Twilight observations suggest unknown sources of HO_x

Measurements of the concentrations of OH and HO_(2) (HO_(x)) in the high-latitude lower stratosphere imply the existence of unknown photolytic sources of HO_(x). The strength of the additional HO_(x) source required to match the observations depends only weakly on solar zenith angle (SZA) for 80° < SZA < 93°. The wavelengths responsible for producing this HO_(x) must be longer than 650 nm because the flux at shorter wavelengths is significantly attenuated at high SZA by scattering and absorption. Provided that the sources involve only a single photon, the strength of the bonds being broken must be < 45 kcal mole^(−1). We speculate that peroxynitric acid (HNO_4) dissociates after excitation to an unknown excited state with an integrated band cross section of 2-3 × 10^(−20) cm^(2) molecule^(−1) nm (650 < λ < 1250 nm)

A brief review on micro-implants and their use in orthodontics and dentofacial orthopaedics

The aim of this study was to review the literature and evaluate the failure rates and factors that affect the stability and success of temporary anchorage devices (TADs) used as orthodontic anchorage. Data was collected from electronic databases: MEDLINE database and Google Scholar. Four combinations of term were used as keywords: \u201cmicro-implant\u201d, \u201cmini-implant\u201d, \u201cmini-screw\u201d, and \u201corthodontics\u201d. The following selection criteria were used to select appropriate articles: articles on implants and screws used as orthodontic anchorage, published in English, with both prospective and retrospective clinical and experimental investigations. The search provided 209 abstracts about TADs used as anchorage. After reading and applying the selection criteria, 66 articles were included in the study. The data obtained were divided into two topics: which factors affected TAD success rate and to what degree and in how many articles they were quoted. Clinical factors were divided into three main groups: patient-related, implant related, and management-related factors. Although all articles included in this meta-analysis reported success rates of greater than 80 percent, the factors determining success rates were inconsistent between the studies analyzed and this made conclusions difficult

Photolysis of sulphuric acid as the source of sulphur oxides in the mesosphere of Venus

The sulphur cycle plays fundamental roles in the chemistry and climate of Venus. Thermodynamic equilibrium chemistry at the surface of Venus favours the production of carbonyl sulphide and to a lesser extent sulphur dioxide. These gases are transported to the middle atmosphere by the Hadley circulation cell. Above the cloud top, a sulphur oxidation cycle involves conversion of carbonyl sulphide into sulphur dioxide, which is then transported further upwards. A significant fraction of this sulphur dioxide is subsequently oxidized to sulphur trioxide and eventually reacts with water to form sulphuric acid. Because the vapour pressure of sulphuric acid is low, it readily condenses and forms an upper cloud layer at altitudes of 60–70 km, and an upper haze layer above 70 km (ref. 9), which effectively sequesters sulphur oxides from photochemical reactions. Here we present simulations of the fate of sulphuric acid in the Venusian mesosphere based on the Caltech/JPL kinetics model, but including the photolysis of sulphuric acid. Our model suggests that the mixing ratios of sulphur oxides are at least five times higher above 90 km when the photolysis of sulphuric acid is included. Our results are inconsistent with the previous model results but in agreement with the recent observations using ground-based microwave spectroscopy and by Venus Express

Eaten out of house and home:impacts of grazing on ground-dwelling reptiles in Australian grasslands and grassy woodlands

Large mammalian grazers can alter the biotic and abiotic features of their environment through their impacts on vegetation. Grazing at moderate intensity has been recommended for biodiversity conservation. Few studies, however, have empirically tested the benefits of moderate grazing intensity in systems dominated by native grazers. Here we investigated the relationship between (1) density of native eastern grey kangaroos, Macropus giganteus, and grass structure, and (2) grass structure and reptiles (i.e. abundance, richness, diversity and occurrence) across 18 grassland and grassy Eucalyptus woodland properties in south-eastern Australia. There was a strong negative relationship between kangaroo density and grass structure after controlling for tree canopy cover. We therefore used grass structure as a surrogate for grazing intensity. Changes in grazing intensity (i.e. grass structure) significantly affected reptile abundance, reptile species richness, reptile species diversity, and the occurrence of several ground-dwelling reptiles. Reptile abundance, species richness and diversity were highest where grazing intensity was low. Importantly, no species of reptile was more likely to occur at high grazing intensities. Legless lizards (Delma impar, D. inornata) were more likely to be detected in areas subject to moderate grazing intensity, whereas one species (Hemiergis talbingoensis) was less likely to be detected in areas subject to intense grazing and three species (Menetia greyii, Morethia boulengeri, and Lampropholis delicata) did not appear to be affected by grazing intensity. Our data indicate that to maximize reptile abundance, species richness, species diversity, and occurrence of several individual species of reptile, managers will need to subject different areas of the landscape to moderate and low grazing intensities and limit the occurrence and extent of high grazing

Stratospheric aerosol - Observations, processes, and impact on climate

Interest in stratospheric aerosol and its role in climate have increased over the last decade due to the observed increase in stratospheric aerosol since 2000 and the potential for changes in the sulfur cycle induced by climate change. This review provides an overview about the advances in stratospheric aerosol research since the last comprehensive assessment of stratospheric aerosol was published in 2006. A crucial development since 2006 is the substantial improvement in the agreement between in situ and space-based inferences of stratospheric aerosol properties during volcanically quiescent periods. Furthermore, new measurement systems and techniques, both in situ and space based, have been developed for measuring physical aerosol properties with greater accuracy and for characterizing aerosol composition. However, these changes induce challenges to constructing a long-term stratospheric aerosol climatology. Currently, changes in stratospheric aerosol levels less than 20% cannot be confidently quantified. The volcanic signals tend to mask any nonvolcanically driven change, making them difficult to understand. While the role of carbonyl sulfide as a substantial and relatively constant source of stratospheric sulfur has been confirmed by new observations and model simulations, large uncertainties remain with respect to the contribution from anthropogenic sulfur dioxide emissions. New evidence has been provided that stratospheric aerosol can also contain small amounts of nonsulfate matter such as black carbon and organics. Chemistry-climate models have substantially increased in quantity and sophistication. In many models the implementation of stratospheric aerosol processes is coupled to radiation and/or stratospheric chemistry modules to account for relevant feedback processes

Cerebrospinal fluid CXCL10 is associated with the presence of low level CSF HIV during suppressive antiretroviral therapy

Surrogate markers of HIV central nervous system (CNS) persistence are needed because direct HIV measurements from the CNS require specialized protocols and are not always detectable or quantifiable. We analyzed paired plasma and CSF samples from people with HIV (PWH) on suppressive therapy (ART) with a validated HIV single copy RNA assay. Two potential markers of CNS persistence were measured (CXCL10 and sCD30). We then examined associations with CSF HIV RNA positivity in univariable and multivariable analyses. Among 66 individuals, 18.2% had detectable CSF HIV. Individuals who had detectable HIV in CSF had higher CSF CXCL10 concentrations (median 514 pg/ml versus median 317 pg/ml, p = 0.019), but did not have significantly different CSF sCD30 concentrations (median 7.5 ng/ml versus median 7.6 ng/ml, p = 0.78). In the multiple logistic analysis, both higher CSF CXCL10 (p = 0.038) and plasma HIV detectability (p = 0.035) were significantly associated with detectable CSF HIV. Both sCD30 and CXCL10 correlated positively with NfL and NSE, two neuronal markers. This study demonstrates that CSF CXCL10 concentrations reflect low level HIV CNS persistence despite virologic suppression on ART. Given that it is readily detectable and quantifiable, this chemokine may be a promising biomarker to evaluate HIV eradication therapies that target the CNS

Novel Psychiatric Disorder 6 Months After Traumatic Brain Injury in Children and Adolescents

OBJECTIVE: To investigate the factors predictive of novel psychiatric disorders in the interval 0-6 months following traumatic brain injury (TBI). METHODS: Children ages 5-14 years consecutively hospitalized for mild to severe TBI at five hospitals were recruited. Participants were evaluated at baseline (soon after injury) for pre-injury characteristics including psychiatric disorders, socioeconomic status (SES), psychosocial adversity, family function, family psychiatric history, and adaptive function. In addition to the psychosocial variables, injury severity and lesion location detected with acquisition of a research MRI were measured to develop a biopsychosocial predictive model for development of novel psychiatric disorders. Psychiatric outcome, including occurrence of a novel psychiatric disorder, was assessed 6 months after the injury. RESULTS: The recruited sample numbered 177 children, and 141 children (80%) returned for the six-month assessment. Of the 141 children, 58 (41%) developed a novel psychiatric disorder. In univariable analyses, novel psychiatric disorder was significantly associated with lower SES, higher psychosocial adversity, and lesions in frontal lobe locations, such as frontal white matter, superior frontal gyrus, inferior frontal gyrus, and orbital gyrus. Multivariable analyses found that novel psychiatric disorder was independently and significantly associated with frontal-lobe white matter, superior frontal gyrus, and orbital gyrus lesions. CONCLUSION: The results demonstrate that occurrence of novel psychiatric disorders following pediatric TBI requiring hospitalization is common and has identifiable psychosocial and specific biological predictors. However, only the lesion predictors were independently related to this adverse psychiatric outcome

Повторна реваскуляризація рецидиву хронічної артеріальної недостатності після реконструкції аорто/клубово-стегнового сегмента

The aim of the work: to improve results of revascularization of the lower extremity arterial bed in patients with relapse of chronic arterial insufficiency by applying endovascular angioplasty methods in the complex of re-operative surgery. Materials and Methods. The results of surgical treatment of 522 patients with atherosclerotic occlusion of the aortoiliac-femoral segment mere studied. 231 patients were diagnosed with stage IIIA arterial insufficiency, 191 had chronic critical arterial ischemia stage IIIB-IV, and 100 had chronic stage IIB. In the analysis of primary surgical interventions, three groups of patients were identified in patients with recurrent chronic arterial ischemia. Group I included 22 observations (28.2 %) – primary surgery – reconstruction of the aortoiliac-femoral area in the absence of hemodynamically significant atherosclerotic process of the femoral-distal segment, group II – 43 observations (55.1 %) – primary surgery – reconstruction aortoiliac-femoral segment in the presence of stenotic-occlusive process of the femoral-popliteal zone. Group III – 13 observations (16.7 %) – primary surgery – reconstruction of the aortoiliac-femoral area with autogenous femoral-distal bypass grafting. Results and Discussion. Revascularization of the lower limb trunk at relapse of chronic arterial ischemia was performed taking into account the features of the primary surgical intervention, localization of the stenotic-occlusive process, prevalence and combination with other segments of the lower extremity arterial bed. Progressive lesions of the atherosclerotic process of the zone of distal anastomosis of the aortoiliac-femoral alloprosthesis were detected in 36 (48.7%) observations, the tibia zone – in 61 (78.2 %) patients. The main intervention at revascularization was femoral-distal shunting operations, which in 32 cases were supplemented with endovascular balloon angioplasty of the tibial artery, of which in 19 interventions angioplasty of two arteries was performed. In the occlusive-stenotic process of the tibial arteries, 23 popliteal-posterior-tibial (anterior-tibial) shunts were performed. The postoperative period in 10 (12.8 %) patients was complicated by the development of reconstruction segment thrombosis and in 2 cases the thrombosis developed after endovascular balloon angioplasty.Цель работы: улучшить результаты повторной реваскуляризации артериального русла нижних конечностей у больных с рецидивом хронической артериальной недостаточности путем применения в комплексе повторного оперативного вмешательства методов эндоваскулярной ангиопластики. Материалы и методы. Прослежено отдаленные результаты хирургического лечения 522 пациентов с атеросклеротическим поражением аорто-бедренно-подколенного сегмента. У 231 пациентов диагностирован ХАН ІІІА ст., по классификации Fontaine R. с учетом критериев Европейской рабочей группы, в 191 – ХКИНК ІІІБ-IV ст., в 100 – ХАН ІІБ ст. Выделено три группы больных. І группа – 22 наблюдения (28,2 %) – первичная операция – реконструкция аорто/подвздошно-бедренной зоны при отсутствии гемодинамически значимого атеросклеротического процесса бедренно-дистального сегмента, II группа – 43 наблюдения (55,1 %) – первичная операция – реконструкция аорто/подвздошно-бедренного сегмента при наличии стенотично-оклюзионного процесса бедренно-подколенной зоны. III группа 13 наблюдений (16,7 %) – первичная операция – реконструкция аорто/подвздошно-бедренной зоны дополненная аутовенозным бедренно-дистальным шунтированием. Результаты исследований и их обсуждение. Повторную реваскуляризацию магистрального русла нижних конечностей при рецидиве ХАН осуществляли с учетом особенностей первичного оперативного вмешательства, локализации стенотично-оклюзионного процесса, его распространенности и сочетании с другими сегментами артериального русла нижних конечностей. Установлено прогрессирующее поражение атеросклеротическим процессом зоны дистального анастомоза аорто/подвздошно-бедренного аллопротеза в 36 (48,7 %) наблюдениях, а берцовой зоны – в 61 (78,2 %) больного. Основным хирургическим вмешательством при повторной реваскуляризации были бедренно-дистальные шунтирующие операции, в 32 случаях дополненные эндоваскулярной баллонной ангиопластикой берцовой артерии, из них в 19-ти вмешательствах выполнено ангиопластику сразу двух артерий. При оклюзивно-стенотическом процессе берцовых артерий выполнено 23 подколенно-задне-большеберцовых (передне-большеберцовых) шунтирований. Послеоперационный период у 10 (12,8 %) пациентов осложнился развитием тромбоза сегмента реконструкции, из них в двух случаях после эндоваскулярной баллонной ангиопластики.Мета роботи: покращити результати повторної реваскуляризації артеріального русла нижніх кінцівок у хворих із рецидивом хронічної артеріальної недостатності шляхом застосування в комплексі повторного оперативного втручання методів ендоваскулярної ангіопластики. Матеріали і методи. В роботу включено 522 пацієнти з атеросклеротичним ураженням аорто-стегно-підколінного сегмента. У 231 пацієнта діагностовано ХАН ІІІА ст., у 191 – ХКІНК ІІІБ-ІV ст., у 100 – ХАН ІІБ ст. Виділено три групи хворих. І група – 22 спостереження (28,2 %) – первинна операція – реконструкція аорто/клубово-стегнової зони за відсутності гемодинамічно значущого атеросклеротичного процесу стегно-дистального сегмента; ІІ група – 43 спостереження (55,1 %) – первинна операція – реконструкція аорто/клубово-стегнового сегмента за наявності стенотично-оклюзивного процесу стегно-підколінної зони; ІІІ група – 13 спостережень (16,7 %) – первинна операція – реконструкція аорто/клубово-стегнової зони доповнена автовенозним стегно-дистальним шунтуванням. Результати досліджень та їх обговорення. Повторну реваскуляризацію магістрального русла нижніх кінцівок при рецидиві ХАН здійснювали із врахуванням особливостей первинного оперативного втручання, локалізації стенотично-оклюзивного процесу, його поширеності та поєднання з іншими сегментами артеріального русла нижніх кінцівок. Виявлено прогресуюче ураження атеросклеротичним процесом зони дистального анастомозу аорто/клубово-стегнового алопротеза у 36 (48,7 %) спостереженнях, а гомілкової зони – у 61 (78,2 %) хворого. Основним хірургічним втручанням при повторній реваскуляризації були стегно-дистальні шунтуючі операції, які в 32 випадках доповнені ендоваскулярною балонною ангіопластикою гомілкової артерії, з них у 19-ти втручаннях виконано ангіопластику одразу двох артерій. При оклюзивно-стенотичному процесі гомілкових артерій виконано 23 підколінно-задньо-великогомілкових (передньо-великогомілкових) шунтувань. Післяопераційний період у 10 (12,8 %) пацієнтів ускладнився розвитком тромбозу сегмента реконструкції, з них у двох випадках після ендоваскулярної балонної ангіопластики

Novel Oppositional Defiant Disorder 6 Months After Traumatic Brain Injury in Children and Adolescents

OBJECTIVE: The investigators aimed to assess predictive factors of novel oppositional defiant disorder (ODD) among children and adolescents in the first 6 months following traumatic brain injury (TBI). METHODS: Children ages 5-14 years who experienced a TBI were recruited from consecutive admissions to five hospitals. Testing of a biopsychosocial model that may elucidate the development of novel ODD included assessment soon after injury (baseline) of preinjury characteristics, including psychiatric disorders, adaptive function, family function, psychosocial adversity, family psychiatric history, socioeconomic status, injury severity, and postinjury processing speed (which may be a proxy for brain injury). MRI analyses were also conducted to examine potential brain lesions. Psychiatric outcome, including that of novel ODD, was assessed 6 months after the injury. RESULTS: A total of 177 children and adolescents were recruited for the study, and 134 who were without preinjury ODD, conduct disorder, or disruptive behavior disorder not otherwise specified (DBD NOS) returned for the 6-month assessment. Of those who returned 6 months postinjury, 11 (8.2%) developed novel ODD, and none developed novel conduct disorder or DBD NOS. Novel ODD was significantly associated with socioeconomic status, preinjury family functioning, psychosocial adversity, and processing speed. CONCLUSIONS: These findings show that an important minority of children with TBI developed ODD. Psychosocial and injury-related variables, including socioeconomic status, lower family function, psychosocial adversity, and processing speed, significantly increase risk for this outcome

ПОВТОРНА РЕВАСКУЛЯРИЗАЦІЯ РЕЦИДИВУ ХРОНІЧНОЇ АРТЕРІАЛЬНОЇ НЕДОСТАТНОСТІ У ПАЦІЄНТІВ ПІСЛЯ РЕКОНСТРУКЦІЇ АОРТО/КЛУБОВО-СТЕГНОВОЇ ЗОНИ

The aim of the work.&nbsp;To improve the results of repeated revascularization of the arterial bed of the lower extremities in patients with relapse of chronic arterial insufficiency in the late postoperative period after aorto/iliofemoral region. Materials and Methods.&nbsp;The results of surgical treatment of 522 patients were monitored during 2006–2019. 353 patients were subjected to surgery, 260 of whom had disturbed blood flow in the thigh-popliteal segment. 159 patients were treated in the specified time for occlusive-stenotic lesion of the iliofemoral zone, 94 of whom had blood flow disorder along the femoral and popliteal arterial bed. At the time of primary surgery, 228 patients were diagnosed with chronic arterial insufficiency (CAI) degree IIIA (according to the Fontaine R. classification, taking into account the criteria of the European Working Group (1992)), in 189 – KhKINC IIB-IV degree, in 98 – CAI degree IIB. 92 (17.6 %) patients were diagnosed with hemodynamically significant stenosis of the extracranial arteries, 75 of them patients underwent surgery on the vessels of the neck in the conditions of surgical treatment of atherosclerotic lesions of the aorto/iliofemoral-popliteal arterial area. Results and Discussion.&nbsp;In 78 patients with recurrent chronic arterial insufficiency of the lower extremities in the distant postoperative period, re-operative intervention was performed taking into account the features of primary revascularization of the arterial bed, localization of the stenotically occlusive process, its combination and the prevalence of atherosclerotic. Re-revascularization was complicated by the development of the thrombosis of the reconstruction segment (10 cases, representing 12.8 % of observations). Conclusions.&nbsp;Non-standard, technically sophisticated, multilevel surgery is the major revascularizing intervention in patients with relapsed chronic arterial insufficiency. For revascularization of the tibial arterial segment, thigh/popliteal and tibial autovenous bypass was used and endovascular balloon angioplasty was used.Мета роботи.&nbsp;Покращити результати повторної реваскуляризації артеріального русла нижніх кінцівок у пацієнтів із рецидивом хронічної артеріальної недостатності у віддаленому післяопераційному періоді після реконструкції аорто/клубово-стегнової зони. Матеріали і методи.&nbsp;Протягом 2006–2019 рр. простежено віддалені результати хірургічного лікування 522 хворих. Оперативне втручання проведено 353 пацієнтам, з яких у 260 мало місце порушення кровотоку по стегно-підколінному сегменті. У вказані терміни прооперовано 159 пацієнтів із приводу оклюзивно-стенотичного ураження клубово-стегнової зони, з яких у 94 мало місце порушення кровоплину по стегно-підколінному артеріальному руслі. На час первинного хірургічного втручання у 228 пацієнтів діагностовано хронічну артеріальну недостатність (ХАН) ІІІА ст. (за класифікацією R. Fontaine з урахуванням критеріїв Європейської робочої групи (1992)), у 189 – ХКІНК ІІІБ–ІV ст., у 98 – ХАН ІІБ ст. У 92 (17,6 %) хворих був гемодинамічно значимий стеноз екстракраніальних артерій, з них 75 проведено оперативне втручання на судинах шиї в умовах хірургічного лікування атеросклеротичного ураження аорто/клубово-стегно-підколінного артеріального русла. Результати й обговорення.&nbsp;У 78 пацієнтів із рецидивом хронічної артеріальної недостатності нижніх кінцівок у віддаленому післяопераційному періоді повторне оперативне втручання здійснювали з урахуванням особливостей первинної реваскуляризації артеріального русла, локалізації стенотично оклюзивного процесу, його поєднання та поширення атеросклеротичного процесу. Повторна реваскуляризація ускладнилася розвитком тромбозу сегмента реконструкції (10 випадків, що становить 12,8 % спостережень). Висновки.&nbsp;Основним реваскулярним втручанням у пацієнтів із рецидивом хронічної артеріальної недостатності є нестандартні, технічно складні, багаторівневі решунтуючі операції. При реваскуляризації гомілкового артеріального сегмента використовували стегно/підколінно-гомілкове аутовенозне шунтування та ендоваскулярну ангіопластику