Head Phantom Optical Properties Validation for Near-Infrared Measurements: A Comparison with Animal Tissue

The interest in optical healthcare technologies has increased significantly over the recent years. The innovation of new optical technologies such as Near Infrared Spectroscopy (NIRS), used for the monitoring of brain perfusion, demands a comprehensive understanding and knowledge of the light tissue interaction. Phantoms can provide a rigorous, reproducible and convenient approach for evaluating an optical sensor's performance. However, up to date literature does not provide a detailed description of a complete head model that involves the human anatomy, physiological changes, and the tissue optical properties. The latter is key for the design, development and testing of optical sensors, such as NIRS technologies. This paper compared the optical properties of the materials chosen to build a head phantom, against the optical properties of real brain and skull tissues extracted from animal models. The spectra of a silicone brain and resin skull samples were compared with the spectra of the respective tissues extracted from pigs and mice. The results of this study demonstrated that both phantom materials have similar optical properties to mice and pigs' tissues. The morphology of the phantom's spectra were very similar to the respective animal tissue comparator.

Telemedicine for international travelers through a Smartphone-based monitoring platform (Trip Doctor®)

BACKGROUND

Overall, more than 50% of international travelers develop symptoms while traveling and 55% of them seek medical assistance during the trip. We conducted a study to evaluate the usefulness of a Smartphone app called TRIP Doctor® to provide telemedicine to international travelers.

METHODS

Participants over 18 years old attending our travel clinic at Hospital Clinic in Barcelona were invited to participate during 2017-2019. After downloading the app, the health status of the traveler was monitored on a daily basis, providing specific medical advice and offering remote contact with specialized physicians through an integrated chat, if needed.

RESULTS

From 449 users, 59 (13%) contacted for medical assistance through the app during the trip. Main reasons for telemedicine were diarrhea (25.7%), skin conditions (19.7%) and fever (12.1%). Among patients who contacted, 90% of the travelers did not require to be referred to a local doctor. Symptomatic treatment was the main treatment prescribed (38%). In a 14.7% of the cases a follow-up was not required, a 63.2% recovered and 22.1% were loss of follow-up. After a multivariate analysis, duration of trip >14 days was found to be the only factor associated with the use of telemedicine (OR 2.2, CI 95% 1.1-4.5, p = 0.03).

CONCLUSION

In conclusion, travelers using telemedicine travelled for longer periods of time and mostly contacted for mild symptoms which could be solved successfully by remote assistance with our specialized doctors.

Brain Light-Tissue Interaction Modelling: Towards a non-invasive sensor for Traumatic Brain Injury

Traumatic brain injury (TBI) is one of the leading causes of death worldwide, yet there is no systematic approach to monitor TBI non-invasively. The main motivation of this work is to create new knowledge relating to light brain interaction using a Monte Carlo Model, which could aid in the development of non-invasive optical sensors for the continuous assessment of TBI. To this aim, a multilayer model tissue-model of adult human head was developed and explored at the near-infrared optical wavelength. Investigation reveals that maximum light (40-50%) is absorbed in the skull and the minimum light is absorbed in the subarachnoid space (0-1%). It was found that the absorbance of light decreases with increasing source-detector separation up to 3cm where light travels through the subarachnoid space, after which the absorbance increases with the increasing separation. Such information will be helpful towards the modelling of neurocritical brain tissue followed by the sensor development.

Real-time incidence of travel-related symptoms through a smartphone-based app remote monitoring system: a pilot study

Trip Doctor®, a Smartphone-based app monitoring system, was developed to detect infections among travelers in real-time. For testing, 106 participants were recruited (62.2% male, mean age 36 years (SD = 11)). Majority of trips were for tourism and main destinations were in South East Asia. Mean travel duration was 14 days (SD = 10). Diarrhea was the most frequently reported symptom (15.5%). The system demonstrated adequate usability and is ready to be used on a larger scale.

Synthetic magnetoelectric coupling in a nanocomposite multiferroic

Given the paucity of single phase multiferroic materials (with large ferromagnetic moment), composite systems seem an attractive solution to realize magnetoelectric coupling between ferromagnetic and ferroelectric order parameters. Despite having antiferromagnetic order, BiFeO₃ (BFO) has nevertheless been a key material due to excellent ferroelectric properties at room temperature. We studied a superlattice composed of 8 repetitions of 6 unit cells of La_0.7Sr_0.3MnO₃ (LSMO) grown on 5 unit cells of BFO. Significant net uncompensated magnetization in BFO, an insulating superlattice, is demonstrated using polarized neutron reflectometry. Remarkably, the magnetization enables magnetic field to change the dielectric properties of the superlattice, which we cite as an example of synthetic magnetoelectric coupling. Importantly, controlled creation of magnetic moment in BFO is a much needed path toward design and implementation of integrated oxide devices for next generation magnetoelectric data storage platforms.

Cyanobacteria-containing biofilms from a Mayan monument in Palenque, Mexico

Surfaces of buildings at the archaeological site of Palenque, Mexico, are colonized by cyanobacteria that form biofilms, which in turn cause aesthetic and structural damage. The structural characterization and species composition of biofilms from the walls of one of these buildings, El Palacio, are reported. The distribution of photosynthetic microorganisms in the biofilms, their relationship with the colonized substratum, and the three-dimensional structure of the biofilms were studied by image analysis. The differences between local seasonal microenvironments at the Palenque site, the bioreceptivity of stone and the relationship between biofilms and their substrata are described. The implications for the development and permanence of species capable of withstanding temporal heterogeneity in and on El Palacio, mainly due to alternating wet and dry seasons, are discussed. Knowledge on how different biofilms contribute to biodegradation or bioprotection of the substratum can be used to develop maintenance and conservation protocols for cultural heritage.

Energy expenditure during allogeneic and autologous bone marrow transplantation

Resting energy expenditure (REE) was measured by indirect calorimetry during allogeneic and autologous bone marrow transplantation in order to evaluate the evolution in allogeneic and autologous recipient patients. REE values obtained with indirect calorimetry and compared with values using the Harris-Benedict formula were different. Evolution of REE during aplasia were significantly different in autologous and allogeneic recipients with an increase 11.5 ' 10.8 cent for autologous and a decrease of - 7.3 ' 8.9 cent in allogeneic bone marrow transplantation (BMT) patients. There were no differences in nutritional status and REE before BMT, at discharge and 1 month after discharge between the two groups but all patients had inflicted damage on their nutritional status at discharge from hospital after BMT. However, these patients differed because of the decrease in oral nutritional intake and an increase in the length of aplasia and hospital stay in allogeneic patients. Currently, there is no proof that recommendations for nutritional interventions or results of nutritional investigations in allogeneic BMT can be extrapolated in autologous patients. Harris-Benedict formula does not estimate the energy expenditure of patients submitted to massive chemotherapy and BMT with enough precision because of the great differences in individuals.

Diagnosis of genital infection caused by human papillomavirus using in situ hybridisation: the importance of the size of the biopsy specimen

AIM

To determine the size of a cervical biopsy specimen with human papillomavirus (HPV) infection required to enable in situ hybridisation to be carried out with a guarantee of a reliable result.

METHODS

In situ hybridisation was carried out in 142 cervical uterine biopsy specimens classified histologically as low grade and high grade squamous intraepithelial lesions. Epithelial length at the level of the basal membrane was measured by image analysis. The specimens were divided into 10 groups based on epithelial length.

RESULTS

Of the biopsy specimens, 61.2% were HPV positive. In specimens with an epithelial length below 5 mm 31.9% were HPV positive; in those between 5 and 9 mm in length 67.5% were HPV positive; and in those greater than 9 mm in length 81.8% were positive for HPV. For low grade squamous intraepithelial lesions (n = 90), 68.4% of specimens with an epithelial length greater than 5 mm were HPV positive. For high grade squamous intraepithelial lesions (n = 52), 86.8% of specimens with an epithelial length greater than 5 mm were HPV positive.

CONCLUSIONS

For a diagnosis of HPV infection using in situ hybridisation, the minimum length of epithelium in a cervical biopsy specimen should be 5 mm. For high grade squamous intraepithelial lesions, specimens over 5 mm in length are suitable. For low grade squamous intraepithelial lesions, to minimise the number of false negative results, the ideal minimum length is 10 mm.

Effects of Boron on Proton Transport and Membrane Properties of Sunflower (Helianthus annuus L.) Cell Microsomes

Boron deficiency and toxicity inhibit ATP-dependent H+ pumping and vanadate-sensitive ATPase activity in sunflower roots and cell suspensions. The effects of boron on H+ pumping and on passive H+ conductance, as well as on fluorescence anisotropy in KI-washed microsomes isolated from sunflower (Helianthus annuus L. cv Enano) cell suspensions, have been investigated. Boron deficiency reduced the total and vanadate-sensitive ATPase activities as well as the vanadate-sensitive ATP-dependent H+ pumping without affecting the amount of antigenic ATPase protein as measured by immunoblotting with an Arabidopsis thaliana plasma membrane anti-H+-ATPase polyclonal antibody. Kinetic studies revealed that boron deficiency reduced Vmax of vanadate-sensitive ATPase activity with little change in the apparent Km for Mg2+-ATP. Proton leakage was greater in microsomal vesicles isolated from cells grown without boron and incubated in reaction medium without added boron, and this effect was reversed by addition of boron to the reaction medium. Fluorescence anisotropy indicated that diphenyl hexatriene and 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene probes were immobilized to a greater extent in microsomes from cells grown without boron than in those from cells grown with 100 [mu]M H3BO3. The apparent decrease of membrane fluidity in microsomes from cells grown without boron was reversed by the addition of boron to the reaction medium. Taken together these data suggest that inhibition of H+ gradient formation in microsomes from sunflower cells grown in the absence of boron could be due to the combined effects of reduced H+-ATPase activity and increased passive conductance across the membrane, possibly resulting from increased membrane rigidity.

Effect of silicone oil on the cornea

Silicone oil can dissolve about seven times more oxygen that can water. Placed in a depot between a rigid scleral lens and the corneal surface, silicone oil might thus be useful for treating severe dry-eye patients and for preventing exposure keratitis. To explore this possibility, generic (300, 500, 1000, and 12,500 cs) and medical-grade (1000 cs) silicone oils were tested on rabbit eyes. When oxygenated silicone oil was placed in a cup formed by the lids and hanging sutures and allowed to remain for 3 h on the eyes of anesthetized rabbits, the immediate reaction was mild epithelial edema. By 3 to 6 days later, the thickness of the epithelium and of the entire cornea had increased irregularly. The most common histologic finding was intracellular epithelial edema, particularly in the basal cell layer. The reaction was most intense for the generic oils of the lowest viscosities. The medical-grade oil was the best tolerated, but it too affected epithelial and corneal thickness. Ultrastructural studies of treated eyes showed abnormal epithelial surfaces but no major changes within the epithelial cells. Biochemical analysis showed some decrease of glycogen in the corneal epithelium of eyes kept under oxygenated medical-grade silicone oil. A smaller decrease of glycogen level persisted after 2 days exposure of the treated eye to air, suggesting that the corneal epithelium was injured by a mechanism other than hypoxia.

Hydrogel implant for scleral buckling. Long-term observations

The authors report long-term follow-up clinical observations of 82 eyes in which episcleral or intrascleral hydrogel implants were used as buckles in the repair of rhegmatogenous retinal detachment. Three fourths of the eyes were observed for 24 months or more. The implant material provided a durable and effective scleral buckle, did not produce erosion or infection, and was tolerated well by all patients.