Multi-mode fiber-based speckle contrast optical spectroscopy: analysis of speckle statistics.

Speckle contrast optical spectroscopy/tomography (SCOS/T) provides a real-time, non-invasive, and cost-efficient optical imaging approach to mapping of cerebral blood flow. By measuring many speckles (n>>10), SCOS/T has an increased signal-to-noise ratio relative to diffuse correlation spectroscopy, which measures one or a few speckles. However, the current free-space SCOS/T designs are not ideal for large field-of-view imaging in humans because the curved head contour cannot be readily imaged with a single flat sensor and hair obstructs optical access. Herein, we evaluate the feasibility of using cost-efficient multi-mode fiber (MMF) bundles for use in SCOS/T systems. One challenge with speckle contrast measurements is the potential for confounding noise sources (e.g., shot noise, readout noise) which contribute to the standard deviation measure and corrupt the speckle contrast measure that is central to the SCOS/T systems. However, for true speckle measurements, the histogram of pixel intensities from light interference follows a non-Gaussian distribution, specifically a gamma distribution with non-zero skew, whereas most noise sources have pixel intensity distributions that are Gaussian. By evaluating speckle data from static and dynamic targets imaged through an MMF, we use histograms and statistical analysis of pixel histograms to evaluate whether the statistical properties of the speckles are retained. We show that flow-based speckle can be distinguished from static speckle and from sources of system noise through measures of skew in the pixel intensity histograms. Finally, we illustrate in humans that MMF bundles relay blood flow information.

[Analysis on individual dosage monitoring of some interventional radiology staffs in Tianjin City from 2016 to 2020].

Objective: To investigate the individual external dose level of some interventional radiology staffs from 2016 to 2020 in Tianjin City. Methods: All 2068 interventional radiology staffs who were included in the work of the Radiation Monitoring Project from 2016 to 2020 were selected as study subjects in March 2021. The individual dose monitoring results of interventional radiology staffs of different ages, working years, time and medical institutions were analyzed. Results: Among 2068 interventional radiology workers, 1406 (67.99%) were male and 662 (32.01%) were female. The age was 44.6 (39.2, 50.3) years, and the working years was 10.5 (4.3, 14.6) years. The annual effective doses per capita of 40-49 age group and ≥50 age group were higher than that of 30-39 age group (P<0.05) . The annual effective dose per capita of 5-9 working years was higher than that of <5 working years, and the annual effective dose per capita of 10-29 working years was higher than that of 5-9 working years (P<0.05) . The median per capita annual effective dose of the interventional radiology staffs was 0.164 mSv. There were 1976 interventional radiology staffs with an annual effective dose of <0.50 mSv/a (95.6%) . The collective dose distribution ration SR(0.5) was 41.1%. The difference of effective dose per capita in each year was statistically significant (H=19.23, P<0.05) . The per capita annual effective dose of interventional radiology staffs in tertiary medical institutions was higher than that in secondary medical institutions, and the difference was statistically significant (P<0.05) . Conclusion: The personal dose of interventional radiology staffs in Tianjin City is at a low level. It is necessary to emphasize the radiation hazard protection of interventional radiology staffs in tertiary medical institutions, 40-49 years old, ≥50 years old age groups and 5-9, 10-29 working years groups.

Spatial variation of the soil bacterial community in major apple producing regions of China.

AIMS: In China, apple production areas are largely from the coastal to inland areas and across varied climate zones. However, the relationship among soil micro-organisms, environmental factors and fruit quality has not been clearly confirmed in orchards. Here we attempted to identify the variation of soil bacteria in the main apple producing regions and reveal the relationship among climatic factor, soil properties, soil bacterial community and fruit quality. METHODS AND RESULTS: Sixty soil samples were collected from six main apple producing areas in China. We examined the soil bacteria using bacterial 16S rRNA gene amplicon profiling. The results show that the soil bacterial diversity of apple orchards varied from the Bohai Bay Region to the Loess Plateau Region. Proteobacteria, Acidobacteria and Actinobacteria were the predominant taxa at the phylum level for all six areas. In the Bohai Bay and the Loess Plateau region, which are the two largest apple producing areas, Proteobacteria and Actinobacteria had the highest relative abundance, respectively. Furthermore, soil bacterial diversity showed positive correlation with the mean annual temperature (MAT), soil organic matter (SOM) and pH. Excluding a direct effect on the apple fruit quality, MAT exerted an indirect influence through soil SOM and pH to alter the relative abundance of dominant taxa and shift the bacterial diversity, which affects the apple fruit titratable acids and soluble solids. CONCLUSIONS: Geographic variables underlie apple orchard soil bacterial communities vary according to spatial scale. Environmental factors exert an indirect effect on apple fruit quality via shaping soil bacterial community. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides a list of bacteria associated with environmental factors and the ecological attributes of their interactions in apple orchards, which will improve our ability to promote soil bacterial functional capabilities in order to reduce the fertilizer input and enhance the fruit quality.

Molecular and Morphological Characterization of The Root -lesion Nematode, Pratylenchus Neglectus, on Corn from Henan Province of China.

Root-lesion nematodes, Pratylenchus spp., are economically important pathogens because of their detrimental and economic impact on a wide range of crops. In August 2018, two samples of both roots and rhizosphere soil were collected from a corn field in Liangyuanqu of Shangqiu city, Henan Province, China. Root-lesion nematodes were recovered from the roots and soil samples using the modified Baermann funnel extraction method. Both the morphological characters and molecular analysis of the internal transcribed spacer (ITS) and D2-D3 expansion region of 28S ribosomal RNA sequences confirmed that the root-lesion nematode population collected from corn in this study was P. neglectus. Phylogenetic analyses showed that this isolate formed a highly supported clade with other P. neglectus isolates. To the best of our knowledge, this is the first report of P. neglectus on corn in Henan Province of China. This study reports the first partial sequences of 28S D2-D3 region of P. neglectus on corn in China. Due to the great harmfulness of root-lesion nematodes to corn, care should be taken to prevent the spread of P. neglectus to other regions in China. At the same time, further study on the biological characteristics of P. neglectus is needed, which will be helpful to develop corresponding management and control strategies.

[Investigation and analysis of work-related occupational musculoskeletal disorders and associated risk factors of manufacturing workers].

Objective: To investigate the prevalence of Work-related musculoskeletal disorders(WMSDs) and identify associated risk factors and provide evidence of taking measures for prevention. Methods: By Cluster sampling, 1 920 employees of 35 manufacturing enterprises were selected as study subjects from May to December 2017. The questionnnaire were including population characteristics、related factors of ergonomics、job burnout、insomnia and WMSDs. Results: The prevalence of waist was the highest among 9 body parts, with 52.0%, followed by the prevalence of neck 50.6%, more than 1 muscle diseases were by the prevalence of 74.7%. Single factor analysis showed that different levels of labor intensity, daily standing time (h) , daily sitting time(h) , daily bending time (h) , daily lifting of 5kg object time (h) group waist disease and prevalence of more than one musculoskeletal disease were different, The difference was statistically sig- nificant (P<0.05). More than 5 years of working year, labor intensity of Class III, daily bending time ≥2 h, depression, disorders (P<0.05). life satisfaction, job burnout, and insomnia are all risk factors for waist and musculoskeletal. The daily sitting time ≥2 h and the high life satisfaction were protective factors for waist and WMSDs (P<0.05). Conclusion: The prevalence rate of WMSDs among manufacturing workers is strong, and Manager should take the aspects of ergonomics and psychological factors meassure to reduce WMSDs, These meassure were including increasing sitting time, reducing bending time.

Differences in expression of serum protein in patients with psoriasis vulgaris and blood heat syndrome and healthy volunteers.

To explore the mechanism of psoriasis vulgaris (PV), serum protein expression profiles between PV patients with blood-heat syndrome and healthy volunteers were detected by isobaric tags for relative and absolute quantitation (iTRAQ). First, sera from 15 PV patients with blood-heat syndrome and 10 healthy volunteers were collected; then, serum proteins were separated and hydrolyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and a specific iTRAQ marker enzyme respectively after further purification and protein abundance treatment. Compared with the control group, differentially expressed proteins in PV patients with blood-heat syndrome were identified and analyzed by tandem mass spectrometry. A total of 787 proteins were identified and 718 proteins had a functional annotation with gene ontology (GO) by iTRAQ in the current study. Significant differences (P <0.05) and great differences (P <0.01) were found in 681 proteins and 536 proteins respectively between the patient group and healthy group. ). Different protein expression profiles in serum existed between PV patients with blood-heat syndrome and healthy volunteers; the differences largely involved immune-related proteins and lipoproteins. The proteins specific for PV with blood-heat syndrome deserves further investigation.

[The optimal cutoff value of waist-to-height ratio in Chinese: based on cardiovascular risk and metabolic disease].

Objective: Waist-to-height ratio (WHtR), a measurement of the distribution of body fat, correlated with abdominal obesity indicating that it might be a better predictor of cardiovascular risk and metabolic disease. We, therefore, evaluated optimal WHtR cutoff points according to the risk of framingham risk score (FRS) and metabolic syndrome (MS) in Chinese. Methods: The subjects were from China National Diabetes and Metabolic Disorders Survey during 2007-2008. Receiver operating characteristic analysis was used to examine the optimal cutoff values of WHtR according to the risk of FRS and MS. Results: A total of 27 820 women and 18 419 men were included in the evaluation. The average age was (45.0±13.7) years. The proportions of FRS ≥10% and MS increased with WHtR both in men and women. The cutoff points of WHtR for the risk of FRS ≥10% and MS were 0.51, 0.52 in men, and 0.52, 0.53 in women, respectively. When FRS ≥10% and MS were taken into consideration with a certain weights, the pooled cutoffs of WHtR were 0.51 in men, and 0.53 in women, respectively. By using the similar method, the optimized cutoff points were 0.52, 0.51, 0.50 for men and 0.51, 0.53, 0.54 for women in age group 20-39, 40-59 and ≥60 years, respectively. Conclusions: The optimal cutoffs of WHtR are 0.51 in men, and 0.53 in women for FRS≥10% in combination with MS indicating that this WHtR cutoff points might be used as indexes to evaluate obesity and risk of obesity-related diseases.

[Efficacy of thrombolytic therapy using reteplase in cases with acute ST-segment elevation myocardial infarction: results from a multicenter clinical trial].

Objective: To evaluate the efficacy and safety of intravenous thrombolytic therapy using reteplase in patients with acute ST-segment elevation myocardial infarction (STEMI). Method: A total of 73 hospitals from Henan province took part in this clinical trials during October 2012 to October 2014, 1 226 cases (1 014 male (82.7%), mean age 59.0 (51.0, 66.0) years) with acute STEMI received reteplase as thrombolytic agent.Reperfusion rate was judged according to the clinical symptoms, electrocardiogram, myocardial enzymes and heart rhythm, and the rate of cardiovascular events and bleeding events during hospitalization was also observed.Bleeding events were evaluated with global utilization of streptokinase and tissues plasminogen activator for occluded coronary arteries (GUSTO) criteria.Subgroup analysis was performed to compare the effects of various thrombolysis timing (time from onset to thrombolysis≤6 h or 6-12 h) on reperfusion rate, cardiovascular events and bleeding events rate. Results: The reperfusion rate was 89.3% (1 089/1 219) at 120 minutes after the thrombolysis, average recanalization time was (59.96±26.86) minutes.The reperfusion rate of ≤6 h thrombolysis group was significantly higher than in 6-12 hours group (90.3% (988/1094) vs. 80.8% (101/125), P=0.001), while in-hospital mortality (2.6%(28/1 094) and 0.8% (1/125), P=0.352) and rate of bleeding (5.9%(64/1 094) and 5.6%(7/125), P=0.910) were similar between the two groups. The total in-hospital mortality after thrombolysis was 2.4% (29/1219), which was significantly higher in failed recanalization group than in recanalization group (10.8%(14/130) vs. 1.4%(15/1089), P< 0.001). The total rate of bleeding after thrombolysis was 5.8% (71/1219), there were 3 severe bleeding cases according to GUSTO classification (0.2%), all of them were cerebral hemorrhage, and 2 out of 3 cases died. Conclusions: Reteplase use is related to high recanalization rate and low cardiovascular events and bleeding rate and our results thus show that reteplase is a safe and effective thrombolytic agent for STEMI patients.

Curative effect and safety of intrathecal transplantation of neural stem cells for the treatment of cerebral hemorrhage.

In this study, we aimed to explore the curative effect and safety of neural stem cell intrathecal transplantation for the treatment of cerebral hemorrhage. We transplanted 4.0 x 10(8) neural stem cells per procedure into the subarachnoid space by lumbar puncture 7 days after cerebral hemorrhage, twice a week, a total of 4 times. NIHSS scores and brain CT scans were conducted to assess neural functions and the volume of perihematoma lesions in patients on days 1, 7, 14, 21, and 28. We found that the NIHSS scores and the volume of the perihematoma lesions were significantly reduced after day 14. The differences before and after treatment were highly significant in intra- and between-group comparisons (P < 0.05). There were no adverse reactions, except for transient fever and shivering in a few patients. Our data suggest that the use of neural stem cells in intrathecal transplantation for the treatment of cerebral hemorrhage is safe and effective.

[Distribution and seasonal fluctuation of visceral leishmaniasis vectors sandflie in Lüliang City of Shanxi Province in 2023].

OBJECTIVE: To investigate the distribution and seasonal fluctuations of visceral leishmaniasis vectors sandflies in Lüliang City, Shanxi Province, so as to provide insights into assessment of the visceral leishmaniasis transmission risk and formulation of visceral leishmaniasis control measures. METHODS: A total of 12 natural villages were sampled from Shilou County, Lishi District, Lanxian County, Linxian County and Wenshui County in Lüliang City, Shanxi Province from June to September, 2023, and sandflies were captured using light traps from 7 breeding habitats, including farmers' houses, sheep pens, cattle pens, chicken coops, pig pens, mule and horse pens, and loess-cave dwellings. Following morphological identification of the sandfly species, the distribution of sandflies and the seasonal fluctuations of the sandfly density were analyzed. In addition, the Leishmania was detected in sandflies using a real-time fluorescence quantitative PCR assay. RESULTS: A total of 2 831 sandflies were captured with 156 light traps in Lüliang City from June to September, 2023, including 2 638 female sandflies (93.18%) and 193 male sandflies (6.82%), and the average density was 16.91 sandflies/(light-night). The seasonal fluctuations of the sandfly density all appeared a unimodal distribution in all survey sites, and the sandfly density peaked in July and then declined rapidly. Among all types of breeding habitats, the greatest sandfly density was found in sheep pens [39.04 sandflies/(light-night)]. In addition, 4.08% (2/49) of the sandfly samples were tested positive for Leishmania nucleic acid as revealed by the real-time fluorescence quantitative PCR assay. CONCLUSIONS: Sandflies were widely distributed in Lüliang City, Shanxi Province in 2023, and the peak of the sandfly density was observed in July, which had a visceral leishmaniasis transmission risk. Intensified surveillance of visceral leishmaniasis and sandfly vectors is required and targeted vector control is recommended.

Influence of protective clothing and masks on facial trustworthiness in an investment game: insights from a Chinese population study.

Facial features are important sources of information about perceived trustworthiness. Masks and protective clothing diminish the visibility of facial cues by either partially concealing the mouth and nose or covering the entire face. During the pandemic, the use of personal protective equipment affected and redefined who trusts whom in society. This study used the classical investment game of interpersonal trust with Chinese participants to explore the impact of occlusion on interpersonal trust. Faces with moderate initial trustworthiness were occluded by a mask or protective clothing in Experiment 1 and were digitally occluded by a square in Experiment 2, and faces with three levels of initial trustworthiness were occluded by a mask in Experiment 3. Results showed that both undergraduates (Experiment 1a) and non-student adults (Experiment 1b) perceived the faces with protective clothing as more trustworthy than faces wearing standard masks and faces not wearing masks. Faces with the top halves showing were perceived as trustworthy as full faces, while faces with the bottom halves showing were perceived as less trustworthy. The effect of masks is weak and complex. Masks reduced participants' trust in faces with high initial trustworthiness, had no effect on faces with low and moderate initial trustworthiness, and only slightly increased the trust of undergraduates in faces with moderate initial trustworthiness. Our findings indicate that the lack of information caused by occlusion and the social significance associated with occlusion collectively affect people's trust behavior in Chinese society. We believe the findings of this study will be useful in elucidating the effects of personal protective equipment usage on perceptions of trustworthiness.

Racial salience modulated the face race lightness illusion: A comparative study of Caucasians and Asians.

Previous research has demonstrated the existence of the face race lightness (FRL) illusion. It indicates that Black faces tend to appear darker than White faces, even when their luminance values are objectively adjusted to be the same. However, the debate over the exclusive influence of face-race categories on the FRL illusion continues, with the impact of racial groups on the illusion remaining relatively unexplored. To address these gaps, we conducted studies to investigate whether the FRL illusion varies in terms of racial salience and racial groups. We manipulated the racial salience by altering the orientation of the faces. A total of 64 Caucasians (Study 1) and 63 Asians (Study 2) were recruited. Participants were shown pairs of faces in rapid succession and were asked to report which face appeared lighter or darker. In each trial, the two faces belonged to the same race category: Black, Black-White ambiguous, or White. The luminance of the first face remained consistent across trials while the luminance of the second face varied and was adjusted across eight levels (- 20, - 12, - 8, - 4, + 4, + 8, + 12, + 20). Our findings reveal that the FRL illusion is largely dependent on the salience of face-race information. When faces were presented upright, the FRL illusion was prominent; however, it disappeared when faces were inverted. Remarkably, the FRL illusion was observed not only in Caucasians but also in Asians. Therefore, our results suggest that the FRL illusion primarily stems from race salience rather than participants' racial groups.

Comprehensive workflow and its validation for simulating diffuse speckle statistics for optical blood flow measurements.

Diffuse optical methods including speckle contrast optical spectroscopy and tomography (SCOS and SCOT), use speckle contrast (κ) to measure deep blood flow. In order to design practical systems, parameters such as signal-to-noise ratio (SNR) and the effects of limited sampling of statistical quantities, should be considered. To that end, we have developed a method for simulating speckle contrast signals including effects of detector noise. The method was validated experimentally, and the simulations were used to study the effects of physical and experimental parameters on the accuracy and precision of κ. These results revealed that systematic detector effects resulted in decreased accuracy and precision of κ in the regime of low detected signals. The method can provide guidelines for the design and usage of SCOS and/or SCOT instruments.

A high-density diffuse optical tomography dataset of naturalistic viewing.

Traditional laboratory tasks offer tight experimental control but lack the richness of our everyday human experience. As a result many cognitive neuroscientists have been motivated to adopt experimental paradigms that are more natural, such as stories and movies. Here we describe data collected from 58 healthy adult participants (aged 18-76 years) who viewed 10 minutes of a movie (The Good, the Bad, and the Ugly, 1966). Most (36) participants viewed the clip more than once, resulting in 106 sessions of data. Cortical responses were mapped using high-density diffuse optical tomography (first- through fourth nearest neighbor separations of 1.3, 3.0, 3.9, and 4.7 cm), covering large portions of superficial occipital, temporal, parietal, and frontal lobes. Consistency of measured activity across subjects was quantified using intersubject correlation analysis. Data are provided in both channel format (SNIRF) and projected to standard space (NIfTI), using an atlas-based light model. These data are suitable for methods exploration as well as investigating a wide variety of cognitive phenomena.

Out of America: tracing the genetic footprints of the global diffusion of maize.

Maize was first domesticated in a restricted valley in south-central Mexico. It was diffused throughout the Americas over thousands of years, and following the discovery of the New World by Columbus, was introduced into Europe. Trade and colonization introduced it further into all parts of the world to which it could adapt. Repeated introductions, local selection and adaptation, a highly diverse gene pool and outcrossing nature, and global trade in maize led to difficulty understanding exactly where the diversity of many of the local maize landraces originated. This is particularly true in Africa and Asia, where historical accounts are scarce or contradictory. Knowledge of post-domestication movements of maize around the world would assist in germplasm conservation and plant breeding efforts. To this end, we used SSR markers to genotype multiple individuals from hundreds of representative landraces from around the world. Applying a multidisciplinary approach combining genetic, linguistic, and historical data, we reconstructed possible patterns of maize diffusion throughout the world from American "contribution" centers, which we propose reflect the origins of maize worldwide. These results shed new light on introductions of maize into Africa and Asia. By providing a first globally comprehensive genetic characterization of landraces using markers appropriate to this evolutionary time frame, we explore the post-domestication evolutionary history of maize and highlight original diversity sources that may be tapped for plant improvement in different regions of the world.

Facial dominance augments perceived proximity: Evidence from a visual illusion.

Dominance is a major organizing principle of human societies that impacts a wide range of human behaviors, from gaze-following to voting choices. Here, we examined how dominance modulates a fundamental perceptual ability: the perception of proximity. We used the "Fat Face" illusion, a novel paradigm that measures perceived proximity implicitly. The illusion depicts a phenomenon that occurs when two identical faces are aligned vertically (one above the other) and the bottom face consistently appears larger. This illusion suggests that our visual system uses a vertical layout to infer the relative proximity of faces, so that the bottom face appears closer, and is thereby perceived as larger than the top one. We found that the illusion was larger for dominant than for submissive faces (Experiment 1). Moreover, when a dominant face was presented below a submissive one, participants reported a larger illusion than when a dominant face was above a submissive face (Experiments 2a and 2b). These findings suggest that dominant faces are perceived to be closer to observers than submissive faces. Furthermore, we found a stronger illusion for other-race faces as opposed to own-race faces, suggesting that we also misperceive other-race faces as closer than own-race faces. Together, these findings suggest that the visual system is highly sensitive to self-relevant, potentially threatening stimuli (e.g., dominant faces and other-race individuals) in the environment by misperceiving them as closer. In line with the recently proposed threat-signal hypothesis, this mechanism may allow for rapid and adaptive behaviors in our everyday social interactions. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

New insights on the luminescence properties and Judd-Ofelt analysis of Er-doped ZnO semiconductor quantum dots.

In this study, Er3+ doped ZnO semiconductor quantum dots (QDs) were synthesized using a wet chemical method. The successful doping of Er3+ ions into the ZnO host lattice and the elemental composition was confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The ZnO and Er3+ doped ZnO QDs with a hexagonal structure, spherical shape, and particle size of approximately 5 nm were revealed by XRD and transmission electron microscopy (TEM). The absorption, luminescence properties, and fluorescence lifetimes of the samples were studied as the concentration of Er3+ ions varied. The intensity parameters, emission transition probabilities, branching ratios, and emission lifetimes of the excited levels of Er3+ ions in the ZnO host were determined using the Judd-Ofelt theory, which provided insight into the covalent relationship between the ions and ligands as well as the nature of the ZnO host lattice. Moreover, the energy transfer process from the ZnO host to Er3+ ions and the yield of this process are explained in detail along with specific calculations. The Er3+ doped ZnO QDs displayed a significantly longer lifetime than undoped ZnO, which opens up many potential applications in fields such as photocatalysis, optoelectronics, photovoltaics, and biosensing.

Controlling the optical and magnetic properties of CdTeSe and Gd-doped CdTeSe alloy semiconductor nanocrystals.

In this study, CdTexSe1-x (0 ≤ x ≤ 1) and CdTeSe:Gd y% (y = 0-8.05) alloy semiconductor nanocrystals (NCs) were prepared by wet chemical method. The presence and composition of the elements in the sample were determined by energy dispersive X-ray (EDX) spectroscopy and X-ray photoelectron spectroscopy (XPS). Structural analysis of X-ray diffraction (XRD) patterns indicated that most NCs crystallized in the zinc blende (ZB) structure however some Gd-doped NCs (y = 4.52 and 8.05%) crystallized in the wurtzite (WZ) structure. The emission peak of CdTexSe1-x (0 ≤ x ≤ 1) NCs varied over a wide range when changing x while the particle size remained almost unchanged. The effect of Gd doping on the structure and optical and magnetic properties of CdTeSe NCs was studied in detail. When the Gd concentration increases from 0-8.05%: (i) the structure of CdTeSe NCs gradually changed from ZB to WZ, (ii) the emission efficiency of the material was significantly reduced, (iii) the PL lifetime of samples increased more than 10 times, and (iv) the ferromagnetic properties of the material were enhanced. The research findings demonstrated that it is possible to control the crystal structure, optical characteristics, and magnetic properties of Gd-doped CdTeSe nanocrystals by adjusting the dopant concentration and chemical composition of the host material.

A comprehensive workflow and its validation for simulating diffuse speckle statistics for optical blood flow measurements.

Diffuse optical methods including speckle contrast optical spectroscopy and tomography (SCOS and SCOT), use speckle contrast (κ) to measure deep blood flow. In order to design practical systems, parameters such as signal-to-noise ratio (SNR) and the effects of limited sampling of statistical quantities, should be considered. To that end, we have developed a method for simulating speckle contrast signals including effects of detector noise. The method was validated experimentally, and the simulations were used to study the effects of physical and experimental parameters on the accuracy and precision of κ. These results revealed that systematic detector effects resulted in decreased accuracy and precision of κ in the regime of low detected signals. The method can provide guidelines for the design and usage of SCOS and/or SCOT instruments.