The voltammograms revealed prominent anodic current peaks at 0.76–0.78 V, which are attributed to isoflavones. Isoflavones, known secondary metabolites with substantial antioxidant potential commonly found in pulses, were identified. The total isoflavone concentrations obtained ranged from 31.5 to 64.3 mg Eq genistein 100 g−1. The results not only validated the efficacy of the electrochemical sensor for quantifying total antioxidant compounds in the samples but also demonstrated that the concentration of total isoflavones in caviar and salmon analogs fell within the expected limits.The global consumption of vegan foods is experiencing an expressive upward trend, underscoring the critical need for quality control measures based on nutritional and functional considerations. This study aimed to evaluate the functional quality of caviar and salmon analog food inks based on pulses combined with nano ingredients and produced in our laboratory (LNANO). The primary objective of this work was to determine the total antioxidant compounds contained in these samples using a voltammetric technique with a glassy carbon electrode. The samples underwent ethanolic extraction (70%) with 1 h of stirring. The voltammograms were acquired in a phosphate buffer electrolyte, pH 3.0 with Ag/AgCl (KCl 3 mol L In recent years, the over-exploitation of seafood populations to meet global market demands resulted in detrimental environmental impacts, including biodiversity depletion, water eutrophication, coral reduction, and pathogen invasions, among others . FurtherSpherification, a technique widely used in molecular gastronomy, enables the creation of products with high added value . It invoDespite the utilization of innovative processing technologies, developing fish and seafood analogs with nutritional profiles similar to animal-based counterparts remains challenging, primarily due to the limited nutritional value of vegetable proteins. Consequently, pulses emerged as intriguing sources for producing alternative meats, given their notable nutritional characteristics such as s protein content (~24%) and carbohydrate content ~63%) [3% [6]. PExtensive research has been conducted on phenolic compounds and their health benefits over the years ,9. PolypGiven the established health benefits associated with plant-based antioxidants and the growing consumption of pulse-based meat analogs, it is crucial to enhance the quality control of these foods by providing precise and comprehensive information about their antioxidant content. This research aims to propose a methodology based on differential pulse voltammetry and a glassy carbon electrode for determining the total phenolic compounds in fish  and seafood (caviar) analogs and evaluating the antioxidant capacity of these food products. Furthermore, this study seeks to contribute to the ongoing discussion on the use of electroanalytical techniques for the quality control of plant-based foods by analyzing additional functional compounds with antioxidant characteristics.2) was purchased from Dinâmica Contemporânea LTDA , white bean flour and isolated soy protein were purchased from Zona Cerealista , soy oil and annatto and saffron dyes were purchased from a local supermarket. Genistein (>99% purity) was purchased from L. C. Laboratories . Phosphate buffers with a pH of 3.0–7.0 were prepared using dibasic sodium phosphate, monobasic potassium phosphate, and phosphoric acid  and used as supporting electrolytes. Ethanol and methanol  were used for phenolic compound extraction in caviar and salmon analogs. Alumina powder < 10 μm , ethanol , ultrapure water, and nitric acid  were used for glassy carbon electrode cleaning.Analytical-reagent grade chemicals and ultrapure water were used to prepare solutions. Sodium alginate (ALG) was purchased from CRQ Química , calcium chloride (CaCl2+ ions. ALG (1.25% w/v) was dissolved by stirring in filtered water for 30 min at room temperature. Simultaneously, an aqueous solution containing 22.5% w/v white bean flour and an oil solution composed of 45% isolated soy protein and annatto dye were produced. The dissolved substances were added to the alginate solution and then stirred for 10 min.Caviar analog A was proTwo food inks (white and orange) were formulated to produce the salmon analog B. For thw/v CaCl2 solution was placed to collect the ink, which formed structures that were left for 5 min, and then washed in distilled water.For the development of caviar analog, the food ink was added to syringes with a 3 mL Luer slip nozzle and a hypodermic needle with a caliber of 21 G. The syringe was positioned on an automatic injector at a speed of 200 µL/min  and a height of 8 cm. Below the needle, a beaker containing 20 mL of a 1.5% For the salmon analog, a computer-aided design (CAD) model was developed in order to contemplate the use of two different food inks. The CAD model considered the two most distinct visual components of the salmon: a white-streaked part and a mostly orange part. The modeling was completed using the Tinkercad platform, and the gcode was generated from Slic3r. The bioprinter control was performed using Pronterface. For the 3D food printing process, 14 G needles without bevels were attached to 5 mL Luer Lock syringes, which were previously filled with the appropriate food ink. These syringes were then placed one after the other in the STARTER bioprinter (3D Biotechnology Solutions–3DBS).g. To optimize the experimental conditions and achieve the highest sensitivity for the differential pulse voltammetry (DPV) method, the influence of the solvent used for phenolics extraction (methanol and ethanol) and the solvent concentration  on the total phenolics oxidation peak currents (Ipa) were studied.Phenolic compounds were extracted in quintuplicate from 0.1 g sample of fresh caviar and salmon analogs using Kline orbital stirring plate  in 2.0 mL of 50% aqueous ethanol. The resulting extract was decanted and the supernatant was transferred to 2.0 mL microtubes and centrifuged for 10 min at 12,100× −1 KCl) electrode as the reference electrode, and a platinum wire as the auxiliary electrode. Before each measurement and between sample measurements, the surface of the glassy carbon electrode was cleaned and electrochemically activated following this procedure: the electrode surface was manually polished with alumina suspension on a polishing cloth for 2 min and rinsed with distilled water; the electrode was immersed in ethanol for 5 min and in HNO3 1:1 v/v for 1 min, then rinsed with ultrapure water; the electrode was immersed in phosphate buffer  and subjected to ten potential cycling with cyclic voltammetry in the potential range between −1.5 and 1.5 V at a scan rate of 50 mV s−1.The voltammetric measurements were conducted on a PGSTAT 128 N Autolab  with electrochemical software . Voltammetric measurements were carried out in an electrochemical cell composed of a glassy carbon electrode (GC) (Φ = 2.0 mm) as the working electrode, Ag/AgCl . Stock solutions of genistein with concentrations of 1.0 × 10−3 mol L−1 were prepared using a mixture of water and ethanol (1:2) and stored in dark vials under freezing. Calibration curves of genistein were obtained by using DPV with six successive additions of 5 μL of 1.0 × 10−3 mol L−1 genistein to the electrochemical cell containing 10 mL of 0.2 mol L−1 phosphate buffer pH 3.0. The voltammetric measurements for each concentration level were performed in triplicate.The voltammetric profile of the samples was obtained in two different pH values by adding 500 and 800 µL of the extract of salmon and caviar analogs, respectively, to the electrochemical cell containing 10 mL of 0.2 mol L−1. The inter-day precision (intermediate precision) of the DPV method was evaluated by measuring the (RSD) value of the genistein oxidation current peaks at fixed concentrations of 0.5, 1.5, and 3.0 µmol L−1 on three different days. Linearity, the limit of detection (LOD), and the limit of quantitation (LOQ) for the DPV method were obtained from the genistein calibration curve [(n−1.1−α) × s, where t is the student distribution for n = 10 independent sample blanks; α is the 95% confidence level, and s is the standard deviation of the sample blank values fortified at the lowest acceptable concentration measured for genistein. The LOQ was calculated from the lower end of the working range [−1) were added to the caviar and salmon analog extracts.The intra-day precision (repeatability) of the DPV method was evaluated by measuring the relative standard deviation (RSD) of seven independent measurements of genistein oxidation current peaks at fixed concentrations of 0.5, 1.5, and 3.0 µmol Lon curve . The LODng range . The tru−1 phosphate buffer, pH 3.0, using the following electrochemical parameters: initial potential (Ei) = 0.0 V, final potential (Ef) = 1.0 V, pulse amplitude = 50 mV, scan rate = 50 mV s−1, working electrode: glassy carbon, reference electrode: Ag/AgCl (KCl 3 mol L−1), auxiliary electrode: platinum wire.The antioxidant capacity evaluation of the samples was carried out using the electrochemical index (EI) value, calculated according to Lino et al. (2014) . The EI The data from the optimization and validation experiments of the voltammetric method were summarized using Microsoft Office Excel (version 365). The voltammograms were constructed using the NOVA 2.16 software, suitable for operating the voltammetric analyzer. Specific statistical tests, such as the Grubbs test (used to remove outliers), and the Crochan test (used to test linearity), were performed following the bibliographic references indicated in the INMETRO document, 2020 . The calIn order to identify the optimal solvent for extracting phenolic compounds from caviar and salmon analogs samples with soy protein and white bean pulse constitution, aqueous methanol and ethanol were used for sample extraction at different concentrations . The selection of the suitable extraction solvent was based on the voltammetric profiles and anodic currents of the samples. Favorable results were characterized by well-formed voltammetric curves without overlapped peaks and higher anodic currents. The DPV profiles of the samples extracted with ethanol and methanol exhibited oxidation current peaks at potentials around 0.2 V and 0.6 V in phosphate buffer pH 6.0 A,B, indi−1 phosphate buffer; pH 3.0 and 6.0 are presented in The differential pulse voltammograms obtained for caviar and salmon analog samples with standard additions of genistein in 10 mL of 0.2 mol L−1) showed more intense oxidation currents at pH = 3.0  was obtained in the range from 0.5 to 3.0 μmol L−1 (Insert of −1 and a limit of quantitation of 0.5 µmol L−1. The linearity of the method within the working range was confirmed by a correlation coefficient (r) greater than 0.99 and the homoscedasticity of the analytical curve, as demonstrated by the calculated Cochran value (α = 95% confidence level) being lower than the theoretical value.enistein . A lineaThe intra-day precision (repeatability) of the DPV method exhibited an oxidation current with a RSD ranging from 4.8 to 5.6% based on seven independent measurements at three concentration levels of genistein. The inter-day precision (intermediate precision) of the DPV method showed an oxidation current with RSD of 7.4 to 9.6%, considering one independent measurement at three levels of genistein concentration in three different days. These results indicate that the method provides satisfactory intra-day and inter-day precisions in the voltammetric determination of total phenolics using genistein as an equivalent standard compound.−1), was determined. The samples were prepared using extrusion and 3D food printing methods. The mean values and standard deviations are presented in −1) in the caviar and salmon analogs. These curves exhibited good sensitivity (slope = 0.098–0.12) and a linear correlation (r > 0.99). The recovery range of added genistein in the caviar samples was 72–112%, while for the salmon analog, it ranged from 75 to 117%.The concentration of total isoflavone compounds in caviar and salmon analogs, expressed as mg of genistein equivalents per 100 g of samples (mg GEN 100 gn = 3) were used in the calculation of the EI, which are listed in The EI was calculated based on the voltammograms obtained from 1 mL of sample extracts . The aveThe quality control of plant-based foods, such as fish and seafood analogs, primarily focuses on nutritional analysis, including protein, carbohydrate, and lipid content, which should be similar to their animal-based counterparts. However, it is equally important to consider the concentration of functional compounds in these foods. In our study, we expected to find isoflavones in caviar and salmon analogs based on the extensive literature highlighting the functional and health benefits of isoflavones in legumes such as soybeans and various types of beans ,24,25,26−1 in soybeans from Brazil [Isoflavones belong to the flavonoid family and are an important subclass of phytoestrogens commonly found in legumes such as soybeans, beans, chickpeas, and sunflower seeds. They possess antioxidant properties and have the potential to benefit human health by reducing the risk of cancer, preventing obesity and diabetes, mitigating cardiovascular diseases, addressing osteoporosis, and alleviating menopausal symptoms . In our m Brazil . The var−1 (acid leach) [−1) and salmon analog (64.3 ± 2.0 mg Genisteína 100 g−1) is higher compared to other reported soy foods. For example, soy burgers contain 0.1–26 mg 100 g−1 of total aglycone equivalents, soy cheeses 2.3–33 mg 100 g−1, and soy milk formulas can have up to 31 mg 100 g−1 [During the processing of soy protein isolate, approximately 52% of the isoflavones are lost . Liu et d leach) . In thei 100 g−1 .Regarding the potential adverse effects of soy consumption, such as the disruption of the sex hormone network, infertility, and allergies, studies have yielded conflicting results with limited clinically confirmed investigations . In 2015−1 in white bean varieties [−1 in white bean seeds [In common beans, phenolic acids, flavonoids, and proanthocyanidins are the primary polyphenols, with pigmented seed coats containing higher polyphenol levels. However, white beans, which are present in the caviar and salmon analog samples, have a deficient presence of isoflavones. Ombra et al. reported total flavonoid content of approximately 5–6 mg 100 garieties . Gharachan seeds .Our results from the DPV demonstrate that a bare glassy carbon sensor can effectively determine polyphenols with good performance. The LOD, linearity, precision, and recovery features of the method confirm its usability. However, it is important to note that the strong adsorption of phenolic compounds on the electrode surface required a longer cleaning process before each analysis, increasing the time required for electrochemical analysis. It is worth mentioning that voltammetric methods have limitations in selectively detecting phenolic compounds. In the voltammograms of the samples, sensitive oxidation current peaks were observed at the same potential. Hence, for quantitative determination, we adopted genistein, resulting in sensitive current peaks free from interferences. Drawing from our previous experience in determining isoflavones in soybeans, we were able to streamline the optimization process, considering parameters such as sweep speed, amplitude, electrolyte, and standards for quantification. All these optimized parameters were employed in the electrochemical analysis of isoflavone determination in caviar and salmon analogs. The evaluation of the sample’s antioxidant capacity using the EI revealed that the salmon analog exhibited better antioxidant capacity, primarily due to its slightly higher polyphenolic content, at the anodic peak potentials . The use of EI is suitable for comparing the antioxidant capacity of a group of samples in the same study and analyzed using the same electroanalytical method. As EI depends on the electrochemical and experimental parameters, it cannot be directly compared in different studies. Additionally, good correlations have been observed between the antioxidant capacity values determined via EI using voltammetry and EC50 determined via spectrophotometry .Looking ahead, future perspectives involve the utilization of lab-made portable sensors modified with nanostructures, such as green synthesized monometallic or bimetallic nanoparticles. These advancements will enhance the application of electrochemical sensors and address the issue of molecule adsorption from the extracts.Furthermore, researchers are exploring various legume proteins derived from sources like fava beans, lentils, chickpeas, and peas as alternatives to soy protein. These studies aim to improve the nutritional value and provide advanced fish and seafood analogs.The growing recognition of the health benefits associated with antioxidants from plants and the increasing consumption of plant-based meat analogs underscores the need to enhance the functional quality control of these foods. In this study, we successfully analyzed the antioxidant content of caviar and salmon analogs using a voltammetric technique with a bare glassy carbon electrode. The method exhibited high sensitivity, satisfactory precision, and low limits of detection and quantification, making it suitable for determining antioxidant compounds, such as isoflavones, in the samples. The ethanolic extraction method employed was simple, rapid, and effective in extracting isoflavones, predominantly in the aglycone form. The concentration of isoflavones in the pulse-based ingredients used in the samples, namely isolated soy protein and white bean, aligned with the data in the literature for total isoflavone content in processed soy-based foods, such as protein isolates. Based on international guidelines, the detected isoflavone levels in the samples were deemed safe for daily consumption, considering the limits established to prevent allergies in children and hormone-related issues in adults. Another relevant aspect is that the voltammetric technique did not detect the natural dyes added to the food inks, either due to the non-electroactive nature of the molecules under the specified analysis conditions or their low solubility in 70% ethanol. The assessment of antioxidant activity through the calculation of the electrochemical index proved useful and straightforward for comparing samples subjected to the same conditions. However, for comparative purposes with data from the literature, this method may not be adequate due to the robustness of data obtained using other techniques. Nevertheless, despite the limited literature on the subject, a correlation between the electrochemical index and the EC50 has been observed. The voltammetric method utilizing a bare glassy carbon electrode proved effective in achieving the objectives of this study. Nonetheless, future investigations should focus on enhancing the efficiency of the presented voltammetric method by reducing the analysis time and streamlining the electrode cleaning process. To this end, the use of laboratory-made portable electrodes with modified working surfaces incorporating metallic nanoparticles holds promise. In conclusion, our study contributes to the advancement of quality control methods for plant-based foods, specifically fish and seafood analogs. By employing voltammetry with a bare glassy carbon electrode, we successfully quantified antioxidant compounds in the samples. This research opens avenues for the further exploration and optimization of electrochemical analysis techniques, paving the way for improved functional quality assessment in the rapidly growing field of plant-based meat analogs.


However, this reduction in carbon stock could be offset in the long term through changes in composition, as clearcut systems promote the expansion of trembling aspen and white birch. In contrast, the use of strategies based on partial cuts on more than 75% or 50% of the managed area was closer to or better than the natural scenario and resulted in greater coniferous cover retention. These strategies seemed to be the best to maximize and stabilize biomass carbon storage and ensure wood supply under different climate change scenarios, yet they would require further access and appropriate infrastructure. Furthermore, these strategies could maintain species compositions and age structures similar to natural scenarios, and thus may consequently help achieve forest ecosystem-based management targets. This study presents promising strategies to guide sustainable forest management in Eastern Canada in the context of climate change.Climate change poses a serious risk to sustainable forest management, particularly in boreal forests where natural disturbances have been projected to become more severe. In three Quebec boreal forest management units, biomass carbon storage under various climate change and management scenarios was projected over 300 years (2010–2310) with a process-based dynamic landscape model (PnET-succession for Landis-II). Several strategies varying in their use of partial cuts and clear cuts, including business as usual (BAU) (clear-cut applied on more than 95% of the managed area), were tested and compared to conservation scenarios (no-harvest). Based on simulation results at the landscape scale, the clearcut-based scenarios such as BAU could result in a decrease of biomass carbon stock by 10 tC ha The boreal forests sequester 500 TgC yr−1 as a net carbon sink and store 25 and 60% of the world’s carbon biomass and soils, respectively. Furthermore, Smyth et al.5 point out that forest management and harvest of wood products may increase the mitigation potential of Canada’s forest sector by 68 and 320 TgC in 2030 and 2050, respectively. Forest management can improve carbon sequestration and storage capacity at the landscape scale6.Boreal forest ecosystems provide a wide range of ecosystem services. Forests offer a multitude of benefits beyond just providing wood products, as they also play an important role in filtering water supplies, controlling floods and erosion, sustaining biodiversity and genetic resources, and providing opportunities to mitigate climate change by reducing atmospheric CO9. Wildfires, windthrows, and spruce budworm (SBW) outbreaks are the primary natural disturbances in Quebec, which play an important role in shaping forest age structure and composition11. In this part of the boreal biome, those disturbances could be classified according to the disturbed area, severity, and carbon impacts in the following order. First are wildfires, which are the most extensive disturbance, with the current annual burn rate varying between 0.04 and 0.26% in Quebec12. It is expected that this rate will increase under climate change, as indicated by studies12. Recent studies14 predict an increasing burned area trend in Quebec forests over the next 100 years, with inter-annual variability, mainly under RCP4.5 and RCP8.5 climate change pathways, thus increasing carbon losses from the biomass carbon pool14. Second is SBW outbreaks, which are characterized by a return interval of 32 years in the eastern regions of Quebec15. The last outbreaks was recorded in 1992 and decreased the average aboveground biomass and belowground biomass by 5.96 and 6.94%, respectively16. Dymond et al.17 state that SBW significantly reduced ecosystem carbon stock enough to change the landscape from a sink (4.6 ± 2.7 gC m−2 y−1 in 2018) to a source (− 16.8 ± 3.0 gC m−2 y−1 in 2018). Lastly, windthrows have a potential impact on the carbon cycle by increasing tree mortality18. The amount of damage caused by wind varies by tree size classes; while large trees may be relatively well anchored and fail via crown or stem break, smaller trees are frequently broken when large trees fall on them19. In addition, their effects are related to the species' root architecture and soil properties19. However, the effects of wind impacts are less than those of fires and SBW, as they affected, on average, 0.0255% of the area per year between 1971 and 200011. All of the three cited disturbances cause carbon loss, increase tree mortality, and a greater amount of carbon being transferred from the live biomass pool to deadwood21.Climate change is increasing both frequency and severity of natural disturbances in Eastern boreal forests, which has an impact on all carbon pools and several processes such as decomposition, forest regeneration, and succession2 concentration, and solar radiation23. Since the late nineteenth century, the climate has been warming due to an increase in radiatively active gases in the atmosphere resulting from human activities. This warming trend is expected to have particularly pronounced impacts on higher latitudes, with anticipated increases in both precipitation and temperatures24. An increase in temperatures may stimulate vegetation growth up to a certain limit, beyond which it might reduce productivity under drought conditions or even cause increased mortality rates25. It is only in the last few years that it has been possible to assess the effect of climate change on the forest carbon cycle, using simulation models which couple plant-soil carbon with the nitrogen and water cycles, integrate atmosphere-vegetation interactions, and represent competitive processes28. Several models report that boreal forests are expected to accumulate more carbon in living biomass under global warming effects, mainly under intermediate scenarios (RCP2.6 and RCP4.5)30. However, climate  has many potential effects on forest growth, mortality, disturbances, and establishment29.The net primary productivity (NPP) and biomass carbon storage are directly influenced by local abiotic factors such as temperature, precipitation, atmospheric CO32. This effect is related to applied canopy removal intensity (CRI). Indeed, 100% CRI using clear-cutting (CC) at the stand scale achieves negative net ecosystem production 20 years following harvest because of high respiration and a lower NPP of the replacing stand32. On the other hand, lower or moderate CRI using partial cuts (PC) and selective cutting maintains the uneven-aged forest system and thus may maximize forest carbon sequestration and storage compared to clear cuts in the long term34. Several studies have used a variety of methodologies  to examine the CRI on forest carbon from empirical data at the stand level and the majority of their findings reflect that PC with lower and/or moderate CRI could increase stand net growth and stabilize biomass carbon storage as well as improve the soil carbon sink6. In Quebec boreal forest, CC systems including CC and careful logging around advanced growth (CLAAG) , which cuts around 95% of the canopy and aims to conserve advanced regeneration), and PC systems  are applied36. Currently, in Quebec, more than 95% of the annual harvest area is managed using CC systems (CC and CPRS)36. However, their impacts at the landscape scale have not been well evaluated. Yet, forest planning and management decisions are always made at the regional (landscape) scale 6. Consequently, we must assess the impact of various harvesting intensities at the landscape scale, where different CRI such as PC and CC or CPRS could be used.In addition to natural disturbances and local abiotic conditions, harvest has a high effect on the forest carbon dynamics37. In this paper, our main objectives were: (i) firstly, to project the effect of forest management and climate change on forest composition and age structure under climate change scenarios for 300 years (2010–2310). (ii) Secondly, to predict the accumulative impacts of SBW, wildfires, and windthrow on the biomass carbon pool (below and above ground) along with their interactions with climate change. (iii) Thirdly, to investigate the potential impact of forest management on carbon biomass storage, as well as annual harvested biomass. To achieve these objectives, a portfolio of strategies including variable proportions of low- and high CRI treatments (PC and CC), including the business-as-usual (BAU), were tested and compared to natural evolution (no-harvest) under different climate change scenarios. Using a mechanistic model (PnET succession for LANDIS-II), this study introduces a new methodology to evaluate the combined effects of forest management and climate change  on carbon dynamics at the regional scale in the high latitudes of the eastern boreal forest of Canada.The annual harvest area percentage per treatment that ensures maximum carbon sequestration and storage, wood supply for industries, and conservation of current habitat (composition and age structure) is unknown. As a hypothesis, we expect that the inclusion of more PC systems at the landscape scale will improve biomass carbon storage since lower/moderate CRI could increase carbon sequestration by 36–40% in the boreal forest region38. These three MUs are distributed along a longitudinal gradient from west to east: North-du-Québec , Saguenay-Lac-Saint-Jean , and Côte-Nord regions  , jack pine (Pinus banksiana), balsam fir , white birch (Betula papyrifera), trembling aspen (Populus tremuloides) and other species36. The soils are characterized by a high clay content in MU1 and a high sand-silt percentage in MU2 and MU3.The study was conducted in three management units (MUs) near Quebec’s northern forest management limit, i.e., the limit of the territories where it was estimated that logging could be carried out profitably, and beyond this limit (~ latitudes > 51°), where forests are not managed because of their lower productivity39. Our analysis includes four climate scenarios: baseline (historic), RCP2.6, RCP4.5, and RCP8.5. The baseline climate scenario from 2010 to 2310 was constant around the monthly means of the historic climate (1900–2010). For RCP scenarios, the climateNA model provides data until 2100, so they were extrapolated at monthly intervals until 2310, using Extended Concentration Pathways (ECPs) rules from Meinshausen et al.40 and Collins et al.41, which describe the RCPs from 2100 to 2500 . CO2 concentration for RCP scenarios was acquired from the RCP database (https://tntcat.iiasa.ac.at/RcpDb), which covers data representing 10-years time frames until 2310. We assumed that CO2 remained constant at 389 ppm (2010) during the simulation for the baseline climatic scenario.The monthly climate data  for each ecoregion were extracted from the climateNA model and the second-generation Canadian Earth System Model (CanESM2) data was used43. The PnET extension is convenient for forest landscape modeling in a changing environment integrating precipitation, temperature, radiation, and atmospheric CO2 concentration  at 20-year step intervals and a 200 × 200 m resolution grid (4 ha). The simulated area was 0.62, 1.16 and 1.15 Mha in MU1, MU2, and MU3, respectively.LANDIS-II is a process-based, stochastic, and spatially explicit forest landscape model that integrates disturbance and succession models Fig. b. The la46, and included longevity, sexual maturity, shade tolerance, fire tolerance, seed dispersal distance, sprouting, and post-fire regeneration , where each cell included the tree species and age-class information. At the beginning of the simulation (2010), the initial dominant age class was 20–40 years in MU1 and 120–200 years in both MU2 and MU3  extension v4.0.1”51. Wildfires were included using the Base-Fire extension. This extension simulates fire regimes through stochastic fire events depending on ignition probability, fire size , fire severity, and the K parameter that determines the strength of the association between fire spread probability and fuel age48. Fire regime input parameters were used from previous works in the Quebec boreal forest and calibrated for each climate scenario53. In addition, the Base Wind extension stochastically simulates windthrows disturbance based on their intensity, size, spread, severity, and rotation period49. The wind size and rotation per ecoregion were parameterized based on historical data from the forest inventory geodatabase36. Similarly, the BDA extension stochastically introduces periodic defoliation events uniquely parameterized by defoliator species; SBW disturbance51. Host tree species for SBW included, from the most to least vulnerable, balsam fir , white spruce (Picea glauca), and black spruce (Picea mariana). Parameters used in this study for BDA extension were calibrated and validated using various sources for the boreal forest54. We assumed that climate change did not directly affect the wind and SBW disturbance regimes, but rather altered forest composition and structure which influenced their spatial and temporal pattern.In order to model forest biomass carbon storage response to natural disturbances and different management scenarios under climate change Fig. b, severa50. This extension requires dividing the landscape into management areas , i.e., the maximum volume that can be harvested annually without reducing future forest production capacity, set by the Chief Forester of Quebec55. At the first-time step, all the scenarios were calibrated to cover the current AAC using the current climate (baseline). Firstly, we designed the prescriptions which reflected the silvicultural treatments used for harvest at stand scale36, including clear cut (100% CRI), CPRS (CRI was fixed at 95% and the cohorts of 1–20 years were conserved) and three forms of PC . The stand ranking was based on species’ economic value and their minimum age criteria for exploitability. Secondly, for the BAU scenario, we used a geodatabase of the harvest history (1970–2010) to calculate the harvested managed area per silvicultural treatment  were calculated in order to assess the biomass carbon balance of each management strategy  relative to the natural scenario  (Eq. (56.i climate scenario: baseline (i = 1), RCP2.6 (i = 2), RCP4.5(i = 3), RCP8.5(i = 4), and j management scenario from 1 to 6  only succession and winds; 2) only succession, winds, and fires; and (3) only succession, winds, fires, and SBW, corresponding to natural scenario (S0). Also, we aimed to compare CC based scenarios  and PC based scenarios  in the selected management units with natural evolution (S0)  , BPF: broadleaves pure forests, BSJP: black spruce and jack pine, BSBF: black spruce and balsam fir, BSOC: black spruce and other coniferous, OCMF: other coniferous mixed forests, BMF: broadleaves mixed forests; BsBMF: black spruce and broadleaves mixed forests, and OCBMF: other coniferous and broadleaves mixed forests. To catch the effect of management on forest composition, the differences between each composition per management scenario and its correspondence in the natural scenario (no harvest) were calculated. All analyses were carried out in Python environment.According to our simulations at the landscape scale in all management units (MUs), the following compositions show the most significant alterations due to management and climate change when compared to natural evolution (S0): BSPF, BSOC, BSBF, BsBMF, OCMF, BPF, and BMF Fig. . In MU1,On the other hand, PC inclusion  diminished the gap between management and natural evolution (S0) Fig. . GeneralRegarding the age structure, independently of climate scenario in all MUs, the abundance of young forests in S1 and S2 (BAU) increased by more than + 25% and mature and old-growth forests decreased by -10% and -16%, respectively, compared to the natural scenario (S0) Fig. . The inc−1 and remained stable in both MU2 and MU3 at around 26 tC ha−1  had a considerable impact mainly on the coniferous biomass of both MU1 and MU2, due to shorter fire cycles. The biomass carbon storage of broadleaved species was close to that of the succession-only scenario for S + W and S + W + F scenarios. When SBW was considered (S + W + F + SBW scenario), the biomass carbon stock of coniferous considerably dropped mainly in MU3 compared to other scenarios and an increase in that of broadleaved species was noticed  and current climate (baseline), coniferous biomass carbon stock increased in MU1 from 27 to 37 tC haa−1 Fig. . Howevera−1 Fig. . For insced Fig. . For exaectively . On the ectively . For the−1 yr−1 over the next 100 years compared to the no harvest scenario  could be compensated after 200 years (2210), because these scenarios accelerated the abundance of intolerant shade species (trembling aspen and white birch) compared to natural scenarios  decreased the total biomass carbon storage by around to 10 tC hario Fig.  under thcenarios , Fig. 3,cenarios .Figure 6−1 yr−1, respectively, in MU1. Similarly in the same order, those carbon stocks dropped by 7, 7, and 4 tC ha−1 yr−1 in MU2. Also, the difference in carbon stocks between these three scenarios was considerable in MU3, where a reduction of 6, 4, and 2 tC ha−1 yr−1 was found for S3, S4 and S5, respectively. However, in all MUs, in terms of biomass carbon storage, S4 and S5 showed a higher performance than BAU (S2), while the effect of S3 was almost similar to BAU.Regarding the reforestation effect, S3 with a 25% replanting rate after CC had lower biomass carbon storage than S4 and S5 which were based on 16.7 and 8.3% replanting rates, respectively, under all climate scenarios  was 1.32, 2.04, and 1.80% of the annual managed area in MU1, MU2, and MU3, respectively  will likely increase and probably double the current productivity because of the shift in forest composition toward broadleaved species and changes in the capacity of trees to grow and sequester atmospheric carbon for both coniferous and broadleaved species14. This positive effect could be explained by the extension of the growing season and the reduction of potential cold-temperature late-frosts57. Our simulated short-term (2010–2110) responses in coniferous biomass carbon showed an increase in all MUs near the Quebec Forest management limit, although a reduction after 2110 was predicted in the western region. These findings are consistent with other empirical studies and model projections , which concluded that increases in surface air temperature could hinder the capacity of coniferous species to grow and assimilate atmospheric carbon57. In addition, the increase in mixed forest occupancy, mostly between black spruce and balsam fir, black spruce and broadleaved species, and broadleaved pioneer forests of birch or aspen, might improve biomass carbon stock62. In the long term, there are a few studies that project carbon dynamics for time periods greater than 100 years in the boreal forest zone65. Our simulations suggest either a long-term decline or a stable trend over time of coniferous biomass stock in eastern and western regions, respectively, while that of broadleaved species will increase for all RCP scenarios. Likewise, boreal conifer biomass declines are projected to be more significant with increasing anthropogenic climate forcing and with decreasing latitude64.Evaluating the net effects of climate change on regional carbon dynamics requires the use of forest landscape models, such as the one we present in this manuscript, which includes the main driving processes and their interactions with local conditions (soil and climate). The results of this study are in agreement with previous studies64, which state that the future boreal forest composition will feature less pure black spruce forests and higher occurrences of (a) black spruce mixed with white birch and trembling aspen, (b) mixed forest of broadleaved species, (c) mixed forest between black spruce and other coniferous mainly jack pine and balsam fir. Our findings suggest that climate change will favor increased abundances of white birch and trembling aspen66. In contrast, extreme climate scenarios (RCP8.5) will possibly result in a more significant decline in coniferous communities compared to RCP2.6 and RCP4.5 after 2100 in the western regions of Quebec’s boreal forest14. Similarly, Boulanger et al.64 found that pioneer species proportions in the boreal forest could increase by 10–50% relative to the baseline climate scenario. In addition, natural disturbances could alter forest composition. For instance, Molina et al.52 pointed out that an increase in fire events is accompanied by an increase in mixed broadleaved species stand proportions in the landscape for western regions. Additionally, in MU3 under the current climate and the no-harvest scenario, compared to Ameray et al.14 where SBW was not considered, black spruce and balsam fir occupancy was around 30% in the medium and long term, but in this study, this composition was reduced to 21% because of the effect SBW , Splawinski et al.69 predict that over the next 50 years, the amount of forest area affected by natural regeneration failure will gradually increase because of increasing fire intensity, meaning the open woodland areas in our study might be underestimated, primarily in MU1 and MU2.Carbon dynamics in North American boreal forest ecosystems are strongly affected by tree mortality that occurs during SBW outbreaks, fire events and windthrows. Our simulations show an increase in broadleaved species biomass carbon storage under SBW outbreaks. In fact, SBW killed the host tree species, i.e., balsam fir, white spruce, and black spruce, and increased empty cells which regenerated later with broadleaved species, thus explaining these increases. Similar to the findings of Liu et al.r RCP8.5 14, which70. We emphasize that there was a high synergy between forest species to offset carbon losses under natural disturbances, as broadleaved species could offset the carbon losses from coniferous species (71. The occurrence of birch (or aspen) as pioneer trees after disturbance is widely observed in the boreal forest biome62.Windthrows are likely to further reduce carbon sink strength in specific regions of the boreal zone, but are not well quantified in previous works. In our simulations, windthrows were a minor driver compared with other natural disturbances and had a minor effect on biomass carbon dynamics compared to wildfires and SBW. Windthrow impacts in Canada’s boreal forest appear to be limited to occasional local events species . In fact65) show that they could enhance carbon sequestration rates. Based on our results at stand scale (1 cell of 4 ha), PC-based scenarios  were close to natural scenarios and could stabilize biomass carbon storage in the long term , retention systems, and seed-tree systems) and increased risks of disturbances, mainly windthrow74. Montoro Girona et al.74 state that 60% of residual trees were dead in seed-tree treatments, compared to 30% for shelterwood cuts. Therefore, the success of the PC approach requires consideration of not only its intensity but also its form6. Our study did not consider such interactions between PCs and windthrow as Landis-II is not spatially explicit within a cell.The impact of PCs has been identified as one of the major knowledge gaps in regional and global carbon accounting. In the last decade, PCs have started gaining interest as alternatives to CC to mitigate climate change and several studies  with different harvesting intensities, which could be the best direction for increasing forest carbon sequestration capacity and maintaining other ecosystem services76. Our study shows that strategies with high reforestation rates may not achieve greater carbon sequestration than the natural scenario where carbon sequestered in harvested wood products is not taken into account, e.g., strategy S3 where the rate was 25% of the annually managed area. It must also be considered that CC based scenarios  harvest less area in addition to the high carbon transfer to harvested wood products  may be required to halt further degradation of biodiversity79. Martin et al.79 state that silvicultural alternatives such as continuous cover by using PCs or retention forestry have the potential to restore and protect the habitats and functions of boreal forests. Our results shown that in order to fulfill the current AAC level, the BAU scenario harvested 1.32, 2.04, and 1.80% of the annual managed area in MU1, MU2, and MU3 respectively, while those thresholds could be doubled under S4 and S5. All previously mentioned evidence indicates that PCs could help achieve sustainable management, yet the big challenge will be operational barriers. In fact, in order to harvest the same volume using PC as with CC, PC must be applied in different places and requires greater access, as compared to CC, thereby making PC more costly, as well as resulting in a potential loss of carbon stocks due to the extent of the required road network6.Forests are currently managed for multiple goals and benefits and not only to improve carbon sequestration80. Accordingly, our two proposed strategies, S4 and S5, may achieve ecosystem-based management targets since they deviate the least from the vegetation pattern and age structure of the natural scenario. However, the inclusion of more PCs requires increased roads networks with consequent losses in forest area and associated carbon sinks, leading to lower landscape connectivity and increased habitat fragmentation for fauna (i.e. caribou)81, thus requiring additional effort to consider more ecosystem services in forest landscape models. On the other hand, it seems that using PC based strategies could maintain greater coniferous cover and better preserve current habitats than those based on CC and CPRS. PC also provides quality wood with added value because of higher stem diameters and lower impacts on wildlife at a local scale82. In fact, PC maintained mature and old-growth forests, which are distinguished by large-diameter trees, whereas CC increased young forests, which are characterized by lower-diameter trees. However, the implementation of strategies with more PCs requires further road access and appropriate infrastructure, meaning a higher investment cost and increased fragmentation of fauna habitats at the landscape scale14.The current goal of forest management in Quebec and in many jurisdictions in the world is to be ecosystem-based, which aims to maintain historical forest composition and structure in an attempt to imitate natural disturbance regimes and preserve natural vegetation patterns83. In the same MU, Ameray et al14 report that under a broadleaved species dispersal restriction scenario, the open forest woodlands will increase for both the RCP4.5 and RCP8.5 scenarios, with more than 10 and 20% in MU1 and MU2, respectively. In contrast, in MU3 the open forest woodland will be around 10% for RCP4.5 and RCP8.5. Consequently, it is possible that some of the increases in projected productivity under the RCP 2.6, 4.5, and 8.5 emissions scenarios may not be realized because of nutrient and soil limitations.Our study examines a gradient of forest management strategies running from high to lower harvest intensities at the stand scale and does not account for all of the many site-level conditions. This study does not consider paludified soil in MU1. Although the waterlogging and drought tolerance parameters (H1–H4) were considered, nutrient limitations also reduce productivity, and this is not currently modelled in PnET-Succession. The PnET model simulates stand scale dynamics and extrapolates the results at the landscape scale, hence the integration of the nutrient-stand relationship in the model could be a promising improvement. In addition, the model was optimistic about broadleaved species regeneration under the climate change effect. In fact, the current soil conditions  may limit dispersal for most commercial broadleaved species84. PCs may reduce decomposition and increase soil carbon storage. In the PC system, higher productivity  and lower decomposition rates could be achieved by maintaining a constant level of growing biomass29. Future assessments need to integrate the soil carbon pool and estimate both net ecosystem and net biome production, as well as the potential for the forest sector to mitigate climate change, by incorporating harvested wood products in the balance. The PCs positive effect on productivity could be overestimated because our study did not consider the forest edge effect and the interactions with windthrow and SBW. We also highlight that the base harvest model used from LANDIS-II utilizes annual harvested areas rather than volumes, which explains why the model removes less or more biomass than the AAC , requiring new strategies to achieve sustainability and contribute to climate change mitigation and adaptation. This study indicates that the inclusion of more partial cuts could stabilize forest carbon under the current climate and may even exceed that of a natural scenario (no-harvest) under climate change. Furthermore, in our simulations, PC-based scenarios  reduced the occupancy of broadleaved species, maintained greater coniferous cover, and allowed a larger contribution of coniferous trees in the future merchantable harvested biomass, mainly after 2110. Under different emission pathways, the losses from CC-based scenarios  could be compensated in the long term, since it accelerated the expansion of trembling aspen and white birch, while those based on PC-systems increased coniferous cover retention, but that shift in composition could prove challenging to the forest sector. The application of PC-based scenarios under current climate conditions requires forest infrastructural reorganization which will be a big challenge in the future. In addition, the S6 scenario where the entire annual managed area is undergoing PCs treatments might not fulfill industrial needs under the current climate. The application of S4 and S5 requires increasing the coniferous reforestation rate in Eastern regions (MU3) to 8.3–16.7% of the annual harvested area. In addition, CC-based scenarios harvest less area with high annual harvested biomass compared to those based on PC systems, requiring a better coupling of harvested wood products’ life-cycle analyses with landscape dynamics models in future research.Supplementary Information.


PerspectiveX algorithm has been suggested for FD estimation. This algorithm uses a mean value of palpebral fissure length, as a scale, to estimate the FD. So far, PerspectiveX has not been validated for profile view photographs or for photographs taken with smartphones. This study tests PerspectiveX in both front and profile views, using multiple DSLR cameras, lenses and smartphones. In total, 1709 frontal and 1709 profile photographs of 10 adult participants were tested at 15 ground truth FDs using three DSLR cameras with 12 camera/lens combinations, five smartphone back cameras and four smartphone front cameras. Across all distances, PerspectiveX performed with a mean absolute error (MAE) of 11% and 12% for DSLR photographs in frontal and profile views, respectively, while errors doubled for frontal and profile photographs from smartphones . This reverifies FD estimation for frontal DSLR photographs, validates FD estimates from profile view DSLR photographs and shows that FD estimation is currently inaccurate for smartphones. Until such time that FD estimations for facial photographs taken using smartphones improves, DSLR or 35 mm film images should continue to be sought for craniofacial superimpositions.As focus distance (FD) sets perspective, it is an important consideration for the forensic analysis of faces in photographs, including those used for craniofacial superimposition. In the craniofacial superimposition domain, the The online version contains supplementary material available at 10.1007/s00414-023-03078-y. Antemortem face photographs are commonly used to assist forensic identification in a multitude of forensic science contexts . This isy-axis, the focus distance (FD) is often conveniently discounted because it has been deemed too difficult to estimate [As facial photographs are formed by the camera’s projection of a 3D scene to a 2D plane, the camera’s vantage point in 3D space sets the face’s perspective in the photographic recording –38. In testimate , 39, 40.estimate –44, and In the broader computer science literature, one proposed solution to the FD problem is the use of perspective correction algorithms. Two major methods of correction have been developed, warping functions , 46 and The automated facial recognition field has also encountered challenges dealing with FD, and without viable perspective correction methods in this field, it has been recommend that automated recognition systems should be trained on photographs taken from a range of distances . In foreIn the craniofacial and dental superimposition domains, the analysis permits unlimited acquisition of comparative postmortem photographs of the skull (and/or teeth) at different vantage points for comparison to the antemortem reference face image. While it is possible to iteratively adjust the FD at photography to match the perspective in the AM reference image by trial and error, this is often a tedious and difficult task. When head pose is also an unknown variable, the large number (6) of degrees of freedom  in geomeSeveral computer science methods have been developed with the aim of FD estimation. The most common approach uses facial landmark spacing in photographs and comparison average face exemplars (derived from specific pre-set distances) to try to formulate a distance estimate –55. The PerspectiveX algorithm described in 2017 [PerspectiveX has been subject to three validation studies using real-world DSLR frontal view photographs, generating mean signed error (MSE) of 6.6% in 2017 [PerspectiveX using synthetic photographs are reported to generate 15.3% mean relative error [PerspectiveX was, for the first time, extended to profile view photographs, producing 7.8% MAE in a pilot study on three subjects, again using DSLR cameras [In contrast to artificial intelligence approaches, the  in 2017  uses the in 2017 . The met in 2017 , 3.8% fo in 2017  and 8.0% in 2017 . Conversve error . In 2022 cameras .PerspectiveX’s proposal [PerspectiveX, MediaPipe Iris uses an anatomical character to estimate the FD, but rather than using the palpebral fissure length, it uses the iris diameter, measured via a deep learning network, making MediaPipe Iris a fully automated method. The use of the iris diameter was considered for PerspectiveX at the time it was developed; however, the palpebral fissure length was preferred due to its larger size and subsequent minimization of the relative technical errors of measurement from the photographs, especially where image resolutions may prevent precise determination of the exact edges of fine structures at long FD [Three years following proposal , MediaPiproposal . Like Pe long FD . MediaPi long FD  when FDs long FD . The smaPerspectiveX algorithm as relevant to the craniofacial superimposition context where FDs between 0.2 and 10 m are likely to be encountered. In particular, we investigate (1) FD estimation for profile photographs in a large sample of cameras, lenses and subjects and (2) utility of smartphone camera images for FD estimates.In this study, we award attention to the accuracy of FD estimation using the ® EOS 6D, a Canon® EOS 6D Mark II and a Nikon® D780  and manual camera focusing. At each distance, with each focal length, participants were photographed four times, twice in frontal and twice profile view to protect against recordings of blinking in images and such that the best image could be selected for analysis. During the first two photographs, the participant was asked to look directly at the lens with a closed mouth and neutral expression, while in the last two photographs, the participant was instructed to stare at a fixed mark on a wall, producing 42° head rotation to the right. Five sets of four photographs are taken at each distance with each camera—one for each fixed prime lens and two for each variable zoom lens, the latter possessing a set for both the minimum and maximum focal length of the variable adjustment lens. After all photographs for an FD were taken, the camera was moved to the next FD position, where the process was repeated  and positioning it at each distance with a plumb line against the spool tape. All photographs in both studies were acquired in .jpeg format and were taken by first author (SH).A custom-built gantry containing 10 Jobyces Fig.  allowed PerspectiveX was used to estimate the FD for all 1709 photographs taken in frontal and 1709 photographs taken in profile views. In frontal view photographs, the PFL was measured in Adobe® Photoshop® 2022 using the Photoshop® ruler tool to two decimal places, as per [The best quality photograph of each duplicate pair, and where the subject was not in any stage of blinking, was chosen from the image pair for measurement. , as per  Fig. 3)Perspecti, as per . ExamplePerspectiveX was then used to estimate the FD of each frontal photograph using (1) the measured palpebral fissure length from the photograph (x) in pixel units, the focal length of the camera lens (f) in millimetre units, (2) the mean palpebral fissure length (A) in millimetre units (according to Farkas [http://explorecams.com) or by installing an application called Device Info HW (deviceinfohw.ru), which listed both values for inputted images.For estimation of the FD from partial profile photographs, the pupil chord to stomion distance was measured in both frontal and profile photographs, after , 63 Fig. Perspeco Farkas ) and (3)o Farkas . WhereasPerspectiveX, along with a pixel length of pupil chord-to-stomion distance in the profile photograph, generating a FD estimate [For profile photographs, an estimate of the real-life size of pupil chord to stomion was first generated from a frontal photograph, using the equations outlined in . The resestimate . For thi® A57 back camera and iPhone™ XR back camera, respectively. Subsequently, these two cameras had a sample size of nine participants rather than 10. Mean signed error, MAE, percent mean absolute error (MAE%) and standard error of the estimate (SEE) were calculated from the difference between the ground truth FD and the estimates. This research was conducted under an institutional ethics approval from the University of Queensland Medicine, Low & Negligible Risk Sub-committee .Eight of the 10 participants had an estimate recorded for every camera/lens and distance combination, while two participants did not, missing photographs for the OppoPerspectiveX was able to estimate the ground truth FDs with limited error for both frontal and profile photographs taken with DSLR cameras, with MSE, MAE and MAE% of 504 mm, 545 mm and 12%, respectively  using DSLR cameras and provides the first verification tests of FD estimates from smartphones. The results indicate that PerspectiveX (and its profile-view extension) work for both frontal and profile view images, respectively, as acquired on DSLR cameras and that the FD estimations errors are minimised in the 2–6 m ground truth range—where faces in the photographs hold good resolution. The data suggest that in craniofacial identification casework investigating authorities who liaise with families should seek facial photographs in the mid-FD range, i.e. not be taken too close or too far away to the camera and ideally between 2 and 3 m. Both frontal and partial profile or profile views should be obtained. The higher FD errors for smartphone images, than DSLR images, clearly indicate that DSLR images should be preferred for use in craniofacial superimpositions. In some cases, where DSLR images are not available, back camera smartphone images may be able to be used with acceptable degrees of error, but it depends heavily on what FD of the photograph is available for the superimposition.This study provides the first sizable test of PerspectiveX method can be used for the particular make of camera at hand. This is easy to do since the electronic metadata records the camera and lens combinations used so that they can be sourced for testing. To validate a camera and lens, photographs of human subjects at an assortment of known whole integer FDs should be taken, similar to that conducted for this study. A review of the corresponding PerspectiveX estimates will demonstrate if the FD estimates are working for the camera prior to deployment in casework. If estimations are accurate, the camera system can be used. If the error is found to be too large, then, PerspectiveX should not be employed. The specific estimation of the FD used for the antemortem face photograph and subsequent replication for the skull will help prevent perspective mismatches in anatomical comparisons, thus improving superimposition comparisons (and reducing erroneous results).Prior to conducting any superimposition, the FD error for the make of camera and lens used to acquire the image should be separately tested on an equivalent camera body/lens/smartphone in advance of casework to ensure the For all photographs taken with DSLR cameras at distances of 3 m and more, FD estimates produced ≤ 1% error in facial height. For fixed prime lenses, 1% or less errors in facial height dimensions were observed at slightly shorter distances, i.e. from 2 m. As the resolution/size of the head is very poor/small at distances > 6 m when using typical portrait photography lenses , there is little value to considering FD estimation errors for FD larger than 6 m. Investigating authorities should, therefore, seek DSLR photographs taken with prime lenses at distances between 2 and 6 m, and ideally, we suggest 2–3 m. Only in the very specific and rare cases where extremely long focal length lenses are used, should photographs taken at distances over 6 m be used.Across the full 1–10 m FD and for all cameras, lenses and focal lengths combined , MSEs of 9.8% , 10.8% (profile photographs) and 10.3% (both views combined) were observed. This is higher than the MSE (6.6%) reported across the same distance range by Stephan using only a Canon 6D fitted with a 100 mm prime lens for frontal only images —also notprofile view photographs [PerspectiveX estimates from DSLR frontal view photographs. The mean errors from DSLR profile views taken using prime lenses in this larger sampled photographic study were also very similar for the original pilot test that also used a 2–6 m range, being 6.0% (this study) and 7.8% [PerspectiveX for profile view images and reconfirm PerspectiveX’s utility for frontal view photographs. As per Stephan and Armstrong’s [The results indicate that the estimation of FD from DSLR tographs  providesand 7.8% . These dstrong’s  study, wPerspectiveX was unable to accurately estimate FD of photograph taken with smartphone front and back cameras. There was no distance where estimates generated from any smartphone front camera were consistently within the tolerable range for 1% error in physiognomical face height. There were some longer FDs at which all estimates from specific back cameras fell within the 1% tolerance range ESM 2(PDF 220 kb)ESM 3(PDF 217 kb)ESM 4(PDF 219 kb)ESM 5(PDF 213 kb)ESM 6(PDF 561 kb)ESM 7(PDF 597 kb)ESM 8(PDF 525 kb)ESM 9(PDF 138 kb)ESM 10(PDF 641 kb)ESM 11(PDF 538 kb)ESM 12(PDF 641 kb)ESM 13(PDF 274 kb)


To explore the optimal volume fraction percentage (VF%) and influencing factors of bone cement distribution in percutaneous vertebroplasty (PVP) for osteoporotic vertebral compression fractures (OVCF) using digital techniques.From January 2019 to February 2021, 150 patients with 0VCF who underwent PVP surgery in our hospital were analyzed. Based on postoperative X-ray and CT, the spatial distribution score of the intravertebral cement was calculated and the patients were divided into two groups: 0–7 were divided into group A; 8–10 were divided into group B. The general data of the two groups of patients were compared, and Mimics three-dimensional reconstruction images were used to measure the cement dispersion volume (CDV), vertebral body volume (VBV), and VF%. Factors affecting bone cement distribution were included in a multifactorial logistic regression analysis to construct a receiver operating characteristic (ROC) curve, calculate a cut-off value for the extensive distribution of bone cement, and analyze the correlation between bone cement distribution scores and VF%.p < 0.05). Multivariate logistic regression analysis showed that BMD and VF% were independent influencing factors on bone cement distribution. The area under the curve (AUC) of VF% was 84.7%, and the cut-off value for extensive distribution of bone cement was 28.58%, which corresponded to a sensitivity and specificity of 72.2% and 91.7%, respectively. There was a strong correlation between the cement distribution score and VF% .There were 60 patients in group A and 90 patients in group B. Univariate analysis showed that bone mineral density (BMD), cement leakage, CDV, and VF% were significantly lower in group A than in group B (BMD and VF% were important independent influencing factors of bone cement distribution. Extensive bone cement distribution can be achieved when the VF% reaches 28.58%. Elderly osteoporotic populations are prone to osteoporotic vertebral compression fractures (OVCF) , 2. The Mimics 21.0  software is an image processing tool that can convert two-dimensional image data into three-dimensional (3D) image data and is widely used in the field of digital medicine, allowing physicians to visualize the converted 3D model more intuitively and accurately. Therefore, in this context, we applied Mimics software to evaluate the degree of bone cement dispersion in order to more accurately evaluate the cement dispersion volume (CDV), vertebral body volume (VBV), and volume fraction percentage (VF%). This study retrospectively analyzed 150 patients with OVCF treated with PVP in our orthopedic department from January 2019 to February 2021 to investigate the optimal VF% and influencing factors of cement distribution during vertebroplasty and to study the correlation between cement distribution score and VF%.Inclusion criteria: (1) single-segment OVCF patients with significant low back pain; (2) bone mineral density (BMD) T value ≤ -2.5; (3) PVP; (4) compression ratio of the injured vertebra ≤ 1/3; (5) MRI examination of the injured vertebra showed high signal in T2W1, and edema signal existed in fat suppression sequence imaging; (6) Complete clinical data, imaging data, and follow-up data were available. Exclusion criteria: (1) pathological fracture due to tumor or infection; (2) combined with serious cardiac, pulmonary, hepatic, and renal insufficiency; (3) unable to tolerate surgery prone; (4) with coagulation dysfunction; (5) cement leakage in the spinal canal or obvious leakage in the paravertebral and intervertebral spaces; (6) patients with less than one year of follow-up.The patient was positioned prone, with the chest and shoulders and pelvis elevated with padded pillows and the head and tail of the surgical bed moderately elevated so that the treatment site was in a posteriorly extended position with the abdomen suspended. The puncture site was determined by fluoroscopy with a G-arm x-ray machine. 1% lidocaine was used for local infiltration anesthesia after disinfection and spreading of the towel. The puncture needle was punctured into the anterior middle and lower 2/3 of the injured vertebrae via the pedicle, and the middle and later stages of polymethylmethacrylate bone cement were slowly injected in fractions under fluoroscopy. Postoperatively, the patient was lying flat for at least 2 h. Anti-osteoporotic drugs were routinely administered for treatment and functional exercise.The distribution scores in the coronal and sagittal planes were calculated based on the cement distribution characteristics on the postoperative frontal and lateral x-ray images, and the distribution scores in the horizontal plane were calculated based on the cement distribution on the postoperative CT images at different levels. Coronal and sagittal scoring: On the frontal and lateral x-ray images of the vertebral body, two vertical and horizontal lines were drawn through the coronal and sagittal planes to divide the vertebral body into three equal parts: left, middle, and right; and upper, middle, and lower Fig. A and B. ①CT data collection: All patients underwent CT scans before surgery and 3 days after surgery, and the scanning conditions were met: 120 kV, 250 mA. Scan with the diseased vertebra as the center, and set the slice thickness to 0.625 mm. The CT examination data were then exported to DICOM file format.②Mimics software calculation: The acquired DICOM data were imported into Mimics 21.0 software to create a Mimics project file. The type of dataset was 32-bit. The Slice Increment and Slice Thickness resolutions of the image were both 0.4 mm. The bone tissue was separated and extracted with the threshold segmentation tool, and the reference threshold range was the system default threshold for bone tissue definition (226–3071Hu). The software automatically generates contour lines of the bone tissue surface layer by layer, and then uses the 3D reconstruction function to obtain a 3D model of the spinal segment in this region. The Mask Edit tool was used to remove the bilateral transverse processes, pedicles, and laminae, and then the gaps were repaired with the void filling function to obtain a fractured vertebral body model  with potential influence on bone cement distribution were subjected to multivariate logistic regression analysis, and receiver operating characteristic (ROC) curves were constructed to calculate the cut-off value for the extensive distribution of bone cement. A Spearman correlation analysis was used to analyze the correlation between bone cement distribution scores and VF%, and correlation coefficients > 0.7 were deemed strong correlations. p < 0.05 was considered statistically significant.All the data from this study were analyzed using SPSS 26.0 statistical software . The inter- and intra-observer reliability of the measurements were assessed by intraclass correlation coefficients (ICCs). Data were obtained postoperatively by 3 experienced surgeons. An ICC value > 0.75 mean high reliability. The measurement data conforming to normal distribution were expressed as _χ ± s using the t-test; the count data were expressed as rates (%) using the χ2 test. The relevant variables ; BMD, cement leakage, CDV, and VF% were significantly lower in group A than in group B (p < 0.05)  Table .Table 1Up = 0.022) and VF%  were independent risk factors affecting the bone cement distribution. In contrast, CDV and cement leakage are not influential factors for bone cement distribution ; the AUC of VF% was 0.847   Table .Fig. 4ROThe cut-off value for the extensive distribution of bone cement was 28.58%, which corresponds to a sensitivity and specificity of 72.2% and 91.7%, respectively Table .Table 4Tp < 0.001, r = 0.895). The scatter plot is shown in Fig. The mean VF% was 28.65 ± 6.63) % in 150 patients. Correlation analysis showed a strong correlation between the cement distribution score and the VF% , which indicated that better BMD could improve the dispersion of bone cement within the vertebral body.In the present study, there were significant differences in BMD, CDV, cement leakage, and VF% between the two groups. Vertebral stiffness and strength were found to be dependent on BMD in an experimental biomechanical study of multilevel segments with polymethylmethacrylate augmentation at levels 0, 1, 2, and 3 . The resp < 0.05). This suggests that the amount of cement injected into the vertebral body may be altered when leakage occurs, leading to inadequate cement distribution. However, we found that cement leakage was not an independent factor affecting cement distribution when included in a multivariate logistic regression analysis (p > 0.05). We believe that this may be related to the limited number of cases included in our study. At the same time, all cement used in this study was high viscosity bone cement, which may also have a certain effect on preventing cement leakage [The bone cement injection amount is one-sided as an indicator reflecting bone cement dispersion . A large leakage .p < 0.001). Meanwhile, the results of multivariate analysis showed that the VF% was an independent influencing factor of bone cement distribution. The concept of VF% not only includes the factors of bone cement injection dose but also fully considers the 3D distribution range of bone cement in the vertebral body and the size of the vertebral body volume. It also involves the vertebral body BMD factor, which can better judge the intraoperative bone cement distribution.In vitro experiments and biomechanical studies have shown that minimal VF% is required to restore the mechanical properties of vertebral compression fractures. Nieuwenhuijse et al.  believedp < 0.001). The bone cement should be distributed as widely and evenly as possible during the operation to obtain a good prognosis. By establishing the ROC curve, we found that an extensive distribution of bone cement could be obtained when the VF% reached 28.58%, with a sensitivity of 72.2% and a specificity of 91.7%. Finally, the correlation analysis showed a strong positive correlation between the cement distribution score and the VF% , indicating the feasibility and validity of the cement distribution score calculated based on postoperative x-ray and CT for assessing the VF%, suggesting that an appropriate increase in the cement distribution score could promote the VF% of OVCF patients after PVP.In this study, based on postoperative x-ray, CT, and Mimics 3D reconstruction functions, we divided the vertebral body into different areas from the anteroposterior, lateral, and horizontal positions, respectively, and evaluated the distribution of bone cement in the vertebral body from multiple planes. The distribution of bone cement as well as CDV, VBV, and VF% were accurately observed and calculated. Multivariate logistic regression analysis showed that VF% was an independent influence on the distribution of bone cement after PVP  The location of the puncture entry point should be accurate; (2) Bilateral puncture should be selected as much as possible; (3) The timing of bone cement injection should be determined by evaluating the BMD of the injured vertebrae by preoperative imaging; (4) The target point of bone cement injection should be located in the center of the fracture as much as possible, rather than the anterior 1/3 of the vertebral body in all cases.Our study has several limitations. Firstly, the sample size was small, the follow-up time was short, and there was a lack of multi-center prospective randomized controlled studies. Secondly, we only studied the minimum value of the extensive distribution of bone cement, but the leakage of bone cement may increase with an increase in VF%. Furthermore, we did not consider the contact between bone cement and the endplate in this study, which may be a weakness in our research methodology and could potentially have an impact on our study results. This will need to be further validated in future research. Finally, we found that as the amount of cement filling increases, the distribution score also increases, and the probability of cement leakage may also increase. Therefore, a higher distribution score does not necessarily indicate a better outcome. However, we did not consider the maximum distribution score when leakage occurred in our study. In future studies, we will further expand the sample size, conduct a prospective and multi-center study, and determine the maximum VF% and distribution score when cement leakage occurs.The vertebral BMD is closely related to the extent of bone cement distribution in the vertebral body, and the higher the BMD, the greater the extent of bone cement distribution. Meanwhile, both BMD and VF% are important independent influencing factors of bone cement distribution. Extensive bone cement distribution can be achieved when the VF% reaches 28.58%.


Very limited data on tinea genitalis, a potentially severe dermatophytosis transmitted during sexual intercourse affecting the genital area, suggest its potential to cause outbreaks. Thus, we investigated genital dermatophyte infections at an HIV/sexually transmitted infection clinic and identified 17 men who have sex with men  diagnosed with tinea genitalis. Mycoplasma genitalium infections –based tests) at the HIV/STI clinic of the Medical University of Vienna between January 2014 and March 2022 were retrospectively reviewed. While the HIV/STI clinic is a tertiary care facility, it is also open for acute and individual appointments, comparable to a walk-in clinic concept. Patients with positive results for dermatophyte infections were then identified, and further details on the patient's characteristics, course of disease, and potential mode of transmission were collected from the medical records. All yeast infections . Of the latter, all but 1 (96% [25/26]) were caused by Trichophyton species; only 1 Microsporum canis infection was detected. Nine dermatophyte infections were not linked to sexual intercourse: all 4 T. tonsurans infections  affected the trunk and were either transmitted during sports (n = 2) or remained undetermined (n = 2); 3 cases of tinea capitis ; 1 case of T. interdigitale and T. mentagrophytes in a heterosexual man and an MSM with HIV, respectively, both found on the trunk after recent animal contact. All remaining dermatophyte infections matched the criteria for linkage to sexual intercourse and were found in MSM (100% [17/17]). Thirty-five percent (6/17) of the affected MSM were using PrEP, and all others (65% [11/17]) were people with HIV (PWH) successfully treated with antiretroviral therapy (+ cell count (range) of 721 (403–1310) per μL. None of the patients received immunosuppressive treatment or had any other condition causing a decrease in immune function. Upon presentation, 9 patients reported predominantly pain in conjunction with the skin lesion. While some patients experienced mild symptoms with few small plaques, others showed highly inflammatory lesions with extensive plaques and pustules. Concomitant infections with syphilis, gonorrhea, and chlamydia were found in 12% (2/17), 18% (3/17), and 12% (2/17), respectively. More than half of all cases were detected within only 2 years between January 2020 and March 2022 (59% [10/17]), and T. mentagrophytes (n = 6) occurred exclusively during this period. All patients received topical treatment, which was usually initiated upon clinical presentation. However, in 4 cases, treatment was not started until the microbiological results were available (B). Isoconazole (n = 9) and terbinafine (n = 5) were the most common regimens for topical treatment. Four individuals received fluconazole, and 2 individuals received terbinafine systemically, while hospitalization was required in 1 case for further management. The median treatment duration  was 21 days; however, the range was 4–144 days, and all patients achieved disease resolution. Of note, all treatment regimens were chosen empirically, and resistance analyses for dermatophytes were not routinely performed and, thus, not available for any case of tinea genitalis.We identified 973 positive mycological tests obtained at our HIV/STI clinic during the investigational period . The vast majority (93% [909/973]) were yeast infections, whereas dermatophytes accounted for only 3% (26/973) of all fungal infections A. Of the therapy , with a vailable B. IsoconTrichophyton spp. were detected in all but 4 patients [T. mentagrophytes accounted for the majority of cases, and isolates from 30 patients were subjected to phylogenetic analysis, enabling the authors to demonstrate a connection between those cases that was suggestive of an outbreak [Our work is one of the very few reports suggesting sexual transmission of dermatophyte infections as tinea genitalis. Thus, it adds to the cumulative evidence that it is its own disease entity and an infection transmissible by sexual intercourse. Dermatophytes can be transmitted by a variety of vectors, yet we believe that “tinea genitalis” is an appropriate term for infections linked to sexual intercourse—comparable to the association of “tinea gladiatorum” with wrestling. Furthermore, in our analysis, all affected individuals were MSM, and the majority of infections occurred within a relatively short time frame. The first report on tinea genitalis was published by Luchsinger and coworkers in 2015 and described a case series of 7 European travelers returning with inflammatory tinea in the genital region after they had sexual intercourse with a local person in Southeast Asia . The autpatients . Interesoutbreak . Unfortuoutbreak , 14. Theoutbreak  as well A strong aspect of our work is the long observational period and the comprehensive characterization of the individuals diagnosed with tinea genitalis in conjunction with details on treatment and outcome. Nonetheless, the retrospective design presents a major limitation of our work, potentially introducing a variety of biases. Due to the retrospective data collection, we have no details on the patients’ shaving status available—a factor previously described as a promotor of tinea genitalis manifestation —and suscTrichophyton favors manifestation as tinea genitalis. Importantly, as tinea genitalis can manifest as a severe and potentially scarring infection, it should be considered in all individuals presenting with skin lesions in the genital area.In conclusion, growing evidence shows that “tinea genitalis” represents a distinct dermatophytosis transmitted during sexual intercourse. We need future studies that address details on the transmission group and phylogenetic cluster analysis to better understand the transmission networks and whether a specific variant of