Characterization of human extreme heat exposure using an outdoor thermal manikin

Extreme heat is a current and growing global health concern. Current heat exposure models include meteorological and human factors that dictate heat stress, comfort, and risk of illness. However, radiation models simplify the human body to a cylinder, while convection ones provide conflicting predictions. To address these issues, we introduce a new method to characterize human exposure to extreme heat with unprecedented detail. We measure heat loads on 35 body surface zones using an outdoor thermal manikin ("ANDI") alongside an ultrasonic anemometer array and integral radiation measurements (IRM). We show that regardless of body orientation, IRM and ANDI agree even under high solar conditions. Further, body parts can be treated as cylinders, even in highly turbulent flow. This geometry-rooted insight yields a whole-body convection correlation that resolves prior conflicts and is valid for diverse indoor and outdoor wind flows. Results will inform decision-making around heat protection, adaptation, and mitigation.

Impact of human body shape on forced convection heat transfer

Predicting human thermal comfort and safety requires quantitative knowledge of the convective heat transfer between the body and its surrounding. So far, convective heat transfer coefficient correlations have been based only upon measurements or simulations of the average body shape of an adult. To address this knowledge gap, here we quantify the impact of adult human body shape on forced convection. To do this, we generated fifty three-dimensional human body meshes covering 1st to 99th percentile variation in height and body mass index (BMI) of the USA adult population. We developed a coupled turbulent flow and convective heat transfer simulation and benchmarked it in the 0.5 to 2.5 m·s^-1 air speed range against prior literature. We computed the overall heat transfer coefficients, h_overall, for the manikins for representative airflow with 2 m·s^-1 uniform speed and 5% turbulence intensity. We found that h_overall varied only between 19.9 and 23.2 W·m^-2 K^-1. Within this small range, the height of the manikins had negligible impact while an increase in the BMI led to a nearly linear decrease of the h_overall. Evaluation of the local coefficients revealed that those also nearly linearly decreased with BMI, which correlated to an inversely proportional local area (i.e., cross-sectional dimension) increase. Since even the most considerable difference that exists between 1st and 99th percentile BMI manikins is less than 15% of h_overall of the average manikin, it can be concluded that the impact of the human body shape on the convective heat transfer is minor.

Human body radiation area factors for diverse adult population

Radiation accounts for a significant fraction of the human body and environment heat exchange and strongly impacts thermal comfort and safety. The direct radiative exchange between an individual and a source or sink can be quantified using the effective (f_eff) and projected radiation area factors (f_p). However, these factors have not been quantified for half of the population of the USA with an above-average body mass index (BMI). Here, we address this gap by developing thirty male and thirty female computational manikin models that cover the 1 to 99 percentile variation in height and BMI of adults in the USA. The radiative simulations reveal that the f_eff and the f_p angular distributions are nearly independent of gender, height, and BMI. Appreciable relative differences from the average models only emerge for manikins with BMI above 80th percentile. However, these differences only occur at low zenith angles and, in absolute terms, are small as compared to variations induced by, for example, the zenith angle increase. We also use the manikin set to evaluate whether the body shape impacts the quality of human representation with several levels of geometrical simplification. We find that the "box/peg" body representation, which is based on the hemispherical f_p average, is independent of the body shape. In turn, the f_p distributions averaged over the azimuth angle range, representing the rotationally symmetric humans, are only impacted to the same degree as for the anatomical manikins. We also show that the anatomical manikins can be closely approximated by the multi-cylinder and sphere representation, at least from a radiation perspective. The developed anatomical manikin set is freely available and can be used to compute how body shape impacts a variety of external heat transport processes.

Melanoma cells can be eliminated by sialylated CD43 × CD3 bispecific T cell engager formats in vitro and in vivo

Targeted cancer therapy with monoclonal antibodies has proven successful for different cancer types but is limited by the availability of suitable antibody targets. CD43s, a unique sialylated form of CD43 expressed by hematologic malignancies, is a recently identified target and antibodies interacting with CD43s may have therapeutic potential against acute myeloid leukemia (AML) and myelodysplastic syndrome. CD43s is recognized by the human antibody AT1413, that was derived from a high-risk AML patient who successfully cleared leukemia after allogeneic stem cell transplantation. Here we observed that AT1413 binds also to certain non-hematopoietic tumor cells, particularly melanoma and breast cancer. AT1413 immune precipitated CD43s from melanoma cells confirming that it recognizes the same target on melanoma as on AML. AT1413 induced antibody-dependent cellular cytotoxicity against short-term cultured patient-derived melanoma samples. However, AT1413 was unable to affect the growth of melanoma cells in vivo. To increase the efficacy of AT1413 as a therapeutic antibody, we generated two different formats of bispecific T-cell engaging antibodies (TCEs): one binding bivalently (bTCE) and the other monovalently (knob-in-hole; KiH) to both CD43s and CD3ε. In vitro, these TCEs redirected T-cell cytotoxicity against melanoma cells with differences in potencies. To investigate their effects in vivo, we grafted mice that harbor a human immune system with the melanoma cell line A375. Treatment with both AT1413 bTCE and AT1413 KiH significantly reduced tumor outgrowth in these mice. These data indicate a broad therapeutic potential of AT1413 that includes AML and CD43s-expressing solid tumors that originate from CD43-negative tissues.

A molecule carrier

We found that anthraquinone diffuses along a straight line across a flat, highly symmetric Cu111 surface. It can also reversibly attach one or two CO2 molecules as "cargo" and act as a "molecule carrier," thereby transforming the diffusive behavior of the CO2 molecules from isotropic to linear. Density functional theory calculations indicated a substrate-mediated attraction of approximately 0.12 electron volt (eV). Scanning tunneling microscopy revealed individual steps of the molecular complex on its diffusion pathway, with increases of approximately 0.03 and approximately 0.02 eV in the diffusion barrier upon attachment of the first and second CO2 molecule, respectively.

Measurement of a linear free energy relationship one molecule at a time

A systematic study of the dehydrogenation of substituted thiophenols by controlled charge injection from the tip of a scanning tunneling microscope (STM) reveals a pronounced dependence of the reaction yield on the position and the chemical nature of the substituent. We evaluate the dehydrogenation rate of para-halo-substituted species within a linear free energy relationship, namely the Hammett equation. The resultant rho value of 1.4 can faithfully predict the reaction rates of molecules that are meta-halo-substituted or para-methyl-substituted. The positive sign of rho suggests a negatively charged transition state at the core of the STM-induced process, and the magnitude of the rho value indicates that the presence of the substrate does not preclude substantial substituent effects. The applicability of the Hammett equation to single-molecule chemistry offers facile prediction of the rate of STM-based single-molecule chemistry in a field, which so far has been addressed by focusing on involved quantum-mechanical modeling of its underlying processes.

Halogen-substituted thiophenol molecules on Cu(111)

Para-halosubstituted thiophenols (X-TPs, where X is Br, Cl, or F) form ordered islands and monolayers on Cu(111) at temperatures as low as 81 K. At incomplete coverages, all X-TPs adsorb with the dehydrogenated thiol group attached to the substrate and the substituted ring inclined toward the surface, as verified experimentally and theoretically. The structure of ordered islands has a pronounced dependence on the nature of the halogen substituent: while unsubstituted TP and pentafluoro-TP molecules do not self-assemble into extended ordered patterns at 81 K, X-TP molecules form a range of different structures which depend both on the size and electronegativity of the substituent, as well as on the coverage.

Low-temperature mobility and structure formation of a prochiral aromatic thiol (2,5-dichlorothiophenol) on Cu(111)

We present a low-temperature scanning tunneling microscopy study of increasing coverages of 2,5-dichlorothiophenol, an asymmetrically halo-substituted aromatic thiol, on Cu(111). At low coverage, deprotonation of the thiol occurs spontaneously upon adsorption at 80 K. Albeit the low deposition temperature, we find the formation of adsorbate islands at low coverage, which coalesce into a well-ordered film of horizontally adsorbed molecules at increasing coverage. This behavior indicates (i) significant mobility of the thiols on Cu(111) even at low temperatures and (ii) attractive adsorbate-adsorbate interactions. At higher coverages intermolecular interactions prevent long-range diffusion of adsorbates and thermal activation of the S-H bond becomes necessary. A close analysis of the molecular films reveals chiral recognition between neighboring molecules, which leads to the formation of enantiopure areas on the surface. Upright orientation of individual molecules starts at the boundaries between such phases and can be induced by scanning tunneling microscopy.

Inducing all steps of a chemical reaction with the scanning tunneling microscope tip: towards single molecule engineering

All elementary steps of a chemical reaction have been successfully induced on individual molecules with a scanning tunneling microscope (STM) in a controlled step-by-step manner utilizing a variety of manipulation techniques. The reaction steps involve the separation of iodine from iodobenzene by using tunneling electrons, bringing together two resultant phenyls mechanically by lateral manipulation and, finally, their chemical association to form a biphenyl molecule mediated by excitation with tunneling electrons. The procedures presented here constitute an important step towards the assembly of individual molecules out of simple building blocks in situ on the atomic scale.

Single-shot measurement of terahertz electromagnetic pulses by use of electro-optic sampling

We demonstrate a simple scheme for capturing the temporal waveforms of a freely propagating terahertz electromagnetic transient in a single shot. The method relies on electro-optic sampling in a noncollinear geometry for the terahertz radiation and the visible probe beam, coupled with multichannel detection. The approach provides time resolution that is comparable to that of conventional electro-optic sampling measurements.

Effects of fasting and glutathione depletors on the GSH-dependent enzyme system in the gastrointestinal mucosa of the rat

In rats, the glutathione content of the gastrointestinal mucosa amounted to 50-60% of that of the liver. The GSH-S-transferase activity towards an aryl substrate (CDNB) was low in the stomach, colon and rectum, i.e. 5% of hepatic activity. In the small intestine there was a typical decline of activity from proximal to distal segments. GSH-Peroxidase was much lower in the intestinal mucosa as compared to the stomach and liver, whereas the GSSG-reductase was 2-3 times higher in the gastrointestinal tract in comparison to the liver. Fasting for 24 h significantly decreased the GSH content, GSH-aryltransferase and GSSG-reductase activities in the liver but not in the intestine, where even higher GSH concentrations were found in the proximal segments. L-Buthionine-sulfoximine, an inhibitor of the GSH-synthesis, caused a marked decrease of the GSH levels in the liver, stomach, proximal small intestine, colon and rectum and a concomitant decline in GSSG-reductase activity. Among the GSH-depleting agents, paracetamol exerted the strongest effect, whereas 1,1-dichloroethylene and phorone only decreased the GSH content in the liver and stomach.

Endaural brain hernia: repair using mastoid cortical bone

We present three cases of endaural brain hernia and a method of repair using sculptured mastoid cortical bone. The literature is reviewed to illustrate etiology, pathology, clinical presentation, and management options of this uncommon clinical entity. We classify the hernias as pedunculated or sessile, with associated factors such as viability of herniated brain, infection, CSF leak, and neurologic complications. A management scheme is proposed encompassing surgical options now available and their attendant risks and complications.