scholarly journals Microfabrication of low-cost customisable counting chambers for standardised estimation of sperm concentration

2020 ◽  
Vol 32 (9) ◽  
pp. 873
Author(s):  
Yue Liu ◽  
Megan Chesnut ◽  
Amy Guitreau ◽  
Jacob Beckham ◽  
Adam Melvin ◽  
...  

Evaluation of sperm concentration is essential for research and procedures involving AI, cryopreservation and sperm quality assessment. Microfabrication technologies have shown tremendous potential for rapid prototyping and fabrication of devices to assist reproduction and fertility research, but such utility has not yet been made available for most reproduction laboratories. The aim of this study was to evaluate the feasibility of using microfabrication techniques to produce counting chambers for estimation of sperm concentration. Zebrafish (Danio rerio) spermatozoa were used as a model for evaluation of functionality of the chambers. These microfabricated enumeration grid chambers (MEGC) were composed of a polydimethylsiloxane (PDMS) coverslip with grid patterns (100 μm×100 μm) and a PDMS base platform to create a known volume with a 10-μm height to restrict the cells to a single layer. The results of cell counts estimated by two of three prototype MEGC devices tested were not significantly different from the control device, a commercially available Makler chamber. The material cost for a MEGC was less than US$0.10 compared with product costs of approximately US$100 for a standard haemocytometer and US$700 for a Makler counting chamber. This study demonstrates the feasibility of microfabrication in creating low-cost counting chambers to enhance standardisation and strengthen interdisciplinary collaborations.

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
J. M. Morrell ◽  
A. Johannisson ◽  
L. Juntilla ◽  
K. Rytty ◽  
L. Bäckgren ◽  
...  

On-stud assessment of stallion sperm quality can be problematic. A new instrument, the Nucleocounter SP-100, was validated for measuring stallion sperm concentration and viability. It was subsequently used to evaluate sperm viability in Kenney's extender and INRA96. There was a strong correlation between sperm concentrations measured by the Nucleocounter SP-100 and by the Bürker counting chamber (; ). Similarly, there was a good correlation between sperm viability results from the Nucleocounter SP-100 and flow cytometric results (; ). Sperm viability at 24 hours was significantly better for samples extended in INRA96 than in Kenney's extender (). Furthermore, sperm kinematics were better for stored samples in INRA96 than in Kenney's extender. Single Layer Centrifugation selected spermatozoa that maintained their viability better during storage for 24 hours than the uncentrifuged samples. In conclusion, the type of semen extender used and Single Layer Centrifugation were found to influence both the kinematics and viability of stallion spermatozoa. The Nucelocounter-SP100 was considered to be a useful instrument for rapidly measuring stallion sperm concentration and viability.


2019 ◽  
Vol 31 (1) ◽  
pp. 133
Author(s):  
E. Hurri ◽  
A. Johannisson ◽  
I. Lim-Verde ◽  
J. M. Morrell

Sperm quality in the first ejaculates of young bulls is often poor, leading to rejection of these samples for commercial freezing. It may be several weeks before sperm quality reaches the thresholds regarded as being acceptable for commercial production. Single-layer centrifugation (SLC) has been shown to separate robust bull spermatozoa from the rest of the ejaculate (Goodla et al. 2015 J. Dairy Sci. 97, 2204-2212; Nongbua et al. 2017 Reprod Domest. Anim. 52, 596-602). The aim of this study was to test whether SLC can be used to select spermatozoa from the ejaculates of young bulls and thus freeze samples earlier than is currently possible. Ejaculates (at least 3 per bull; n=33) were collected from 9 young Holstein or Swedish Red bulls, 255 to 415 days old. The sperm concentration was adjusted to 69×106 spermatozoa mL−1 with Andromed™ (Minitub, Tiefenbach, Germany) before layering part of the sample over 4mL of Bovicoll colloid. The remaining sample served as the unselected control. After centrifugation at 300×g for 20min, the sperm pellet was aspirated into fresh extender. Both control (uncentrifuged) and SLC samples were frozen and stored in LN pending analysis. Membrane integrity was evaluated by flow cytometry after staining for 10min at 37°C with SYBR14/propidium iodide (Live-Dead Sperm Viability Kit, L-7011; Invitrogen, Carlsbad, CA, USA). Paired t-test was used to compare results for control and SLC samples, and Pearson correlation was used for age and membrane integrity. The median age at which the samples were taken was 319 days (range: 255-415 days). Membrane integrity varied considerably among bulls (range: 11-72%). The mean proportion of membrane-intact spermatozoa in controls and SLC samples was 40±15 and 47±16%, respectively (P<0.01). In 21 of the 33 ejaculates (64%), the SLC sample had a higher membrane integrity than the controls (Table 1). Age in days was positively correlated with membrane integrity for SLC samples (r=0.40; P<0.05) but not for controls. These results suggest that SLC might be a useful technique for selecting membrane-intact spermatozoa from the ejaculates of young bulls. However, there is considerable variation among bulls, possibly due to age, which is currently being investigated. Other parameters of sperm quality, such as chromatin integrity, mitochondrial membrane potential reactive oxygen species production, and motility, are also being evaluated. Table 1.Age and membrane integrity (mean±standard deviation) in ejaculates from young bulls before and after SLC (n=33) This project was funded by the Royal Swedish Academy of Agriculture and Forestry, Viking Genetics, and the Faculty for Veterinary Medicine and Animal Health, SLU. We thank Viking Genetics for supplying the semen samples.


The evaluation of sperm quality in the laboratory is essential to improve efficiency in assisted reproduction. As in other species, for the dog there are reports that prolonged contact of sperm with some components of seminal plasma is associated with decreased motility and sperm viability. Thus, the centrifugation is a technique widely used to concentrate the spermatozoa and eliminate the supernatant. The purpose of this study was to evaluate the effect of double layer centrifugation on the percentages of total sperm motility and progressive sperm motility of the dog’s semen submitted to the dilution, single layer centrifugation, cooling and storage at 5 °C for 24 and 48 hours. For this purpose, ejaculates of 30 healthy male dogs were evaluated, by taking into account the comparison among the conventional sperm parameters (ejaculate volume, sperm concentration, total sperm motility and sperm progressive motility). The semen samples were examined in standard baseline condition of fresh semen (FS), after dilution (AD), after dilution and single layer centrifugation (SLC), after double layer centrifugation (DLC). According to the different time points, the semen samples were evaluated in baseline conditions, immediately after their collection at (T0), at 24 h (T24) and at 48 h (T48), to evaluate the effect of different treatments on the semen’s quality. Results showed a significant effect of double layer centrifugation on the improvement of total sperm motility and progressive sperm motility percentages of dogs. The use of cooling fresh semen soon after the double layer centrifugation will improve the semen quality up to 48h, with a special emphasis for the percentages of total sperm motility and sperm progressive motility, adding an alternative technical approach to reproductive performance in male breeding dogs.


2020 ◽  
Vol 4 (1) ◽  
pp. 41-48
Author(s):  
Teodoro Astorga Amatosa ◽  
Michael E. Loretero

Bamboo is a lightweight and high-strength raw materials that encouraged researchers to investigate and explore, especially in the field of biocomposite and declared as one of the green-technology on the environment as fully accountable as eco-products. This research was to assess the technical feasibility of making single-layer experimental Medium-Density Particleboard panels from the bamboo waste of a three-year-old (Dendrocalamus asper). Waste materials were performed to produce composite materials using epoxy resin (C21H25C105) from a natural treatment by soaking with an average of pH 7.6 level of sea-water. Three different types of MDP produced, i.e., bamboo waste strip MDP (SMDP), bamboo waste chips MDP (CMDP) and bamboo waste mixed strip-chips MDP (MMDP) by following the same process. The experimental panels tested for their physical-mechanical properties according to the procedures defined by ASTM D1037-12. Conclusively, even the present study shows properties of MDP with higher and comparable to other composite materials; further research must be given better attention as potential substitute to be used as hardwood materials, especially in the production, design, and construction usage.


Author(s):  
Keyur Mahant ◽  
Hiren Mewada ◽  
Amit Patel ◽  
Alpesh Vala ◽  
Jitendra Chaudhari

Aim: In this article, wideband substrate integrated waveguide (SIW) and rectangular waveguide (RWG) transition operating in Ka-band is proposed Objective: In this article, wideband substrate integrated waveguide (SIW) and rectangular waveguide (RWG) transition operating in Ka-band is proposed. Method: Coupling patch etched on the SIW cavity to couple the electromagnetic energy from SIW to RWG. Moreover, metasurface is introduced into the radiating patch to enhance bandwidth. To verify the functionality of the proposed structure back to back transition is designed and fabricated on a single layer substrate using standard printed circuit board (PCB) fabrication technology. Results: Measured results matches with the simulation results, measured insertion loss is less than 1.2 dB and return loss is better than 3 dB for the frequency range of 28.8 to 36.3 GHz. By fabricating transition with 35 SRRs bandwidth of the proposed transition can be improved. Conclusion: The proposed transition has advantages like compact in size, easy to fabricate, low cost and wide bandwidth. Proposed structure is a good candidate for millimeter wave circuits and systems.


Author(s):  
Ziyad Al‐Kass ◽  
Alexander Brown ◽  
Anders Johannisson ◽  
Theodoros Ntallaris ◽  
Jane M. Morrell
Keyword(s):  

2021 ◽  
Vol 45 (5) ◽  
pp. 2470-2477
Author(s):  
P. Golvari ◽  
E. Nouri ◽  
N. Mohsenzadegan ◽  
M. R. Mohammadi ◽  
S. O. Martinez-Chapa

Cost-effective DSCs with superior electronic properties are gained by a reduction in electronic trap states and outstanding light scattering and harvesting.


Electronics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 37
Author(s):  
Roberto Vincenti Gatti ◽  
Riccardo Rossi ◽  
Marco Dionigi

In this work, the issue of limited bandwidth typical of microstrip antennas realized on a single thin substrate is addressed. A simple yet effective design approach is proposed based on the combination of traditional single-resonance patch geometries. Two novel shaped microstrip patch antenna elements with an inset feed are presented. Despite being printed on a single-layer substrate with reduced thickness, both radiators are characterized by a broadband behavior. The antennas are prototyped with a low-cost and fast manufacturing process, and measured results validate the simulations. State-of-the-art performance is obtained when compared to the existing literature, with measured fractional bandwidths of 3.71% and 6.12% around 10 GHz on a 0.508-mm-thick Teflon-based substrate. The small feeding line width could be an appealing feature whenever such radiating elements are to be used in array configurations.


Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 267
Author(s):  
Minyu Bai ◽  
Zhuoman Wang ◽  
Jijie Zhao ◽  
Shuai Wen ◽  
Peiru Zhang ◽  
...  

Weak absorption remains a vital factor that limits the application of two-dimensional (2D) materials due to the atomic thickness of those materials. In this work, a direct chemical vapor deposition (CVD) process was applied to achieve 2D MoS2 encapsulation onto the silicon nanopillar array substrate (NPAS). Single-layer 2D MoS2 monocrystal sheets were obtained, and the percentage of the encapsulated surface of NPAS was up to 80%. The reflection and transmittance of incident light of our 2D MoS2-encapsulated silicon substrate within visible to shortwave infrared were significantly reduced compared with the counterpart planar silicon substrate, leading to effective light trapping in NPAS. The proposed method provides a method of conformal deposition upon NPAS that combines the advantages of both 2D MoS2 and its substrate. Furthermore, the method is feasible and low-cost, providing a promising process for high-performance optoelectronic device development.


Robotica ◽  
2020 ◽  
pp. 1-17
Author(s):  
Wenzhong Yan ◽  
Ankur Mehta

SUMMARY To improve the accessibility of robotics, we propose a design and fabrication strategy to build low-cost electromechanical systems for robotic devices. Our method, based on origami-inspired cut-and-fold and E-textiles techniques, aims at minimizing the resources for robot creation. Specifically, we explore techniques to create robots with the resources restricted to single-layer sheets (e.g., polyester film) and conductive sewing threads. To demonstrate our strategy’s feasibility, these techniques are successfully integrated into an electromechanical oscillator (about 0.40 USD), which can generate electrical oscillation under constant-current power and potentially be used as a simple robot controller in lieu of additional external electronics.


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