43,658 research outputs found
Factors affecting sperm recovery rates and survival after centrifugation of equine semen
Conventional centrifugation protocols result in important sperm losses during removal of the supernatant. In this study, the effect of centrifugation force (400 or 900 × g), duration (5 or 10 min), and column height (20 or 40 mL; Experiment 1); sperm concentration (25, 50, and 100 × 10[superscript 6]/mL; Experiment 2), and centrifugation medium (EZ-Mixin CST [Animal Reproduction Systems, Chino, CA, USA], INRA96 [IMV Technologies, Maple Grove, MN, USA], or VMDZ [Partnar Animal Health, Port Huron, MI, USA]; Experiment 3) on sperm recovery and survival after centrifugation and cooling and storage were evaluated. Overall, sperm survival was not affected by the combination of centrifugation protocol and cooling. Total sperm yield was highest after centrifugation for 10 min at 400 × g in 20-mL columns (95.6 ± 5%, mean ± SD) or 900 × g in 20-mL (99.2 ± 0.8%) or 40-mL (91.4 ± 4.5%) columns, and at 900 × g for 5 min in 20-mL columns (93.8 ± 8.9%; P < 0.0001). Total (TMY) and progressively motile sperm yield followed a similar pattern (P < 0.0001). Sperm yields were not significantly different among samples centrifuged at various sperm concentrations. However, centrifugation at 100 × 10[superscript 6]/mL resulted in significantly lower total sperm yield (83.8 ± 10.7%) and TMY (81.7 ± 6.8%) compared with noncentrifuged semen. Centrifugation in VMDZ resulted in significantly lower TMY (69.3 ± 22.6%), progressively motile sperm yield (63.5 ± 18.2%), viable yield (60.9 ± 36.5%), and survival of progressively motile sperm after cooling (21 ± 10.8%) compared with noncentrifuged semen. In conclusion, centrifuging volumes of ≤ 20 mL minimized sperm losses with conventional protocols. With 40-mL columns, it may be recommended to increase the centrifugal force to 900 × g for 10 min and dilute the semen to a sperm concentration of 25 to 50 × 10[superscript 6]/mL in a milk- or fractionated milk-based medium. The semen extender VMDZ did not seem well suited for centrifugation of equine semen
Viscoelastic optical nonlocality of low-loss epsilon-near-zero nanofilms
Optical nonlocalities are elusive and hardly observable in traditional
plasmonic materials like noble and alkali metals. Here we report experimental
observation of viscoelastic nonlocalities in the infrared optical response of
doped cadmium-oxide, epsilon-near-zero nanofilms. The nonlocality is detectable
thanks to the low damping rate of conduction electrons and the virtual absence
of interband transitions at infrared wavelengths. We describe the motion of
conduction electrons using a hydrodynamic model for a viscoelastic fluid, and
find excellent agreement with experimental results. The electrons elasticity
blue-shifts the infrared plasmonic resonance associated with the main
epsilon-near-zero mode, and triggers the onset of higher-order resonances due
to the excitation of electron-pressure modes above the bulk plasma frequency.
We also provide evidence of the existence of nonlocal damping, i.e., viscosity,
in the motion of optically-excited conduction electrons using a combination of
spectroscopic ellipsometry data and predictions based on the viscoelastic
hydrodynamic model.Comment: 19 pages, 5 figure
Primordial Gravitational Waves Enhancement
We reconsider the enhancement of primordial gravitational waves that arises
from a quantum gravitational model of inflation. A distinctive feature of this
model is that the end of inflation witnesses a brief phase during which the
Hubble parameter oscillates in sign, changing the usual Hubble friction to
anti-friction. An earlier analysis of this model was based on numerically
evolving the graviton mode functions after guessing their initial conditions
near the end of inflation. The current study is based on an equation which
directly evolves the normalized square of the magnitude. We are also able to
make a very reliable estimate for the initial condition using a rapidly
converging expansion for the sub-horizon regime. Results are obtained for the
energy density per logarithmic wave number as a fraction of the critical
density. These results exhibit how the enhanced signal depends upon the number
of oscillatory periods; they also show the resonant effects associated with
particular wave numbers.Comment: 25 pages, 14 figure
High-sensitivity troponin I concentrations are a marker of an advanced hypertrophic response and adverse outcomes in patients with aortic stenosis
Aims:
High-sensitivity cardiac troponin I (cTnI) assays hold promise in detecting the transition from hypertrophy to heart failure in aortic stenosis. We sought to investigate the mechanism for troponin release in patients with aortic stenosis and whether plasma cTnI concentrations are associated with long-term outcome.
Methods and results:
Plasma cTnI concentrations were measured in two patient cohorts using a high-sensitivity assay. First, in the Mechanism Cohort, 122 patients with aortic stenosis (median age 71, 67% male, aortic valve area 1.0 ± 0.4 cm2) underwent cardiovascular magnetic resonance and echocardiography to assess left ventricular (LV) myocardial mass, function, and fibrosis. The indexed LV mass and measures of replacement fibrosis (late gadolinium enhancement) were associated with cTnI concentrations independent of age, sex, coronary artery disease, aortic stenosis severity, and diastolic function. In the separate Outcome Cohort, 131 patients originally recruited into the Scottish Aortic Stenosis and Lipid Lowering Trial, Impact of REgression (SALTIRE) study, had long-term follow-up for the occurrence of aortic valve replacement (AVR) and cardiovascular deaths. Over a median follow-up of 10.6 years (1178 patient-years), 24 patients died from a cardiovascular cause and 60 patients had an AVR. Plasma cTnI concentrations were associated with AVR or cardiovascular death HR 1.77 (95% CI, 1.22 to 2.55) independent of age, sex, systolic ejection fraction, and aortic stenosis severity.
Conclusions:
In patients with aortic stenosis, plasma cTnI concentration is associated with advanced hypertrophy and replacement myocardial fibrosis as well as AVR or cardiovascular death
Introducing medical parasitology at the University of Makeni, Sierra Leone
The file attached to this record is the author's final peer reviewed version.Capacity building in Sierra Leone (West Africa) is critical to prevent potential future outbreaks similar to
the 2013-16 Ebola outbreak that had devastating effects for the country and its poorly developed
healthcare system. De Montfort University (DMU) in the United Kingdom (UK), in collaboration with
parasitologists from the Spanish Universities of San Pablo CEU and Miguel Hernández de Elche, is
leading a project to build the teaching and research capabilities of medical parasitology at the University
of Makeni (UniMak, Sierra Leone). This project has two objectives: a) to introduce and enhance the
teaching of medical parasitology, both theoretical and practical; and b) to implement and develop
parasitology research related to important emerging human parasites such as Cryptosporidium spp. due
to their public health significance. Two UniMak academics, hired to help initiate and implement the
research part of the project, shared their culturally sensitive public health expertise to broker parasitology
research in communities and perform a comprehensive environmental monitoring study for the detection
of different emerging human parasites. The presence of targeted parasites are being studied
microscopically using different staining techniques, which in turn have allowed UniMak’s academics to
learn these techniques to develop new practicals in parasitology. To train UniMak’s academics and
develop both parts of our project, a DMU researcher visited UniMak for two weeks in April 2019 and
provided a voluntary short training course in basic parasitology, which is currently not taught in any of
their programmes, and was attended by 31 students. These sessions covered basic introduction to
medical parasitology and life-cycle, pathogenesis, detection, treatment and prevention of: a) coccidian
parasites (Cryptosporidium, Cyclospora and Cystoisospora); b) Giardia intestinalis, Entamoeba and
free-living amoebas; c) malaria and d) microsporidia. A theoretical session on common staining
techniques was also provided. To facilitate the teaching and learning of these parasites, the novel
resource DMU e-Parasitology was used, a package developed by the above participating universities
and biomedical scientists from the UK National Health Service (NHS): http://parasitology.dmu.ac.uk/
index.htm. Following the two weeks of training, UniMak’s academics performed different curriculum
modifications to the undergraduate programme ‘Public Health: Medical Laboratory Sciences’, which
includes the introduction of new practicals in parasitology and changes to enhance the content of
medical parasitology that will be subjected to examination. Thus, a new voluntary practical on Kinyoun
stain for the detection of coccidian parasites was introduced in the final year module of ‘Medical
Bacteriology and Parasitology’; eighteen students in pairs processed faecal samples from pigs provided
by the Department of Agriculture and Food Security from a nearby farm. Academics at UniMak used the
Kinyoun staining unit (available at http://parasitology.dmu.ac.uk/learn/lab/Kinyoun/story_html5.html; [1])
to deliver this practical. Although our project is at a preliminary stage, it has been shown to be effective
in promoting the introduction and establishment of medical parasitology at UniMak and could be viewed
as a case-study for other universities in low-income countries to promote the United Nations (UN)
Sustainable Development Goals (SDGs) and improve public health understanding of infectious
diseases
Steroid hormone signaling is involved in the age-dependent behavioral response to sex pheromone in the adult male moth Agrotis ipsilon
In most animals, including insects, male reproduction depends on the detection and processing of female-produced sex pheromones. In the male moth, Agrotis ipsilon, both behavioral response and neuronal sensitivity in the primary olfactory center, the antennal lobe (AL), to female sex pheromone are age- and hormone-dependent. In many animal species, steroids are known to act at the brain level to modulate the responsiveness to sexually relevant chemical cues. We aimed to address the hypothesis that the steroidal system and in particular 20-hydroxyecdysone (20E), the main insect steroid hormone, might also be involved in this olfactory plasticity. Therefore, we first cloned the nuclear ecdysteroid receptor EcR (AipsEcR) and its partner Ultraspiracle (AipsUSP) of A. ipsilon, the expression of which increased concomitantly with age in ALs. Injection of 20E into young sexually immature males led to an increase in both responsiveness to sex pheromone and amount of AipsEcR and AipsUSP in their ALs. Conversely, the behavioral response decreased in older, sexually mature males after injection of cucurbitacin B (CurB), an antagonist of the 20E/EcR/USP complex. Also, the amount of AipsEcR and AipsUSP significantly declined after treatment with CurB. These results suggest that 20E is involved in the expression of sexual behavior via the EcR/USP signaling pathway, probably acting on central pheromone processing in A. ipsilon
Dbl oncogene expression in MCF-10 A epithelial cells disrupts mammary acinar architecture, induces EMT and angiogenic factor secretion.
The proteins of the Dbl family are guanine nucleotide exchange factors (GEFs) of Rho GTPases and are known to be involved in cell growth regulation. Alterations of the normal function of these proteins lead to pathological processes such as developmental disorders, neoplastic transformation, and tumor metastasis. We have previously demonstrated that expression of Dbl oncogene in lens epithelial cells modulates genes encoding proteins involved in epithelial-mesenchymal-transition (EMT) and induces angiogenesis in the lens. Our present study was undertaken to investigate the role of Dbl oncogene in epithelial cells transformation, providing new insights into carcinoma progression. To assess how Dbl oncogene can modulate EMT, cell migration, morphogenesis, and expression of pro-apoptotic and angiogenic factors we utilized bi- and three-dimensional cultures of MCF-10â–‘A cells. We show that upon Dbl expression MCF-10â–‘A cells undergo EMT. In addition, we found that Dbl overexpression sustain
NILAI RELIGIOSITAS DALAM KUMPULAN CERPEN KARYA HABIBURRAHMAN EL-SHIRAZY
Penelitian ini bertujuan untuk mendeskripsikan nilai religiositas dalam kumpulan cerpen karya Habiburrahman El-Shirazy. Nilai religiositas yang terkandung dalam kumpulan cerpen tersebutdapat digunakan sebagai bahan alternatif dalam pembelajaran sastra di sekolah. Pendekatan penelitian yang digunakan, yaitu deskriptif kualitatif. Sumber datanya berupa kumpulan cerpen karya Habiburrahman El-Shirazy. Hasil penelitian dari nilai religiositas dalam kumpulan cerpen ini ialah akidah yang meliputi 1) iman kepada Allah Swt, 2) iman kepada kitab Allah Swt, 3) iman kepada rasul Allah Swt., dan 4) iman kepada qada dan qadar. Syariah yang meliputi 1) taaruf, 2) pinangan, 3) pernikahan, dan 4) wudu. Akhlak yang meliputi 1) akhlak pribadi, 2) akhlak dalam keluarga, dan 3) akhlak dalam bergaul
PENDEKATAN SAINTIFIK PADA PEMBELAJARAN TEKS DRAMA DI KELAS VIII SMP NEGERI 1 BANJARMASIN TAHUN AJARAN 2018/2019
Penelitian ini bermaksud untuk menggambarkan pelaksanaan implementasi pendekatan ilmiah dalam pembelajaran teks drama di kelas VIII A SMP Negeri 1 Banjarmasin. Penelitian ini adalah penelitian deskriptif kualitatif dengan sasaran penelitian guru Bahasa Indonesia dan peserta didik kelas VIII A. Secara keseluruhan, proses kegiatan berjalan dengan baik dan sesuai harapan. Guru sudah menerapkan kegiatan mengamati/ memperhatikan dengan teliti, mengajukan pertanyaan, mengumpulkan/menggabungkan data, menghubungkan, dan mengkomunikasikan/menyampaikan pada pembelajaran drama dengan baik. Peserta didik melakukan pengamatan dengan suasana kondusif. Peserta didik dipisahkan menjadi beberapa kelompok untuk mencoba berdiskusi agar menemukan informasi dan menuliskan hasil temuannya. Guru mengarahkan peserta didik untuk aktif. Namun pada teknik mengkomunikasikan belum terlaksana secara maksimal, dikarenakan ada sedikit kendala
Optimal focusing for maximal collection of entangled narrow-band photon pairs into single-mode fibers
We present a theoretical and experimental investigation of the emission
characteristics and the flux of photon pairs generated by spontaneous
parametric downconversion in quasi-phase matched bulk crystals for the use in
quantum communication sources. We show that, by careful design, one can attain
well defined modes close to the fundamental mode of optical fibers and obtain
high coupling efficiencies also for bulk crystals, these being more easily
aligned than crystal waveguides. We distinguish between singles coupling,
conditional coincidence, and pair coupling, and show how each of these
parameters can be maximized by varying the focusing of the pump mode and the
fiber-matched modes using standard optical elements. Specifically we analyze a
periodically poled KTP-crystal pumped by a 532 nm laser creating photon pairs
at 810 nm and 1550 nm. Numerical calculations lead to coupling efficiencies
above 94% at optimal focusing, which is found by the geometrical relation L/z_R
to be ~ 1 to 2 for the pump mode and ~ 2 to 3 for the fiber-modes, where L is
the crystal length and z_R is the Rayleigh-range of the mode-profile. These
results are independent on L. By showing that the single-mode bandwidth
decreases as 1/L, we can therefore design the source to produce and couple
narrow bandwidth photon pairs well into the fibers. Smaller bandwidth means
both less chromatic dispersion for long propagation distances in fibers, and
that telecom Bragg gratings can be utilized to compensate for broadened photon
packets--a vital problem for time-multiplexed qubits. Longer crystals also
yield an increase in fiber photon flux proportional to sqrt{L}, and so,
assuming correct focusing, we can only see advantages using long crystals.Comment: 19 pages, 15 figures, ReVTeX4, minor revisio
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