Significant Inflection Point Research Articles

Trends in estimated total retail dispensed prescriptions of purported COVID-19 treatments and preventions in Canada

Abstract Objectives Several medications were proposed for the treatment and prophylaxis of COVID-19 but with limited supporting evidence. Herein, we assessed trends in the volume of projected total retail dispensed prescriptions for 12 agents proposed for treatment and prevention of COVID-19 before and after March 2020 in Canada. Methods We conducted a cross-sectional study using monthly prescription volumes obtained from IQVIA’s CompuScript database. We used joinpoint regression to identify significant inflection points and calculate the monthly percent change (MPC). Key findings Dispensations peaked after March 2020 for several medications, including hydroxychloroquine, fluvoxamine, ivermectin, colchicine, tocilizumab, sarilumab and famotidine. Although most peaks were short lived, large increases were observed for ivermectin (MPC from September 2020 to January 2021 = 28%) and famotidine (MPC from June 2021 to October 2021 = 14%). Conclusions Overall, Canadian prescribing patterns were mostly consistent with recommendations from guidelines and health regulatory bodies. Nonetheless, active monitoring of trends should continue.

Abstract P185: Disparities in Cardiovascular Disease and HIV Related Mortality in the United States

Introduction: Great strides have been made in microbiology and infectious diseases regarding HIV, revolutionizing the disease course. In the last forty years, advances in combination antiretroviral therapy (ART) have allowed HIV to become a chronic disease by dramatically decreasing the rates of acquired AIDS-defining illnesses. In contrast, a significant proportion of deaths in individuals infected with HIV due to cardiovascular events have been noted. Hypothesis: Disproportionate trends exist regarding CVD-related death within subpopulations of individuals infected with HIV in the United States (US). Methods: We utilized the CDC Wide-ranging Online Data for Epidemiologic Research database to ascertain mortality data using death certificate information from the National Vital Statistics System. All CVD-related deaths (ICD10 Codes: I00-I78) as the underlying cause of death and HIV (ICD10 Code: B20-B24) as the multiple causes of death from 1999 to 2020 were queried. The underlying cause of death is defined as the disease that directly led to death and multiple causes of death were defined as the diseases that contributed to death. Data were represented as age-adjusted mortality rates (AAMR) per 100,000 population and 95% confidence intervals, stratified by gender, racial, and geographic subgroups. Joinpoint regression (National Cancer Institute) was utilized for trend analysis and average annual percentage change (AAPC) calculation. Results: A total of 8,950 deaths were observed from 1999 to 2020. AAMR increased from 0.10 in 1999 to 0.15 in 2020 (p <0.05). AAMR was more likely to be related to non-ischemic heart disease (0.06) compared to ischemic heart disease (0.05) (p <0.05). AAMR was higher in males (0.20) compared with females (0.05) (p <0.05). AAMR was disproportionately higher in Black populations (0.53) compared to White populations (0.08) (p <0.05). No differences were observed for AAMR between Hispanic (0.12) and non-Hispanic (0.12) populations (p >0.05). AAMR was highest in the Northeast (0.15) and South (0.16) regions, followed by Western (0.11) regions, then finally the Midwest (0.06) regions (p <0.05). Cumulative AAPC from 1999 to 2020 was calculated at +1.7% (p <0.05) with a significant inflection point in 2010. AAPC increased significantly among male subgroups (+1.5%), Black subgroups (+0.8%), White subgroups (+1.6%), metro regions (+1.7%), Midwest regions (+2.3%), and Southern regions (+2.1%) (p <0.05), however, AAPC was not significantly different among female subgroups, Hispanic and non-Hispanic populations, non-metro regions, Northeast regions, and Western regions (p >0.05). Conclusion: Disparities linked to CVD-related death in the population infected with HIV exist among various gender, racial, and geographic subgroups. Research targeted at CVD prevention and management in this population is tantamount to addressing these healthcare disparities.

DOSE AND DOSE-RATE DEPENDENCE OF DSB-TYPE MUTANTS INDUCED BY X-RAYS OR TRITIUM BETA-RAYS: AN APPROACH USING A HYPERSENSITIVE SYSTEM.

To evaluate biological effects triggered by low levels of radiation, we established a uniquely sensitive experimental system to detect somatic mutations. By using the system, we found that mutant frequencies induced by X-rays were statistically significant at doses over 0.15Gy, and a linear dose relationship with the mutant frequency was observed at doses over 0.15Gy. The mutation spectra analysis revealed that mutation events generated by X-ray doses below 0.1Gy were similar to those observed in unirradiated controls. In addition, a significant inflection point for both, the mutant frequency and the mutation spectra, was found at dose-rates around 11mGy/day when cells were cultured in medium containing tritiated water. Because induced radiation-type events presented a clear dose/dose-rate dependency above the critical dose or the inflection point, these observations suggest that mutation events generated by radiation could change at a threshold dose-rate or a critical dose.

Ischemic Stroke Systems of Care in California: Evolution in the Organization During the Mechanical Thrombectomy Era

Background Optimized stroke systems of care enable access to timely care, including endovascular thrombectomy (EVT). Stroke systems have likely evolved after publication of EVT benefit (2015). Our objective was to map the stroke patient transfer network in California in terms of EVT access and patient transfer patterns, and to examine changes after 2015. Methods In this observational study, we identified all ischemic stroke encounters, transfers, alteplase use, and EVT procedures in California from 2010 to 2017. An established connection between any hospital pair was defined as the transfer of ≥2 patients between them. A 2‐level logistic regression model assessed whether encounters were more frequently transferred to EVT‐capable hospitals post‐2015, adjusting for patient‐ and hospital‐level factors. Linear regression examined trends in key network characteristics over time, and interrupted time series regressions examined for changes post‐2015. Results Among 336 247 encounters, 3.4% were transferred, 9.3% received alteplase, and 2.3% underwent EVT. From 2010 to 2017 the proportion that were EVT treated increased (1.0%–4.3%; P ‐for‐trend<0.001) with a significant increase post‐2015 ( P =0.01). Odds of transfer to EVT‐capable hospital were greater post‐2015 (adjusted odds ratio, 6.54; [95% CI 5.52–7.74]), but were lower for patients who were older, Black, Hispanic, and presented to a rural hospital. Significant network changes from 2010 to 2017 included increased number of encounters transferred, increased number of transferring hospitals, decreasing number of receiving hospitals, and increased proportion of receiving hospitals performing EVT. However, none of these network changes demonstrated a significant inflection point after 2015. Conclusion The California stroke network has been dynamic over time. Although most changes have been incremental, after the release of EVT trial data in 2015 changes in transfer patterns did lead to increased access to EVT.

Determining Optimal Sampling Numbers to Investigate the Soil Organic Matter in a Typical County of the Yellow River Delta, China

Soil organic matter (SOM) plays a crucial role in promoting soil tillage, improving soil fertility and providing crop nutrients. Investigation and sampling are the premise and basis for understanding the spatial distribution of SOM. The number of sampling points will affect the accuracy of spatial variation of SOM. Therefore, it is important scientific work to determine a reasonable number of sampling points under the premise of ensuring accuracy. In this study, Kenli County, a typical area of the Yellow River Delta in China, was taken as an example to investigate the effect of different sampling points on spatial-variation expression of SOM. A total of 12 sample subsets (including 900 samples) were randomly sampled at equal intervals from the 900 sample points, using geographic information system (GIS) technology and geostatistical analyses to explore the optimal number of samples. The results showed that the SOM content in the study area had a lower-middle degree of variation. As the number of sample points decreased, the spatial distribution of SOM showed the gradual weakening of detail-characterization ability; and when the number of sample points was too small (<100), there was a wrong expression that was not consistent with the actual situation. The value of RMSE has no obvious regularity with the change of sample number. The values of both ME and ASE showed a significant inflection point when the number of samples was 150 and remained around 0 and 4 as the number of samples increased, respectively. Combined with the three indicators of ME, RMSE and ASE, collecting at least 150 samples can satisfy the spatial-variation expression of SOM, equivalent to 107 sample points within the area of 1000 km2. The research results could provide important references for investigation of SOM content in areas with similar natural geographical conditions.

Political environment and mortality rates in the United States, 2001-19: population based cross sectional analysis

ObjectiveTo assess recent trends in age adjusted mortality rates (AAMRs) in the United States based on county level presidential voting patterns.DesignCross sectional study.SettingUSA, 2001-19.Participants99.8% of the US population.Main outcome measuresAAMR...

Study of the Influencing Factors on the Small-Quantity Fuel Injection of Piezoelectric Injector.

The piezoelectric injection-system provides a reliable approach for precise small-quantity fuel injection due to its fast, dynamic response. Considering the nonlinearity of a piezoelectric actuator, the complete electro-mechanical-hydraulic model of the piezoelectric injector was established and verified experimentally, which showed that it could accurately predict the fuel injection quantity. The small-quantity fuel injection with different driving voltages, pulse widths, and rail pressures was analyzed. The effects of key structural parameters of the injector on the delivery, control-chamber pressure fluctuation, and small-quantity injection characteristics were studied. The results show that the linearity of the curve of the injection volume with the pulse width was relatively poor, and there was a significant inflection point when the piezoelectric injector worked in the small pulse width region (PW < 0.6 ms). The bypass valve significantly accelerated the establishment of the control-chamber pressure, reduced the pressure fluctuation in the chamber, shortened the closing delay and duration of the needle valve, and reduced the rate of the fuel-quantity change so that it provided a greater control margin for the pulse width over the same fuel volume change interval. Under the condition of a small-quantity fuel injection of 20 mm3, decreasing the inlet orifice diameter and increasing the outlet orifice diameter shortened the minimum control pulse width and fuel injection duration required for the injector injection, which is beneficial for multiple and small-quantity fuel injection. However, these behaviors reduce the control margin for the pulse width, especially in small pulse width regions.

Temporal Trends in Adverse Pregnancy Outcomes in Birthing Individuals Aged 15 to 44Years in the United States, 2007 to 2019.

BackgroundAdverse pregnancy outcomes (APOs) (hypertensive disorders of pregnancy [HDP], preterm delivery [PTD], or low birth weight [LBW]) are associated adverse maternal and offspring cardiovascular outcomes. Therefore, we sought to describe nationwide temporal trends in the burden of each APO (HDP, PTD, LBW) from 2007 to 2019 to inform strategies to optimize maternal and offspring health outcomes.Methods and ResultsWe performed a serial cross‐sectional analysis of APO subtypes (HDP, PTD, LBW) from 2007 to 2019. We included maternal data from all live births that occurred in the United States using the National Center for Health Statistics Natality Files. We quantified age‐standardized and age‐specific rates of APOs per 1000 live births and their respective mean annual percentage change. All analyses were stratified by self‐report of maternal race and ethnicity. Among 51 685 525 live births included, 15% were to non‐Hispanic Black individuals, 24% Hispanic individuals, and 6% Asian individuals. Between 2007 and 2019, age standardized HDP rates approximately doubled, from 38.4 (38.2–38.6) to 77.8 (77.5–78.1) per 1000 live births. A significant inflection point was observed in 2014, with an acceleration in the rate of increase of HDP from 2007 to 2014 (+4.1% per year [3.6–4.7]) to 2014 to 2019 (+9.1% per year [8.1–10.1]). Rates of PTD and LBW increased significantly when co‐occurring in the same pregnancy with HDP. Absolute rates of APOs were higher in non‐Hispanic Black individuals and in older age groups. However, similar relative increases were seen across all age,racial and ethnic groups.ConclusionsIn aggregate, APOs now complicate nearly 1 in 5 live births. Incidence of HDP has increased significantly between 2007 and 2019 and contributed to the reversal of favorable trends in PTD and LBW. Similar patterns were observed in all age groups, suggesting that increasing maternal age at pregnancy does not account for these trends. Black–White disparities persisted throughout the study period.

Examining Whether Government Environmental Regulation Promotes Green Innovation Efficiency—Evidence from China’s Yangtze River Economic Belt

Based on the panel data of 11 provinces and cities in the Yangtze River Economic Belt from 2005 to 2018, this paper uses the SBM-DEA efficiency model with undesired output to measure the green innovation efficiency of the Yangtze River Economic Belt. The panel Tobit empirical analysis model was used to quantitatively analyze the impact of three different forms of government environmental regulations on the efficiency of green innovation. The research results show that the government’s mandatory environmental regulations and government financial subsidies for green innovation technology are two regulatory methods that positively promote the efficiency of regional green innovation, but government investment in environmental governance has a negative impact on the efficiency of regional green innovation. Then the study found that this negative impact has a significant inflection point effect: when it exceeds a certain threshold, the negative impact turns into a positive effect. At the same time, the impact of environmental regulations on the efficiency of green innovation has significant regional heterogeneity, and the three environmental regulations have a greater impact on downstream provinces and cities.

Alkalinity, pH, and pCO2 in the Laurentian Great Lakes: An initial view of seasonal and inter-annual trends

Ongoing human perturbations to the global inorganic carbon cycle can cause various changes in the pH and alkalinity of aquatic systems. Here seasonal and inter-annual trends in these variables were investigated in the five Laurentian Great Lakes using data from the U.S. EPA GLENDA database. These observations, along with temperature, were also used to predict the partial pressure of carbon dioxide in surface water (pCO2). There are strong seasonal differences in pH in all five lakes, with higher pH levels in summer than in spring. All lakes show significantly higher pCO2 values in spring than in summer. Michigan and Ontario show higher alkalinity values in spring; Huron shows lower spring values. Inter-annually, open-lake pH shows the highest values in all lakes around 2010, the time frame of lowest lake water levels, though only lakes Superior and Erie show statistically significant inflection points at that time. Inter-annual alkalinity trends differ considerably from those of pH. Superior’s alkalinity increases until ∼2008 and then begins dropping; Ontario’s alkalinity decreases until ∼2004 and then begins increasing, with the decrease coinciding with the introduction and establishment of Dreissenid mussels. The other lakes show much less clear inter-annual alkalinity trends. For pCO2, inter-annual trends in each lake show either increases from 1992 to 2019 (for Superior, Michigan, and Huron) or shifts from slightly decreasing values to increasing values for the other lakes. The timing of this shift is from 2008 to 2010.

Acute mental health service use following onset of the COVID-19 pandemic in Ontario, Canada: a trend analysis.

Background:The extent to which heightened distress during the COVID-19 pandemic translated to increases in severe mental health outcomes is unknown. We examined trends in psychiatric presentations to acute care settings in the first 12 months after onset of the pandemic.Methods:This was a trends analysis of administrative population data in Ontario, Canada. We examined rates of hospitalizations and emergency department visits for mental health diagnoses overall and stratified by sex, age and diagnostic grouping (e.g., mood disorders, anxiety disorders, psychotic disorders), as well as visits for intentional self-injury for people aged 10 to 105 years, from January 2019 to March 2021. We used Joinpoint regression to identify significant inflection points after the onset of the pandemic in March 2020.Results:Among the 12 968 100 people included in our analysis, rates of mental health–related hospitalizations and emergency department visits declined immediately after the onset of the pandemic (peak overall decline of 30% [hospitalizations] and 37% [emergency department visits] compared to April 2019) and returned to near prepandemic levels by March 2021. Compared to April 2019, visits for intentional self-injury declined by 33% and remained below prepandemic levels until March 2021. We observed the largest declines in service use among adolescents aged 14 to 17 years (55% decline in hospitalizations, 58% decline in emergency department visits) and 10 to 13 years (56% decline in self-injury), and for those with substance-related disorders (33% decline in emergency department visits) and anxiety disorders (61% decline in hospitalizations).Interpretation:Contrary to expectations, the abrupt decline in acute mental health service use immediately after the onset of the pandemic and the return to near prepandemic levels that we observed suggest that changes and stressors in the first 12 months of the pandemic did not translate to increased service use. Continued surveillance of acute mental health service use is warranted.

Induction of somatic mutations by low concentrations of tritiated water (HTO): evidence for the possible existence of a dose-rate threshold.

Tritium is a low energy beta emitter and is discharged into the aquatic environment primarily in the form of tritiated water (HTO) from nuclear power plants or from nuclear fuel reprocessing plants. Although the biological effects of HTO exposures at significant doses or dose rates have been extensively studied, there are few reports concerning the biological effects of HTO exposures at very low dose rates. In the present study using a hyper-sensitive assay system, we investigated the dose rate effect of HTO on the induction of mutations. Confluent cell populations were exposed to HTO for a total dose of 0.2 Gy at dose rates between 4.9 mGy/day and 192 mGy/day by incubating cells in medium containing HTO. HTO-induced mutant frequencies and mutation spectra were then investigated. A significant inflection point for both the mutant frequency and mutation spectra was found between 11 mGy/day and 21.6 mGy/day. Mutation spectra analysis revealed that a mechanistic change in the nature of the mutation events occurred around 11 mGy/day. The present observations and published experimental results from oral administrations of HTO to mice suggest that a threshold dose-rate for HTO exposures might exist between 11 mGy/day and 21.6 mGy/day where the nature of the mutation events induced by HTO becomes similar to those seen in spontaneous events.

Menopause does not modify disability trajectories in a longitudinal cohort of women with clinically isolated syndrome and multiple sclerosis followed from disease onset.

To evaluate the effect of menopause on disability accumulation in women followed from their clinically isolated syndrome (CIS). We examined the longitudinal changes in Expanded Disability Status Scale (EDSS) scores from CIS until the last follow-up in women belonging to the Barcelona CIS prospective cohort, followed through their menopausal transition. The analysis is based on 13,718 EDSS measurements, with an average of 28 EDSS measurements per patient. Differences in EDSS trajectories between menopausal and nonmenopausal women, controlling for age and disease duration, were evaluated. We performed two sensitivity analyses in women with confirmed MS and in those experiencing early menopause. From 764 eligible women, 496 (65%) responded to the questionnaire, and 74 (14.9%) reached menopause over the follow-up. We did not find a significant inflection point in EDSS trajectories around menopause (slope change -0.009; 95% CI -0.066; 0.046). The annual increase in EDSS over the complete course of the disease was significantly higher in menopausal women (0.049; 95% CI, 0.026-0.074) versus nonmenopausal (0.019; 95% CI, 0.008-0.031; interaction p value 0.025). This difference was lost when controlling for age and disease duration (EDSS annual increase of 0.059; 95% CI, 0.025-0.094 vs. 0.038; 95% CI, 0.021-0.057, respectively; interaction p value 0.321). No inflection point was detected when the analysis was restricted to women with confirmed MS or with earlier menopause. Menopause is not associated with an increased risk of disability in a CIS population, considering EDSS trajectories throughout the course of the disease together with age and disease duration.

The Diaries of Queen Liliuokalani of Hawaii, 1885–1900 ed. by David W. Forbes

Reviewed by: The Diaries of Queen Liliuokalani of Hawaii, 1885–1900 ed. by David W. Forbes Ronald Williams Jr., Ph.D. The Diaries of Queen Liliuokalani of Hawaii, 1885–1900. Edited and with Annotations by David W. Forbes. Honolulu: Hui Hānai, 2019. xxxvii + 538 pp. Bibliography. Notes. Illustrated. Index. $40.00 cloth There can be little argument that the editor of this text—over the past several decades of in-person archival research—has seen, read, and transcribed more material related to Hawai'i and its history that anyone else of our time and likely of the past century. His bibliographic and editorial work has produced canonical texts that have benefited countless researchers and delivered a greater understanding of Hawai'i's past to all. His four-volume Hawaiian National Bibliography stands out as an authoritative first stop for any historian on the trail of an elusive document or looking to broaden their research of a given topic. With his latest project, The Diaries of Queen Liliuokalani of Hawaii, 1885–1900, Forbes delivers another significant historical resource. Publication of the diaries of the last reigning sovereign of the Hawaiian Kingdom, Her Majesty Queen Lili'uokalani, adds significant content to the study of a life that still yet remains relatively under-explored and misunderstood. In a beautifully designed and illustrated book of over 500 pages, diary entries of the Queen are interspersed with annotations from the editor that offer further information about the many people, places, and events named within the diaries. Footnotes add biographical information to names mentioned in the original text. While these editorial insertions are a common, accepted method of delivering further content and context to the reader, they do mark places of outside authorship within an otherwise straightforward delivery of the subject's voice. [End Page 179] Issues of historiography in Hawai'i have taken center stage as a clear understanding of the past broad elision of Native voice propels demands for more inclusive histories. A prolific archive of Hawaiian-language writing—more than 125,000 pages of Hawaiian-language newspapers and likely an equal amount of government documents, private correspondence, and publications—is now being accessed by a growing number of scholars literate in the 'ōlelo makuahine (mother tongue) of these Islands. They are producing more inclusive, complex histories that often challenge long-entrenched master narratives of Hawai'i and its people. These important methodological shifts underway are not only about the inclusion of Native-language sources. In her brilliant biography of the Hawaiian statesman, John Papa 'Ī'ī, Facing The Spears of Change, Marie Alohalani Brown casts a paradigm that reaches beyond the mere use of Native-language sources and towards a cultural literacy that properly contextualizes and defines the sources gathered.11 The absence of both of these tools within this text is problematic. The Diaries of Queen Liliuokalani of Hawaii, 1885–1900 contains significant annotations and over a thousand footnotes that offer Hawaiian history from the sole perspective of English-language sources. The reign of Her Majesty Queen Lili'uokalani was one of the most significant inflection points in Hawaiian history and voices of the period engaged in polemic rhetorical battles in attempts to influence the public both domestically and abroad. Time and again the text offers a window into this period through the eyes of the opposition English-language press. One of the most quoted sources among the book's annotations is the Pacific Commercial Advertiser, a newspaper purchased in May 1888 by William Richards Castle (a staunch opponent of the monarchy and a central member of the Committee of Safety that overthrew the Queen on January 17, 1893). An insertion following the Queen's July 6, 1898 diary entry offers an important note that this was the date of the passing of the annexation resolution in the U.S. Congress. The annotation goes on to platform the response of the Pacific Commercial Advertsier in its July 14 headline: "Annexation! Here to Stay!" Responses to these events that led to the loss of their nation from the Native-language press such as "Lawe Lima Nui o Amerika I Na Paemoku O Hawaii," "Me ka Ae Ole o ka Poe Nona ka Aina," and...

The impact of COVID-19 pandemic on pornography habits: a global analysis of Google Trends.

As the COVID-19 spread globally, social distancing, self-isolation/quarantine, and national lockdowns have become crucial to control the pandemic. However, these measures may also lead to increases in social isolation, loneliness, and stress, which can alter the consumption of pornography habits. The aim of the study was thus to explore the interest pattern in pornography and coronavirus-themed pornography during the COVID-19 outbreak. Google Trends® was employed to determine the most popular porn websites (Porn, XNXX, PornHub, xVideos, and xHamster), and coronavirus-themed pornography worldwide and in six nations with different COVID-19 outbreak and self-isolation recommendations. We analyzed every search trend on Google® from January 9, 2020 to May 25, 2020 using “joint point regression analysis”. Comparisons of week relative search volume (WRSV) and temporal patterns were analyzed to assess the change of interest in search terms during nations lockdowns. Paired t-test was used to compare WRSV values among the porn websites during the national lockdowns and the equivalent timespan of the weeks in the previous 4 years. The research trend of almost every keyword increased with significant inflection points for those nations with a straight “stay at home orders” (China, Italy, Spain, and France). “PornHub” and “Porn” showed the highest increase of interest worldwide with an average weekend percentage change (AWPC) of 4.9 and 3.8, respectively. The mean WRSV for keywords in USA and Sweden did not show a similar increase as the other nations. The WRSV percentage change with the historical data had a peak during the straight nations’ lockdowns (p < 0.01). All the nations had a significant increase in WRSV coronavirus-themed pornography for each keyword (p < 0.01) with an AWPC, ranging worldwide between 18.5 and 61.8 (p < 0.01), after the beginning of self-quarantine. As strengths this study uses a big data technology to collect worldwide trend of interest, however, data are anonymous and do not allow analysis of subpopulation groups. In conclusion, we demonstrated an increased interest in pornography and coronavirus-themed pornography after the outbreak of COVID-19 in nations with a straight “stay at home orders”.

Pre-Pregnancy Hypertension Among Women in Rural and Urban Areas of the United States

BackgroundRates of maternal mortality are increasing in the United States with significant rural-urban disparities. Pre-pregnancy hypertension is a well-established risk factor for adverse maternal and offspring outcomes. ObjectivesThe purpose of this study was to describe trends in maternal pre-pregnancy hypertension among women in rural and urban areas in 2007 to 2018 in order to inform community-engaged prevention and policy strategies. MethodsWe performed a nationwide, serial cross-sectional study using maternal data from all live births in women age 15 to 44 years between 2007 and 2018 (CDC Natality Database). Rates of pre-pregnancy hypertension were calculated per 1,000 live births overall and by urbanization status. Subgroup analysis in standard 5-year age categories was performed. We quantified average annual percentage change using Joinpoint Regression and rate ratios (95% confidence intervals [CIs]) to compare yearly rates between rural and urban areas. ResultsAmong 47,949,381 live births to women between 2007 and 2018, rates of pre-pregnancy hypertension per 1,000 live births increased among both rural (13.7 to 23.7) and urban women (10.5 to 20.0). Two significant inflection points were identified in 2010 and 2016, with highest annual percentage changes between 2016 and 2018 in rural and urban areas. Although absolute rates were lower in younger compared with older women in both rural and urban areas, all age groups experienced similar increases. The rate ratios of pre-pregnancy hypertension in rural compared with urban women ranged from 1.18 (95% CI: 1.04 to 1.35) for ages 15 to 19 years to 1.51 (95% CI: 1.39 to 1.64) for ages 40 to 44 years in 2018. ConclusionsMaternal burden of pre-pregnancy hypertension has nearly doubled in the past decade and the rural-urban gap has persisted.

Influence of the depletion region in GaAs/AlGaAs quantum well nanowire photodetector

In semiconductor nanowire (NW) photodetectors, the Schottky barrier formed by the contact between metal and semiconductor can act as a depletion layer. For NW structures with a smaller diameter, the depletion region is especially important to the carrier transport. We prepared a GaAs/AlGaAs quantum well NW photodetector with a two-dimensional electron-hole tube, in which the two-dimensional hole tube (2DHT) formed by the inner layer of GaAs and AlGaAs has the most important role in the regulation of carriers. By adjusting the bias voltage to vary the depth of the depletion region, we have confirmed the influence of the depletion region in a 2DHT. A significant inflection point was found in the responsivity-voltage curve at 1.5 V. By combining the depletion region and 2DHT, the responsivity of the fabricated device was increased by 18 times to 0.199 A W−1 and the detectivity is increased by 5 times to 5.8 × 1010 Jones, compared to the pure GaAs NW photodetector. Reasonable combination of depletion layer and 2DHT was proved to promote high-performance NW photodetector.

Application of a water infiltration model for simulating water repellency of humus soil

AbstractOne‐dimensional infiltration experiments were conducted using hydrophilic and water‐repellent soils from the Guishui River Basin to study the effects of soil water repellency on cumulative infiltration (CI) and the infiltration rate (IR). The test results show that, for the hydrophilic soil (HS) sample, CI increases monotonously with time and IR decreases monotonously. For the water‐repellent soil (W‐RS), however, the following characteristics were observed: (a) There is an inflection point in CI and a sudden increase in IR. Larger values of the initial soil water content produce an earlier and more significant inflection point in CI, and a larger peak value of IR. (b) The post‐peak stable IR is greater than the pre‐peak value, ignoring the beginning of rapid infiltration, and the overall IR presents a single peak. The applicability of various water infiltration models was analysed for the two soil types. Numerical analysis suggests the following conclusions: (a) For both HS and W‐RS, the Kostiakov function, Gamma function, and Beta function (BF) models exhibit good applicability. (b) For W‐RS, the Gauss function model not only reflects the monotonous decrease in IR, but also produces a steady IR in the initial stage, a gradual increase before the peak value, and a gradual decrease after the peak value. Similarly, the BF model reflects the monotonous decrease in IR. A piecewise BF reproduces the U‐shaped change in rapid infiltration before the inflection point, as well as the gradual increase and right‐skewed distribution curve of W‐RS infiltration before and after the inflection point. The BF model achieves the best simulation accuracy and has the widest applicability.

DDES analysis of unsteady flow evolution and pressure pulsation at off-design condition of a centrifugal pump

In the present paper, to investigate unsteady flow structures and pressure pulsations at off-design conditions, a low specific speed centrifugal pump is investigated by the DDES (Delayed Detached Eddy Simulation) method. Emphasis is laid on the unsteady evolution of flow structure and pressure pulsation at the stalled condition. Results show that the jet-wake flow pattern could be captured by the current numerical simulation method, and it shows a high calculation precision for the jet flow. Relative velocity decreases rapidly in the wake region towards the blade suction side. Significant inflection point exists between the jet and wake flow regions, and it almost keeps unchanged at the identical impeller-volute position under various flow rates. At the stalled status, the inflection point moves towards the blade pressure side with the blade passing the volute tongue, and evident non-uniform flow distributions are formed in the blade channels characterized by the multiple vortices. The blade channel is gradually blocked by the corresponding stall cell when the blade approaches the volute tongue, and it indicates that the volute tongue has a significant effect on the evolution process of the stall structure. By combination analysis of the unsteady evolution of the stall structure and pressure spectrum, the stall frequency at 0.25fn (being fn the impeller rotating frequency) is captured for the current model pump.

Association between dietary calcium intake and BMD in children and adolescents.

AimEnsuring adequate calcium (Ca) intake during childhood and adolescence is critical to acquire good peak bone mass to prevent osteoporosis during older age. As one of the primary strategies to build and maintain healthy bones, we aimed to determine whether dietary Ca intake has an influence on bone mineral density (BMD) in children and adolescents.MethodsWe conducted a cross-sectional study composed of 10,092 individuals from the National Health and Nutrition Examination Survey (NHANES). Dietary Ca intake and total BMD were taken as independent and dependent variables, respectively. To evaluate the association between them, we conducted weighted multivariate linear regression models and smooth curve fittings.ResultsThere was a significantly positive association between dietary Ca intake and total BMD. The strongest association was observed in 12–15 year old whites, 8–11 year old and 16–19 year old Mexican Americans, and 16–19 year old individuals from other race/ethnicity, in whom each quintile of Ca intake was increased. We also found that there were significant inflection points in females, blacks, and 12–15 year old adolescents group, which means that their total BMD would decrease when the dietary Ca intake was more than 2.6–2.8 g/d.ConclusionsThis cross-sectional study indicated that a considerable proportion of children and adolescents aged 8–19 years would attain greater total BMD if they increased their dietary Ca intake. However, higher dietary Ca intake (more than 2.6–2.8 g/d) is associated with lower total BMD in females, blacks, and 12–15 year old adolescents group.