scholarly journals The XyloPhone: toward democratizing access to high-quality macroscopic imaging for wood and other substrates

IAWA Journal ◽  
2020 ◽  
Vol 41 (4) ◽  
pp. 699-719
Author(s):  
Alex C. Wiedenhoeft
Keyword(s):  
Computer Vision ◽  
Spherical Aberration ◽  
Research Quality ◽  
Limiting Factor ◽  
Identification System ◽  
Wood Identification ◽  
Focal Distance ◽  
Uv Illumination ◽  
3D Printed ◽  
Rate Limiting

Abstract One rate-limiting factor in the fight against illegal logging is the lack of powerful, affordable, scalable wood identification tools for field screening. Computer vision wood identification using smartphones fitted with customized imaging peripherals offers a potential solution, but to date, such peripherals suffer from one or more weaknesses: low image quality, lack of lighting control, uncontrolled magnification, unknown distortion, and spherical aberration, and/or no access to or publication of the system design. To address cost, optical concerns, and open access to designs and parameters, I present the XyloPhone, a 3D printed research quality macroscopic imaging attachment adaptable to virtually any smartphone. It provides a fixed focal distance, exclusion of ambient light, selection of visible light or UV illumination, uses the lens from a commercially available loupe, is powered by a rechargeable external battery, is fully open-sourced, at a price point of less than USD 110 is a highly affordable tool for the laboratory or the field, and can serve as the foundational hardware for a scalable field-deployable computer vision wood identification system.

scholarly journals The XyloPhone: democratizing access to high-quality macroscopic imaging for wood and other substrates

2020 ◽  
Author(s):  
Alex C. Wiedenhoeft
Keyword(s):  
Computer Vision ◽  
Spherical Aberration ◽  
Research Quality ◽  
Limiting Factor ◽  
Identification System ◽  
Wood Identification ◽  
Focal Distance ◽  
Uv Illumination ◽  
3D Printed ◽  
Rate Limiting

AbstractOne rate-limiting factor in the fight against illegal logging is the lack of powerful, affordable, scalable wood identification tools for field screening. Computer vision wood identification using smartphones fitted with customized imaging peripherals offer a potential solution but to date, such peripherals suffer from one or more weaknesses: low image quality, lack of lighting control, uncontrolled magnification, unknown distortion and spherical aberration, and/or no access to or publication of the system design. To address cost, optical concerns, and open access to designs and parameters, I present the XyloPhone, a 3D printed research quality macroscopic imaging attachment adaptable to any smartphone. It provides a fixed focal distance, exclusion of ambient light, selection of visible light or UV illumination, uses the lens from a commercially available loupe, is powered by a rechargeable external battery, is fully open-sourced, and at a price point of less than 110 USD is a highly affordable tool for the laboratory or the field, and can serve as the foundational hardware for a scalable field deployable computer vision wood identification system.

scholarly journals Field-Deployable Computer Vision Wood Identification of Peruvian Timbers

2021 ◽  
Vol 12 ◽  
Author(s):  
Prabu Ravindran ◽  
Frank C. Owens ◽  
Adam C. Wade ◽  
Patricia Vega ◽  
Rolando Montenegro ◽  
...  
Keyword(s):  
Computer Vision ◽  
Training Data ◽  
Identification System ◽  
Wood Identification ◽  
Illegal Logging ◽  
Natural Protected Areas ◽  
Indigenous Territories ◽  
Timber Trade ◽  
The Tropics

Illegal logging is a major threat to forests in Peru, in the Amazon more broadly, and in the tropics globally. In Peru alone, more than two thirds of logging concessions showed unauthorized tree harvesting in natural protected areas and indigenous territories, and in 2016 more than half of exported lumber was of illegal origin. To help combat illegal logging and support legal timber trade in Peru we trained a convolutional neural network using transfer learning on images obtained from specimens in six xylaria using the open source, field-deployable XyloTron platform, for the classification of 228 Peruvian species into 24 anatomically informed and contextually relevant classes. The trained models achieved accuracies of 97% for five-fold cross validation, and 86.5 and 92.4% for top-1 and top-2 classification, respectively, on unique independent specimens from a xylarium that did not contribute training data. These results are the first multi-site, multi-user, multi-system-instantiation study for a national scale, computer vision wood identification system evaluated on independent scientific wood specimens. We demonstrate system readiness for evaluation in real-world field screening scenarios using this accurate, affordable, and scalable technology for monitoring, incentivizing, and monetizing legal and sustainable wood value chains.

Toward High-Resolution Low-Voltage SEM

1988 ◽  
Vol 46 ◽  
pp. 218-219
Author(s):  
Zhifeng Shao
Keyword(s):  
Low Voltage ◽  
Spherical Aberration ◽  
Chromatic Aberration ◽  
Limiting Factor ◽  
Operating Voltage ◽  
Probe Radius ◽  
Non Local ◽  
Electron Microscopes ◽  
Image Position ◽  
Scanning Electron Microscopes

Recently, low voltage (≤5kV) scanning electron microscopes have become popular because of their unprecedented advantages, such as minimized charging effects and smaller specimen damage, etc. Perhaps the most important advantage of LVSEM is that they may be able to provide ultrahigh resolution since the interaction volume decreases when electron energy is reduced. It is obvious that no matter how low the operating voltage is, the resolution is always poorer than the probe radius. To achieve 10Å resolution at 5kV (including non-local effects), we would require a probe radius of 5∽6 Å. At low voltages, we can no longer ignore the effects of chromatic aberration because of the increased ratio δV/V. The 3rd order spherical aberration is another major limiting factor. The optimized aperture should be calculated as

Automated calibration of 3D-printed microfluidic devices based on computer vision

2021 ◽  
Vol 15 (2) ◽  
pp. 024102
Author(s):  
Junchao Wang ◽  
Kaicong Liang ◽  
Naiyin Zhang ◽  
Hailong Yao ◽  
Tsung-Yi Ho ◽  
...  
Keyword(s):  
Computer Vision ◽  
Microfluidic Devices ◽  
Automated Calibration ◽  
3D Printed

Freezing in Silicon at Large Undercooling

1989 ◽  
Vol 157 ◽  
Author(s):  
P.A. Stolk ◽  
A. Polman ◽  
W.C. Sinke
Keyword(s):  
Interface Temperature ◽  
Limiting Factor ◽  
Time Resolved ◽  
Large Undercooling ◽  
Explosive Crystallization ◽  
Crystallization Speed ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Rate Limiting

ABSTRACTPulsed laser irradiation is used to induce epitaxial explosive crystallization of amorphous silicon layers buried in a (100) oriented crystalline matrix. This process is mediated by a self-propagating liquid layer. Time-resolved determination of the crystallization speed combined with numerical calculation of the interface temperature shows that freezing in silicon saturates at 16 m/s for large undercooling (> 130 K). A comparison between data and different models for melting and freezing indicates that the crystallization behavior at large undercooling can be described correctly if the rate-limiting factor is assumed to be diffusion in liquid Si at the solid/liquid interface.

scholarly journals Recognized and Emerging Features of Erythropoietic and X-Linked Protoporphyria

Diagnostics ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 151
Author(s):  
Elena Di Pierro ◽  
Francesca Granata ◽  
Michele De Canio ◽  
Mariateresa Rossi ◽  
Andrea Ricci ◽  
...  
Keyword(s):  
Biosynthetic Pathway ◽  
Aminolevulinic Acid ◽  
Protoporphyrin Ix ◽  
Limiting Factor ◽  
Zinc Protoporphyrin ◽  
Complete Understanding ◽  
Inherited Disorders ◽  
Rate Limiting ◽  
Systemic Accumulation ◽  
Made In

Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are inherited disorders resulting from defects in two different enzymes of the heme biosynthetic pathway, i.e., ferrochelatase (FECH) and delta-aminolevulinic acid synthase-2 (ALAS2), respectively. The ubiquitous FECH catalyzes the insertion of iron into the protoporphyrin ring to generate the final product, heme. After hemoglobinization, FECH can utilize other metals like zinc to bind the remainder of the protoporphyrin molecules, leading to the formation of zinc protoporphyrin. Therefore, FECH deficiency in EPP limits the formation of both heme and zinc protoporphyrin molecules. The erythroid-specific ALAS2 catalyses the synthesis of delta-aminolevulinic acid (ALA), from the union of glycine and succinyl-coenzyme A, in the first step of the pathway in the erythron. In XLP, ALAS2 activity increases, resulting in the amplified formation of ALA, and iron becomes the rate-limiting factor for heme synthesis in the erythroid tissue. Both EPP and XLP lead to the systemic accumulation of protoporphyrin IX (PPIX) in blood, erythrocytes, and tissues causing the major symptom of cutaneous photosensitivity and several other less recognized signs that need to be considered. Although significant advances have been made in our understanding of EPP and XLP in recent years, a complete understanding of the factors governing the variability in clinical expression and the severity (progression) of the disease remains elusive. The present review provides an overview of both well-established facts and the latest findings regarding these rare diseases.

scholarly journals Neutrophil Extracellular Traps-DNase Balance and Autoimmunity

Cells ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2667
Author(s):  
Andrea Angeletti ◽  
Stefano Volpi ◽  
Maurizio Bruschi ◽  
Francesca Lugani ◽  
Augusto Vaglio ◽  
...  
Keyword(s):  
Lupus Erythematosus ◽  
Causative Factor ◽  
Neutrophil Extracellular Traps ◽  
Limiting Factor ◽  
Systemic Lupus ◽  
Extracellular Traps ◽  
Number Of Patients ◽  
Selective Depletion ◽  
Dna Antibodies ◽  
Rate Limiting

Neutrophil extracellular traps (NETs) are macromolecular structures programmed to trap circulating bacteria and viruses. The accumulation of NETs in the circulation correlates with the formation of anti-double-stranded (ds) DNA antibodies and is considered a causative factor for systemic lupus erythematosus (SLE). The digestion of DNA by DNase1 and DNases1L3 is the rate- limiting factor for NET accumulation. Mutations occurring in one of these two DNASE genes determine anti-DNA formation and are associated with severe Lupus-like syndromes and lupus nephritis (LN). A second mechanism that may lead to DNase functional impairment is the presence of circulating DNase inhibitors in patients with low DNase activity, or the generation of anti-DNase antibodies. This phenomenon has been described in a relevant number of patients with SLE and may represent an important mechanism determining autoimmunity flares. On the basis of the reviewed studies, it is tempting to suppose that the blockade or selective depletion of anti-DNase autoantibodies could represent a potential novel therapeutic approach to prevent or halt SLE and LN. In general, strategies aimed at reducing NET formation might have a similar impact on the progression of SLE and LN.

scholarly journals Glypican-1 drives unconventional secretion of Fibroblast Growth Factor 2

2021 ◽  
Author(s):  
Carola Sparn ◽  
Eleni Dimou ◽  
Annalena Meyer ◽  
Roberto Saleppico ◽  
Sabine Wegehingel ◽  
...  
Keyword(s):  
Growth Factor ◽  
Heparan Sulfate ◽  
Fibroblast Growth Factor ◽  
Fibroblast Growth Factor 2 ◽  
Structural Basis ◽  
Limiting Factor ◽  
Fibroblast Growth ◽  
Unconventional Secretion ◽  
Rate Limiting

Fibroblast Growth Factor 2 (FGF2) is a tumor cell survival factor that is transported into the extracellular space by an unconventional secretory mechanism. Cell surface heparan sulfate proteoglycans are known to play an essential role in this process. Unexpectedly, we found that among the diverse sub-classes consisting of syndecans, perlecans, glypicans and others, Glypican-1 (GPC1) is both the principle and rate-limiting factor that drives unconventional secretion of FGF2. By contrast, we demonstrate GPC1 to be dispensable for FGF2 signaling into cells. We provide first insights into the structural basis for GPC1-dependent FGF2 secretion, identifying disaccharides with N-linked sulfate groups to be enriched in the heparan sulfate chains of GPC1 to which FGF2 binds with high affinity. Our findings have broad implications for the role of GPC1 as a key molecule in tumor progression.

Availability of Cosubstrates as a Rate-Limiting Factor

2020 ◽  
pp. 119-178
Author(s):  
Gerard J. Mulder ◽  
Klaas R. Krijgsheld
Keyword(s):  
Limiting Factor ◽  
Rate Limiting
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