-dependent 5d braneworld
geometry, which is determined self-consistently by potentials for the scalar
field in the bulk and at two orbifold branes, supplemented by boundary
conditions at the branes. We describe the BraneCode, an algorithm which we
designed to solve the dynamical equations numerically. We applied the BraneCode
to braneworld models and found several novel phenomena of the brane dynamics.
Starting with static warped geometry with de Sitter branes, we found
numerically that this configuration is often unstable due to a tachyonic mass
of the radion during inflation. If the model admits other static configurations
with lower values of de Sitter curvature, this effect causes a violent
re-structuring towards them, flattening the branes, which appears as a lowering
of the 4d effective cosmological constant. Braneworld dynamics can often lead
to brane collisions. We found that in the presence of the bulk scalar field,
the 5d geometry between colliding branes approaches a universal, homogeneous,
anisotropic strong gravity Kasner-like asymptotic, irrespective of the
bulk/brane potentials. The Kasner indices of the brane directions are equal to
each other but different from that of the extra dimension.Comment: 38 pages, 10 figure
Lymphatic mapping and sentinel node biopsy in gynecological cancers: a critical review of the literature
Although it does not have a long history of sentinel node evaluation (SLN) in female genital system cancers, there is a growing number of promising study results, despite the presence of some aspects that need to be considered and developed. It has been most commonly used in vulvar and uterine cervivcal cancer in gynecological oncology. According to these studies, almost all of which are prospective, particularly in cases where Technetium-labeled nanocolloid is used, sentinel node detection rate sensitivity and specificity has been reported to be 100%, except for a few cases. In the studies on cervical cancer, sentinel node detection rates have been reported around 80–86%, a little lower than those in vulva cancer, and negative predictive value has been reported about 99%. It is relatively new in endometrial cancer, where its detection rate varies between 50 and 80%. Studies about vulvar melanoma and vaginal cancers are generally case reports. Although it has not been supported with multicenter randomized and controlled studies including larger case series, study results reported by various centers around the world are harmonious and mutually supportive particularly in vulva cancer, and cervix cancer. Even though it does not seem possible to replace the traditional approaches in these two cancers, it is still a serious alternative for the future. We believe that it is important to increase and support the studies that will strengthen the weaknesses of the method, among which there are detection of micrometastases and increasing detection rates, and render it usable in routine clinical practice
Congenital Diaphragmatic hernia – a review
Congenital Diaphragmatic hernia (CDH) is a condition characterized by a defect in the diaphragm leading to protrusion of abdominal contents into the thoracic cavity interfering with normal development of the lungs. The defect may range from a small aperture in the posterior muscle rim to complete absence of diaphragm. The pathophysiology of CDH is a combination of lung hypoplasia and immaturity associated with persistent pulmonary hypertension of newborn (PPHN) and cardiac dysfunction. Prenatal assessment of lung to head ratio (LHR) and position of the liver by ultrasound are used to diagnose and predict outcomes. Delivery of infants with CDH is recommended close to term gestation. Immediate management at birth includes bowel decompression, avoidance of mask ventilation and endotracheal tube placement if required. The main focus of management includes gentle ventilation, hemodynamic monitoring and treatment of pulmonary hypertension followed by surgery. Although inhaled nitric oxide is not approved by FDA for the treatment of PPHN induced by CDH, it is commonly used. Extracorporeal membrane oxygenation (ECMO) is typically considered after failure of conventional medical management for infants ≥ 34 weeks’ gestation or with weight >2 kg with CDH and no associated major lethal anomalies. Multiple factors such as prematurity, associated abnormalities, severity of PPHN, type of repair and need for ECMO can affect the survival of an infant with CDH. With advances in the management of CDH, the overall survival has improved and has been reported to be 70-90% in non-ECMO infants and up to 50% in infants who undergo ECMO
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