Reconsidering Rural-Nonrural College Enrollment Gaps: The Role of Socioeconomic Status in Geographies of Opportunity.

Rural students enroll in college at lower rates than nonrural students. This has been partially attributed to lower average socioeconomic status (SES) in rural areas. However, this assertion tends to ignore heterogeneity that may mask how SES shapes rural students' college-going experiences. Utilizing a geography of opportunity framework, this study investigated how rural-nonrural differences in college-going vary based on SES. Analyses reveal that (a) rural and nonrural students in the High School Longitudinal Study (HSLS) had very similar mean SES; (b) rural status still predicted lower college enrollment rates overall, as well as four-year enrollment specifically; (c) the overall rural-nonrural enrollment gap was primarily a gap for low- and middle-SES students; and (d) there was greater socioeconomic inequality in college access in rural geographies than in nonrural geographies. These findings reinforce the fact rural students are not a monolithic group and emphasize the continued importance of SES between and within geographies. Given these findings, recommendations are provided with the intent of making college enrollment more equitable by the joint consideration of rurality and SES. Supplementary Information: The online version contains supplementary material available at 10.1007/s11162-023-09737-8 .

The impact of communal learning contexts on adolescent self-concept and achievement: Similarities and differences across race and gender.

Misalignment between students' communal values and those expressed in classrooms is an obstacle to academic engagement, especially in mathematics, and especially for racial ethnic minority and female students. Using 10 schools across the United States, we conducted a longitudinal field study in 8th grade mathematics classes to investigate: (a) how perceptions of communally oriented classrooms influence student outcomes in early adolescence, (b) what psychological processes mediate these relations, and (c) whether the influence of perceived communal practices in classrooms have similar or different effects on students with varying social identities based on race, ethnicity, and gender. Results showed that middle school classes that emphasize communality (both social relevance of math and peer collaboration) significantly predicted stronger math self-concept, more behavioral engagement, and better performance in math. These associations were mediated through three psychological processes-belonging, challenge, and self-efficacy. Among racial ethnic minority adolescents, feelings of belonging and challenge in math class were key psychological processes that enhanced math learning outcomes. These processes were activated when classes connected communal values to math. Finally, communal learning contexts benefited girls and boys equally. In sum, communal values practiced by emphasizing social relevance of academic content and using collaborative learning practices engage all students, especially students of color, at a formative period of academic learning in mathematics. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Microanatomic Distribution of Myeloid Heme Oxygenase-1 Protects against Free Radical-Mediated Immunopathology in Human Tuberculosis.

Heme oxygenase-1 (HO-1) is a cytoprotective enzyme that controls inflammatory responses and redox homeostasis; however, its role during pulmonary tuberculosis (TB) remains unclear. Using freshly resected human TB lung tissue, we examined the role of HO-1 within the cellular and pathological spectrum of TB. Flow cytometry and histopathological analysis of human TB lung tissues showed that HO-1 is expressed primarily in myeloid cells and that HO-1 levels in these cells were directly proportional to cytoprotection. HO-1 mitigates TB pathophysiology by diminishing myeloid cell-mediated oxidative damage caused by reactive oxygen and/or nitrogen intermediates, which control granulocytic karyorrhexis to generate a zonal HO-1 response. Using whole-body or myeloid-specific HO-1-deficient mice, we demonstrate that HO-1 is required to control myeloid cell infiltration and inflammation to protect against TB progression. Overall, this study reveals that zonation of HO-1 in myeloid cells modulates free-radical-mediated stress, which regulates human TB immunopathology.

The influence of STEM definitions for research on women's college attainment.

BACKGROUND: Prior research has inconsistently operationalized Science, Technology, Engineering, and Math (STEM) fields, presenting an interpretation challenge. A content analysis of 51 quantitative, gender-focused, higher education-oriented, STEM-related studies in the ERIC database published between January 2010 and July 2018 revealed that only 13 articles used an existing STEM definition. In 15, STEM was not explicitly defined, and others defined STEM independently. This wide range of definitions may lead to confusion or misrepresentation of findings for interventions and practices to support women in STEM. To illustrate the issue and prompt recommendations for future research, this study uses data from the United States National Center for Education Statistics' Education Longitudinal Study (ELS:2002/12) to investigate the connection between STEM definition and the outcome of college degree completion, comparing results by gender for five ways of operationalizing STEM fields. RESULTS: We found the size, direction, and significance of the gender gap depended on STEM operationalization. When STEM was defined as high paradigm fields, the odds of women attaining a non-STEM degree were higher than otherwise. When social science fields were included in STEM, there was no statistically significant difference by gender. When looking specifically at fields considered related to science and engineering, the direction of the relationship was reversed. CONCLUSION: While our findings follow expectations about social science fields and gender, it is noteworthy that results regarding STEM degree completion by gender for science and engineering-related fields were opposite those of high paradigm STEM fields. This result highlights that the definition of STEM matters, and inconsistent operationalization in the literature presents an interpretation challenge. We argue the field should strive to find common categorizations of STEM that retain the legitimate variation in how STEM can and should be defined, while providing a basis for consistent comparison. We recommend researchers and practitioners developing research-based practices: 1) interpret research findings understanding potential inconsistency from different STEM operationalizations, 2) explicitly describe STEM operational definitions to enable comparing findings, 3) routinely analyze sensitivity to alternate STEM definitions, and 4) find common STEM categorizations that retain legitimate variation while providing a basis for consistent comparison.

Force time-history affects fatigue accumulation during repetitive handgrip tasks.

Muscle fatigue is associated with a higher risk of workplace injury, in particular during repetitive tasks. This study aimed to identify the effect of a complex force-time history (a task with multiple different submaximal effort levels) on fatigue accumulation and recovery during a handgrip task. We measured surface electromyography of the brachioradialis (BRD) and flexor carpi ulnaris (FCU) of ten right hand dominant females with no history of upper limb injury while they performed a complex submaximal visually targeted gripping task. The task consisted of 15%, 30%, 45%, 30%, and 15% maximum voluntary contraction (MVC) plateaus. Each plateau was held for 15s, followed by a 3s MVC and 3s of rest. The "pyramid" was repeated until fatigue criteria were met. Grip force, average EMG and mean power frequency (MnPF) for first cycle and fatigued last cycle, were compared. Post-plateau peak grip force was on average 20.5% MVC lower during the last cycle (p<0.01). Post-plateau grip forces decreased on average by 5.1% MVC after the first 15% MVC plateau (from baseline), by 5.3% MVC after the 30% MVC plateau and 6.8% MVC after the 45% MVC plateau. Further accumulation of fatigue after the second 30% MVC plateau however was minimal, only decreasing by 1.6% MVC. Recovery appeared to occur during the last 15% MVC plateau with an increase in post plateau grip force of 1.6% MVC. Interestingly, MnPF parameters confirmed significant fatigue accumulation during the back end of a force pyramid. We conclude that in a pattern of contractions with ascending, then descending force intensity, voluntary force recovery was present when the preceding force was of a lower intensity. These findings indicate preceding demands play a role in fatigue accumulation during complex tasks.

Self-poisoning of Mycobacterium tuberculosis by interrupting siderophore recycling.

Siderophores are small iron-binding molecules secreted by bacteria to scavenge iron. Mycobacterium tuberculosis (Mtb), the etiologic agent of tuberculosis, produces the siderophores mycobactin and carboxymycobactin. Complexes of the mycobacterial membrane proteins MmpS4 and MmpS5 with the transporters MmpL4 and MmpL5 are required for siderophore export and virulence in Mtb. Here we show that, surprisingly, mycobactin or carboxymycobactin did not rescue the low-iron growth defect of the export mutant but severely impaired growth. Exogenous siderophores were taken up by the export mutant, and siderophore-delivered iron was used, but the deferrated siderophores accumulated intracellularly, indicating a blockade of siderophore recycling. This hypothesis was confirmed by the observation that radiolabeled carboxymycobactin was taken up and secreted again by Mtb. Addition of iron salts to an Mtb siderophore biosynthesis mutant stimulated more growth in the presence of a limiting amount of siderophores than iron-loaded siderophores alone. Thus, recycling enables Mtb to acquire iron at lower metabolic cost because Mtb cannot use iron salts without siderophores. Exogenous siderophores were bactericidal for the export mutant in submicromolar quantities. High-resolution mass spectrometry revealed that endogenous carboxymycobactin also accumulated in the export mutant. Toxic siderophore accumulation is prevented by a drug that inhibits siderophore biosynthesis. Intracellular accumulation of siderophores was toxic despite the use of an alternative iron source such as hemin, suggesting an additional inhibitory mechanism independent of iron availability. This study indicates that targeting siderophore export/recycling would deliver a one-two punch to Mtb: restricting access to iron and causing toxic intracellular siderophore accumulation.

The Physiology and Genetics of Oxidative Stress in Mycobacteria.

During infection, Mycobacterium tuberculosis is exposed to a diverse array of microenvironments in the human host, each with its own unique set of redox conditions. Imbalances in the redox environment of the bacillus or the host environment serve as stimuli, which could regulate virulence. The ability of M. tuberculosis to evade the host immune response and cause disease is largely owing to the capacity of the mycobacterium to sense changes in its environment, such as host-generated gases, carbon sources, and pathological conditions, and alter its metabolism and redox balance accordingly for survival. In this article we discuss the redox sensors that are, to date, known to be present in M. tuberculosis, such as the Dos dormancy regulon, WhiB family, anti-σ factors, and MosR, in addition to the strategies present in the bacillus to neutralize free radicals, such as superoxide dismutases, catalase-peroxidase, thioredoxins, and methionine sulfoxide reductases, among others. M. tuberculosis is peculiar in that it appears to have a hierarchy of redox buffers, namely, mycothiol and ergothioneine. We discuss the current knowledge of their biosynthesis, function, and regulation. Ergothioneine is still an enigma, although it appears to have distinct and overlapping functions with mycothiol, which enable it to protect against a wide range of toxic metabolites and free radicals generated by the host. Developing approaches to quantify the intracellular redox status of the mycobacterium will enable us to determine how the redox balance is altered in response to signals and environments that mimic those encountered in the host.

Discovery of a siderophore export system essential for virulence of Mycobacterium tuberculosis.

Iron is an essential nutrient for most bacterial pathogens, but is restricted by the host immune system. Mycobacterium tuberculosis (Mtb) utilizes two classes of small molecules, mycobactins and carboxymycobactins, to capture iron from the human host. Here, we show that an Mtb mutant lacking the mmpS4 and mmpS5 genes did not grow under low iron conditions. A cytoplasmic iron reporter indicated that the double mutant experienced iron starvation even under high-iron conditions. Loss of mmpS4 and mmpS5 did not change uptake of carboxymycobactin by Mtb. Thin layer chromatography showed that the ΔmmpS4/S5 mutant was strongly impaired in biosynthesis and secretion of siderophores. Pull-down experiments with purified proteins demonstrated that MmpS4 binds to a periplasmic loop of the associated transporter protein MmpL4. This interaction was corroborated by genetic experiments. While MmpS5 interacted only with MmpL5, MmpS4 interacted with both MmpL4 and MmpL5. These results identified MmpS4/MmpL4 and MmpS5/MmpL5 as siderophore export systems in Mtb and revealed that the MmpL proteins transport small molecules other than lipids. MmpS4 and MmpS5 resemble periplasmic adapter proteins of tripartite efflux pumps of Gram-negative bacteria, however, they are not only required for export but also for efficient siderophore synthesis. Membrane association of MbtG suggests a link between siderophore synthesis and transport. The structure of the soluble domain of MmpS4 (residues 52-140) was solved by NMR and indicates that mycobacterial MmpS proteins constitute a novel class of transport accessory proteins. The bacterial burden of the mmpS4/S5 deletion mutant in mouse lungs was lower by 10,000-fold and none of the infected mice died within 180 days compared to wild-type Mtb. This is the strongest attenuation observed so far for Mtb mutants lacking genes involved in iron utilization. In conclusion, this study identified the first components of novel siderophore export systems which are essential for virulence of Mtb.

Comparison of initial antibiotic choice and treatment of cellulitis in the pre- and post-community-acquired methicillin-resistant Staphylococcus aureus eras.

UNLABELLED: Treatment success of cellulitis in the age of community-acquired methicillin-resistant Staphylococcus aureus (CAMRSA). A comparison of initial antibiotic choice and treatment success in the pre- and post-CAMRSA eras. OBJECTIVE: The objective of this study is to determine antibiotic prescribing patterns and treatment failure rates for cellulitis in the pre- and post-CAMRSA eras. METHODS: We performed an electronic chart review of patients seen in our emergency department with cellulitis in 2000 and 2005. Inclusion criteria included age 18 years or more and received a single oral antibiotic for cellulitis. Exclusion criteria were incision and drainage, surgery, or admission on initial visit. Treatment failure was defined as a repeat visit in the subsequent 30 days and a change in antibiotics, admission to the hospital, incision and drainage of abscess, or surgical intervention. Antibiotic-prescribing practices and treatment failure rates were then compared in the pre- and post-CAMRSA eras. RESULTS: There was a significant decrease in beta-lactam antibiotics and an increase in CAMRSA-effective antibiotics prescribed in 2005 vs 2000. The difference in treatment failure rates of the beta-lactams and CAMRSA antibiotics was statistically insignificant. There has not been an increase in failure rates of the beta-lactam antibiotics for simple cellulitis since the emergence of CAMRSA. CONCLUSION: Our study demonstrates that prescribing practices for simple cellulitis have changed since the emergence of CAMRSA. This may not be appropriate because beta-lactam antibiotics perform as well as 'CAMRSA antibiotics' in our study.

The retrospective prevalence of community-acquired methicillin-resistant Staphylococcus aureus in soft tissue abscesses at two military level I trauma centers.

STUDY OBJECTIVE: Many studies have shown that community-acquired methicillin-resistant Staphylococcus aureus (CAMRSA) is a very prevalent organism. However, no data have been published to date with regard to CAMRSA prevalence in patients presenting to the emergency department (ED) of a military medical facility. Our objective is to estimate the period prevalence of CAMRSA in cases of soft tissue abscesses seen in the emergency departments of two major military hospitals. METHODS: A retrospective review of electronic records was performed from January 1, 2004 to August 10, 2005. This database was used to identify patients with the diagnosis of abscess, the procedure code for incision and drainage, and culture of wound. After data were accumulated, standard prevalence calculations were applied to determine prevalence of CAMRSA in abscesses at our emergency departments. Antibiotic susceptibilities were then evaluated with regard to the CAMRSA bacteria. RESULTS: The prevalence at our two emergency departments was 68% (751 abscesses, 220 cultured, 155 methicillin-resistant S. aureus (MRSA)-positive cultures). The prevalence at Brooke Army Medical Center and Wilford Hall Medical Center emergency departments was 70% (520 abscesses, 145 cultured, and 101 MRSA positive) and 65% (231 abscesses, 75 cultured, and 49 MRSA positive), respectively. CONCLUSION: The occurrence of CAMRSA is not isolated to the civilian population. The prevalence of CAMRSA in this population is significant, and may pose serious operational and deployment-related ramifications requiring the attention of military medical planners as well as forward medical care providers. The probability of CAMRSA infection should be considered when treating soft tissue abscesses in the military emergency department.

Treatment of yellow scorpion (Leiurus quinquestriatus) sting: a case report.

OBJECTIVES: To report the treatment given to a 26-year-old Air Force medic who was stung twice by a yellow scorpion (Leiurus quinquestriatus) while stationed in Iraq and to describe the problems and issues related to the use of the scorpion antivenin. PATIENT CASE: The patient presented 2 hours after envenomation to the local military treatment facility, where she was minimally symptomatic initially. Shortness of breath and anxiety developed, and the patient was sedated, intubated, and evacuated to a large Air Force medical facility for more advanced care. Vasopressor support was required during flight. At the medical facility, antivenin was administered, and the patient's cardiac condition was stabilized with norepinephrine drip, mild hydration, and vasopressor support. A second dose of antivenin diluted in sodium chloride and further pressor support were required. ST-segment depression eventually resolved, and the patient was gradually taken off norepinephrine and extubated. She recovered fully within 2 weeks and returned to active duty. DISCUSSION: Because the antivenin used is not licensed by the Food and Drug Administration, informed consent was needed; however, it could not be obtained because the patient was unconscious, intubated, and in a life-or-death situation. Antivenin selection is based on the species of scorpion and symptom severity; therefore, the scorpion should be, with great care, killed for identification. In the military setting, inventory control, storage, and accountability are vital issues surrounding antivenin use, and these are discussed in this article. CONCLUSION: Immediate action and effective communication, along with timely antivenin administration and well-equipped intensive care facilities, were integral in saving the life of this victim of a yellow scorpion envenomation. All level 3 facilities in Southwest Asia must be familiar with ordering, administering, and documenting this antivenin because it is difficult to obtain and infrequently available.