Wide-field computational imaging of pathology slides using lens-free on-chip microscopy

Optical examination of microscale features in pathology slides is one of the gold standards to diagnose disease. However, the use of conventional light microscopes is partially limited owing to their relatively high cost, bulkiness of lens-based optics, small field of view (FOV), and requirements for lateral scanning and three-dimensional (3D) focus adjustment. We illustrate the performance of a computational lens-free, holographic on-chip microscope that uses the transport-of-intensity equation, multi-height iterative phase retrieval, and rotational field transformations to perform wide-FOV imaging of pathology samples with comparable image quality to a traditional transmission lens-based microscope. The holographically reconstructed image can be digitally focused at any depth within the object FOV (after image capture) without the need for mechanical focus adjustment and is also digitally corrected for artifacts arising from uncontrolled tilting and height variations between the sample and sensor planes. Using this lens-free on-chip microscope, we successfully imaged invasive carcinoma cells within human breast sections, Papanicolaou smears revealing a high-grade squamous intraepithelial lesion, and sickle cell anemia blood smears over a FOV of 20.5 mm(2). The resulting wide-field lens-free images had sufficient image resolution and contrast for clinical evaluation, as demonstrated by a pathologist's blinded diagnosis of breast cancer tissue samples, achieving an overall accuracy of ~99%. By providing high-resolution images of large-area pathology samples with 3D digital focus adjustment, lens-free on-chip microscopy can be useful in resource-limited and point-of-care settings.

Pixel super-resolution using wavelength scanning

Undersampling and pixelation affect a number of imaging systems, limiting the resolution of the acquired images, which becomes particularly significant for wide-field microscopy applications. Various super-resolution techniques have been implemented to mitigate this resolution loss by utilizing sub-pixel displacements in the imaging system, achieved, for example, by shifting the illumination source, the sensor array and/or the sample, followed by digital synthesis of a smaller effective pixel by merging these sub-pixel-shifted low-resolution images. Herein, we introduce a new pixel super-resolution method that is based on wavelength scanning and demonstrate that as an alternative to physical shifting/displacements, wavelength diversity can be used to boost the resolution of a wide-field imaging system and significantly increase its space-bandwidth product. We confirmed the effectiveness of this new technique by improving the resolution of lens-free as well as lens-based microscopy systems and developed an iterative algorithm to generate high-resolution reconstructions of a specimen using undersampled diffraction patterns recorded at a few wavelengths covering a narrow spectrum (10-30 nm). When combined with a synthetic-aperture-based diffraction imaging technique, this wavelength-scanning super-resolution approach can achieve a half-pitch resolution of 250 nm, corresponding to a numerical aperture of ~1.0, across a large field of view (>20 mm²). We also demonstrated the effectiveness of this approach by imaging various biological samples, including blood and Papanicolaou smears. Compared with displacement-based super-resolution techniques, wavelength scanning brings uniform resolution improvement in all directions across a sensor array and requires significantly fewer measurements. This technique would broadly benefit wide-field imaging applications that demand larger space-bandwidth products.

Field-portable pixel super-resolution colour microscope

Based on partially-coherent digital in-line holography, we report a field-portable microscope that can render lensfree colour images over a wide field-of-view of e.g., >20 mm(2). This computational holographic microscope weighs less than 145 grams with dimensions smaller than 17×6×5 cm, making it especially suitable for field settings and point-of-care use. In this lensfree imaging design, we merged a colorization algorithm with a source shifting based multi-height pixel super-resolution technique to mitigate 'rainbow' like colour artefacts that are typical in holographic imaging. This image processing scheme is based on transforming the colour components of an RGB image into YUV colour space, which separates colour information from brightness component of an image. The resolution of our super-resolution colour microscope was characterized using a USAF test chart to confirm sub-micron spatial resolution, even for reconstructions that employ multi-height phase recovery to handle dense and connected objects. To further demonstrate the performance of this colour microscope Papanicolaou (Pap) smears were also successfully imaged. This field-portable and wide-field computational colour microscope could be useful for tele-medicine applications in resource poor settings.

Reliability and validity of the Persian version of Foot and Ankle Ability Measure (FAAM) to measure functional limitations in patients with foot and ankle disorders

OBJECTIVE

To translate the Foot and Ankle Ability Measure (FAAM) into Persian and to evaluate the psychometric properties of the Persian version of FAAM.

METHODS

93 patients with a range of foot and ankle disorders, completed the Persian version of the FAAM and Short-Form 36 Health Survey (SF-36) in the test session. With an interval of 2-6 days, 60 patients filled out the FAAM in the retest session. The FAAM is composed of two subscales including activities of daily living (ADL) and SPORTS. Internal consistency was assessed using Cronbach's alpha, test-retest reliability using intraclass correlation coefficient (ICC) and standard error of measurement (s.e.m.), item internal consistency and discriminant validity using Spearman's correlation coefficient and construct validity using Spearman's correlation coefficient and Independent t-test.

RESULTS

Cronbach's alpha coefficient of 0.97 and 0.94 was obtained for ADL and SPORTS subscales, respectively. The ICC and s.e.m. were 0.98 and 3.13 for ADL and 0.98 and 3.53 for SPORTS subscale. Items were stronger measures of their hypothesized subscale than of other subscale. The ADL and SPORTS subscales had stronger correlation with SF-36 physical function (r=0.60, 0.53) and physical health summary measure (r=0.61, 0.48) than with SF-36 mental health (r=0.21, 0.10) and mental health summary measure (r=0.36, 0.27). A high correlation was found between FAAM scores and global scale of functional status for SPORTS (r=0.73) but not for ADL (r=0.42). FAAM scores were greater in individuals who rated their function as normal or nearly normal compared with those who rated as abnormal or severely abnormal for SPORTS (P=0.04) but not for ADL (P=0.15).

CONCLUSION

The Persian version of FAAM is a reliable and valid measure to quantify physical functioning in patients with foot and ankle disorders.

High-throughput and label-free single nanoparticle sizing based on time-resolved on-chip microscopy

Sizing individual nanoparticles and dispersions of nanoparticles provides invaluable information in applications such as nanomaterial synthesis, air and water quality monitoring, virology, and medical diagnostics. Several conventional nanoparticle sizing approaches exist; however, there remains a lack of high-throughput approaches that are suitable for low-resource and field settings, i.e., methods that are cost-effective, portable, and can measure widely varying particle sizes and concentrations. Here we fill this gap using an unconventional approach that combines holographic on-chip microscopy with vapor-condensed nanolens self-assembly inside a cost-effective hand-held device. By using this approach and capturing time-resolved in situ images of the particles, we optimize the nanolens formation process, resulting in significant signal enhancement for the label-free detection and sizing of individual deeply subwavelength particles (smaller than λ/10) over a 30 mm(2) sample field-of-view, with an accuracy of ±11 nm. These time-resolved measurements are significantly more reliable than a single measurement at a given time, which was previously used only for nanoparticle detection without sizing. We experimentally demonstrate the sizing of individual nanoparticles as well as viruses, monodisperse samples, and complex polydisperse mixtures, where the sample concentrations can span ∼5 orders-of-magnitude and particle sizes can range from 40 nm to millimeter-scale. We believe that this high-throughput and label-free nanoparticle sizing platform, together with its cost-effective and hand-held interface, will make highly advanced nanoscopic measurements readily accessible to researchers in developing countries and even to citizen-scientists, and might especially be valuable for environmental and biomedical applications as well as for higher education and training programs.

Alterations of tumor microenvironment by carbon monoxide impedes lung cancer growth

We hypothesized that tumor-associated macrophages (TAMs) are controlled by the diffusible gas carbon monoxide (CO). We demonstrate that induction of apoptosis in lung tumors treated with low doses of CO is associated with increased CD86 expression and activation of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinases (Erk) 1/2 pathway in tumor microenvironment. Presence of CD86-positive cells was required for the anti-tumoral effects of CO in established A549 xenografts. We show that the effects of CO on tumor stroma and reprogramming of macrophages towards the anti-tumoral phenotype is mediated by reactive oxygen species (ROS)-dependent activation of MAPK/Erk1/2-c-myc pathway as well as Notch 1-dependent negative feedback on the metabolic enzyme heme oxygenase-1 (HO-1). We find a similar negative correlation between HO-1 and active MAPK-Erk1/2 levels in human lung cancer specimens.

In summary, we describe novel non-cell autonomous mechanisms by which the diffusible gas CO dictates changes in the tumor microenvironment through the modulation of macrophages.

Total, dietary, and supplemental calcium intake and mortality from all-causes, cardiovascular disease, and cancer: A meta-analysis of observational studies

AIMS

This systematic review and meta-analysis of observational studies was conducted to summarize the evidence on the association between calcium intake and mortality.

METHODS AND RESULTS

PubMed, Institute for Scientific Information (ISI) (Web of Science), SCOPUS, SciRUS, Google Scholar, and Excerpta Medica dataBASE (EMBASE) were searched to identify related articles published through May 2014. We found 22 articles that assessed the association between total, dietary, and supplementary intake with mortality from all-causes, cardiovascular disease (CVD), and cancer. Findings from this meta-analysis revealed no significant association between total and dietary calcium intake and mortality from all-causes, CVD, and cancer. Subgroup analysis by the duration of follow-up revealed a significant positive association between total calcium intake and CVD mortality for cohort studies with a mean follow-up duration of >10 years (relative risk (RR): 1.35; 95% confidence interval (CI): 1.09-1.68). A significant inverse association was seen between dietary calcium intake and all-cause (RR: 0.84; 95% CI: 0.70-1.00) and CVD mortality (RR: 0.88; 95% CI: 0.78-0.99) for studies with a mean follow-up duration of ≤10 years. Although supplemental calcium intake was not associated with CVD (RR: 0.95; 95% CI: 0.82-1.10) and cancer mortality (RR: 1.22; 95% CI: 0.81-1.84), it was inversely associated with the risk of all-cause mortality (RR: 0.91; 95% CI: 0.88-0.94).

CONCLUSIONS

We found a significant relationship between the total calcium intake and an increased risk of CVD mortality for studies with a long follow-up time and a significant protective association between dietary calcium intake and all-cause and CVD mortality for studies with a mean follow-up of ≤10 years. Supplemental calcium intake was associated with a decreased risk of all-cause mortality.

The effect of antioxidant vitamins E and C on cognitive performance of the elderly with mild cognitive impairment in Isfahan, Iran: a double-blind, randomized, placebo-controlled trial

PURPOSE

This study was carried out to investigate the effect of vitamins E and C on cognitive performance among the elderly in Iran.

METHODS

About 256 elderly with mild cognitive impairment, aged 60-75 years, received 300 mg of vitamin E plus 400 mg of vitamin C or placebo daily just for 1 year.

BACKGROUND

Demographic characteristics, anthropometric variables food consumption, cognitive function by Mini-Mental State Examination (MMSE), and some of the oxidative stress biomarkers were examined.

RESULTS

Antioxidant supplementation reduced malondialdehyde level (P < 0.001) and raised total antioxidant capacity (P < 0.001) and glutathione (P < 0.01). The serum 8-hydroxydeoxyguanosine remained unchanged (P < 0.4). After adjusting for the covariates effects, MMSE scores following 6- (25.88 ± 0.17) and 12-month antioxidant supplementation (26.8 ± 0.17) did not differ from control group (25.86 ± 0.18 and 26.59 ± 0.18, respectively).

CONCLUSION

Despite significant improvement in most of the oxidative stress biomarkers, antioxidants' supplementation was not observed to enhance cognitive performance. A large number of kinetic and/or dynamic factors could be suspected.

Rapid, portable and cost-effective yeast cell viability and concentration analysis using lensfree on-chip microscopy and machine learning

Monitoring yeast cell viability and concentration is important in brewing, baking and biofuel production. However, existing methods of measuring viability and concentration are relatively bulky, tedious and expensive. Here we demonstrate a compact and cost-effective automatic yeast analysis platform (AYAP), which can rapidly measure cell concentration and viability. AYAP is based on digital in-line holography and on-chip microscopy and rapidly images a large field-of-view of 22.5 mm². This lens-free microscope weighs 70 g and utilizes a partially-coherent illumination source and an opto-electronic image sensor chip. A touch-screen user interface based on a tablet-PC is developed to reconstruct the holographic shadows captured by the image sensor chip and use a support vector machine (SVM) model to automatically classify live and dead cells in a yeast sample stained with methylene blue. In order to quantify its accuracy, we varied the viability and concentration of the cells and compared AYAP's performance with a fluorescence exclusion staining based gold-standard using regression analysis. The results agree very well with this gold-standard method and no significant difference was observed between the two methods within a concentration range of 1.4 × 10⁵ to 1.4 × 10⁶ cells per mL, providing a dynamic range suitable for various applications. This lensfree computational imaging technology that is coupled with machine learning algorithms would be useful for cost-effective and rapid quantification of cell viability and density even in field and resource-poor settings.

Air quality monitoring using mobile microscopy and machine learning

Rapid, accurate and high-throughput sizing and quantification of particulate matter (PM) in air is crucial for monitoring and improving air quality. In fact, particles in air with a diameter of ≤2.5 μm have been classified as carcinogenic by the World Health Organization. Here we present a field-portable cost-effective platform for high-throughput quantification of particulate matter using computational lens-free microscopy and machine-learning. This platform, termed c-Air, is also integrated with a smartphone application for device control and display of results. This mobile device rapidly screens 6.5 L of air in 30 s and generates microscopic images of the aerosols in air. It provides statistics of the particle size and density distribution with a sizing accuracy of ~93%. We tested this mobile platform by measuring the air quality at different indoor and outdoor environments and measurement times, and compared our results to those of an Environmental Protection Agency-approved device based on beta-attenuation monitoring, which showed strong correlation to c-Air measurements. Furthermore, we used c-Air to map the air quality around Los Angeles International Airport (LAX) over 24 h to confirm that the impact of LAX on increased PM concentration was present even at >7 km away from the airport, especially along the direction of landing flights. With its machine-learning-based computational microscopy interface, c-Air can be adaptively tailored to detect specific particles in air, for example, various types of pollen and mold and provide a cost-effective mobile solution for highly accurate and distributed sensing of air quality.

The effect of cognitive behavioural psycho-education on premenstrual syndrome and related symptoms

Premenstrual syndrome (PMS) is a distressing group of symptoms related to menstrual cycle during reproductive age. Its substantial burden on daily function and quality of life, particularly on mental aspects, was to the impetus for this study with the aim of determining the effectiveness of a psycho-educational package on premenstrual syndrome and related symptoms. In a randomized clinical trial, 123 (17-19-year-old) adolescent girls with PMS were randomized to psycho-educational intervention (including 62 subjects) and control (including 61) groups. The participants completed a demographic questionnaire, premenstrual syndrome symptom daily record scale and the Symptom Checklist-90-Revised (SCL-90-R). A paired and two independent samples t-test and chi-squared test were used for analysing data using SPSS statistical package. At the end of the study there was statistically significant decrease in severity of total PMS in intervention compared with control group (P < 0.001). Also, a significant difference in somatization, anxiety and hostility was observed between two groups (P < 0.05). However, depression marginally decreased (P < 0.1) in intervention group, and interpersonal sensitivity was not statistically different between intervention and control groups. Intervention alleviated the severity of PMS and related somatization, anxiety and hostility, yet it could not change the severity of depression and interpersonal sensitivity.

Patterns of diet-related practices and prevalence of gastro-esophageal reflux disease

BACKGROUND

No studies have evaluated associations between patterns of diet-related practices as determined by latent class analysis (LCA) and gastro-esophageal reflux disease (GERD). We aimed to assess this relationship in a large sample of Iranian adults.

METHODS

In a cross-sectional study in 4763 adults, diet-related practices were assessed in four domains, 'meal pattern', 'eating rate', 'intra-meal fluid intake', and 'meal-to-sleep interval', using a pretested questionnaire. LCA was applied to identify classes of diet-related practices. We defined GERD as the presence of heartburn sometimes, often or always.

KEY RESULTS

The prevalence of GERD in the study population was 23.5% (n = 1120). We identified two distinct classes of meal patterns: 'regular' and 'irregular', three classes of eating rates: 'moderate', 'moderate-to-slow', and 'moderate-to-fast', two major classes of fluid ingestion with meals: 'moderate' and 'much intra-meal drinking', and two classes regarding the interval between meals and sleeping: 'short' and 'long meal-to-sleep' interval. After adjustment for potential confounders, subjects with 'irregular meal pattern' had higher odds of GERD compared with subjects with 'regular meal pattern' (OR: 1.21; 1.00-1.46). However, when taking into account BMI, the association disappeared. 'Long meal-to-sleep interval' was inversely associated with GERD compared with 'short meal-to-sleep interval' (OR: 0.73; 95% CI: 0.57-0.95). 'Eating rate' and 'intra-meal fluid intake' were not significantly associated with GERD.

CONCLUSIONS & INFERENCES

Our data suggest certain associations between dietary patterns and GERD. These findings warrant evaluation in prospective studies to establish the potential value of modifications in dietary behaviors for the management of GERD.

Wide-field computational color imaging using pixel super-resolved on-chip microscopy

Lens-free holographic on-chip imaging is an emerging approach that offers both wide field-of-view (FOV) and high spatial resolution in a cost-effective and compact design using source shifting based pixel super-resolution. However, color imaging has remained relatively immature for lens-free on-chip imaging, since a 'rainbow' like color artifact appears in reconstructed holographic images. To provide a solution for pixel super-resolved color imaging on a chip, here we introduce and compare the performances of two computational methods based on (1) YUV color space averaging, and (2) Dijkstra's shortest path, both of which eliminate color artifacts in reconstructed images, without compromising the spatial resolution or the wide FOV of lens-free on-chip microscopes. To demonstrate the potential of this lens-free color microscope we imaged stained Papanicolaou (Pap) smears over a wide FOV of ~14 mm(2) with sub-micron spatial resolution.

Efficacy and safety of oral insulin compared to subcutaneous insulin: a systematic review and meta-analysis

INTRODUCTION

A systematic review and meta-analysis of interventional studies was conducted to compare the efficacy and safety of oral insulin versus subcutaneous (SC) insulin in diabetic patients.

METHODS

Medline, Scopus, ISI Web of Knowledge and Cochrane Central Register of Controlled Trials were searched. Two independent reviewers evaluated studies for eligibility and quality and extracted the data. The primary outcomes were fasting blood glucose (FBG), 1h and 2h postprandial blood glucose, HbA1c, AUC of insulin, C max and T max of insulin, and T max of glucose infusion rate. Secondary outcomes were adverse events.

RESULTS

Eleven studies (n = 373) met the inclusion criteria. Meta-analyses showed that there is no significant difference between oral and SC insulin in controlling HbA1c, FBG, 1 and 2 h postprandial blood glucose and producing C max of insulin (P > 0.05); however oral insulin had faster action as indicated by the shorter T max, compared to SC insulin (P < 0.05). The most included studies were varied in their methodological quality.

CONCLUSION

This systematic review and meta-analysis showed that oral insulin is comparable to SC insulin with regard to glycemic efficacy and safety. However, is necessary to conduct additional studies in which oral insulin administered to large number of patients for long enough periods of time.

Computational cytometer based on magnetically modulated coherent imaging and deep learning

Detecting rare cells within blood has numerous applications in disease diagnostics. Existing rare cell detection techniques are typically hindered by their high cost and low throughput. Here, we present a computational cytometer based on magnetically modulated lensless speckle imaging, which introduces oscillatory motion to the magnetic-bead-conjugated rare cells of interest through a periodic magnetic force and uses lensless time-resolved holographic speckle imaging to rapidly detect the target cells in three dimensions (3D). In addition to using cell-specific antibodies to magnetically label target cells, detection specificity is further enhanced through a deep-learning-based classifier that is based on a densely connected pseudo-3D convolutional neural network (P3D CNN), which automatically detects rare cells of interest based on their spatio-temporal features under a controlled magnetic force. To demonstrate the performance of this technique, we built a high-throughput, compact and cost-effective prototype for detecting MCF7 cancer cells spiked in whole blood samples. Through serial dilution experiments, we quantified the limit of detection (LoD) as 10 cells per millilitre of whole blood, which could be further improved through multiplexing parallel imaging channels within the same instrument. This compact, cost-effective and high-throughput computational cytometer can potentially be used for rare cell detection and quantification in bodily fluids for a variety of biomedical applications.

Dietary glycaemic index and glycaemic load and upper gastrointestinal disorders: results from the SEPAHAN study

BACKGROUND

Little is known about the effects of carbohydrate, particularly any association between dietary glycaemic index or glycaemic load and uninvestigated heartburn or uninvestigated chronic dyspepsia in the community. The present study aimed to determine associations between dietary glycaemic index or glycaemic load and uninvestigated heartburn or uninvestigated chronic dyspepsia.

METHODS

This cross-sectional study was conducted in 2987 adults. Dietary glycaemic index and glycaemic load were estimated using a validated food-frequency questionnaire. Uninvestigated heartburn and uninvestigated chronic dyspepsia were determined using a modified and validated version of the Rome III questionnaire.

RESULTS

After controlling for various confounders, high glycaemic load was associated with an increased risk of uninvestigated heartburn [odds ration (OR) = 1.75; 95% confidence interval CI = 1.03, 2.97; P = 0.04] and uninvestigated chronic dyspepsia (OR = 2.14; 95% CI: 1.04, 4.37; P = 0.04) in men but not in women. In normal-weight individuals, high glycaemic index was related to an increased risk of uninvestigated heartburn (OR = 1.52; 95% CI: 1.07, 2.15; P = 0.02) and high glycaemic load to an increased risk of uninvestigated chronic dyspepsia (OR=1.78; 95% CI: 1.05, 3.01; P = 0.03). No significant associations were observed in subjects with excess body weight.

CONCLUSIONS

Our data suggest that there are body mass index- and sex-specific associations between dietary carbohydrate quality with uninvestigated heartburn and uninvestigated chronic dyspepsia.

Monobody adapter for functional antibody display on nanoparticles for adaptable targeted delivery applications

Vascular endothelial cells (ECs) play a central role in the pathophysiology of many diseases. The use of targeted nanoparticles (NPs) to deliver therapeutics to ECs could dramatically improve efficacy by providing elevated and sustained intracellular drug levels. However, achieving sufficient levels of NP targeting in human settings remains elusive. Here, we overcome this barrier by engineering a monobody adapter that presents antibodies on the NP surface in a manner that fully preserves their antigen-binding function. This system improves targeting efficacy in cultured ECs under flow by >1000-fold over conventional antibody immobilization using amine coupling and enables robust delivery of NPs to the ECs of human kidneys undergoing ex vivo perfusion, a clinical setting used for organ transplant. Our monobody adapter also enables a simple plug-and-play capacity that facilitates the evaluation of a diverse array of targeted NPs. This technology has the potential to simplify and possibly accelerate both the development and clinical translation of EC-targeted nanomedicines.

Evaluation of Self-Perceived Changes in Gastrointestinal Symptoms During Ramadan Fasting

Little is known regarding the effects of Ramadan fasting on common gastrointestinal symptoms. The aim of this study was to assess the alterations of these symptoms in a healthy Iranian adult population during Ramadan. In a cross-sectional study, self-administered questionnaires were used to evaluate the alterations in seven groups of gastrointestinal symptoms (esophageal symptoms, dyspeptic symptoms, bloating and abdominal distension, constipation, diarrhea, abdominal pain, and nausea) after Ramadan. A total of 900 individuals participated in the study. Almost 87 % of participants reported to fast for at least 2 weeks during Ramadan. After adjusting for potential confounders, we found no relationship between alteration in frequency of gastrointestinal symptoms and Ramadan fasting, except for constipation which increased significantly after Ramadan fasting (odds ratio 1.99, 95 % confidence interval 1.05-3.80, P < 0.05). In addition, those who fasted for at least 2 weeks reported to experience severe or very severe constipation-related symptoms three times more in comparison with those who fasted for less than 2 weeks (P < 0.05). There was no relationship between severity of other gastrointestinal symptoms and Ramadan fasting. We found that Ramadan fasting does not increase frequency and severity of common gastrointestinal symptoms in the general population except for constipation that may be experienced more frequently and severely among those who fast for 2 weeks or more.

Accurate color imaging of pathology slides using holography and absorbance spectrum estimation of histochemical stains

Holographic microscopy presents challenges for color reproduction due to the usage of narrow-band illumination sources, which especially impacts the imaging of stained pathology slides for clinical diagnoses. Here, an accurate color holographic microscopy framework using absorbance spectrum estimation is presented. This method uses multispectral holographic images acquired and reconstructed at a small number (e.g., three to six) of wavelengths, estimates the absorbance spectrum of the sample, and projects it onto a color tristimulus. Using this method, the wavelength selection is optimized to holographically image 25 pathology slide samples with different tissue and stain combinations to significantly reduce color errors in the final reconstructed images. The results can be used as a practical guide for various imaging applications and, in particular, to correct color distortions in holographic imaging of pathology samples spanning different dyes and tissue types.

Oral health behaviours and oral health-related dietary behaviours: The interrelationship and determinants by latent class analysis

OBJECTIVE

This study aimed to investigate the level of oral health behaviours (OHB) and oral health-related dietary behaviours (OHD-B) and to find out their relationship and their determinants among a relatively large sample of university students. Research design and participants: In a cross-sectional study, 535 Iranian university students were selected in order to investigate their OHB and OHD-B through a self-administrated questionnaire.

MAIN OUTCOME MEASURES

Tooth brushing, flossing, use of fluoride toothpaste, and sugary snacking collected data on OHB. Consumption frequency of 16 common cariogenic and non-cariogenic foodstuffs was used for evaluation of OHD-B. Latent class analysis (LCA) and latent class regression (LCR) were applied to identify classes of OHB and OHD-B and their potential determinants, respectively. ANOVA, Chi-square and Spearman's correlation were used.

RESULTS

In total, 49.7% and 53.2% of participants had good OHB and OHD-B, respectively. The results of LCR indicated that female gender (OR: 8.22, 95% CI: 3.42-19.72), higher age (OR: 1.39, 95% CI: 1.04-1.85), doctorate level (OR: 6.99, 95% CI: 2.22-21.98), and being single (OR: 3.54, 95% CI: 1.36-9.19) were related to good OHB. Furthermore, LCR analysis showed that students who lived with their families had greater chance for having good OHD-B (OR: 3.01, 95% CI: 2.00-4.53). Students with good OHD-B reported brushing and flossing their teeth more frequently than those with poor OHD-B (P⟨0.05).

CONCLUSIONS

The shortage of favourable oral health behaviours among university students highlights the importance of planning oral health programs to improve their oral health, especially their dietary behaviours.

Frequency of bacteria causing urinary tract infections and their antimicrobial resistance patterns among pediatric patients in Western Iran from 2007-2009

Urinary Tract infections ( UTIs) are among the most common infections in infants and neonates. The aim of the current study was to evaluate the frequency of bacteria causing UTI and their relevant drug resistance patterns among infants and neonates hospitalized in Ilam province, Western Iran during 2007-2009. A total of 220 cases of UTI were enrolled in this cross-sectional retrospective study. A standard checklist was used for demographic and clinical data to be collected from their health records. Data was then analyzed using SPSS version 16.0. More than two-thirds (64.8%) of the cases were female. E. coli (44.5%), Klebsiella spp., (18.6%), Enterobacter spp., (15%) and Staphylococcus spp. (12.7%) were the most common microorganisms isolated from UTIs, respectively. High rates of resistance to tetracycline, ampicillin, and nalidixic acid were observed among these isolates. Similar to other studies, E. coli was the most common bacteria causing UTI and showed a high rate of resistance against most of the antimicrobial agents. Determining the antimicrobial sensitivity can be helpful for physicians in choosing an appropriate treatment for patients suffering from UTI, and also to reduce the complications related to serious UTI.

Fabricating Patient-Specific 3D Printed Drill Guides to Treat Femoral Head Avascular Necrosis

Background

Femoral head avascular necrosis (AVN), or death of femoral head tissue due to a lack of blood supply, is a leading cause of total hip replacement for non-geriatric patients. Core decompression (CD) is an effective treatment to re-establish blood flow for patients with AVN. Techniques aimed at improving its efficacy are an area of active research. We propose the use of 3D printed drill guides to accurately guide therapeutic devices for CD.

Methods

Using femur sawbones, image processing software, and 3D modeling software, we created a custom-built device with pre-determined drill trajectories and tested the feasibility of the 3D printed drill guides for CD. A fellowship trained orthopedic surgeon used the drill guide to position an 8 ga, 230 mm long decompression device in the three synthetic femurs. CT scans were taken of the sawbones with the drill guide and decompression device. CT scans were processed in the 3D modeling software. Descriptive statistics measuring the angular and needle-tip deviation were compared to the original virtually planned model.

Results

Compared to the original 3D model, the trials had a mean displacement of 1.440±1.03 mm and a mean angle deviation of 1.093±0.749°.

Conclusions

The drill guides were demonstrated to accurately guide the decompression device along its predetermined drill trajectory. Accuracy was assessed by comparing values to literature-reported values and considered AVN lesion size. This study demonstrates the potential use of 3D printing technology to improve the efficacy of CD techniques.

Fabricating patient-specific 3D printed drill guides to treat femoral head avascular necrosis

BACKGROUND

Femoral head avascular necrosis (AVN), or death of femoral head tissue due to a lack of blood supply, is a leading cause of total hip replacement for non-geriatric patients. Core decompression (CD) is an effective treatment to re-establish blood flow for patients with AVN. Techniques aimed at improving its efficacy are an area of active research. We propose the use of 3D printed drill guides to accurately guide therapeutic devices for CD.

METHODS

Using femur sawbones, image processing software, and 3D modeling software, we created a custom-built device with pre-determined drill trajectories and tested the feasibility of the 3D printed drill guides for CD. A fellowship trained orthopedic surgeon used the drill guide to position an 8 ga, 230 mm long decompression device in the three synthetic femurs. CT scans were taken of the sawbones with the drill guide and decompression device. CT scans were processed in the 3D modeling software. Descriptive statistics measuring the angular and needle-tip deviation were compared to the original virtually planned model.

RESULTS

Compared to the original 3D model, the trials had a mean displacement of 1.440 ± 1.03 mm and a mean angle deviation of 1.093 ± 0.749º.

CONCLUSIONS

The drill guides were demonstrated to accurately guide the decompression device along its predetermined drill trajectory. Accuracy was assessed by comparing values to literature-reported values and considered AVN lesion size. This study demonstrates the potential use of 3D printing technology to improve the efficacy of CD techniques.