DEGRO practical guideline for partial-breast irradiation

Purpose

This consensus statement from the Breast Cancer Working Group of the German Society for Radiation Oncology (DEGRO) aims to define practical guidelines for accelerated partial-breast irradiation (APBI).

Methods

Recent recommendations for relevant aspects of APBI were summarized and a panel of experts reviewed all the relevant literature. Panel members of the DEGRO experts participated in a series of conferences, supplemented their clinical experience, performed a literature review, and formulated recommendations for implementing APBI in clinical routine, focusing on patient selection, target definition, and treatment technique.

Results

Appropriate patient selection, target definition for different APBI techniques, and basic rules for appropriate APBI techniques for clinical routine outside of clinical trials are described. Detailed recommendations for APBI in daily practice, including dose constraints, are given.

Conclusion

Guidelines are mandatory to assure optimal results of APBI using different techniques.

Effects of hypnotics on sleep quality and daytime well-being. Data from a comparative multicentre study in outpatients with insomnia

The effect of treatment (28 days) with zopiclone, triazolam, flunitrazepam and placebo on sleep quality and daytime well-being was proven in a randomised, double-blind, parallel group, multicentre study in private practice. Results of an exploratory statistic of treatment efficacy in a subgroup of 1,291 patients suffering from insomnia are presented. Patients met the following criteria: insomnia lasting at least four weeks and the presence of at least two of the following: 1) sleep latency ≥ 45 minutes, 2) total sleep time ≤ 6 hours, and 3) nocturnal awakening ≥3 times. Treatment efficacy was assessed according to the following factors: either a shortening of sleep latency by at least 15 minutes, or prolongation of total sleep time by at least 20%, or reduction of the number of nocturnal awakenings to three or less and a refreshed feeling in the morning as well as no impairment in daytime well-being due to tiredness or anxiety. The total response rate was markedly higher with zopiclone (42.3%; p = 0.0003) than with placebo (29.0%). Triazolam (36.6%; p = 0.0905) and flunitrazepam (33.1%; p = 0.3401) were also more effective than the placebo, but they both tended to have a lower response rate than with zopiclone (p = 0.1199 and 0.0151, respectively). Total response was found to be essentially a reflection of the response of the socially important parameter of daytime well-being. These results suggest that zopiclone is more effective in the treatment of insomnia than either triazolam or flunitrazepam. Since the response of daytime well-being to therapy was generally poor, this parameter embodies the next main therapeutic challenge in the treatment of patients with insomnia.

DEGRO practical guidelines for radiotherapy of breast cancer VI: therapy of locoregional breast cancer recurrences

Objective

To update the practical guidelines for radiotherapy of patients with locoregional breast cancer recurrences based on the current German interdisciplinary S3 guidelines 2012.

Methods

A comprehensive survey of the literature using the search phrases “locoregional breast cancer recurrence”, “chest wall recurrence”, “local recurrence”, “regional recurrence”, and “breast cancer” was performed, using the limits “clinical trials”, “randomized trials”, “meta-analysis”, “systematic review”, and “guidelines”.

Conclusions

Patients with isolated in-breast or regional breast cancer recurrences should be treated with curative intent. Mastectomy is the standard of care for patients with ipsilateral breast tumor recurrence. In a subset of patients, a second breast conservation followed by partial breast irradiation (PBI) is an appropriate alternative to mastectomy. If a second breast conservation is performed, additional irradiation should be mandatory. The largest reirradiation experience base exists for multicatheter brachytherapy; however, prospective clinical trials are needed to clearly define selection criteria, long-term local control, and toxicity.

Following primary mastectomy, patients with resectable locoregional breast cancer recurrences should receive multimodality therapy including systemic therapy, surgery, and radiation +/− hyperthermia. This approach results in high local control rates and long-term survival is achieved in a subset of patients. In radiation-naive patients with unresectable locoregional recurrences, radiation therapy is mandatory. In previously irradiated patients with a high risk of a second local recurrence after surgical resection or in patients with unresectable recurrences, reirradiation should be strongly considered. Indication and dose concepts depend on the time interval to first radiotherapy, presence of late radiation effects, and concurrent or sequential systemic treatment. Combination with hyperthermia can further improve tumor control.

In patients with isolated axillary or supraclavicular recurrence, durable disease control is best achieved with multimodality therapy including surgery and radiotherapy. Radiation therapy significantly improves local control and should be applied whenever feasible.

A magnetooptical study of (4-(2-dibutylaminoethanolato-N,O,O,O) chlorido copper(II)): a cubane complex with dominant ferromagnetic interactions

This paper reports the experimental and theoretical study of a tetranuclear (CuClOCH2CH2N(C4H9)2)4 complex. Analysis of the magnetic circular dichroism spectrum was performed based on the Hamiltonian that includes the crystal field of the nearest ligands and the spin-orbit interaction. The crystal field parameters were evaluated in the framework of the exchange charge model that accounts for the exchange and covalence effects. The values of the crystal field parameters obtained during the analysis of the magnetic circular dichroism spectrum were used for the calculation of the principal values and the directions of the principal axes of the local g-tensors and for the simulation of both temperature dependence of the magnetic susceptibility and field dependence of the magnetization. The value of the exchange parameter (Jex = 30 cm(-1)) was obtained. It was demonstrated that the description of the low temperature magnetic properties requires taking into account the intercluster interaction.

The long-term outcome of the refractive error in children with hypermetropia

PURPOSE

The purpose of this study was to investigate the long-term outcome of high hypermetropic refractive errors in childhood.

METHODS

We retrospectively reviewed data from the clinical records of 164 children with spherical equivalent (SE) hypermetropic refractive errors in three medical centers collected over 29 years. Refractive errors between +1.00 and +3.00 diopter (D) on initial examination were classified as mild hypermetropia and those +5.00 D or greater were classified as high hypermetropia. The four variables studied were, age, refractive error, strabismus, and gender. The rate of reduction in hypermetropic refractive error was calculated over time in years. We identified subgroups according to age, gender, and initial refractive error.

RESULTS

Seventy-eight children with high hypermetropia and 86 children with mild hypermetropia were studied. High hypermetropia was detected at a mean age of 3.3 years, while mild hypermetropia was detected at a mean 4 years of age. The mean follow-up was 6.6 years for high hypermetropia and 6.4 years for mild hypermetropia. Over the follow-up period, children in all subgroups tended to reduce their refractive errors. The reduction in refraction power was small for both mild and high hypermetropic refractive errors. Amblyopia in the high hypermetropia group was more common and more refractory to treatment.

CONCLUSIONS

Most children with hypermetropia of less than +3.00 D experience a reduction in hyperopic refractive error over time and will outgrow any need for corrective lenses. Children with hyperopia greater than +5.00 D will not experience a significant reduction in the power of the refractive error.

Metal complexes derived from hydrazoneoxime ligands: V. Spectral and structural studies on diacetylmonoxime n-alkanoylhydrazones and their nickel(II) and copper(II) complexes

A series of diacetylmonoxime n-alkanoylhydrazones (H₂L(n), n=4, 5, 6, 12 and 16) were prepared by the condensation of diacetylmonoxime with the corresponding n-alkanoylhydrazine in ethanol. The X-ray crystal structure of diacetylmonoxime octadecanoyl hydrazone has been solved and its molecular and supramolecular structures have been discussed. Both neutral dinuclear Cu(II) and Ni(II) complexes, [{M(L(n))}₂] (M=Cu, Ni and n=4, 5, 6, 12 and 16) as well as cationic dinuclear Cu(II) complexes, [Cu₂(L(n))(HL(n))]NO₃ (n=12 and 16) have been also prepared and characterized by elemental analyses, FD- and ESI-mass spectra as well as IR, UV-Vis, (1)H NMR, (13)C NMR spectra. Variable temperature magnetic susceptibility measurements for dinuclear Cu(II) complexes have been also discussed.

Electro-optic and dielectric properties of a ferroelectric liquid crystal doped with chemically and thermally stable emissive carbon dots

Dispersion of the C-dots in n-hexane under ambient light and under 366 nm illumination indicating the bright photoluminescence of the C-dots; PL spectra of C-dots at different excitation wavelengths (360 nm to 540 nm) increasing at 20 nm intervals.

Order Parameter Temperature Dependence of Some Nematic Liquids Related to Magnetic and Optical Anisotropies

The diamagnetic susceptibilities, refractive indices and densities were measured as a function of temperature for three 4,4'-disubstituted benzoic acid-phenylester compounds. The polarizabilities were calculated using the Vuks formula and Neugebauer's relations. The orientational order parameters obtained from the magnetic and from the optical data as a function of temperature, in the absence of single crystal data, were compared.

[Mn(SPh)Cl3]2-, [Mn(SPh)3Cl]2-, [Mn2(SPh)6]2- und [Mn4(SPh)6Br4]2–: Synthese, Struktur und ausgewählte Eigenschaften einiger neuer Chalkogenolatkomplexe des zweiwertigen Mangans / [Mn(SPh)Cl3]2-, [Mn(SPh)3Cl]2-, [Mn2(SPh)6]2- und [Mn4(SPh)6Br4]2-: Synthesis, Structure and Selected Properties of Some New Chalkogenolate Complexes of Divalent Manganese

[Me4N]2[Mn(SPh)Cl3] (1) was obtained by reaction of MnCl2·4H2O with one equivalent of NaSPh from methanolic solutions in the presence of [Me4N]Cl. Under similar conditions the compound [Et4N]2[Mn(SPh)3Cl] (2) waso isolated using [Et4N]+ cations. Crystal data: 1: a = 9.425(3), b = 11.903(3)t c -19.073(4) Å, space group P 21cn, Z = 4; 2: a = 14.420(7), b = 13.834(8), c = 17.918(10) Å, β = 90.69(4)°, space group P21/c, Z = 4. The structures were refined to R = 0.0839 (1) and 0.0328 (2), respectively. Besides the dianion [Mn(SPh)3Cl]2- (6), crystals of 2 contain traces of [Mn(SPh)2Cl2]2- (7) distributed over 3.8% of the anion positions. The existence of [Mn(SPh)Cl3]2- (5), 6 and 7 under similar conditions is interpreted in terms of ligand exchange solution equilibria. Within these mononuclear anions, the central metal/sulfur/halide cores show distorted tetrahedral stereochemistries. The reaction of MnCl2 with NaSPh (molar ratio 1:3) in hot mixtures of acetonitrile and DMF leads to [Mn2(SPh)6]2- (8), which can be isolated as crystalline [Ph4P]2[Mn2(SPh)6] (3) with a = 13.383(2), b = 13.565(2), c = 20.438(4) Å, β = 106.41(1)°, space group P21/c, Z = 2. The final refinement converged to R = 0.0380. 8 consists of two edge-sharing MnS4 tetrahedra showing structural similarities with other tetrahedral complexes of the type [M2(SR)6]2-. According to magnetochemical studies, the manganese atoms are antiferromagnetically coupled with J=-18.6(2) cm-1. Reaction of 3:2:1 molar ratio mixtures of NaSPh/MnBr2/[Et4N]Br in hot acetonitrile leads to [Et4N]2[Mn4(SPh)6Br4] (4) which crystallizes with a = 14.109(3), b = 27.556(5), c = 16.194(4) Å, β = 95.35(2)°, space group P 21/n, Z=4. The structure was refined to R = 0.0583. This compound is also available by reaction of [Et4N]2[Mn(SPh)4] with MnBr2 in a molar ratio of 3:5. The anion [Mn4(SPh)6Br4]2- (9) contains a central {Mn4S6Br4} core which exhibits an adamantane-like structure: A Mn4 tetrahedron is inscribed into a S6 octahedron with the S atoms bridging the edges of the Mn4 tetrahedron. Terminally bonded Br atoms complete the tetrahedral coordination spheres of the manganese atoms and thus form an outer Br4 tetrahedron. As a result, the symmetry of the central core comes close to Td. The observed distortion is attributed to intramolecular repulsions of the organic residues. Selected properties of compounds 1-4 are reported.

Structure and Magnetic Properties of a Dinuclear Copper(II) Complex

[Cu2L] (L=N-2-hydroxy-4-methylphenyl-4-oxo-2-pentalketimine) was synthesized and its crystal structure determined. C24H26Cu2N2O4 monoclinic space group P21/n with a= 10.978(2), 17.045(3), c= 11.958(2) Å, β = 101.89(1)°, V = 2189.6(7) Å3,Z = 4. Two copper(II) atoms in a distorted square-planar coordination are bridged by two oxygen atoms to form a dinuclear unit. The copper(II) centers are separated by 3.025(1) Å and antiferromagnetically coupled (J =-222.3 cm-1 ), which follows from temperature-dependent magnetic susceptibility measurements in the range 4.2 to 300 K.

Kristallstruktur von α-Bromo(2-dibutylaminoäthanolato)kupfer(II) / The Crystal Structure of a-Bromo(2-dibutylaminoethanolato)copper(II)

The crystal structure of α-Bromo(2-dibutylaminoethanolato)copper(II) has been determined by single-crystal X-ray diffractometer methods using 1488 independent reflexions and MoKα radiation. The compound crystallized in the orthorhombic space group P212121 with four dimers in a unit cell of dimensions a = 21.235(13), b = 15.220(8) and c = 8.390(5) Å. The structure was refined by least-squares methods giving a final residue of R = 0.087. The dimer molecules with Cu-Cu-separations of 3.019(4) Å consist of nonplanar Cu2O2-rings with Cu-O-distances of 1.92(2) Å (mean value). The coordination around each copper atom is distorted square planar. The averaged Cu-N-distance is 2.06(2) Å and Cu-Br-separations are 2.333(4) A. In good agreement with the calculated density of 1.55 g cm-3 is the experimental value of 1.53(3) g cm-3.

Structure and Spin-Spin Interactions in a Linear Trinuclear Ni(II) Complex

[Ni3(C2H3O2)2(C3H8NO)2L2] [(L=N,N′-1,3-propyl-disalicylaldimine), (C2H3O2)=acetate, (C3H8NO)=hydroxymethyl-dimethylamine] has been synthesized and its crystal structure determined, [C44H54N6O10Ni3], triclinic, space group P1̄, a = 9.560(1), b = 10.681(1), c = 12.200(1) Å, α = 112.17(1), β = 101.25(1), γ = 90.32(1)°, V = 1127.3 Å, Z = 1.The molecule is linearly trinuclear with octahedral coordination of each nickel ion. The Ni-Ni distance is 3.048( 1) Å. Each nickel(II) atom is in an octahedral coordination. Magnetic susceptibility measurements in the range 4.2 < T < 280 K have revealed antiferromagnetic coupling between adjacent Ni atoms (J1 = -2.2 cm-1) and between the terminal Ni atoms (J2 = -1.7 cm-1).

Structures and Magnetic Properties of Dinuclear Iron(III) Complexes

The compounds [FeL1(MeOH)Cl]2 (1), [FeL2Cl]2 (2) and [FeL3Cl]2 (3), with L1 for N-2-hydroxy-4-chlorophenylsalicylaldimin, L2 for N-2-hydroxyphenyl-3-hydroxy-2-naphthaldimin, and L3 for N-2-hydroxy-4-chlorophenyl-3-hydroxy-2-naphthaldimin, have been synthesized. 1 crystallizes in the monoclinic system, space group P21/c. The lattice parameters are a = 7.347(1), b = 21.390(1), c = 9.555(2) Å, β = 104.92(1)° with Z = 2. The crystal structures of 2 and 3 were reported previously. In all structures, two identical [FeL] fragments, related by an inversion center, are connected by two bridging oxygen atoms to form a binuclear unit in the supported condition. Magnetic susceptibility measurements in the range 4.2 < T < 286.5 K re­vealed the diiron (III) centers of 1, 2, and 3 to be weakly antiferromagnetically coupled with spin exchange coupling constants J1 = -7.7(1) cm-1, J2 = -6.5(1) cm-1, and J3 = -10.9(1) cm-1, respectively.

Die Kristallstruktur von Thiocyanato(2-dimethylaminoäthanolato)kupfer(II) / The Crystal Structure of Thiocyanato(2-dimethylaminoethanalato)copper(II)

The crystal structure of the title compound has been determined from three-dimensional X-ray diffractometer data. Crystals are monoclinic, space group P21/c with 8 Cu(C4H10NO)SCN units in a cell of dimensions α = 11.951(4), b = 8.954(3), c = 16.805(6) Å, and β = 107.5(1)°. The structure was refined by least squares techniques to a final discrepancy factor of 0.041 based on 2234 observed independent reflexions.

The compound is polymeric with copper atoms alternately bridged by two oxygen atoms and two thiocyanato groups. The coordination geometry around each copper atom is distorted square pyramidal. The basal plane consists of the two bridging oxygen atoms (mean value Cu-O: 1.914(3) Å), the amino nitrogen atom (mean value Cu-N: 2.035(3) Å) and the nitrogen atom from the thiocyanato group (mean value Cu-N: 1.908(3) Å) while the axial coordination site is occupied by a sulfur atom from a thiocyanato group (mean value Cu-S: 2.979(2) Å) centrosymmetric to the first.

The magnetic susceptibility of the compound shows a broad maximum at 200 K

Die Kristall- und Molekülstruktur von β -Bromo(2-diäthylaminoäthanolato)kupfer(ll) / The Crystal and Molecular Structure of β-Bromo(2-diethylaminoethanolato)copper(II)

The crystal and molecular structure of β-bromo(diethylaminoethanolato)copper(II) has been determined from three dimensional X-ray diffractometer data. The compound crystallizes in the triclinic space group Pï with one dimer in a unit cell of dimensions α=10.180(II), b=7.999(9), c=6.227(7) Å and a=110.69(4), β=103.12(4), γ=73.82(4)[°]. The structure was refined by least-squares methods using 1944 independent reflexions to give a final R-index of 0,05. The molecule consists of dimeric Cu2O2-units with Cu—O distances of 1.900(4) Å and 1.914(4) A, respectively. The dimers are additional bridged by bromines, so that a “polymeric” structure results; Cu—Br distances are 2.357(2) and 3.660(2) A, respectively. The Cu—Cu distances are 3.003(2) (oxygen bridges) and 4.506(2) Å (bromine bridges).

Different Temperature Dependence of Magnetic Susceptibility of Different Molecular Complexes of Copper (II) with 7-Hydroxy-4-methyl-5-aza-hept-4-en-2-on

Two principally different molecular structures in the crystalline state are known from the copper (II) complex with 7-hydroxy-4-methyl-5-aza-hept-4-en-2-on. The magnetic susceptibilities of three forms of this compound [α-(CuEIA)4, β-(CuEIA)4, and β-(CuEIA)4·2 C6H6] have been measured in the temperature range 2.6-300 K. The results indicate that principally different molecular structures correspond to principally different magnetic properties. While the α-form shows antiferromagnetic spin coupling in the S′ = 0 ground state, the electrons in the β-form are coupled ferromagnetically in the S′ = 2 ground state. A fitting procedure of a theoretical equation based on the isotropic HDVV-model led to a satisfactory agreement between calculated and experimental data for α-(CuEIA)4 and β-(CuEIA)4 , while this was not possible for β-(CuEIA)4·2C6H6 . The exchange parameters obtained for α-(CuEIA)4 (g=2.13, J12= -17cm-1, J13=+3.5cm-1, and Na=60-10-8 cgs-emu) are in good agreement with the values given by Ginsberg et al. For β-(CuEIA)4 a weak antiferromagnetic intercluster interaction could be determined at low tempera­tures. The fitting procedure yielded the following values: g=2.05, J12=-6.4 cm-1, J13=+24.2 cm-1, Na=10·10-6 cgs-emu, ⊖=-0.27°.

X-Ray Structure and Magnetic Properties of the Tetracupferronato-bis(μ-methoxy)-diiron(III) Complex

The tetracupferronato-bis(μ-methoxy)-diiron(III) complex has been synthesized in acetonitrile and its crystal structure determined. C26H26N8O10Fe2, monoclinic, space group C2/c, a =18.425(3), b = 12.999(2), c = 15.046(3) Å, β = 124.66(2)°,V = 2964(1) Å3, Z = 4, wR(2) = 0.097 from 1491 reflections (F2). Two iron(III) atoms are at special positions in six-fold coordination, bridged by O with a Fe-O-Fe angle of 102.4(1)° and a distance between two iron(III) centers of 3.075(1) Å. Temperature-dependent magnetic susceptibility measurements reveal a antiferromagnetic exchange interaction (J = -14 cm-1) between the iron(III) centers.

Structure and Magnetic Properties of a Dinuclear Complex with Iron(III) in Octahedral and Pyramidal Coordination

[FeL(MeOH)Cl]2 (L = N-(2-hydroxyphenyl)salicylaldimine) was synthesized and its crystal structure determined, [C27H20N 2O5Cl2Fe2], monoclinic, space group P21/c, a = 9.528(1), b = 7.684(1), c = 18.365(2) Å, β = 109.83(1)°, V = 1264.8 Å3, Z = 2. Two identical [FeL(MeOH)Cl] fragments, related by an inversion centre, are combined by the two bridging O atoms, to form a binuclear unit. The iron(III) centers are separated by 3.163(2) Å and weakly antiferromagnetically coupled (J = -8 .0 (1 ) cm-1), which follows from temperature - dependent magnetic susceptibility measurements in the range 4.2 to 288 K. The effective magnetic moment per iron(III) is μeff = 7.4 μB at 288 K

Discontinuous anchoring transition and photothermal switching in composites of liquid crystals and conducting polymer nanofibers

We prepared nanocomposites of a nematic liquid crystal and nanofibers of a conducting polymer (polyaniline). All the nanocomposites exhibit a discontinuous surface anchoring transition from planar to homeotropic in the nematic phase on a perfluoropolymer coated surface with a thermal hysteresis (≈ 5.3 °C). We observe a relatively large bistable conductivity and demonstrate a light driven switching of conductivity and dielectric constant in dye doped nanocomposites in the thermal hysteresis (bistable) region. The experimental results have been explained based on the reorientation of the nanofibers driven by the anchoring transition of the nematic liquid crystal. We show a significant enhancement of the bistable temperature range (≈ 13 °C) by an appropriate choice of compound in the binary system.

DEGRO practical guidelines: radiotherapy of breast cancer I: radiotherapy following breast conserving therapy for invasive breast cancer

Background and purpose

The aim of the present paper is to update the practical guidelines for postoperative adjuvant radiotherapy of breast cancer published in 2007 by the breast cancer expert panel of the German Society for Radiooncology (Deutsche Gesellschaft für Radioonkologie, DEGRO). The present recommendations are based on a revision of the German interdisciplinary S-3 guidelines published in July 2012.

Methods

A comprehensive survey of the literature concerning radiotherapy following breast conserving therapy (BCT) was performed using the search terms “breast cancer”, “radiotherapy”, and “breast conserving therapy”. Data from lately published meta-analyses, recent randomized trials, and guidelines of international breast cancer societies, yielding new aspects compared to 2007, provided the basis for defining recommendations according to the criteria of evidence-based medicine. In addition to the more general statements of the DKG (Deutsche Krebsgesellschaft), this paper addresses indications, target definition, dosage, and technique of radiotherapy of the breast after conservative surgery for invasive breast cancer.

Results

Among numerous reports on the effect of radiotherapy during BCT published since the last recommendations, the recent EBCTCG report builds the largest meta-analysis so far available. In a 15 year follow-up on 10,801 patients, whole breast irradiation (WBI) halves the average annual rate of disease recurrence (RR 0.52, 0.48–0.56) and reduces the annual breast cancer death rate by about one sixth (RR 0.82, 0.75–0.90), with a similar proportional, but different absolute benefit in prognostic subgroups (EBCTCG 2011).

Furthermore, there is growing evidence that risk-adapted dose augmentation strategies to the tumor bed as well as the implementation of high precision RT techniques (e.g., intraoperative radiotherapy) contribute substantially to a further reduction of local relapse rates. A main focus of ongoing research lies in partial breast irradiation strategies as well as WBI hypofractionation schedules. The potential of both in replacing normofractionated WBI has not yet been finally clarified.

Conclusion

After breast conserving surgery, no subgroup even in low risk patients has yet been identified for whom radiotherapy can be safely omitted without compromising local control and, hence, cancer-specific survival. In most patients, this translates into an overall survival benefit.

Size dependence of harvested BaTiO3 nanoparticles on the electro-optic and dielectric properties of ferroelectric liquid crystal nanocolloids

The influence of the size of harvested barium titanate nanoparticles on the properties of ferroelectric liquid crystal (FLC) nanocolloids was investigated by electro-optical and dielectric methods. The spontaneous polarization and the switching time are decreased for the liquid crystalline nanocolloids compared to nondoped FLC mixtures of different dipole strengths; this dependence is stronger for small size particles (9 nm) and weaker for larger size particles (26 nm) by the same concentration in weight. The decrease of the Goldstone mode (GM) relaxation frequency and the decrease of the dielectric GM absorption strength of the nanocomposites compared to the nondoped FLC mixture go stepwise with the increase of the nanoparticles diameter. Results have been interpreted via strong interaction between the FLC dipoles and the dipoles of the highly polar barium titanate nanoparticles.

Ametropic amblyopia

Hypermetropia of more than 5 diopters or an astigmatism of 2 diopters or more is often the cause of amblyopia in the master eye, independent of the presence of a simultaneous strabismus or anisometropia. This amblyopia can be prevented with early spectacle correction. In the authors' study of 218 patients with high ametropia a correlation was not always present between visual acuity and the age of the first spectacle correction or the degree of ametropia. In some patients even correction of ametropia as late as seven to ten years of age led to spontaneous functional improvement of single optotypes acuity. The treatment of choice is to give the full ametropic correction at an early age.