Pertinence of Children’s Chest X-Ray Request Form and Practice at the Regional Hospital of Ngaoundere Cameroon

Background: Chest X-ray is frequently performed for evaluation of chest disease in both adults and children. Children are more exposed to the adverse effects of radiation as compared to adults. During our daily practice, we noticed that most of children’s chest X-ray results were normal. Purpose: This study aimed to evaluate the indications, the technic, the irradiation and the result of chest X-rays in children in order to know if the practice of these X-rays was relevant. Method: Cross-sectional and descriptive study conducted at the Imaging Regional Center of Ngaoundere from April to August 2017. A total number of 145 radiographs and 140 X-ray requests of 140 children were considered in this work. The conformity of the request were verified according to the recommendations of the National Agency for Accreditation and Health Evaluation in France (NAAHE), technical condition of realization and results were appreciated and the entrance surface dose (ESD) of the patients was estimated using a mathematical algorithm. Results: Children under 5 years (63.5%) were more represented in our study. The main indications were: cough (22.1%), suspicion of pneumonia (16.4%) and bronchitis (15.7%). No indication was mentioned on 69.3% of the request forms. After confrontation to the “Guide for proper use of medical imaging examinations” (GPU), we only had 24% conformity of indications. 82.7% of the examinations required immobilization assistance by the parents. Most of the children were imaged in a standing-up position (82.9%) and the anterior-posterior view (77.9%) was more practiced. After the analysis of the pictures, 62% of them presented an optimal contrast, while 42.1% of X-ray were performed without beam collimation. 25 X-rays were repeated: 12 (48%) because of patient’s motion and 13 (52%) of mispositionning. After interpretation, 87 (62.14%) chest X-ray were normal. Main lesion observed were pneumonia (17.14%) followed by bronchopeumopathy (5.71%) and bronchitis (5%). The obtained ESD values were 0.11, 0.15 and 0.17 mGy respectively for the 0 - 1 year, 1 - 5 year and 5 - 10 year age groups;0.2 and 0.57 respectively for postero-anterior (PA) and lateral (LAT) view for the age group 10 - 15 years, which were slightly greater than the values in internationally published studies. Conclusion: The request for children chest X-ray is not relevant in terms of indication, technical conditions of realization and irradiation.

Complex Formation of 1,6-Anhydro-<i>β</i>-Maltose and Sodium Ions Using Single-Crystal X-Ray Crystallography and NMR Spectroscopy

Complex formation of 1,6-anhydro-β-maltose and sodium ions was characterized using single-crystal X-ray crystallography and solution- and solid-state NMR spectroscopy. The 7-coordination structure, comprising two 1,6-anhydro-β-maltoses, a thiocyanate ion and a sodium ion, was identified in the crystal of the complex, where a sodium ion was positioned in the center of the pentagon. In the NMR study, the line broadening of 23Na signals and the decrease of the spin-lattice relaxation times (T1) of 23Na were observed in CD3OD in the presence of 1,6-anhydro-β-maltose, indicating complex formation.

实用化导向的X射线晶体学与结构解析教学改革探索

结构决定性能。物质结构是当代化学、材料、生物学科前沿探索的基石和导引,测定解析物质结构是很多科研工作者必备的技能和研究手段。X射线衍射是结构测定最常见的方法之一。在科研一线工作的师生对X射线晶体学知识和结构解析技能有着大量的需求。然而,当前国内高校开设专业X射线晶体学课程较少,课程内容理论性强,实践环节不足,不能完全满足非晶体专业方向学生需求。面对X射线衍射结构解析的实际问题,学生难以从传统课程和导师等渠道得到足够支持帮助,需求和供给存在缺口。本文分析国内X射线晶体学教学和知识传播现状以及存在的问题,从知识提升、技能培养和信心树立三个方面针对性地改革X射线晶体学与结构解析的教学方式和内容,通过将传统课程拆分为X射线衍射原理、简明晶体学和结构解析技术三部分,扩充实践内容环节,特别是晶体数据收集和结构解析精修的要点技巧,辅以必要的基础理论知识,有效补充广大非晶体专业方向师生亟需的X射线晶体学基础知识和结构解析技术,围绕学生科研一线实际需要,以提升实战技能来解决学生的痛点和难点,同时树立学生面对结构解析的自信心。

Synthesis, Characterization and X-ray Crystal Structure of 4-Fluoro-N-(2-methyl-5-((2-(p-tolyloxy)acetamido)- methyl)pyrimidin-4-yl)benzamide

A new crystal of 4-fluoro-N-（2-methyl-5-（（2-（p-tolyloxy）acetamido）methyl）pyrimi- din-4-yl）benzamide has been prepared at room temperature and characterized by 1H NMR, 13C- NMR, IR, MS, elemental analysis and X-ray single-crystal determination. The compound crystallizes in monoclinic, space group P21 /c with a = 17.226（5）, b = 13.934（4）, c = 17.262（5）, μ= 92.180（5）°, V = 4140（2） ？3, Dc = 1.311 g/cm3, Z = 8, F（000） = 1712 and ？？= 0.095 mm-1. The molecular packing in the crystal is the result of N-H…ydrogen bonds.

Synthesis,Characterization and X-ray Crystal Structure of 2-Methylpropan-2-aminium Methyl ((4-Fluorobenzamido)(4-fluorophenyl)methyl) phosphonate·H_2O

A new crystal of 2-methylpropan-2-aminium methyl （（4-fluorobenzamido）（4- fluorophenyl）methyl）phosphonate has been prepared at room temperature and characterized by ZH- NMR, 13C NMR, IR, MS, elemental analysis and X-ray single-crystal determination. The compound crystallizes in monoclinic space, group C2/c with a = 20.719（2）, b = 11.8559（13）, c = 18.176（2） A,β = 94.434（2）°, V= 4451.4（9） A3, Dc = 1.317 Mg/m3, Z= 8, F（000） = 1864 and μ= 0.174 mm-1. The crystal packing is stabilized by intermolecular N-H……O and O-H……O hydrogen bonds, as well as by weak π-π stacking interactions.

Synthesis, Characterization and X-ray Crystal Structure of O,O~ˊ-Dipropyl α-（2,4-Dichlorolphenoxyacylamido）-α-（4-methoxyphenyl） Methylphosphonates

A new crystal of O,Oˊ-dipropyl-α-（2,4-dichlorolphenoxyacylamido）-α-（4-methoxyphenyl） methylphosphonates has been prepared at room temperature and characterized by elemental analysis and IR,MS,1H NMR spectra,13C NMR spectra and X-ray single-crystal determination.The complex crystallizes in triclinic,space group P1 with a = 7.858（2）,b = 12.621（4）,c = 12.621（4）,α = 96.17（3）,β = 90.960（3）,γ = 90.960（3）°,V = 1243.9（7）3,Dc = 1.346 Mg/m3,Z = 2,μ = 0.362 mm-1and F（000） = 528.

Preparation, crystallization and preliminary X-ray diffraction analysis of PH1948, predicted RNA methyltransferase from Pyrococcus horikoshii

RNA methyltransferase is responsible for transferring methyl and resulting in methylation on the bases or ribose ring of RNA, which existed widely but mostly remains an open question. A recombinant protein PH1948 predicting RNA methyl- transferase from Pyrococcus horikoshii OT3 has been crystallized. The crystals of selenomethionyl PH1948 belong to space group C2, with unit-cell parameters a=207.0 ?, b=43.1 ?, c=118.2 ?, β=92.1°, and diffract X-rays to 2.2 ? resolution. The VM value was determined to be 2.8 ?3/Da, indicating the presence of four protein molecules in the asymmetric unit.

Synthesis,Characterization and X-ray Crystal Structure of N,N'-Bis(4-nitrophenylcarba-mothioyl)-isophthalamide·DMF

A new crystal of N,N＇-bis（4-nitrophenylcarbamothioyl）isophthalamide DMF solva-te has been prepared at room temperature and characterized by elemental analysis and IR,MS,1H NMR spectra and X-ray single-crystal determination.The complex crystallizes in monoclinic,space group P21/c with a = 11.2093（12）,b = 22.081（2）,c = 13.9640（15） ,β= 112.128（2）°,V = 3201.8（6） 3,C28H30N8O8S2,Mr = 670.72,Dc = 1.391 Mg/m3,Z = 4,μ= 0.228 mm-1,F（000） = 1400,the final R = 0.0483 and wR = 0.1411（I 2σ（I））.The molecular packing in the crystal is the result of N-H…O hydrogen bonding.

Synthesis, Characterization, X-ray Crystal Structure and Herbicidal Activity of(E)-2-(2,4-Dichlorophenoxy)-1-(5,5-dimethyl-2-oxido-1,3,2-dioxaphosphinan-2-yl)vinyl 2-(2,4-Dichlorophenoxy)acetate

A new crystal of（E）-2-（2,4-dichlorophenoxy）-1-（5,5-dimethyl-2-oxido-1,3,2-dioxaphosphinan-2-yl）vinyl 2-（2,4-dichlorophenoxy）acetate has been determined by single-crystal X-ray diffraction. The compound crystallizes in triclinic, space group P1 with a = 7.9393（17）, b = 11.974（3） ？, c = 13.532（3） ？, α = 90.937（4）, β = 101.998（3）, γ = 101.363（4）°, V = 1231.5（5） ？3, Dc = 1.500 Mg/m3, Z = 2, F（000） = 568 and μ = 0.585 mm^（-1）. The molecular packing in the crystal is the result of C（10）–H（10）···O（5） hydrogen bond, as well as weak π-π stacking interactions. The herbicidal activity results indicated that the title compound 3 showed 80~100% inhibitory activities against all of the tested weeds at a dosage of 150 g×ai/ha.

X-ray Structure of 1- (3' -Phenyl-4' -morpholinyl-2' 5' - dithiole-1' - ylidene)-3, 4-biscarboethoxy-2-thionaphthalene

The title compound (C28H27NO5S3, Mr= 553. 69) was prepared bythe reaction of a-thiobenzoylthioformmorholine with diethyl acetylene dicarboxylate.The crystal is monoclinic, space group P21/n with a= 9. 160(3), b= 17. 726(3), c=16. 602(3) A ; β= 100. 375(13)°; V=2651. 4(10) A3, Z=4, Dc= 1. 387 g/cm3, μ(MoKa) =0. 319 mm-1, F(000) =1160, R=0. 0428, wR(F2) =0. 0910 for 2438 observed reflections (I】2(I)). X-ray analysis reveals that interatomic distances for C(5)-C(6), C(13)-C(14) and C(21)-C(22) are 1. 331(4), 1. 351(4), 1. 344(4)A respectively, which show that they are normal C=C double bonds. All S-C bondlengths are similar to typical S-C single bonds (1. 75 - 1. 78 A ). The five-membered ring A (C(5) -C(6) -S(2)-C(13) -S(1) ) (Fig. 1) and six-membered ringB (C(14) -C(15) -C(20) -C(21)-C(22)-S(3) ) (Fig. 1) adopt the flat twist conformation. Furthermore, the morpholine ring adopts chair conformtion.

X-ray Structure of 1- (3' -Phenyl-4' -morpholinyl-2' 5' - dithiole-1' - ylidene)-3, 4-biscarboethoxy-2-thionaphthalene

The title compound (C28H27NO5S3, Mr= 553. 69) was prepared bythe reaction of a-thiobenzoylthioformmorholine with diethyl acetylene dicarboxylate.The crystal is monoclinic, space group P21/n with a= 9. 160(3), b= 17. 726(3), c=16. 602(3) A ; β= 100. 375(13)°; V=2651. 4(10) A3, Z=4, Dc= 1. 387 g/cm3, μ(MoKa) =0. 319 mm-1, F(000) =1160, R=0. 0428, wR(F2) =0. 0910 for 2438 observed reflections (I>2(I)). X-ray analysis reveals that interatomic distances for C(5)-C(6), C(13)-C(14) and C(21)-C(22) are 1. 331(4), 1. 351(4), 1. 344(4)A respectively, which show that they are normal C=C double bonds. All S-C bondlengths are similar to typical S-C single bonds (1. 75 - 1. 78 A ). The five-membered ring A (C(5) -C(6) -S(2)-C(13) -S(1) ) (Fig. 1) and six-membered ringB (C(14) -C(15) -C(20) -C(21)-C(22)-S(3) ) (Fig. 1) adopt the flat twist conformation. Furthermore, the morpholine ring adopts chair conformtion.

结晶矿物岩相学课程教学实践与探索

结晶矿物岩相学是材料科学相关本科专业的一门非常重要的专业基础课。结合我校的具体教学改革与实践,本文探讨了实际教学中积累的几点基本经验,确保课程教学的教学质量和学习效果,并在课程教学中通过多种途径培养学生的综合素质。

结晶学实验三维动画演示的制作

利用３ＤＳｔｕｄｉｏ Ｍａｘ 强大的建模、材质选择、渲染和动画设计制作功能可使结晶学中大量抽象的概念和三维晶体模型变得具体生动。

Combination of NMR spectroscopy and X-ray crystallography offers unique advantages for elucidation of the structural basis of protein complex assembly

NMR spectroscopy and X-ray crystallography are two premium methods for determining the atomic structures of macro-biomolecular complexes.Each method has unique strengths and weaknesses.While the two techniques are highly complementary,they have generally been used separately to address the structure and functions of biomolecular complexes.In this review,we emphasize that the combination of NMR spectroscopy and X-ray crystallography offers unique power for elucidating the structures of complicated protein assemblies.We demonstrate,using several recent examples from our own laboratory,that the exquisite sensitivity of NMR spectroscopy in detecting the conformational properties of individual atoms in proteins and their complexes,without any prior knowledge of conformation,is highly valuable for obtaining the high quality crystals necessary for structure determination by X-ray crystallography.Thus NMR spectroscopy,in addition to answering many unique structural biology questions that can be addressed specifically by that technique,can be exceedingly powerful in modern structural biology when combined with other techniques including X-ray crystallography and cryo-electron microscopy.

Sequence-Based Protein Crystallization Propensity Prediction for Structural Genomics: Review and Comparative Analysis

Structural genomics (SG) is an international effort that aims at solving three-dimensional shapes of important biological macro-molecules with primary focus on proteins. One of the main bottlenecks in SG is the ability to produce dif-fraction quality crystals for X-ray crystallogra-phy based protein structure determination. SG pipelines allow for certain flexibility in target selection which motivates development of in- silico methods for sequence-based prediction/ assessment of the protein crystallization pro-pensity. We overview existing SG databanks that are used to derive these predictive models and we discuss analytical results concerning protein sequence properties that were discov-ered to correlate with the ability to form crystals. We also contrast and empirically compare mo- dern sequence-based predictors of crystalliza-tion propensity including OB-Score, ParCrys, XtalPred and CRYSTALP2. Our analysis shows that these methods provide useful and compli-mentary predictions. Although their average ac- curacy is similar at around 70%, we show that application of a simple majority-vote based en-semble improves accuracy to almost 74%. The best improvements are achieved by combining XtalPred with CRYSTALP2 while OB-Score and ParCrys methods overlap to a larger extend, although they still complement the other two predictors. We also demonstrate that 90% of the protein chains can be correctly predicted by at least one of these methods, which suggests that more accurate ensembles could be built in the future. We believe that current protein crystalli-zation propensity predictors could provide useful input for the target selection procedures utilized by the SG centers.

Crystal Structure and Thermodynamic Study of Ephedrine Hydrochloride C_(10)H_(16)NOCl(s)

The crystal structure of ephedrine hydrochloride was determined by means of X-ray crystallography. The crystal system of the compound is monoclinic, and the space group is P21. Unit cell parameters are a=0.7308（6） nm, b=0.6124（5） nm, and c= 1.2618（11） nm; β=90°, β= 102°, and γ =90°; Z=2. Low-temperature heat capacities of the title compound were measured with an improved precision automated adiabatic calorimeter over a temperature range from 77 K to 396 K. A polynomial equation of the heat capacities as a function of temperature in the temperature region was fitted by the least-squares. Based on the fitted polynomial equation, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated and tabulated at the intervals of 5 K.

基于G-蛋白偶联受体激酶2抑制剂治疗心力衰竭的合理药物设计（英文）

G protein-coupled receptors(GPCRs)convert extracellular stimuli in the form of hormones,odorants and light into profound changes in cell homeostasis.Their timely desensitization is critical for cells to rapidly respond to changes in their environment and to avoid damage from sustained signaling.Seven GPCR kinases(GRKs)phosphorylate and regulate the activity of most of the^800 GPCRs in the human genome.Although GRKs normally play an adaptive role,in conditions such as chronic heart failure they are overexpressed and linked to disease progression.GRK2 and GRK5 have thus become important targets for the treatment of heart failure and pathological cardiac hypertrophy,respectively.Our lab has determined atomic structures representing all three vertebrate GRK subfamilies,and is now in the midst of a campaign to develop selective inhibitors of these enzymes using structure-based rational design.We have identified the FDA approved drug paroxetine as a selective GRK2 inhibitor,determined the crystal structure of the GRK2·paroxetine complex and,in collaboration with the Koch lab,showed that the drug improves contractility in myocytes and,most impressively,recovery in postmyocardial infarcted mice.Since then,we have identified additional chemical scaffolds that exhibit even higher potency and/or selectivity for GRK5.Using a"hybrid"inhibitor design approach we have generated GRK selective chemical probes that exhibit improved potency and stability and are able to increase inotropy and dampen the hypertrophic response in cardiomyocytes and small animal models.Structural analysis has revealed the molecular basis for selectivity and potency in many of these compounds,allowing for the design of future generations of GRK chemical probes.

New ternary compound La_8Al_(13)Sn_3

A new ternary compound La8Al13Sn3 was synthesized and studied by means of X-ray powder diffraction technique. The compound La8Al13Sn3 crystallizes in a hexagonal AlB2-type structure with space group P6/mmm （No. 191） and the lattice parameters a = 0.44919（1） nm and c = 0.43835（1） nm. The Smith and Snyder figure of merit for index, FN, is F30 = 197.3（30）. The Rietveld refinement for the crystal structure of the compound was carried out successfully. The liability R-factors of Rietveld refinement are Rp = 0.114 and Rwp = 0.148. The compound La8Al13Sn3 decomposes into LaAl2 with cubic structure and space group Fd 3m （227）, LaAl3 with hexagonal structure and space group P63/mmc （194）, and Sn at 720°C.

Synthesis,Crystal Structure and Cytotoxic Activities of Oxazolidin-2-one Derivatives

Four cytotoxic oxazolidin-2-one derivatives were prepared from alkynyl alcohol and isocynate with high yields of 83～95%, and their structures were characterized by IR, H-RESI-MS and NMR analysis. Meanwhile, the crystal of （Z）-4-benzylidene-3-ethyl-1-oxa-3-azaspiro[4.4] nonan-2-one （5a） was obtained and determined by X-ray single-crystal diffraction. Crystal data： monoclinic system, space group P121/c1, a = 10.9284（2）, b = 9.47510（10）, c = 14.2510（2） ？, β = 111.917（2）o, V = 1369.01（3） ？3, Z = 4, F（000） = 552.0, Dc = 1.248 Mg/m3, μ = 0.652 mm-1, R = 0.0473 and wR = 0.1207 for 2699 independent reflections （Rint = 0.0206） and 2581 observed ones （I 〉 2σ（I））.

Crystal structure of PqqB from <i>Pseudomonas putida</i>at 2.2 Åresolution

Pyrroloquinoline quinone (PQQ) is an important redox-active cofactor for many bacterial dehy-drogenases. It's biosynthetic pathway involves six or seven genes, one of which is pqqB. Former studies indicated that the protein encoded by pqqB, namely PqqB, functions as a PQQ transporter. Here we report the crystal structure of PqqB from Pseudomonas putida at 2.2 ? resolution together with functional studies to verify this theory.