bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence for Multi-stage Melt Transport in the Lower Ocean Crust: the Atlantis Bank Gabbroic Massif (IODP Hole U1473A, SW Indian Ridge)
Authors: Zhang Wei-Qi , Liu Chuan-Zhou , Dick Henry J B
Published: August 2020

The architecture of lower oceanic crust at slow- and ultraslow-spreading ridge is diverse, yet the mechanisms that produce this diversity are not well understood. Particularly, the 660-km2 gabbroic massif at Atlantis Bank (Southwest Indian Ridge) exhibits significant compositional zonation, representing a high magma supply end member for accretion of the lower ocean crust at slow and ultraslow-spreading ridges. We present the petrographic and geochemical data of olivine gabbros from the 809-metre IODP Hole U1473A at Atlantis Bank gabbroic massif. Structurally, the upper portion of U1473A consists of a ∼600-metre shear zone; below this, the hole is relatively undeformed, with several minor shear zones. Olivine gabbros away from the shear zones have mineral trace element compositions indicative of high-temperature reaction with an oxide-undersaturated melt. By contrast, olivine gabbros within shear zones display petrographic and chemical features indicative of reaction with a relatively low-temperature, oxide-saturated melt. These features indicate an early stage of primitive to moderately evolved melt migration, followed by deformation-driven transport of highly evolved Fe–Ti-rich melts to high levels in this gabbroic massif. The close relationship between shear zones and the reaction with oxide-saturated melts suggests that syn-magmatic shear zones provide a conduit for late-stage, Fe–Ti-rich melt transport through Atlantis Bank lower crust. This process is critical to generate the compositional zonation observed. Thus, the degree of syn-magmatic deformation, which is fundamentally related to magma supply, plays a dominant role in developing the diversity of lower ocean crust observed at slow- and ultraslow-spreading ridges.
Neutrophil subpopulations and their activation potential in patients with antiphospholipid syndrome and healthy individuals
Authors: Mauracher Lisa-Marie , Krall Moritz , Roiß Johanna , Hell Lena , Koder Silvia , Hofbauer Thomas M , Gebhart Johanna , Hayden Hubert , Brostjan Christine , Ay Cihan , Pabinger Ingrid
Published: August 2020

Objectives

Patients with APS are at increased risk of thromboembolism. Neutrophils have been shown to play a role in inducing thrombosis. We aimed to investigate differences in neutrophil subpopulations, their potential of activation and neutrophil extracellular trap (NET) formation comparing high and low-density neutrophils (HDNs/LDNs) as well as subpopulations in patients with APS and controls to gain deeper insight into their potential role in thrombotic manifestations in patients with APS.

Methods

HDNs and LDNs of 20 patients with APS and 20 healthy donors were isolated by density gradient centrifugation and stimulated. Neutrophil subpopulations, their activation and NET release were assessed by flow cytometry.

Results

LDNs of both groups showed higher baseline activation, lower response to stimulation (regulation of activation markers CD11b/CD66b), but higher NET formation compared with HDNs. In patients with APS, the absolute number of LDNs was higher compared with controls. HDNs of APS patients showed higher spontaneous activation [%CD11b high: median (interquartile range): 2.78% (0.58–10.24) vs 0.56% (0.19–1.37)] and response to stimulation with ionomycin compared with HDNs of healthy donors [%CD11b high: 98.20 (61.08–99.13) vs 35.50% (13.50–93.85)], whereas no difference was found in LDNs. NET formation was increased in patients’ HDNs upon stimulation.

Conclusion

HDNs and LDNs act differently, unstimulated and upon various stimulations in both healthy controls and APS patients. Differences in HDNs and LDNs between patients with APS and healthy controls indicate that neutrophils may enhance the risk of thrombosis in these patients and could thus be a target for prevention of thrombosis in APS.
Transfusion-transmissible dengue infections
Authors: Perera Lakshika , De Zoysa Nandrani , Jayarajah Umesh , Senanayake Nilanthi , De Zoysa Ishan , Seneviratne Suranjith L
Published: August 2020

Dengue is an important global health problem and is endemic in many developing and developed countries. Transmission of dengue may occur in several ways and information on transfusion-transmitted dengue is limited. We conducted a literature search on transfusion-related dengue using the PubMed, Scopus, Embase and Google Scholar databases and have summarized the findings. A number of apparently healthy blood donors have been found to be infected with the dengue virus (DENV) and thus may transmit the virus onto recipients of this blood. It is not possible to identify and exclude such donors at the donor selection stage and thus reliable screening tests should be available in highly endemic areas to ensure a safe blood supply.
Peiminine inhibits the progression of colorectal cancer through up-regulating miR-760 via declining the expression of long noncoding RNA LINC00659
Authors: Li Jianfeng , Qin Yeyu , Wang Weijun , Yang Kai , Zhang Min
Published: August 2020

Colorectal cancer (CRC) is a commonly diagnosed type of cancer globally. The molecular mechanism by which peiminine suppressed the progression of CRC is not fully addressed. The viability was assessed through cell counting kit 8 assay. Colony formation assay was used to analyze the colony formation ability. The metastasis was evaluated by transwell migration and invasion assays. Quantitative real-time PCR was performed to measure the expression of LINC00659 and miR-760 in CRC cells. The binding sites between miR-760 and LINC00659 were predicted by Starbase software and verified by dual-luciferase reporter assay, RNA immunoprecipitation assay and RNA-pull down assay. The in-vivo function of peiminine in CRC progression was confirmed by murine xenograft model. Peiminine inhibited the viability, colony formation and metastasis of CRC cells. Peiminine notably down-regulated the expression of LINC00659, while the expression of miR-760 was up-regulated by peiminine treatment. MiR-760 was a direct target of LINC00659 in CRC cells. The depletion of miR-760 attenuated the inhibitory effects of LINC00659 intervention on the viability, colony formation and metastasis of CRC cells. Peiminine restrained the progression of CRC through LINC00659 and miR-760. LINC00659 inhibited the growth of CRC tumors through LINC00659/miR-760 axis in vivo. Peiminine suppressed the development of CRC through inhibiting the viability, colony formation and metastasis of CRC cells via LINC00659/miR-760 axis. LINC00659/miR-760 axis might be an underlying target for CRC therapy.
Impact of sarcopenia on the efficacy of pembrolizumab in patients with advanced urothelial carcinoma: a preliminary report
Authors: Fukushima Hiroshi , Fukuda Shohei , Moriyama Shingo , Uehara Sho , Yasuda Yosuke , Tanaka Hajime , Yoshida Soichiro , Yokoyama Minato , Matsuoka Yoh , Fujii Yasuhisa
Published: August 2020

Sarcopenia, the degenerative and systemic loss of skeletal muscle mass, is a multifactorial syndrome reflecting frailty, poor general health status, and the possible presence of cancer cachexia. Here, we aimed to investigate the effect of sarcopenia on the efficacy of pembrolizumab in patients with advanced urothelial carcinoma (aUC). This retrospective study included 28 patients with aUC treated with pembrolizumab as a second or later-line therapy. Sarcopenia was determined based on computed tomography images. Associations of sarcopenia with objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) were evaluated. In total, 19 (68%) patients had sarcopenia. ORR was 21% in the patients with sarcopenia, while those without sarcopenia showed significantly higher ORR (67%, P = 0.019). PFS was significantly shorter in patients with sarcopenia than in those without (median, 3 vs. 15 months, P = 0.038). Although the statistical significance was not reached, OS was shorter in patients with sarcopenia than in those without (median, 7 months vs. not reached; P = 0.086). Our preliminary results demonstrated that more than half of patients with aUC who received pembrolizumab had sarcopenia, which was significantly associated with poor therapeutic efficacy. This indicates the clinical relevance of sarcopenia in pembrolizumab therapy for patients with aUC.
The impact of heart rate on pulse wave velocity: an in-silico evaluation
Authors: Bikia Vasiliki , Stergiopulos Nikolaos , Rovas Georgios , Pagoulatou Stamatia , Papaioannou Theodore G.
Published: August 2020

Background:

Clinical and experimental evidence regarding the influence of heart rate (HR) on arterial stiffness and its surrogate marker carotid-to-femoral pulse wave velocity (cf-PWV) is conflicting. We aimed to evaluate the effect of HR on cf-PWV measurement under controlled haemodynamic conditions and especially with respect to blood pressure (BP) that is a strong determinant of arterial stiffness.

Method:

Fifty-nine simulated cases were created using a previously validated in-silico model. For each case, cf-PWV was measured at five HR values, 60, 70, 80, 90, 100 bpm. With increasing HR, we assessed cf-PWV under two scenarios: with BP free to vary in response to HR increase, and with aortic DBP (aoDBP) fixed to its baseline value at 60 bpm, by modifying total peripheral resistance accordingly. Further, we quantified the importance of arterial compliance (C) on cf-PWV changes caused by increasing HR.

Results:

When BP was left free to vary with HR, a significant HR-effect on cf-PWV (0.66 ± 0.24 m/s per 10 bpm, P < 0.001) was observed. This effect was reduced to 0.21 ± 0.14 m/s per 10 bpm (P = 0.048) when aoDBP was maintained fixed with increasing HR. The HR-effect on the BP-corrected cf-PWV was higher in the case of low C = 0.8 ± 0.3 ml/mmHg (0.26 ± 0.15 m/s per 10 bpm, P = 0.014) than the case of higher C = 1.7 ± 0.5 ml/mmHg (0.16 ± 0.07 m/s per 10 bpm, P = 0.045).

Conclusion:

Our findings demonstrated that relatively small HR changes may only slightly affect the cf-PWV. Nevertheless, in cases wherein HR might vary at a greater extent, a more clinically significant impact on cf-PWV should be considered.
Combined effect of high depressive symptom burden and hypertension on new-onset stroke: evidence from a nationwide prospective cohort study
Authors: Liu Siyuan , Qiao Yanan , Zhang Yuxia , Wu Ying , Ke Chaofu , Shen Yueping
Published: August 2020

Objective:

The aim of this study was to investigate whether the combination of high depressive symptom burden and hypertension increased the risk of stroke among the middle-aged and elderly Chinese using a nationwide prospective study.

Methods:

Data from the China Health and Retirement Longitudinal Study (CHARLS) during 2011–2015 were used. A total of 12 604 Chinese participants aged 45 years and older were included for final analysis. Multivariate Cox proportional hazards regression model was used to explore the associations between high depressive symptom burden, hypertension and new-onset stroke.

Results:

There were 244 stroke events occurred during a 4-year follow-up. Compared with those without high depressive symptom burden and hypertension, the adjusted hazard ratios (95% confidence intervals) were 1.96 (1.13–3.42) for individuals with high depressive symptom burden alone, 2.84 (1.77–4.57) for individuals with hypertension alone and 4.38 (2.66–7.20) for individuals with comorbid high depressive symptom burden and hypertension, respectively. In the subgroup analyses, people with the coexistence of high depressive symptom burden and hypertension had the highest risk of new-onset stroke in all subgroups.

Conclusion:

Our results suggest a combined effect of high depressive symptom burden and hypertension on stroke risk among the middle-aged and elderly Chinese.
Cisapride Use in Pediatric Patients With Intestinal Failure and Its Impact on Progression of Enteral Nutrition
Authors: Martinez Andrea , Belza Christina , Betts Zachary , de Silva Nicole , Avitzur Yaron , Wales Paul W.
Published: August 2020

Objective:

Gastrointestinal dysmotility is common in patients with pediatric intestinal failure (PIF), leading to delays in advancement of enteral nutrition (EN). Few studies have been published regarding the safety and efficacy of cisapride for improvement of enteral tolerance and ability to wean parenteral nutrition. Our objective was to describe a single center experience on the use of cisapride in patients with PIF.

Methods:

Retrospective chart review of patients was performed. Demographic, intestinal anatomy, and outcome data were collected. Percentage of EN before initiation of cisapride, progression of EN at 3 and 6 months, and ability to wean parenteral nutrition after initiation of cisapride were calculated.

Results:

Prokinetics were used in 61 of 106 patients (56.6%); 29 of 60 patients (48.3%) failed to progress EN on other prokinetics and started on cisapride. Before cisapride the progress of EN plateaued for a mean of 42.3 (standard deviation [SD] 60.2) days. The rate of feed progression was 0.14% (SD 0.19)/day pre‐cisapride and 0.69%/day (SD 0.31) after cisapride initiation (P < 0.001). Percentage of EN improved significantly from baseline to 3 months postinitiation (23.9% vs 79.4%, respectively; P < 0.001). Electrocardiogram was performed on initiation of cisapride and after every dose change. Medication was discontinued in 2 of 29 (6.8%).

Conclusion:

This retrospective study suggests that cisapride may be beneficial in PIF patients who fail to progress EN on first line prokinetics. The most significant period of improvement occurs within 3 months of cisapride initiation. Cardiac side effects in our cohort were lower than previously reported; however, cardiac monitoring is still recommended.
Use of Anthropometry Versus Ultrasound for the Assessment of Body Fat and Comorbidities in Children With Obesity
Authors: El‐Koofy Nehal , Soliman Hend , Elbarbary Mennat‐Allah , Garhy Al Shimaa El , Sheba Maha , Fouad Hanan
Published: August 2020

Objectives:

We aimed to examine the association between abdominal fat measured by ultrasound and anthropometric indices in children with obesity, and those with normal weight. We also examined the association between anthropometry and fat measures in the prediction of comorbidities in children with obesity.

Methods:

Forty children with body mass index of >95th percentile were included as cases, and a comparable group of 32 healthy average‐weight peers were included as controls in this study. All children underwent clinical assessment, anthropometric measures, and evaluation of abdominal subcutaneous fat (SCF) and visceral fat by ultrasound. Fasting blood sugar, serum transaminases, and lipid profile of all the included children were also evaluated.

Results:

Children with obesity had a mean age of 8.7 ± 2.9 years (range 3–13). The SCF and intraperitoneal fat (IPF) values correlated well with each other and with anthropometric measurements in children with obesity. Among all the included cases, 90% were metabolically unhealthy, 70% had hypertension, 52.5% had dyslipidemia, and 22.5% had echogenic liver. Anthropometric measures, abdominal SCF and IPF were higher in children with complications. SCF was observed as a good predictor for hepatic echogenicity among the measured ultrasound parameters (P: 0.03, odds ratio 4.6). The best cutoff value for SCF in cases with hepatic echogenicity was 23.2 mm with an overall accuracy of 80%.

Conclusions:

In children with obesity, abdominal SCF and IPF correlated well with anthropometric measures and were higher in children with comorbidities. This finding, however, did not predict comorbidities apart from those with echogenic liver.
HIV Screening Among Gonorrhea-Diagnosed Individuals; Baltimore, Maryland; April 2015 to April 2019
Authors: Williford Sarah L. , Humes Elizabeth , Greenbaum Adena , Schumacher Christina M.
Published: August 2020

Background

Individuals diagnosed with gonorrhea are at elevated risk for HIV. Per US Centers for Disease Control and Prevention guideline, individuals being evaluated for gonorrhea should be screened for HIV concurrently. There is limited information on HIV screening among gonorrhea-diagnosed individuals across different health care settings. Our objective was to identify potential gaps in HIV screening among gonorrhea-diagnosed individuals in Baltimore City, Maryland.

Methods

We used Sexually Transmitted Disease Surveillance Network project data collected on a random sample of all gonorrhea diagnoses reported to the health department between April 2015 and April 2019. Individuals with known HIV diagnoses were excluded. HIV screening was confirmed through surveys administered to the gonorrhea-diagnosing provider. HIV screening across groups was assessed using Poisson regression models with robust SEs. We examined those with and without recent (≤12 months) sexually transmitted infection (STI) history separately.

Results

Among 2830 gonorrhea-diagnosed individuals with completed Sexually Transmitted Disease Surveillance Network provider surveys, less than half (35.2% with and 44.8% without recent STI history) received concurrent HIV screening. HIV screening was 73% less prevalent among those diagnosed in emergency departments/urgent care centers/hospitals versus sexual health clinics (with and without recent STI history: adjusted prevalence ratio, 0.27 [95% confidence interval, 0.19–0.39]; adjusted prevalence ratio, 0.27 [0.23–0.33]), controlling for diagnosis year, sex, race/ethnicity, age, infection site, and insurance.

Conclusions

Our findings suggest a considerable gap in HIV screening among individuals at elevated risk for HIV acquisition in Baltimore City, particularly among those diagnosed in emergency departments/urgent care centers/hospital settings. Future work should focus on identifying provider-level barriers to concurrent HIV/STI screening to inform provider education programs.
Time to Scale Up Preexposure Prophylaxis Beyond the Highest-Risk Populations? Modeling Insights From High-Risk Women in Sub-Saharan Africa
Authors: Grant Hannah , Gomez Gabriela B. , Kripke Katharine , Barnabas Ruanne V. , Watts Charlotte , Medley Graham F. , Mukandavire Zindoga
Published: August 2020

Objectives

New HIV infections remain higher in women than men in sub-Saharan Africa. Preexposure prophylaxis (PrEP) is an effective HIV prevention measure, currently prioritized for those at highest risk, such as female sex workers (FSWs), for whom it is most cost-effective. However, the greatest number of HIV infections in sub-Saharan Africa occurs in women in the general population. As countries consider wider PrEP scale-up, there is a need to weigh the population-level impact, cost, and relative cost-effectiveness to inform priority setting.

Methods

We developed mathematical models of HIV risk to women and derived tools to highlight key considerations for PrEP programming. The models were fitted to South Africa, Zimbabwe, and Kenya, spanning a range of HIV burden in sub-Saharan Africa. The impact, cost, and cost-effectiveness of PrEP scale-up for adolescent girls and young women (AGYW), women 25 to 34 years old, and women 35 to 49 years old were assessed, accounting for differences in population sizes and the low program retention levels reported in demonstration projects.

Results

Preexposure prophylaxis could avert substantially more infections a year among women in general population than among FSW. The greatest number of infections could be averted annually among AGYW in South Africa (24-fold that for FSW). In Zimbabwe, the greatest number of infections could be averted among women 25 to 34 years old (8-fold that for FSW); and in Kenya, similarly between AGYW and women 25 to 34 years old (3-fold that for FSW). However, the unit costs of PrEP delivery for AGYW, women 25 to 34 years old, and women 35 to 49 years old would have to reduce considerably (by 70.8%–91.0% across scenarios) for scale-up to these populations to be as cost-effective as for FSW.

Conclusions

Preexposure prophylaxis has the potential to substantially reduce new HIV infections in HIV-endemic countries in sub-Saharan Africa. This will necessitate PrEP being made widely available beyond those at highest individual risk and continued integration into a range of national services and at community level to significantly bring down the costs and improve cost-effectiveness.
Acceptability of a Tenofovir Disoproxil Fumarate Intravaginal Ring for HIV Pre-Exposure Prophylaxis Among Sexually Active Women
Authors: Dobkin April , McWalters Jessica , Barnett Rebecca , Ray Laurie L. , Espinoza Lilia , McGinn Aileen P. , Atrio Jessica M. , Keller Marla J.
Published: August 2020

Introduction

Vaginal ring delivery of antiretroviral drugs may provide protection against acquisition of HIV-1 when used as Pre-Exposure prophylaxis. As part of a randomized placebo-controlled safety trial of a tenofovir disoproxil fumarate (TDF) intravaginal ring (IVR), we assessed product acceptability through surveys of women after continuous ring use.

Methods

Sexually active, HIV-negative women were enrolled to investigate the safety and pharmacokinetics of 3 months of continuous TDF IVR use. The study was designed to include 40 US participants randomly assigned (3:1) to a TDF or placebo IVR. Twelve were randomized to TDF and 5 to the placebo group before the study was electively discontinued because of the development of vaginal ulcerations in 8 women in the TDF group. Acceptability data were gathered via self-administered, computer-based questionnaires.

Results

The average age of the 17 participants was 31 years (range, 18–42 years). Sixteen participants (94%) completed all questions at 2 study visits. When asked about ring likeability after 1 month of ring use, 12 (75%) of 16 reported overall liking the ring, including 6 (75%) of 8 who developed ulcerations. In addition, 10 (83%) of 12 who had their menses during the first month of ring use were not bothered by the ring, and 11 (69%) of 16 stated that the ring was not bothersome with use during sex.

Conclusions

Despite unanticipated ulcers, TDF and placebo IVRs were acceptable to some women, even when used with menses and during sex, which is promising for continued development of IVRs for HIV prevention.
Factors Associated With the Recurrence, Persistence, and Clearance of Asymptomatic Bacterial Vaginosis Among Young African American Women: A Repeated-Measures Latent Class Analysis
Authors: Coudray Makella S. , Sheehan Diana M. , Li Tan , Cook Robert L. , Schwebke Jane , Madhivanan Purnima
Published: August 2020

Background

Although risk factors of recurrent and persistent bacterial vaginosis (BV) have been explored in the literature, the longitudinal incidence patterns of BV remain elusive.

Methods

We conducted a secondary analysis of longitudinal data from a randomized clinical trial of metronidazole treatment for asymptomatic BV. Repeated-measures latent class analysis was used to identify distinct longitudinal patterns of incident BV cases. Multinomial regression analysis was used to determine the predictors of class membership. The multivariable model included age, last BV treatment, douching frequency, birth control, sexual risk behavior, and assignment to treatment arm.

Results

A total of 858 African American women who were asymptomatic for BV were included in the analysis. Three emergent patterns of BV for 12 months were identified by repeated-measures latent class analysis: persistent (55.9%), recurrent (30.5%), and clearance (13.5%). Participants who had douched at least once had significantly lower odds to be in the recurrent class versus the clearance class (adjusted odds ratio [adjOR], 0.55; 95% confidence interval [CI], 0.18–0.63). Women who had sex with women had significantly lower odds of belonging to the persistent class versus the clearance class (adjOR, 0.38; 95% CI, 0.22–0.68) and the recurrent class (adjOR, 0.43; 95% CI, 0.23–0.81). Those who were assigned to the treatment arm had significantly increased odds of being in the recurrent class versus the clearance class (adjOR, 1.92; 95% CI, 1.22–3.03). Women older than 21 years were significantly more likely to be in the recurrent class (adjOR, 1.88; 95% CI, 1.17–3.00) than in the clearance class.

Conclusions

Assessment of BV cases revealed distinct patterns of recurrence and persistence of BV, which were significantly associated with douching, being in the treatment arm, and being a woman who had sex with women.
Accommodative Behavior, Hyperopic Defocus, and Retinal Image Quality in Children Viewing Electronic Displays
Authors: Sah Raman Prasad , Ramasubramanian Viswanathan , Reed Olivia , Meyer Dawn , Bradley Arthur , Kollbaum Pete S.
Published: August 2020

SIGNIFICANCE

The prevalence of myopia and use of electronic displays by children has grown rapidly in recent years. We found that children viewing electronic displays, however, experience hyperopic defocus levels similar to those previously reported for other stimuli.

PURPOSE

This study aimed to compare accommodative behavior of nonmyopic and myopic children viewing a computer screen or mobile phone.

METHODS

Accommodative behavior was examined in 11 nonmyopic and 8 myopic children (11.32 ± 2.90 and 14.13 ± 2.30 years, respectively;P= .04; refractions, +0.51 ± 0.51 and −2.54 ± 1.29, respectively) using an open-field autorefractor (Grand Seiko) at target vergences from −0.25 to −5.95 D. Different size (scaled or nonscaled) and type (text or movie) stimuli were presented on an LCD monitor (distant) or an iPhone (near), with subjects viewing monocularly or binocularly in an illuminated or dark room.

RESULTS

At the typical reading distances (16.8 and 29.8 cm), all 19 children exhibited some amount of accommodative lag. Stimulus type had little impact on accommodation. However, slightly but statistically significant lower slopes were observed (Bonferroni-corrected significance level ofP≤ .01) for low room lighting (0.80 vs. 0.76;ttest,t= 3.88;P= .003), nonscaled targets (0.83 vs. 0.77;ttest,t= 4.28;P= .001), and monocular viewing (0.83 vs. 0.74;ttest,t= 4.0;P= .002) in the nonmyopic group only. When viewing nonscaled stimuli binocularly (natural viewing), the means and standard deviations of accommodative lags (averaged across room lights on and off, and text and movie) were generally larger for the nonmyopes at all distances and were largest at 16.8 cm (1.31 ± 0.32 D for the nonmyopes and 1.11 ± 0.35 for the myopes;ttest,t= 2.62;P= .01).

CONCLUSIONS

Generally small (mostly <1.00 D) amounts of hyperopic defocus are present in children binocularly viewing handheld electronic devices (nonmyopes slightly more than myopes). Modern electronic devices do not expose children to unusually high levels of hyperopic defocus.
The Effect of Retinal Illuminance on the Subjective Amplitude of Accommodation
Authors: Lara Francisco , Del Águila-Carrasco Antonio J. , Marín-Franch Iván , Riquelme-Nicolás Resurrección , López-Gil Norberto
Published: August 2020

SIGNIFICANCE

We show that the amplitude of accommodation decreases with retinal illumination even under photopic reading conditions and a constant pupil size. This result provides a basis for clinical approaches that are not based on an optical explanation.

PURPOSE

We investigated the effect of retinal illuminance on the amplitude of accommodation while the pupil of the eye remained constant.

METHODS

The amplitudes of accommodation of 10 young subjects (from 20 to 38 years of age) and that of 10 presbyopic subjects (from 45 to 54 years of age) were measured subjectively through an artificial pupil of 5 mm using a Badal optometer and for four values of retinal illuminance: 222, 821, 2138, and 5074 trolands. Phenylephrine was instilled to all the subjects to ensure that their natural pupil was greater than the artificial one in all experimental runs. Linear mixed-effects model for repeated measures with age and log luminance as covariates were used to check whether changes in amplitude of accommodation with retinal illumination were statistically significant.

RESULTS

In the range of illuminances tested, the amplitude of accommodation decreased on average from 6.34 to 4.35 D in the young subjects and from 1.69 to 1.04 D in the presbyopic subjects. Illuminance was associated with the amplitude of accommodation in both young and presbyopic groups, withP< .01.

CONCLUSIONS

The reduction in the amplitude of accommodation with target illumination (a phenomenon namednight presbyopia) under photopic light conditions is not only due to a reduction in the depth of focus as a consequence of pupil dilation; it is strongly affected by the decrease of retinal illumination.
Case Report: Transient Myopic Shift and Other Sequelae in Response to Adverse Reaction to Sulfamethoxazole-trimethoprim
Authors: Whorff John S.
Published: August 2020

SIGNIFICANCE

There are several isolated reports of systemic medications or medical conditions that can cause acute transient myopic shifts along with other ocular sequelae, but rarely has this been reported for the combination antibiotic sulfamethoxazole-trimethoprim.

PURPOSE

This case illustrates a rarely seen condition that may result from treatment with sulfamethoxazole-trimethoprim and result in serious, vision-threatening conditions. These can be treated by immediate discontinuation of the drug, steroids, ocular hypertensive medication, and cycloplegia, depending on the circumstances.

CASE REPORT

A 20-year-old woman presented complaining of blindness upon waking. She had been experiencing fever, malaise, and significant abdominal pain for weeks. Blood culture revealed infection withStaphylococcus aureusandEscherichia colifor which she was prescribed sulfamethoxazole (800 mg) and trimethoprim (160 mg) twice daily. After a week of treatment, she awoke unable to see. Examination revealed narrowed angles, bilateral 6-D myopic shift, macular folding with scattered microaneurysms, and intraretinal hemorrhages with mild macular edema and field defects. The condition resolved with discontinuation of the drug and use of steroids, ocular hypertensive, and cycloplegic agents. Her visual acuity returned to near normal within 3 days. Resolution of macular edema, field defects, and hemorrhages followed.

CONCLUSIONS

An adverse reaction possibly caused by sulfamethoxazole-trimethoprim is described causing ciliochoroidal effusion resulting in acute myopic shift and other sequelae. Successful treatment is demonstrated, and implications are discussed.
Field-wide Quantification of Aniseikonia Using Dichoptic Localization
Authors: Willeford Kevin T. , Butera Marianna , LeBlanc Jeffrey , Sample Alina
Published: August 2020

SIGNIFICANCE

We validated a novel paradigm to measure aniseikonia across the visual field and used a mathematical approach that is able to describe the magnitude and shape of aniseikonia in a concise, clinically meaningful fashion.

PURPOSE

The measurement of aniseikonia has been performed clinically for more than half a century; however, amalgamation of field-wide local variations in binocular spatial localization into clinically applicable global metrics has yet to be attempted. Thus, the goal of the current study was twofold: first, to measure field-wide aniseikonia and second, to compare how local and global metrics each capture optically induced aniseikonia.

METHODS

Twelve visually normal observers performed a dichoptic localization task at 24 locations in the visual field. This was done in four conditions: (A) while wearing red-green filters, (B) while wearing green-red filters, (C) while wearing a monocular 5% overall size lens, and (D) while wearing a monocular 6% meridional size lens. The physical settings at perceptual equality were then used to compute both local (relative magnification) and global (coefficients for Zernike terms) descriptors of aniseikonia.

RESULTS

The comparison of each lens condition to the baseline condition confirmed predicted shifts in both the sign and magnitude of aniseikonia at both the local and global levels; however, the intraobserver levels of precision were moderate, and systematic underestimations were present across all locations in conditions C and D.

CONCLUSIONS

Local and global analyses derived from dichoptic localization data were both able to capture optically induced changes in binocular spatial perception; however, solutions that address the diagnostic and therapeutic challenges associated with this paradigm are needed before clinical implementation can proceed.
A Novel Automated Visual Acuity Test Using a Portable Head-mounted Display
Authors: Ong Sze Chuan , Pek Li Cheng (Ivy) , Chiang Tsuey Ling (Carol) , Soon Hock Wei , Chua Kuang Chua , Sassmann Chanakarn , Razali Muhammad Azri Bin , Koh Teck Chang (Victor)
Published: August 2020

SIGNIFICANCE

We developed a head-mounted display (HMD) as an automated way of testing visual acuity (VA) to increase workplace efficiency. This study raises its potential utility and advantages, analyzes reasons for its current limitations, and discusses areas of improvement in the development of this device.

PURPOSE

Manual VA testing is important but labor-intensive in ophthalmology and optometry clinics. The purpose of this exploratory study is to assess the performance and identify potential limitations of an automated HMD for VA testing.

METHODS

Sixty patients from National University Hospital, Singapore, were enrolled in a prospective observational study. The HMD was constructed based on the Snellen chart, with single optotypes displayed at a time. Each subject underwent VA testing of both eyes with the manual Snellen chart tested at 6 m from the subject and the HMD.

RESULTS

Fifty-three subjects were included in the final analysis, with an incompletion rate of 11.7% (n = 7). The mean difference in estimated acuity between the HMD and Snellen chart was 0.05 logMAR. However, 95% limits of agreement were large at ±0.33 logMAR. The HMD overestimated vision in patients with poorer visual acuities. In detecting VA worse than 0.30 logMAR (6/12), sensitivity was 63.6% (95% confidence interval, 0.31 to 0.89%), and specificity was 81.0% (95% confidence interval, 0.66 to 0.91%). No significant correlation existed between mean difference and age (r = −0.15, P = .27) or education level (r = 0.04, P = .76).

CONCLUSIONS

Advantages of our novel HMD technology include its fully automated nature and its portability. However, the device in its current form is not ready for widespread clinical use primarily because of its low accuracy, which is limited by both technical and user factors. Future studies are needed to improve its accuracy and completion rate and to evaluate for test-retest reliability in a larger population.
Thoracic Cardiovascular Complications of Tuberculosis
Authors: Restrepo Carlos S. , Gonzalez Tomas V. , Brar Rahat , Ocazionez Daniel , Velasco Marta Lucia , Reyna Lopez Rolando A. , Arias Liliana , Baxi Ameya J. , Carrillo Jorge
Published: August 2020

Mycobacterium infection remains a leading cause of morbidity and mortality worldwide. Although rare, thoracic cardiovascular complications are associated with devastating consequences if not promptly diagnosed using computed tomography. Intrapulmonary complications include tuberculous aortitis, Rasmussen aneurysms, involvement of bronchial and nonbronchial systemic arteries, and thromboembolic events. Extrapulmonary complications include pericarditis, myocarditis, endocarditis, involvement of coronary arteries, annular-subvalvular left ventricle aneurysms and mediastinal fibrosis. This article will review these complications and their computed tomography features.
Radiation Dose Reduction for Computed Tomography Localizer Radiography Using an Ag Additional Filter
Authors: Nomura Keiichi , Fujii Keisuke , Goto Takahiro , Tsukagoshi Shinsuke , Ota Hiroyuki , Iwabuchi Yuto , Suzuki Hidenobu , Muramatsu Yoshihisa , Kobayashi Tatsushi
Published: August 2020

Objective

This study aimed to assess the potential of an Ag additional filter attached to the bow tie filter of a computed tomography (CT) scanner to reduce the radiation dose in CT localizer radiography.

Methods

Radiation doses in CT localizer radiography with Cu and Ag additional filters were evaluated based on dose measurements and Monte Carlo simulations. Image quality evaluations of an adult torso phantom were performed, and the automatic exposure control performance was evaluated in terms of the water-equivalent thickness estimated from CT localizer radiographs.

Results

With the Ag additional filter, effective doses were approximately 72% to 75% lower than those with the Cu additional filter. The image quality and water-equivalent thickness with the Ag additional filter were similar to those with the Cu additional filter.

Conclusions

The Ag additional filter helped significantly reduce radiation doses in CT localizer radiography while maintaining image quality and performance.
John Couch Adams: mathematical astronomer, college friend of George Gabriel Stokes and promotor of women in astronomy
Authors: Krajnović Davor
Published: August 2020

John Couch Adams predicted the location of Neptune in the sky, calculated the expectation of the change in the mean motion of the Moon due to the Earth’s pull, and determined the origin and the orbit of the Leonids meteor shower which had puzzled astronomers for almost a thousand years. With his achievements Adams can be compared with his good friend George Stokes. Not only were they born in the same year but were also both senior wranglers, received the Smith’s Prizes and Copley medals, lived, thought and researched at Pembroke College, and shared an appreciation of Newton. On the other hand, Adams’ prediction of Neptune’s location had absolutely no influence on its discovery in Berlin. His lunar theory did not offer a physical explanation for the Moon’s motion. The origin of the Leonids was explained by others before him. Adams refused a knighthood and an appointment as Astronomer Royal. He was reluctant and slow to publish, but loved to derive the values of logarithms to 263 decimal places. The maths and calculations at which he so excelled mark one of the high points of celestial mechanics, but are rarely taught nowadays in undergraduate courses. The differences and similarities between Adams and Stokes could not be more striking. This volume attests to the lasting legacy of Stokes’ scientific work. What is then Adams’ legacy? In this contribution, I will outline Adams’ life, instances when Stokes’ and Adams’ lives touched the most, his scientific achievements and a usually overlooked legacy: female higher education and support of a woman astronomer.

This article is part of the theme issue ‘Stokes at 200 (part 2)’.
The fluid mechanics of poohsticks
Authors: Cartwright Julyan H. E. , Piro Oreste
Published: August 2020

The year 2019 marked the bicentenary of George Gabriel Stokes, who in 1851 described the drag—Stokes drag—on a body moving immersed in a fluid, and 2020 is the centenary of Christopher Robin Milne, for whom the game of poohsticks was invented; his father A. A. Milne’s
The House at Pooh Corner
, in which it was first described in print, appeared in 1928. So this is an apt moment to review the state of the art of the fluid mechanics of a solid body in a complex fluid flow, and one floating at the interface between two fluids in motion. Poohsticks pertains to the latter category, when the two fluids are water and air.

This article is part of the theme issue ‘Stokes at 200 (part 2)’.
Stokes drift in coral reefs with depth-varying permeability
Authors: Webber Joseph J. , Huppert Herbert E.
Published: August 2020

In his famous paper of 1847 (Stokes GG. 1847 On the theory of oscillatory waves.
Trans. Camb. Phil. Soc.
8
, 441–455), Stokes introduced the drift effect of particles in a fluid that is undergoing wave motion. This effect, now known as Stokes drift, is the result of differences between the Lagrangian and Eulerian velocities of the fluid element and has been well-studied, both in the laboratory and as a mechanism of mass transport in the oceans. On a smaller scale, it is of vital importance to the hydrodynamics of coral reefs to understand drift effects arising from waves on the ocean surface, transporting nutrients and oxygen to the complex ecosystems within. A new model is proposed for a class of coral reefs in shallow seas, which have a permeable layer of depth-varying permeability. We then note that the behaviour of the waves above the reef is only affected by the permeability at the top of the porous layer, and not its properties within, which only affect flow inside the porous layer. This model is then used to describe two situations found in coral reefs; namely, algal layers overlying the reef itself and reef layers whose permeability decreases with depth.

This article is part of the theme issue ‘Stokes at 200 (part 2)’.
Stokes at 200 (part 2)
Authors: Cardoso Silvana S. S. , Cartwright Julyan H. E. , Huppert Herbert E. , Ness Christopher
Published: August 2020

We present the second half of the papers from the Stokes
200
symposium celebrating the bicentenary of George Gabriel Stokes.

This article is part of the theme issue ‘Stokes at 200 (part 2)’.
Alkalibaculum sporogenes sp. nov., isolated from a terrestrial mud volcano and emended description of the genus Alkalibaculum
Authors: Khomyakova M.A. , Merkel A.Y. , Petrova D.A. , Bonch-Osmolovskaya E.A. , Slobodkin A.I.
Published: August 2020

A novel anaerobic, endospore-forming bacterium (strain M08 DMBT) was isolated from a terrestrial mud volcano (Taman Peninsula, Russia). Cells of the strain were motile rods 1.3–2.0 µm long and 0.4 µm in diameter. The temperature range for growth was 5–42 °C, with an optimum at 30 °C. The pH range for growth was H 6.5–11.0, with an optimum at pH 8.0. Growth of strain M08 DMBTwas observed at NaCl concentrations of 0–5.0 % (w/v) with an optimum at 1.0 %. Strain M08 DMBTutilized 3,4-dimethoxybenzoic acid, 2-methoxyphenol, carbon monoxide, glucose, fructose, mannose, xylose and yeast extract. The end product of glucose fermentation was acetate. The DNA G+C content of strain M08 DMBTwas 32.3 mol% (obtained via whole genome sequencing). The closest phylogenetic relative of strain M08 DMBTwasAlkalibaculum bacchi(familyEubacteriaceae, classClostridia) with 95.17 % 16S rRNA gene sequence similarity. Based on the phenotypic, genotypic and phylogenetic characteristics of the isolate, strain M08 DMBTis considered to represent a novel species of the genusAlkalibaculum, for which the nameAlkalibaculum sporogenessp. nov. is proposed. The type strain ofAlkalibaculum sporogenesis M08 DMBT(=KCTC 15840T=VKM B-3387T).
Modified SIR-model applied to covid-19, similarity solutions and projections to further development
Authors: Rebhan E.
Published: August 2020

The SIR-model is adapted to the covid-19 pandemic through a modification that consists in making the basic reproduction number variable. Independent of it, another reproduction number is introduced, which is defined similarly to the usual net reproduction number. Due to its simple analytic form, it enables a clear interpretation for all values. A further parameter, provisionally called acceleration parameter, is introduced and applied, which enables a more differentiated characterization of the infection number dynamics. By a variable transformation the 3 equations of the modified SIR-model can be reduced to 2. The latter are solved up to ordinary integrations. The solutions are evaluated for current situations, yielding a pretty good match with the data reported. Encouraged by this, a variety of possible future developments is examined, including linear and exponential growth of the infection numbers as well as sub- and super-exponential growth. In particular, the behavior of the two reproduction numbers and the acceleration parameter is studied, which in some cases leads to surprising results. With regard to the number of unreported infections it is shown, that from the solution for a special one solutions for others can be derived by similarity transformations.
Molecular Parallelism Underlies Convergent Highland Adaptation of Maize Landraces
Authors: Wang Li , Josephs Emily B. , Lee Kristin M. , Roberts Lucas M. , Rellán-Álvarez Rubén , Ross-Ibarra Jeffrey , Hufford Matthew B.
Published: August 2020

Convergent phenotypic evolution provides some of the strongest evidence for adaptation. However, the extent to which recurrent phenotypic adaptation has arisen via parallelism at the molecular level remains unresolved, as does the evolutionary origin of alleles underlying such adaptation. Here, we investigate genetic mechanisms of convergent highland adaptation in maize landrace populations and evaluate the genetic sources of recurrently selected alleles. Population branch excess statistics reveal strong evidence of parallel adaptation at the level of individual SNPs, genes and pathways in four independent highland maize populations, even though most SNPs show unique patterns of local adaptation. The majority of selected SNPs originated via migration from a single population, most likely in the Mesoamerican highlands. Polygenic adaptation analyses of quantitative traits reveal that alleles affecting flowering time are significantly associated with elevation, indicating the flowering time pathway was targeted by highland adaptation. In addition, repeatedly selected genes were significantly enriched in the flowering time pathway, indicating their significance in adapting to highland conditions. Overall, our study system represents a promising model to study convergent evolution in plants with potential applications to crop adaptation across environmental gradients.
Respiration and brain neural dynamics associated with interval timing during odor fear learning in rats
Authors: Dupin Maryne , Garcia Samuel , Messaoudi Belkacem , Doyère Valérie , Mouly Anne-Marie
Published: August 2020

In fear conditioning, where a conditioned stimulus predicts the arrival of an aversive stimulus, the animal encodes the time interval between the two stimuli. Freezing, the most used index to assess learned fear, lacks the temporal resolution required to investigate interval timing at the early stages of learning. Here we monitored respiration to visualize anticipatory behavioral responses in an odor fear conditioning in rats, while recording theta (5-15Hz) and gamma (40-80Hz) brain oscillatory activities in the medial prefrontal cortex (mPFC), basolateral amygdala (BLA), dorsomedial striatum (DMS) and olfactory piriform cortex (PIR). We investigated the temporal patterns of respiration frequency and of theta and gamma activity power during the odor-shock interval. We found that akin to respiration patterns, theta temporal curves were modulated by the duration of the odor-shock interval in the four recording sites, and respected scalar property in mPFC and DMS. In contrast, gamma temporal curves were modulated by the interval duration only in the mPFC, and in a manner that did not respect scalar property. This suggests a preferential role for theta rhythm in interval timing. In addition, our data bring the novel idea that the respiratory rhythm might take part in the setting of theta activity dynamics.