ALBERT

Beschreibung: This study presents a 2-D lidar odometry based on an ICP (iterative closest point) variant used in a simple and straightforward platform that achieves real-time and low-drift performance. With a designated multi-scale feature extraction procedure, the lidar cloud information can be utilized at multiple levels and the speed of data association can be accelerated according to the multi-scale data structure, thereby achieving robust feature extraction and fast scan-matching algorithms. First, on a large scale, the lidar point cloud data are classified according to the curvature into two parts: smooth collection and rough collection. Then, on a small scale, noise and unstable points in the smooth or rough collection are filtered, and edge points and corner points are extracted. Then, the proposed tangent-vector-pairs based on edge and corner points are applied to evaluate the rotation term, which is significant for producing a stable solution in motion estimation. We compare our performance with two excellent open-source SLAM algorithms, Cartographer and Hector SLAM, using collected and open-access datasets in structured indoor environments. The results indicate that our method can achieve better accuracy.

Beschreibung: Volcanic ash fall-out represents a serious hazard for air and road traffic. The forecasting models used to predict its time–space evolution require information about the core characteristics of volcanic particles, such as their granulometry. Typically, such information is gained by the spot direct observation of the ash collected at the ground or by using expensive instrumentation. In this paper, a vision-based methodology aimed at the estimation of ash granulometry is presented. A dedicated image processing paradigm was developed and implemented in LabVIEW™. The methodology was validated experimentally using digital reference images resembling different operating conditions. The outcome of the assessment procedure was very encouraging, showing an accuracy of the image processing algorithm of 1.76%.

Beschreibung: Low birthweight (LBW) is a worldwide problem that particularly affects developing countries. However, limited information is available on its magnitude in rural area of Burkina Faso. This study aimed to estimate the prevalence of low birthweight and to identify its associated factors in Nanoro health district. A secondary analysis of data collected during a cross-sectional survey was conducted to assess the prevalence of low birthweight in Nanoro health and demographic surveillance system area (HDSS). Maternal characteristics extracted from antenatal care books or by interview, completed by malaria diagnosis were examined through a multi-level logistic regression to estimate odd-ratios of association with low birthweight. Significance level was set at 5%. Of the 291 neonates examined, the prevalence of low birthweight was 12%. After adjustment for socio-demographic, obstetric and malaria prevention variables, being primigravid (OR = 8.84, [95% CI: 3.72–21.01]), or multigravid with history of stillbirth (OR = 5.03, [95% CI: 1.54–16.40]), as well as the lack of long-lasting insecticide treated bed net use by the mother the night preceding the admission for delivery (OR = 2.5, [95% CI: 1.1–5.9]) were significantly associated with neonate low birthweight. The number of antenatal visits however did not confer any direct benefit on birthweight status within this study area. The prevalence of low birthweight was high in the study area and represents an important public health problem in Burkina Faso. In light of these results, a redefinition of the content of the antenatal care package is needed.

Beschreibung: Periprocedural antithrombotic management with glycoprotein IIb/IIIa inhibitors (GPI) for intracranial artery stenting is still controversial. We sought to assess the safety and efficacy of prophylactic tirofiban infusion for acute intracranial intraprocedural stent thrombosis in routine clinical practice. From January 2013 to December 2019, consecutive patients treated with endovascular stenting for symptomatic intracranial atherosclerotic stenosis (ICAS) were identified and dichotomized by whether tirofiban was used. The efficacy and safety outcomes were compared by propensity score matching. A total of 160 consecutive patients in the tirofiban group and 177 patients in the non-tirofiban group were enrolled. Propensity score matching analysis selected 236 matched patients. One acute intraprocedural stent thrombosis (AIST) occurred in patients receiving prophylactic tirofiban, while 8 in the non-tirofiban group. The incidence of AIST in the tirofiban group was significantly lower than that in the non-tirofiban group (0.8% vs 6.8%, P = 0.039). The periprocedural ischemic events (8.5% vs 5.1%, P = 0.424), periprocedural intracranial hemorrhage (4.2% vs 0.8%, P = 0.219) and 30-day total mortality (3.4% vs 0%, P = 0.125) were not statistically different between the two groups. Compared with conventional stenting angioplasty without tirofiban, tirofiban prophylactic infusion can lower the incidence of AIST, without increasing the risk of periprocedural intracranial hemorrhage and 30-day total mortality. However, there is no superiority in reducing periprocedural ischemic events. The current study adds more important insights to the available clinical evidence on the use of tirofiban during stenting of ICAS.

Beschreibung: There have been several reports about the difficulties in removing 3.5-mm titanium locking screws from plates due to the stripping or rounding of the hexagonal screw socket. We investigated whether stripping the locking screw sockets can be prevented by using different screwdrivers or interposing materials into the socket during removal. We overtightened 120 3.5-mm titanium locking screws (Depuy Synthes, Paoli, PA) equally into locking plates on sawbone tibia models, applying a uniform torque of 4.5 Nm, exceeding the recommended torque of 1.5 Nm. Twenty screws each were removed using a straight-handle 2.5-mm screwdriver, T-handle screwdriver, hex key wrench, and straight-handle screwdriver with a non-dominant hand. In addition, 20 screws were removed using foil from a suture packet inserted into the screw socket or using parts of a latex glove inserted into the screw socket. The incidence rates of screw stripping using the straight-handle screwdriver, T-handle screwdriver, hex key wrench, non-dominant hand, foil interposition, and latex glove interposition were 75%, 40%, 35%, 90%, 60%, and 70%, respectively. When a T-handle screwdriver or hex key wrench was used, the probability of screw stripping was 4.50 times (odds ratio = 4.50, 95% confidence interval = 1.17 to 17.37, p = 0.03) and 5.57 times (odds ratio = 5.57, 95% confidence interval = 1.42 to 21.56, p = 0.01) lower than that with the straight-handle screwdriver, respectively. Foil or latex glove interpositions did not prevent screw stripping. Thus, in the current experimental study, T-handle screwdriver or hex key wrench usage decreased the incidence rate of screw stripping during removal compared to straight-handle screwdriver use.

Beschreibung: Air quality improvements pollution changes due to COVID-19 restrictions have been reported for many urban developments and large metropolitan areas, but the respective impacts at rural and remote zones are less frequently analysed. This study evaluated air pollution changes across all Portugal (68 stations) considering all urban, suburban and rural zones. PM10, PM2.5, NO2, SO2, ozone was analysed in pre-, during, and post-lockdown period (January–May 2020) and for a comparison also in 2019. NO2 was the most reduced pollutant in 2020, which coincided with decreased traffic. Significant drop (15–71%) of traffic related NO2 was observed specifically during lockdown period, being 55% for the largest and most populated region in country. PM was affected to a lesser degree (with substantial differences found for largely populated areas (Lisbon region ~ 30%; North region, up to 49%); during lockdown traffic-related PM dropped 10–70%. PM10 daily limit was exceeded 50% less in 2020, with 80% of exceedances before lockdown period. SO2 decreased by 35%, due to suspended industrial productions, whereas ozone concentrations slightly (though not significantly) increased (83 vs. 80 µg m–3).

Beschreibung: Calcination treatments in the range of 500–900 °C of TiO2 synthesised by the sol–gel resulted in materials with variable physicochemical (i.e., optical, specific surface area, crystallite size and crystalline phase) and morphological properties. The photocatalytic performance of the prepared materials was evaluated in the oxygen evolution reaction (OER) following UV-LED irradiation of aqueous solutions containing iron ions as sacrificial electron acceptors. The highest activity for water oxidation was obtained with the photocatalyst thermally treated at 700 °C (TiO2-700). Photocatalysts with larger anatase to rutile ratio of the crystalline phases and higher surface density of oxygen vacancies (defects) displayed the best performance in OER. The oxygen defects at the photocatalyst surface have proven to be responsible for the enhanced photoactivity, acting as important active adsorption sites for water oxidation. Seeking technological application, water oxidation was accomplished by immobilising the photocatalyst with the highest OER rate measured under the established batch conditions (TiO2-700). Experiments operating under continuous mode revealed a remarkable efficiency for oxygen production, exceeding 12% of the apparent quantum efficiency (AQE) at 384 nm (UV-LED system) compared to the batch operation mode.

Beschreibung: Preeclampsia is a multi-organ system disorder of pregnancy and is responsible for a significant rate of maternal morbidity and mortality worldwide. In Bangladesh, a large number of obstetric deaths occur every year but the exact reasons are not well investigated. The data regarding preeclampsia and its associated risk factors are scarce or limited in pregnant women in Bangladesh. Therefore, we aimed to conduct a cross-sectional study to estimate the prevalence of preeclampsia and identify the possible risk factors in a pregnant women cohort in Bangladesh. In this cross-sectional study, a total of 111 participants were enrolled and asked to include their anthropometric, socio-demographic, and other related lifestyle information in a standard questionnaire form. Blood samples were also collected from each participant to analyze serum levels of lipid profile, liver enzymes, uric acid, and creatinine by using standard methods. Logistic regression analysis was performed to identify the factors associated with preeclampsia. The overall prevalence of preeclampsia was 14.4%. About 10% of the pregnancies were found to have preeclampsia after 20 weeks of gestation without a previous history of hypertension. On the other hand, the prevalence of preeclampsia that superimposed on chronic hypertension was found to be 5.4%. Serum levels of TC, LDL-C, ALT and uric acid were significantly higher and HDL-C was significantly lower in preeclamptic pregnancies than the non-preeclamptic pregnancies. Respondents who required to take antihypertensive medications (AOR 5.45, 95% CI [1.09, 27.31]) and who never took antenatal care (AOR 6.83, 95% CI [1.00, 46.48]) were more likely to be preeclamptic. In conclusion, the present study showed a comparatively high prevalence of preeclampsia among pregnant women in Bangladesh. Some programmatic interventions such as medication for hypertension, antenatal visits to doctors, delivery and postnatal care services should be considered to reduce and prevent the hypertensive pregnancy disorders in Bangladesh.