FUS-mediated BBB opening leads to transient perfusion decrease and inflammation without acute or chronic brain lesion.

Impact: The permeabilization of the BBB to deliver therapeutics with MR-guided FUS redefines therapeutic strategies as it improves patient outcomes. To ensure the best translation towards clinical treatment, the evaluation of hemodynamic modifications in the CNS is necessary to refine treatment parameters. Methods: MR-guided FUS was applied at 1.5 MHz with a 50 ms burst every 1 s to open the BBB. CBF, BVf and ADC parameters were monitored with MRI. Cavitation was monitored with a PCD during the FUS sequence and classified with the IUD index into three cavitation levels. We distinctly applied the FUS in the cortex or the striatum. After the BBB permeabilization, neuroinflammation markers were quantified longitudinally. Results: The BBB was successfully opened in all animals in this study and only one animal was classified as "hard" and excluded from the rest of the study. 30 min after FUS-induced BBB opening in the cortex, we measured a 54% drop in CBF and a 13% drop in BVf compared to the contralateral side. After permeabilization of the striatum, a 38% drop in CBF and a 15% drop in BVf were measured. CBF values rapidly returned to baseline, and 90 min after BBB opening, no significant differences were observed. We quantified the subsequent neuroinflammation, noting a significant increase in astrocytic recruitment at 2 days and microglial activation at 1 day after FUS. After 7 days, no more inflammation was visible in the brain. Conclusion: FUS-induced BBB opening transiently modifies hemodynamic parameters such as CBF and BVf, suggesting limited nutrients and oxygen supply to the CNS in the hour following the procedure.

Progression in low-intensity ultrasound-induced tumor radiosensitization.

BACKGROUND: Radiotherapy (RT) is a widely utilized tumor treatment approach, while a significant obstacle in this treatment modality is the radioresistance exhibited by tumor cells. To enhance the effectiveness of RT, scientists have explored radiosensitization approaches, including the use of radiosensitizers and physical stimuli. Nevertheless, several approaches have exhibited disappointing results including adverse effects and limited efficacy. A safer and more effective method of radiosensitization involves low-intensity ultrasound (LIUS), which selectively targets tumor tissue and enhances the efficacy of radiation therapy. METHODS: This review summarized the tumor radioresistance reasons and explored LIUS potential radiosensitization mechanisms. Moreover, it covered diverse LIUS application strategies in radiosensitization, including the use of LIUS alone, ultrasound-targeted intravascular microbubble destruction, ultrasound-mediated targeted radiosensitizers delivery, and sonodynamic therapy. Lastly, the review presented the limitations and prospects of employing LIUS-RT combined therapy in clinical settings, emphasizing the need to connect research findings with practical applications. RESULTS AND CONCLUSION: LIUS employs cost-effective equipment to foster tumor radiosensitization, curtail radiation exposure, and elevate the quality of life for patients. This efficacy is attributed to LIUS's ability to utilize thermal, cavitation, and mechanical effects to overcome tumor cell resistance to RT. Multiple experimental analyses have underscored the effectiveness of LIUS in inducing tumor radiosensitization using diverse strategies. While initial studies have shown promising results, conducting more comprehensive clinical trials is crucial to confirm its safety and effectiveness in real-world situations.

Neuroinflammation in the Rat Brain After Exposure to Diagnostic Ultrasound.

OBJECTIVE: To date there have been no studies exploring the potential for neuroinflammation as an intracranial bio-effect associated with diagnostic ultrasound during neonatal cranial scans in a mammalian in vivo model. The study described here was aimed at investigating the effects of B-mode and Doppler mode ultrasound on inflammation in the rat brain. METHODS: Twelve Wistar rats (7-9 wk old) were divided into a control group and an ultrasound-exposed group (n = 6/group). A craniotomy was performed, followed by 10 min of B-mode and spectral Doppler interrogation of the middle cerebral artery. The control group was subjected to sham treatment, with the transducer held stationary over the craniotomy site, but the ultrasound machine switched off. Animals were euthanized 48 h after exposure, and the brains formalin fixed for immunohistochemical analysis using allograft inflammatory factor 1 (IBA-1) and glial fibrillary acidic protein (GFAP) as markers of microglia and astrocytes, respectively. The numbers of IBA-1- and GFAP-immunoreactive cells were manually counted and expressed as areal density (cells/mm2). Results were analyzed using Student's unpaired t-test and one-way repeated-measures analysis of variance. RESULTS: The ultrasound-exposed brain exhibited significant increases in IBA-1 and GFAP immunoreactive cell density in all regions of B-mode and Doppler mode exposure compared with the control group (p < 0.001). CONCLUSION: Ten minutes of B-mode and Doppler mode ultrasound may induce neuroinflammatory changes in the rat brain. This suggests that exposure of brain tissue to current diagnostic ultrasound intensities may not be completely without risk.

The Behavior of Phenolic Compounds from Apples during Simulated Gastrointestinal Digestion with Focus on Chlorogenic Acid.

The fate of phenolic compounds during digestion is important for their bioactive effects in the digestive tract. The aim was to study the various phenolic compounds occurring in the peel and flesh of apples in in vitro simulated gastrointestinal digestion, focusing on the behavior of chlorogenic acids. Additionally, the behavior of individual chlorogenic acids (chlorogenic, neochlorogenic, and cryptochlorogenic) was studied in models of simulated salivary, gastric, and intestinal fluid electrolyte solutions (SSF, SGF, SIF). At the end of the intestinal phase of the digestion of peel and flesh, the amount of recovered dihydrochalcones and flavonols increased or was similar to the amount in the gastric phase, which showed their stability. Anthocyanins and flavan-3-ols decreased, which suggests their biotransformation. Chlorogenic acid isomerized into neochlorogenic and cryptochlorogenic acid: chlorogenic acid from the peel into 22% and 41% of the isomers in the salivary and intestinal phases, respectively; chlorogenic acid from the flesh into 12% of the isomers in the intestinal phase. Similarly, chlorogenic acid isomerized in model solutions (20% and 26% of the isomers in SSF and SIF, respectively). Neochlorogenic and cryptochlorogenic acid isomerized in SSF and SIF into other two forms. They were all stable in SGF. For bioactive effects in the digestive tract, the biotransformation of chlorogenic acids should be considered.

In vivo high-speed microscopy of microbubbles in the chorioallantoic membrane model.

Rationale: The acoustic stimulation of microbubbles within microvessels can elicit a spectrum of therapeutically relevant bioeffects from permeabilization to perfusion shutdown. These bioeffects ultimately arise from complex interactions between microbubbles and microvascular walls, though such interactions are poorly understood particularly at high pressure, due to a paucity of direct in vivo observations. The continued development of focused ultrasound methods hinges in large part on establishing links between microbubble-microvessel interactions, cavitation signals, and bioeffects. Methods: Here, a system was developed to enable simultaneous high-speed intravital imaging and cavitation monitoring of microbubbles in vivo in a chorioallantoic membrane model. Exposures were conducted using the clinical agent DefinityTM under conditions previously associated with microvascular damage (1 MHz, 0.5-3.5 MPa, 5 ms pulse length). Results: Ultrasound-activated microbubbles could be observed and were found to induce localized wall deformations that were more pronounced in smaller microvessels and increased with pressure. A central finding was that microbubbles could extravasate from microvessels (from 34% of vessels at 1 MPa to 79% at 3 MPa) during insonation (94% within 0.5 ms) and that this occurred more frequently and in progressively larger microvessels (up to 180 µm) as pressure was increased. Following microbubble extravasation, transient or sustained red blood cell leakage ensued at the extravasation site in 96% of cases for pressures ≥1 MPa. Conclusions: The results here represent the first high-speed in vivo investigation of high-pressure focused ultrasound-induced microbubble-microvessel interactions. This data provides direct evidence that the process of activated microbubble extravasation can occur in vivo and that it is linked to producing microvessel wall perforations of sufficient size to permit red blood cell leakage. The association of red blood cell leakage with microbubble extravasation provides mechanistic insight into the process of microvessel rupture, which has been widely observed in histology.

Histotripsy: A Method for Mechanical Tissue Ablation with Ultrasound.

Histotripsy is a relatively new therapeutic ultrasound technology to mechanically liquefy tissue into subcellular debris using high-amplitude focused ultrasound pulses. In contrast to conventional high-intensity focused ultrasound thermal therapy, histotripsy has specific clinical advantages: the capacity for real-time monitoring using ultrasound imaging, diminished heat sink effects resulting in lesions with sharp margins, effective removal of the treated tissue, a tissue-selective feature to preserve crucial structures, and immunostimulation. The technology is being evaluated in small and large animal models for treating cancer, thrombosis, hematomas, abscesses, and biofilms; enhancing tumor-specific immune response; and neurological applications. Histotripsy has been recently approved by the US Food and Drug Administration to treat liver tumors, with clinical trials undertaken for benign prostatic hyperplasia and renal tumors. This review outlines the physical principles of various types of histotripsy; presents major parameters of the technology and corresponding hardware and software, imaging methods, and bioeffects; and discusses the most promising preclinical and clinical applications.

Safety of Ultrasound Exposure: Awareness of Ultrasound Bioeffects among Saudi Sonographers.

BACKGROUND: Ultrasound tends to produce biological effects on body tissues. Therefore, the application of ultrasound safety rules is needed in all ultrasound examinations to avoid bioeffects that may occur because of a high thermal index (TI) and mechanical index (MI). This study aimed to explore the Saudi sonographers' awareness of ultrasound safety and bioeffects. METHODS: A descriptive cross-sectional study was conducted, and the data was collected using an online survey google forms questionnaire disseminated through social media (Telegram, WhatsApp, and Twitter) as an electronic link. A total of 70 participants responded to the survey directly, and then, the data was analyzed using SPSS (Statistical Package for Social Science). RESULTS: Regarding the awareness of TI and MI, 64.3% of the participants were aware of TI and 65.7% of MI as safety ultrasound indices; moreover, 74.3% of the participants were aware of the ALARA principle "As Low as Reasonably Achievable." Participants' knowledge concerning more heat production in pulsed Doppler ultrasound modes was poor (31.5%). Most of the sonographers, i.e., 77.1% were aware of the relationship between the risk of activation and MI, and 58.6% of the participants were acquainted with the current FDA output limits. In comparison, 58.6% of the participants were aware of the bioeffects of ultrasound contrast agents. There was no significant correlation between the educational level and the degree of awareness of ultrasound bioeffects and safety (P-value> 0.05). CONCLUSION: In this study, it was found that sonographers were aware of the theoretical principles of ultrasound safety indices and the ALARA principle, although they had poor knowledge of ultrasound bioeffects in Doppler mode.

The Effects of mmW and THz Radiation on Dry Eyes: A Finite-Difference Time-Domain (FDTD) Computational Simulation Using XFdtd.

The importance of investigating the health effects of RF radiation on the cornea cannot be overstated. This study aimed to address this need by utilizing a mathematical simulation to examine the absorption of millimeter wave (mmW) and terahertz (THz) waves by the cornea, considering both normal and pathological conditions. The simulation incorporated variations in tear film thickness and hydration levels, as these factors play a crucial role in corneal health. To assess the impact of RF radiation on the cornea, the study calculated temperature rises, which indicate heating effects for both dry and normal eyes. XFdtd, a widely used commercial software based on the Finite-Difference Time Domain (FDTD) method, was employed to evaluate the radiation absorption and resulting temperature changes. The outcomes of this study demonstrated a crucial finding, i.e., that changes in the water ratio and thickness of the tear film, which are associated with an increased risk of dry eye syndrome, directly impact the absorption of mmW and THz waves by the cornea. This insight provides valuable evidence supporting the interconnection between tear film properties and the vulnerability of the cornea to RF radiation.

Prediction of experimental cardiac magnetostimulation thresholds using pig-specific body models.

PURPOSE: Modern high-amplitude gradient systems can be limited by the International Electrotechnical Commission 60601-2-33 cardiac stimulation (CS) limit, which was set in a conservative manner based on electrode experiments and E-field simulations in uniform ellipsoidal body models. Here, we show that coupled electromagnetic-electrophysiological modeling in detailed body and heart models can predict CS thresholds, suggesting that such modeling might lead to more detailed threshold estimates in humans. Specifically, we compare measured and predicted CS thresholds in eight pigs. METHODS: We created individualized porcine body models using MRI (Dixon for the whole body, CINE for the heart) that replicate the anatomy and posture of the animals used in our previous experimental CS study. We model the electric fields induced along cardiac Purkinje and ventricular muscle fibers and predict the electrophysiological response of these fibers, yielding CS threshold predictions in absolute units for each animal. Additionally, we assess the total modeling uncertainty through a variability analysis of the 25 main model parameters. RESULTS: Predicted and experimental CS thresholds agree within 19% on average (normalized RMS error), which is smaller than the 27% modeling uncertainty. No significant difference was found between the modeling predictions and experiments (p < 0.05, paired t-test). CONCLUSION: Predicted thresholds matched the experimental data within the modeling uncertainty, supporting the model validity. We believe that our modeling approach can be applied to study CS thresholds in humans for various gradient coils, body shapes/postures, and waveforms, which is difficult to do experimentally.

Barrier-breaking effects of ultrasonic cavitation for drug delivery and biomarker release.

Recently, emerging evidence has demonstrated that cavitation actually creates important bidirectional channels on biological barriers for both intratumoral drug delivery and extratumoral biomarker release. To promote the barrier-breaking effects of cavitation for both therapy and diagnosis, we first reviewed recent technical advances of ultrasound and its contrast agents (microbubbles, nanodroplets, and gas-stabilizing nanoparticles) and then reported the newly-revealed cavitation physical details. In particular, we summarized five types of cellular responses of cavitation in breaking the plasma membrane (membrane retraction, sonoporation, endocytosis/exocytosis, blebbing and apoptosis) and compared the vascular cavitation effects of three different types of ultrasound contrast agents in breaking the blood-tumor barrier and tumor microenvironment. Moreover, we highlighted the current achievements of the barrier-breaking effects of cavitation in mediating drug delivery and biomarker release. We emphasized that the precise induction of a specific cavitation effect for barrier-breaking was still challenged by the complex combination of multiple acoustic and non-acoustic cavitation parameters. Therefore, we provided the cutting-edge in-situ cavitation imaging and feedback control methods and suggested the development of an international cavitation quantification standard for the clinical guidance of cavitation-mediated barrier-breaking effects.

Lung Ultrasound Induction of Pulmonary Capillary Hemorrhage in Rats With Consideration of Exposimetric Relationships to Previous Similar Observations in Neonatal Swine.

OBJECTIVE: Lung ultrasound (LUS) has become an essential clinical tool for pulmonary evaluation. LUS has been found to induce pulmonary capillary hemorrhage (PCH) in animal models, posing a safety issue. The induction of PCH was investigated in rats, and exposimetry parameters were compared with those of a previous neonatal swine study. METHODS: Female rats were anesthetized and scanned in a warmed water bath with the 3Sc, C1-5 and L4-12t probes from a GE Venue R1 point-of-care ultrasound machine. Acoustic outputs (AOs) of sham, 10%, 25%, 50% or 100% were applied for 5-min exposures with the scan plane aligned with an intercostal space. Hydrophone measurements were used to estimate the in situ mechanical index (MIIS) at the lung surface. Lung samples were scored for PCH area, and PCH volumes were estimated. RESULTS: At 100% AO, the PCH areas were 73 ± 19 mm2 for the 3.3 MHz 3Sc probe (4 cm lung depth), 49 ± 20 mm2 (3.5 cm lung depth) or 96 ± 14 mm2 (2 cm lung depth) for the 3.0 MHz C1-5 probe and 7.8 ± 2.9 mm2 for the 7 MHz L4-12t (1.2 cm lung depth). Estimated volumes ranged from 378 ± 97 mm3 for the C1-5 at 2 cm to 1.3 ± 1.5 mm3 for the L4-12t. MIIS thresholds for PCH were 0.62, 0.56 and 0.48 for the 3Sc, C1-5 and L4-12t, respectively. CONCLUSION: Comparison between this study and previous similar research in neonatal swine revealed the importance of chest wall attenuation. Neonatal patients may be most susceptible to LUS PCH because of thin chest walls.

Frame Rate Exposimetry for Pulmonary Capillary Hemorrhage During Lung Ultrasound.

OBJECTIVES: Lung ultrasound (LUS) is a powerful and accessible clinical tool for pulmonary diagnosis, but risk of pulmonary capillary hemorrhage (PCH) presents a safety issue. The dependence of PCH in a rat model of LUS was evaluated for image frames-per-second (fps) and associated on-screen Mechanical Index (MIOS ) and Thermal Index (TI). METHODS: A Philips iE33 machine with L15-7io probe was used to scan anesthetized rats in a warmed water bath. B mode was applied at 9 MHz with settings of 34, 61 and 118 fps. After 2 minutes of exposure at an MIOS setting, samples were obtained for assessment of PCH areas on the lung surface. Ultrasound parameters were measured to determine the in situ MIIS at the lung surface. RESULTS: The PCH trend counter-intuitively decreased with increasing fps, with areas of 19.5 mm2 for 34 fps (MIOS  = 1.0, TI = 0.8, 4080 images), 9.6 mm2 at 61 fps (MIOS  = 1.0, TI = 0.5, 7320 images) and 7.5 mm2 at 118 fps (MIOS  = 1.1, TI = 0.4, 14,160 images). The PCH was not significantly different for 34 fps (TI = 0.5, MIOS  = 0.8) (10.7 mm2 ), compared to 61 and 118 fps, above, indicating some value for the TI as a predictive indicator of PCH. MIIS thresholds were 0.42, 0.46, and 0.49 for 34, 61 and 118 fps, respectively. CONCLUSIONS: The increase in PCH at low fps was associated with delivering more relatively high amplitude grazing pulse exposures during slower image scans. No significant PCH was found for the MIOS setting of 0.5, corresponding to in MIIS values of 0.35-0.39.

Vessel Rupture Thresholds for Vessel-Bubble Interactions Using an Earthworm Vasculature Model.

OBJECTIVE: Intravenous microbubble oscillation in the presence of ultrasound has the potential to yield a wide range of therapeutic benefits. However, the likelihood of vessel damage caused by mechanical effects has not been quantified as a function of the numerous important parameters in therapeutic ultrasound procedures. In this study, we examined the effects of microbubbles injected into the vasculature of the earthworm. It was found that the elastic properties of earthworm blood vessels are similar to those of arteries in older humans, and that earthworms are well suited to the large number of experiments necessary to investigate safety of procedures involving microbubble oscillation in sonicated vessels. METHODS: Microbubbles were infused into earthworm vessels, and the rupture time during sonication was recorded as a function of ultrasound frequency, pulse repetition frequency and acoustic pressure. DISCUSSION: A modified mechanical index (MMI) was defined that successfully captured the trends in rupture probability and rupture time for the different parameter values, creating a database of vessel rupture thresholds. In the absence of bubbles, the product of MMI squared and rupture time was approximately constant, indicating a possible radiation-force effect. CONCLUSION: The MMI was an effective correlating parameter in the presence of bubbles, though the mathematical dependence is not yet apparent. The results of the study are expected to be valuable in designing more refined studies in vertebrate models, as well as informing computational models.

Bio-effects of 5th generation electromagnetic waves on organs of human beings / 《全球健康杂志（英文）》

Objectives:The uses of devices of electromagnetic waves(EMWs)are increasing day by day.Similarly,the gen-eration of the waves is increasing.The frequency spectrum of the generation of waves is also increased.In this manuscript,an analysis of the high frequency EMWs has been made by the electric fields generated due to the exposure of 5th generation(5 G)of mobile phones. Methods:Due to the emission of waves from the towers,the electric field is generated around the transmission tower of mobile phones.The electric fields are computed by the power of the transmission tower.The electric fields across the biological tissues/cells are also computed when the EMWs penetrate inside the body.The electric fields are made across the organs of different depths inside the body. Results:The induced electric fields inside the organs of the human beings are responsible for the absorption of energy from high frequency EMWs.The absorbed amount of energy from high frequency waves may become the cause of harmful effects on the life of organs of human beings. Conclusion:In this manuscript,after analysis of the computed electric fields inside the organs of human beings,it is concluded that the EMWs of 5 G spectrum of mobile phone towers may more harmful for the life of organs as 4th generation(4 G)spectrum of mobile phone waves.The energy absorption by the 4 G spectrum is lower than 5 G spectrum due to the range of frequency of waves.The effects on the pancreas,retina,skin,intestine,spleen,stomach and uterus are more than low water content organs like nails,bone,teeth etc.

Lung Ultrasound Induction of Pulmonary Capillary Hemorrhage in Neonatal Swine.

This study investigated induction of pulmonary capillary hemorrhage (PCH) in neonatal pigs (piglets) using three different machines: a GE Venue R1 point-of-care system with C1-5 and L4-12t probes, a GE Vivid 7 Dimension with a 7L probe and a SuperSonic Imagine machine with an SL15-4 probe and shear wave elastography (SWE). Female piglets were anesthetized, and each was mounted vertically in a warm bath for scanning at two or three intercostal spaces. After aiming at an innocuous output, the power was raised for a test exposure. Hydrophone measurements were used to calculate in situ values of mechanical index (MIIS). Inflated lungs were removed and scored for PCH area. For the C1-5 probe at 50% and 100% acoustical output (AO), a PCH threshold of 0.53 MIIS was obtained by linear regression (r2 = 0.42). The L4-12t probe did not induce PCH, but the 7L probe induced zones of PCH in the scan planes. The Venue R1 automated B-line tool applied with the C1-5 probe did not detect PCH induced by the C1-5 probe as B-line counts. However, when PCH induced by C1-5 and 7L exposures were subsequently scanned with the L4-12t probe using the automated tool, B-lines were counted in association with the PCH. The SWE induced PCH at push-pulse positions for 3, 30 and 300 s of SWE with PCH accumulating at 0.33 mm2/s and an exponential rise to a maximum of 18.4 mm2 (r2 = 0.61). This study demonstrated the induction of PCH by LUS of piglets, and supports the safety recommendation for use of MIs <0.4 in neonatal LUS.

Una mirada a la seguridad del ultrasonido en ecotomografía obstétrica / A look at the safety of ultrasound in obstetric echotomography

Resumen Los índices térmico y mecánico son estimadores de riesgo fetal en una ecografía y se deben controlar sus valores minimizando la exposición. Comparamos los valores de los índices térmico y mecánico obtenidos en exámenes ecográficos obstétricos de pacientes gestantes, con el valor recomendado por la comunidad internacional. Se realizó la estimación de estos índices en 421 ecografías obstétricas en 2019. Los valores fueron comparados entre ellos y con el valor recomendado para cada índice y según el modo de visualización (B, Doppler color y Doppler espectral). Del total de la muestra, para el índice térmico en modo Doppler color un 0,24% superó el valor estándar recomendado y en modo Doppler espectral un 2,85%. Para el índice mecánico se sobrepasó el valor recomendado en modo B en un 11,16%, en un 8,08% en modo Doppler color y, por último, en un 0,48% para el modo Doppler espectral. Los índices mecánico y térmico en esta muestra de exámenes ecográficos obstétricos se encuentran en promedio bajo el valor de referencia. Sin embargo, existe un número importante de casos en que se superan las normas, lo que debe ser una voz de alerta para la comunidad médica.

Abstract The thermal and mechanical indices are the best estimators of fetal risk in an ultrasound and their values should be controlled in order to minimize exposure as much as possible. We compared the values of the thermal and mechanical indices obtained in obstetric ultrasound examinations of pregnant patients, with the value recommended by the international community. These indices were estimated in 421 obstetric ultrasounds during 2019. The estimated values were compared with each other and with the recommended value for each index and according to the display mode (B, color Doppler and spectral Doppler). Of the total sample, for the thermal index in color Doppler mode, 0.24% exceeded the recommended standard value and 2.85%. in spectral Doppler mode. For the mechanical index, the recommended value was exceeded in B mode by 11.16%, in 8.08% in color Doppler mode and, finally, by 0.48% for spectral Doppler mode. The mechanical and thermal indices in this sample of obstetric ultrasound examinations are on average below the reference value. However, there is a significant number of cases in which the standards are exceeded, which should be a warning to the medical community.

The impact of low intensity ultrasound on cells: Underlying mechanisms and current status.

Low intensity ultrasound (LIUS) has been adopted for a variety of therapeutic purposes because of its bioeffects such as thermal, mechanical, and cavitation effects. The mechanism of impact and cellular responses of LIUS in cellular regulations have been revealed, which helps to understand the role of LIUS in tumor treatment, stem cell therapy, and nervous system regulation. The review summarizes the bioeffects of LIUS at the cellular level and its related mechanisms, detailing the corresponding theoretical basis and latest research in the study of LIUS in the regulation of cells. In the future, the design of specific LIUS-mediated treatment strategies may benefit from promising investigations which is hoped to provide encouraging therapeutic data.

Validation of a vulnerability index of exposure to chemicals of emerging concern in surface water and sediment of Great Lakes tributaries of the United States.

Widespread occurrence of emerging contaminants in Great Lakes tributaries led to the development and publication of a vulnerability index (VI) to assess the potential exposure of aquatic communities to chemicals of emerging concern (CEC) in the Great Lakes basin. The robust nature of the VI was tested to evaluate the underlying statistical model and expand the spatial domain of the index. Data collected at 131 new sampling sites (Test 1) and published data from independent studies (Test 2) were used to test the model predictions. Test 1 water and sediment samples were analyzed for the same classes of CEC chemicals and compared to the predictions for the original VI. Concentrations and numbers of unique CECs detected in water and sediment samples were similar between the original data and the two test datasets, although CECs tended to have higher detection frequencies in the original dataset compared to the Test 1 and Test 2 datasets. For example, 69 CECs were detected in ≥30% of water samples in the original dataset compared with 17 CECs in the Test 1 data and 59 in the Test 2 data. Predicted vulnerability for test sites agreed with actual vulnerability 64% of the time for water and 71% of the time for sediment. Agreement percentage results were greater when individual sites were grouped by river, with 82% agreement between predictions and actual vulnerability for water and 78% agreement for sediment. For the entire dataset, the VI ranks correlated with an independent estimate of potential biological impact. Agreement percentage was the greatest for low or high vulnerability index values but highly variable for sites that are classified as having medium vulnerability. Despite the underlying variability, there is a significant correlation (R2 = 0.26; p < 0.01) between the VI ranking of tributaries and the independent ranking of potential negative biological impact.

Ocular Ultrasound: Review of Bioeffects and Safety, Including Fetal and Point of Care Perspective: Review of Bioeffects and Safety, Including Fetal and Point-of-Care Perspective.

Ocular ultrasound is an invaluable tool for the evaluation of the eye and orbit. However, the eye and orbit are potentially sensitive to the thermal and mechanical effects of ultrasound. When performing B-mode imaging, dedicated ocular settings should be used. If these settings are not available, limiting the acoustic output to Food and Drug Administration (FDA) recommended maximum levels is strongly advised. Especially important is the acoustic output in spectral (pulsed) and color Doppler modes, which can exceed the FDA's maximum recommended levels for the eye. Adjusting settings to decrease acoustic output and limiting the time of the examination should be done when performing a Doppler examination. The acoustic output of shear wave elastography is significantly higher than FDA guidelines for the eye and should be considered experimental.

Space Radiation Protection Countermeasures in Microgravity and Planetary Exploration.

BACKGROUND: Space radiation is one of the principal environmental factors limiting the human tolerance for space travel, and therefore a primary risk in need of mitigation strategies to enable crewed exploration of the solar system. METHODS: We summarize the current state of knowledge regarding potential means to reduce the biological effects of space radiation. New countermeasure strategies for exploration-class missions are proposed, based on recent advances in nutrition, pharmacologic, and immune science. RESULTS: Radiation protection can be categorized into (1) exposure-limiting: shielding and mission duration; (2) countermeasures: radioprotectors, radiomodulators, radiomitigators, and immune-modulation, and; (3) treatment and supportive care for the effects of radiation. Vehicle and mission design can augment the overall exposure. Testing in terrestrial laboratories and earth-based exposure facilities, as well as on the International Space Station (ISS), has demonstrated that dietary and pharmacologic countermeasures can be safe and effective. Immune system modulators are less robustly tested but show promise. Therapies for radiation prodromal syndrome may include pharmacologic agents; and autologous marrow for acute radiation syndrome (ARS). CONCLUSIONS: Current radiation protection technology is not yet optimized, but nevertheless offers substantial protection to crews based on Lunar or Mars design reference missions. With additional research and human testing, the space radiation risk can be further mitigated to allow for long-duration exploration of the solar system.