One-way visibility using two parallel aerosol clouds.

In this article, we experimentally and theoretically test the range of applicability of a patent that predicts one-way visibility through two successive parallel aerosol clouds, one scattering dominant and the other absorption dominant. A laboratory environment experiment has been designed to determine the ranges of transmissivity and contrast enhancement that might be of interest for military applications. In this study we show that transmissivities in the several percent range and lower are essential for any reasonable contrast enhancement between the two sides of the clouds.

Effect of Gender, Toe Extension Position, and Plantar Fasciitis on Plantar Fascia Thickness.

BACKGROUND:: Ultrasound is a widely used diagnostic tool for patients with plantar fasciitis. However, the lack of standardization during the measurement for plantar fascia thickness has made it challenging to understand the etiology of plantar fasciitis, as well as identify risk factors, such as gender. The purpose of this study was to investigate gender differences regarding plantar fascia thickness while controlling for metatarsophalangeal (MTP) joint position in the healthy and those with unilateral plantar fasciitis. METHODS:: Forty participants (20 with unilateral plantar fasciitis and 20 controls) with plantar fascia thickness (mean age, 44.8 ± 12.2 years) participated in this study. The majority were females (n = 26, 65%). Plantar fascia thickness was measured via ultrasound 3 times at 3 different MTP joint positions: (1) at rest, (2) at 30 degrees of extension, and (3) at maximal extension. RESULTS:: When comparing gender differences, the males in the plantar fasciitis group had a significantly thicker plantar fascia than the females ( P = .048, η2 = 2.35). However, no significant differences were observed between healthy males and females. The males with unilateral plantar fasciitis also had significantly thicker asymptomatic plantar fasciae collectively compared with controls ( P < .05), whereas females with unilateral plantar fasciitis had a similar but not significant change. CONCLUSION:: It appears that healthy males and females have similar plantar fascia thickness. However, as plantar fasciitis develops, males tend to develop thicker plantar fasciae than their female counterparts, which could have future treatment implications. LEVEL OF EVIDENCE:: Level III, case-control comparative study.

Increased HIV diagnoses in West Virginia counties highly vulnerable to rapid HIV dissemination through injection drug use: a cautionary tale.

PURPOSE: To investigate HIV transmission potential from a cluster of HIV infections among men who have sex with men to persons who inject drugs in 15 West Virginia counties. These counties were previously identified as highly vulnerable to rapid HIV dissemination through injection drug use (IDU) associated with high levels of opioid misuse. METHODS: We interviewed persons with 2017 HIV diagnoses about past-year risk behaviors and elicited sexual, IDU, and social contacts. We tested contacts for HIV and assessed risk behaviors. To determine HIV transmission potential from persons with 2017 diagnoses to persons who inject drugs, we assessed viral suppression status, HIV status of contacts, and IDU risk behaviors of persons living with HIV and contacts. RESULTS: We interviewed 78 persons: 39 with 2017 diagnoses and 39 contacts. Overall, 13/78 (17%) injected drugs in the past year. Of 19 persons with 2017 diagnoses and detectable virus, 9 (47%) had more than or equal to 1 sexual or IDU contacts of negative or unknown HIV status. During the past year, 2/9 had injected drugs and shared equipment, and 1/9 had more than or equal to 1 partner who did so. CONCLUSIONS: We identified IDU risk behavior among persons with 2017 diagnoses and their contacts. West Virginia HIV prevention programs should continue to give high priority to IDU harm reduction.

Metatarsophalangeal joint extension changes ultrasound measurements for plantar fascia thickness.

BACKGROUND: Ultrasound is an inexpensive method for quantifying plantar fascia thickness, especially in those with plantar fasciitis. Ultrasound has also been used to assess the effectiveness of various treatments for plantar fasciitis by comparing plantar fascia thickness before and after an intervention period. While a plantar fascia thickness over 4 mm via ultrasound has been proposed to be consistent with plantar fasciitis, some researchers believe the 4 mm plantar fascia thickness level to be a dubious guideline for diagnosing plantar fasciitis due to the lack of standardization of the measurement process for plantar fascia thickness. In particular, no universal guidelines exist on the positioning of the metatarsophalangeal (MTP) joints during the procedure and the literature also has inconsistent protocols. The purpose of this study is to investigate and compare the influence of MTP joint extension on plantar fascia thickness in healthy participants and those with unilateral plantar fasciitis. METHODS: The plantar fascia thickness of forty participants (20 with unilateral plantar fasciitis and 20 control) was measured via ultrasound three times at three different MTP joint positions: 1) at rest, 2) 30° of extension from the plantar surface, and 3) maximal extension possible. RESULTS: The plantar fascia became significantly thinner as MTP joint extension increased in both the plantar fasciitis group (p < 0.001) and the control group (p < 0.001). In the plantar fasciitis group, the involved plantar fascia was 1.2 to 1.3 mm thicker (p < 0.001) than the uninvolved side depending on the MTP joint position. In the control group, the difference in plantar fascia thickness between the two sides was less than 0.1 mm (p < 0.92) at any MTP joint position. CONCLUSIONS: MTP joint position can influence the ultrasound measurement of plantar fascia thickness. It is recommended that plantar fascia thickness measurements be performed with the toes at rest. If MTP joints must be extended, then the toes should be extended maximally and then noted to ensure subsequent ultrasound procedures are repeated. Standardizing the position of the MTP joints is not only important for attaining the most accurate thickness measurement of the plantar fascia, but is also important to researchers who use plantar fascia thickness to determine the effectiveness of various plantar fasciitis interventions.

Moist heat or dry heat for delayed onset muscle soreness.

BACKGROUND: Heat is commonly used in physical therapy following exercise induced delayed onset muscle soreness (DOMS). Most heat modalities used in a clinical setting for DOMS are only applied for 5 to 20 minutes. This minimal heat exposure causes little, if any, change in deep tissue temperature. For this reason, long duration dry chemical heat packs are used at home to slowly and safely warm tissue and reduce potential heat damage while reducing pain associated from DOMS. Clinically, it has been shown that moist heat penetrates deep tissue faster than dry heat. Therefore, in home use chemical moist heat may be more efficacious than dry heat to provide pain relief and reduce tissue damage following exercise DOMS. However, chemical moist heat only lasts for 2 hours compared to the 8 hours duration of chemical dry heat packs. The purpose of this study was to compare the beneficial effect of dry heat versus moist heat on 100 young subjects after exercise induce DOMS. METHODS: One hundred subjects exercised for 15 minutes accomplishing squats. Before and for 3 days after, strength, muscle soreness, tissue resistance, and the force to passively move the knee were recorded. Heat and moist heat were applied in different groups either immediately after exercise or 24 hours later. RESULTS: The research results of this study showed that immediate application of heat, either dry (8 hours application) or moist (2 hours application), had a similar preservation of quadriceps muscle strength and muscle activity. Results also revealed that the greatest pain reduction was shown after immediate application of moist heat. Never the less, immediate application of dry heat had a similar effect but to a lesser extent. CONCLUSION: It should be noted that moist heat had not only similar benefits of dry heat but in some cases enhanced benefits, and with only 25% of the time of application of the dry heat.