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1.
Math Biosci Eng ; 20(12): 21032-21048, 2023 Nov 24.
Article in English | MEDLINE | ID: mdl-38124586

ABSTRACT

Pad printing is used in automotive, medical, electrical and other industries, employing diverse materials to transfer a 2D image onto a 3D object with different sizes and geometries. This work presents a universal fixation system for pad printing of plastic parts (UFSP4) in response to the needs of small companies that cannot afford to invest in the latest technological advances. The UFSP4 comprises two main subsystems: a mechanical support system (i.e., support structure, jig matrix and braking system) and a control system (i.e., an electronic system and an electric-hydraulic system). A relevant feature is the combination of a jig matrix and jig pins to fixate complex workpieces with different sizes. Using finite element analysis (FEA), in the mesh convergence, the total displacement converges to 0.00028781 m after 12,000 elements. The maximum equivalent stress value is 1.22 MPa for the polycarbonate plate in compliance with the safety factor. In a functionality test of the prototype performed in a production environment for one hour, the jigs fixed by the plate did not loosen, maintaining the satisfactory operation of the device. This is consistent with the displacement distribution of the creep analysis and shows the absence of the creep phenomenon. Based on FEA that underpinned the structural health computation of the braking system, the prototype was designed and built, seeking to ensure a reliable and safe device to fixate plastic parts, showing portability, low-cost maintenance and adaptability to the requirements of pad printing of automotive plastic parts.

2.
Ecol Evol ; 7(23): 9991-10004, 2017 12.
Article in English | MEDLINE | ID: mdl-29238531

ABSTRACT

We have little knowledge of the response of invertebrate assemblages to climate change in tropical ecosystems, and few studies have compiled long-term data on invertebrates from tropical rainforests. We provide an updated list of the 72 species of Saturniidae moths collected on Barro Colorado Island (BCI), Panama, during the period 1958-2016. This list will serve as baseline data for assessing long-term changes of saturniids on BCI in the future, as 81% of the species can be identified by their unique DNA Barcode Index Number, including four cryptic species not yet formally described. A local species pool of 60 + species breeding on BCI appears plausible, but more cryptic species may be discovered in the future. We use monitoring data obtained by light trapping to analyze recent population trends on BCI for saturniid species that were relatively common during 2009-2016, a period representing >30 saturniid generations. The abundances of 11 species, of 14 tested, could be fitted to significant time-series models. While the direction of change in abundance was uncertain for most species, two species showed a significant increase over time, and forecast models also suggested continuing increases for most species during 2017-2018, as compared to the 2009 base year. Peaks in saturniid abundance were most conspicuous during El Niño and La Niña years. In addition to a species-specific approach, we propose a reproducible functional classification based on five functional traits to analyze the responses of species sharing similar functional attributes in a fluctuating climate. Our results suggest that the abundances of larger body-size species with good dispersal abilities may increase concomitantly with rising air temperature in the future, because short-lived adults may allocate less time to increasing body temperature for flight, leaving more time available for searching for mating partners or suitable oviposition sites.

3.
Gac Med Mex ; 152(5): 582-586, 2016.
Article in Spanish | MEDLINE | ID: mdl-27792690

ABSTRACT

PROBLEM: The effect of donor/recipient age disparity on living-donor renal graft function is controversial. The objective of this study is to find new clinical predictors of renal graft function and evaluate the effect of donor/recipient age disparity in our series. METHODS: A retrospective review of our institutional renal transplantation database was performed. We calculated the glomerular filtration rate of our patients with the Chronic Kidney Disease Epidemiology Collaboration formula. Our receptors were categorized using a cut-off of 60 ml/min calculated glomerular filtration rate. An index called "Donor/Recipient Age Index" was created based on the interaction between donor/recipient ages. Univariable and multivariable regression analysis were performed. The Mantel-Cox model was used for statistical analysis. RESULTS: A total of 220 donor/recipient pairs were selected from January 2005 to August 2013. Only 186 pairs completed the one-year follow-up. The mean age of the donors was 35.3 ± 10.4 years and 31.6 ± 11.7 years for the recipients. The Donor/Recipient Age Index significantly predicted a glomerular filtration rate < 60 ml/min at one-year follow-up in univariable (p = 0.02) and multivariable (p = 0.033) regression models. CONCLUSION: We propose the Donor/Recipient Age Index as a significant predictor of long-term graft function.


Subject(s)
Age Factors , Glomerular Filtration Rate/physiology , Kidney Transplantation/statistics & numerical data , Kidney/physiology , Living Donors/statistics & numerical data , Transplant Recipients/statistics & numerical data , Transplants/physiology , Adult , Female , Humans , Male , Middle Aged , Reference Values , Regression Analysis , Retrospective Studies , Time Factors , Treatment Outcome , Young Adult
4.
PLoS One ; 10(8): e0136623, 2015.
Article in English | MEDLINE | ID: mdl-26305111

ABSTRACT

Few data are available about the regional or local extinction of tropical butterfly species. When confirmed, local extinction was often due to the loss of host-plant species. We used published lists and recent monitoring programs to evaluate changes in butterfly composition on Barro Colorado Island (BCI, Panama) between an old (1923-1943) and a recent (1993-2013) period. Although 601 butterfly species have been recorded from BCI during the 1923-2013 period, we estimate that 390 species are currently breeding on the island, including 34 cryptic species, currently only known by their DNA Barcode Index Number. Twenty-three butterfly species that were considered abundant during the old period could not be collected during the recent period, despite a much higher sampling effort in recent times. We consider these species locally extinct from BCI and they conservatively represent 6% of the estimated local pool of resident species. Extinct species represent distant phylogenetic branches and several families. The butterfly traits most likely to influence the probability of extinction were host growth form, wing size and host specificity, independently of the phylogenetic relationships among butterfly species. On BCI, most likely candidates for extinction were small hesperiids feeding on herbs (35% of extinct species). However, contrary to our working hypothesis, extinction of these species on BCI cannot be attributed to loss of host plants. In most cases these host plants remain extant, but they probably subsist at lower or more fragmented densities. Coupled with low dispersal power, this reduced availability of host plants has probably caused the local extinction of some butterfly species. Many more bird than butterfly species have been lost from BCI recently, confirming that small preserves may be far more effective at conserving invertebrates than vertebrates and, therefore, should not necessarily be neglected from a conservation viewpoint.


Subject(s)
Butterflies/genetics , DNA Barcoding, Taxonomic , Extinction, Biological , Phylogeny , Animals , Butterflies/physiology , Ecosystem , Islands , Panama , Tropical Climate
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