Computational Study of Copper(II) Complexation and Hydrolysis in Aqueous Solutions Using Mixed Cluster/Continuum Models

We use density functional theory (B3LYP) and the COSMO continuum solvent model to characterize the structure and stability of the hydrated Cu(II) complexes [Cu(MeNH_2)(H_2O)_(n−1)]^(2+) and [Cu(OH)_x(H_2O)_(n−x)]^(2−x) (x = 1−3) as a function of metal coordination number (4−6) and cluster size (n = 4−8, 18). The small clusters with n = 4−8 are found to be the most stable in the nearly square-planar four-coordinate configuration, except for [Cu(OH)_3(H_2O)]^−, which is three-coordinate. In the presence of the two full hydration shells (n = 18), however, the five-coordinate square-pyramidal geometry is the most favorable for Cu(MeNH_2)^(2+) (5, 6) and Cu(OH)^+ (5, 4, 6), and the four-coordinate geometry is the most stable for Cu(OH)_2 (4, 5) and Cu(OH)_3^− (4). (Other possible coordination numbers for these complexes in the aqueous phase are shown in parentheses.) A small energetic difference between these structures (0.23−2.65 kcal/mol) suggests that complexes with different coordination numbers may coexist in solution. Using two full hydration shells around the Cu^(2+) ion (18 ligands) gives Gibbs free energies of aqueous reactions that are in excellent agreement with experiment. The mean unsigned error is 0.7 kcal/mol for the three consecutive hydrolysis steps of Cu^(2+) and the complexation of Cu^(2+) with methylamine. Conversely, calculations for the complexes with only one coordination shell (four equatorial ligands) lead to a mean unsigned error that is >6.0 kcal/mol. Thus, the explicit treatment of the first and the second shells is critical for the accurate prediction of structural and thermodynamic properties of Cu(II) species in aqueous solution

Obstetrical complications among adolescent girls at the maternity ward of Ignace Deen National Hospital

Background: The objective of this study was to highlight obstetrical complications that occurred among adolescent girls who delivered at the ward and to identify factors associated with the occurrence of such complications.Methods: This was a prospective study of descriptive and analytical type extending over a period of one year from September 1, 2016 to August 31, 2017 carried out at the maternity ward of Ignace Deen National Hospital at Conakry Teaching Hospital (CHU). It covered a continuous series of 1034 deliveries among adolescent girls.Results: The frequency of childbirth among adolescent girls was 16.7%. The main complications identified were dystocia, severe preeclampsia, eclampsia, retroplacental hematoma, placenta previa, uterine rupture, severe anemia, postpartum hemorrhage and puerperal endometritis. These complications occurred among adolescent girls aged 18 to 19, christian, skin and pelvic bones secondary school or university students. Factors associated with such complications were the marital status (p=0.010), the gestational age (p=0.012), the number of prenatal consultations (p=0.001), the place of prenatal consultation (p=0.001), the reason for admission (p=0.000) and the mode of admission (p=0.000).Conclusions: Childbirth among adolescent girls is frequent in this context; complications are numerous but they are preventable in the vast majority of cases

PAMAM Dendrimers Undergo pH Responsive Conformational Changes without Swelling

Atomistic molecular dynamics (MD) simulations of a G4-NH2 PAMAM dendrimer were carried out in aqueous solution using explicit water molecules and counterions (with the Dreiding III force field optimized using quantum mechanics). Our simulations predict that the radius of gyration (R_g) of the dendrimer changes little with pH from 21.1 Å at pH 10 (uncharged PAMAM) to 22.1 Å at pH 5 (charged with 126 protons), which agrees quantitatively with recent small angle neutron scattering (SANS) experiments (from 21.4 Å at pH 10 to 21.5 Å at pH 5). Even so we predict a dramatic change in the conformation. The ion pairing in the low pH form leads to a locally compact dense shell with an internal surface area only 37% of the high pH form with a dense core. This transformation from “dense core” at high pH to “dense shell” at low pH could facilitate the encapsulation and release of guest molecules (e.g., drugs) using pH as the trigger, making dendrimers a unique drug delivery vehicle

Evaluation of B3LYP, X3LYP, and M06-class density functionals for predicting the binding energies of neutral, protonated, and deprotonated water clusters

In this paper we assess the accuracy of the B3LYP, X3LYP, and newly developed M06-L, M06-2X, and M06 functionals to predict the binding energies of neutral and charged water clusters including (H_2O)_n, n = 2−8, 20), H_3O+(H_2O_)n, n = 1−6, and OH−(H_2O)_n, n = 1−6. We also compare the predicted energies of two ion hydration and neutralization reactions on the basis of the calculated binding energies. In all cases, we use as benchmarks calculated binding energies of water clusters extrapolated to the complete basis set limit of the second-order Møller−Plesset perturbation theory with the effects of higher order correlation estimated at the coupled-cluster theory with single, double, and perturbative triple excitations in the aug-cc-pVDZ basis set. We rank the accuracy of the functionals on the basis of the mean unsigned error (MUE) between calculated benchmark and density functional theory energies. The corresponding MUE (kcal/mol) for each functional is listed in parentheses. We find that M06-L (0.73) and M06 (0.84) give the most accurate binding energies using very extended basis sets such as aug-cc-pV5Z. For more affordable basis sets, the best methods for predicting the binding energies of water clusters are M06-L/aug-cc-pVTZ (1.24), B3LYP/6-311++G(2d,2p) (1.29), and M06/aug-cc-PVTZ (1.33). M06-L/aug-cc-pVTZ also gives more accurate energies for the neutralization reactions (1.38), whereas B3LYP/6-311++G(2d,2p) gives more accurate energies for the ion hydration reactions (1.69)

Surgical intervention on uterine fibromyoma in a country with limited resources: case of the gynaecology-obstetrics department of the Communal Medical Centre of Ratoma Conakry - Guinea

Background: In developing countries, treatment of uterine fibromyoma is confronted with numerous problems, namely: financial inaccessibility to the proposed treatments, fear of surgery and the weakness of the technical platform. The objectives of the study were to calculate the frequency of uterine fibromyomas, describe the socio-demographic characteristics of patients, identify the main clinical data and to describe the modalities of surgical management.Methods: It was a mixed descriptive study, cumulative over a period of 5 years (60 months) with data collection in two phases: a 4-year retrospective study from January 1, 2015 to December 31, 2018 and a 1-year prospective study from January 1, 2019 to December 31, 2019.Results: Authors collected 135 cases of uterine fibromyomas operated on out of a total of 260 cases of gynaecological pathologies, i.e. a frequency of 51.92%. Nulliparous women were the most concerned (45.18%), and women who attended school (60%) and those who did not attend school (40%). Women at home and housewives accounted for 42.20% and 54.07% respectively. Clinically, the circumstances of discovery were dominated by menometrorrhagia and menorrhagia respectively 77.77% and 68.14%. The large uterus was the most frequent physical sign found in 96.29% of cases. Uterine fibromyomas were recorded in 86.6% of cases in women with genital activity. The operative indications were dominated by the large polymyomatous uterus (64.44%), followed by hemorrhagic fibroma (18.52%) The surgical treatment was conservative in 92.60%. The total hysterectomy was performed in 7.40. Lethality was 1.4%.Conclusions: The surgical management of fibroids contrasts conservative treatment (myomectomy) with radical treatment (hysterectomy) with multiple possible approaches (hysteroscopy, vaginal surgery, laparoscopy or laparotomy). In this context, only laparotomy was possible due to lack of equipment. Laparoscopy and hysteroscopy equipment are necessary for less invasive surgery

pK_a Calculations of Aliphatic Amines, Diamines, and Aminoamides via Density Functional Theory with a Poisson−Boltzmann Continuum Solvent Model

In order to make reliable predictions of the acid−base properties of macroligands with a large number of ionizable sites such as dendrimers, one needs to develop and validate computational methods that accurately estimate the acidity constants (pK_a) of their chemical building blocks. In this article, we couple density functional theory (B3LYP) with a Poisson−Boltzmann continuum solvent model to calculate the aqueous pK_a of aliphatic amines, diamines, and aminoamides, which are building blocks for several classes of dendrimers. No empirical correction terms were employed in the calculations except for the free energy of solvation of the proton (H^+) adjusted to give the best match with experimental data. The use of solution-phase optimized geometries gives calculated pK_a values in excellent agreement with experimental measurements. The mean absolute error is 0.5 pK_a unit compared to experimental measurements. We find that geometry optimization in solution is essential for making accurate pK_a predictions for systems possessing intramolecular hydrogen bonds

Census-Independent Population Estimation using Representation Learning

Knowledge of population distribution is critical for building infrastructure, distributing resources, and monitoring the progress of sustainable development goals. Although censuses can provide this information, they are typically conducted every 10 years with some countries having forgone the process for several decades. Population can change in the intercensal period due to rapid migration, development, urbanisation, natural disasters, and conflicts. Census-independent population estimation approaches using alternative data sources, such as satellite imagery, have shown promise in providing frequent and reliable population estimates locally. Existing approaches, however, require significant human supervision, for example annotating buildings and accessing various public datasets, and therefore, are not easily reproducible. We explore recent representation learning approaches, and assess the transferability of representations to population estimation in Mozambique. Using representation learning reduces required human supervision, since features are extracted automatically, making the process of population estimation more sustainable and likely to be transferable to other regions or countries. We compare the resulting population estimates to existing population products from GRID3, Facebook (HRSL) and WorldPop. We observe that our approach matches the most accurate of these maps, and is interpretable in the sense that it recognises built-up areas to be an informative indicator of population

Partitioning of Poly(amidoamine) Dendrimers between n-Octanol and Water

Dendritic nanomaterials are emerging as key building blocks for a variety of nanoscale materials and technologies. Poly(amidoamine) (PAMAM) dendrimers were the first class of dendritic nanomaterials to be commercialized. Despite numerous investigations, the environmental fate, transport, and toxicity of PAMAM dendrimers is still not well understood. As a first step toward the characterization of the environmental behavior of dendrimers in aquatic systems, we measured the octanol−water partition coefficients (logK_(ow)) of a homologous series of PAMAM dendrimers as a function of dendrimer generation (size), terminal group and core chemistry. We find that the logKow of PAMAM dendrimers depend primarily on their size and terminal group chemistry. For G1-G5 PAMAM dendrimers with terminal NH_2 groups, the negative values of their logK_(ow) indicate that they prefer to remain in the water phase. Conversely, the formation of stable emulsions at the octanol−water (O/W) interface in the presence of G6-NH_2 and G8-NH_2 PAMAM dendrimers suggest they prefer to partition at the O/W interface. In all cases, published studies of the cytotoxicity of Gx-NH_2 PAMAM dendrimers show they strongly interact with the lipid bilayers of cells. These results suggest that the logKow of a PAMAM dendrimer may not be a good predictor of its affinity with natural organic media such as the lipid bilayers of cell membranes

Prophylactic and emergency cesareans: a comparative study on 718 observations at the maternity ward of Ignace Deen National hospital

Background: The objective of the study is to compare the frequency, the socio-demographic characteristics, the indications, the fetal maternal prognosis and the Robson classification of prophylactic and emergency caesarean sections.Methods: This was a comparative study of prophylactic and emergency caesarean sections at the maternity of Ignace Deen national hospital. It was a 12 month (July 1, 2016 to June 30, 2017) descriptive and analytical study.Results: Prophylactic caesarean sections accounted for 12, 51% of caesarean sections and 3.96% of deliveries at the ward. Prophylactic caesarean sections involved pregnant women aged from 20 to 29, holder of higher education degrees (51.54%), married (92.76%) employed (56.83%) and whose prenatal visit was provided by the obstetrician (73.54%). While the emergency caesarean section concerned parturient aged between 20 and 34, mostly non-schooled (36.49%), transferred patients (80.22%) and nulliparous (58.5%). Surgical indications were mainly scarred uterus (32.32%) and maternal pathologies (18.11%) prophylaxis; bleeding in the last quarter (25.90%) acute fetal distress (20.33%) in emergency. Groups 6 and 5 of the Robson classification were the most represented with a 2.23% morbidity and a zero maternal lethality in prophylaxis versus groups 5 and 6 with a 10.03% morbidity and a 1.67% maternal lethality in emergency.Conclusions: Improving this prognosis would be achieved through an increase in the frequency of prophylactic caesarean sections

Post-operative maternal morbidity and mortality after caesarean delivery and laparotomy for uterine rupture at the gynecology and obstetrics service of the Ignace Deen National Hospital in Guinea

Background: The aim of the work was to study post-operative maternal morbidity and mortality after caesarean delivery and laparotomy for uterine failure, to describe the main causes and to analyze the risk factors.Methods: It was a descriptive, comparative and analytical study lasting 2 years with data collection in 2 phases, one of which was a retrospective study lasting one year from July 2018 to June 2019 and the other a prospective study also lasting one year, from July 2019 to June 2020. It concerned all pregnant women who had been caesarized or had had a laparotomy for uterine rupture with complications and those who had not developed any complications. The parameters studied were types of complications, risk factors and maternal mortality. The Chi-square test was used to compare the two populations with a significance level p=0.05.Results: During the study period, 6141 hospitalizations were recorded among which 5682 surgical procedures were performed, i.e. 92.52% of hospitalizations. Caesarean delivery accounted for 90.55% of surgical procedures and laparotomy for uterine rupture for 1.10%. The overall maternal post-operative morbidity rate was 7.60%. Post-operative anemia was by far the most common complication (75.76%) followed by infection (23.46%). The maternal death rate was 0.92% with a ratio of 409.97 maternal deaths per 100,000 live births and more than 2/3 of these deaths were due to caesarean delivery. Anemia and septic shock were the main causes of death. Factors related to this post-operative maternal morbidity were: age greater than or equal to 40 years, multi-parity, illiteracy, emergency obstetric evacuation, low socio-economic level, poor quality of prenatal follow-up and rupture of membranes before admission.Conclusion: In the emergency context concerning majority of our cesarean deliveries and the totality of uterine ruptures predispose the mother to high significant morbidity and mortality