Experimental demonstration of a fully inseparable quantum state with nonlocalizable entanglement.

Localizability of entanglement in fully inseparable states is a key ingredient of assisted quantum information protocols as well as measurement-based models of quantum computing. We investigate the existence of fully inseparable states with nonlocalizable entanglement, that is, with entanglement which cannot be localized between any pair of subsystems by any measurement on the remaining part of the system. It is shown, that the nonlocalizable entanglement occurs already in suitable mixtures of a three-qubit GHZ state and white noise. Further, we generalize this set of states to a two-parametric family of fully inseparable three-qubit states with nonlocalizable entanglement. Finally, we demonstrate experimentally the existence of nonlocalizable entanglement by preparing and characterizing one state from the family using correlated single photons and linear optical circuit.

Experimental investigation of a four-qubit linear-optical quantum logic circuit.

We experimentally demonstrate and characterize a four-qubit linear-optical quantum logic circuit. Our robust and versatile scheme exploits encoding of two qubits into polarization and path degrees of single photons and involves two crossed inherently stable interferometers. This approach allows us to design a complex quantum logic circuit that combines a genuine four-qubit C(3)Z gate and several two-qubit and single-qubit gates. The C(3)Z gate introduces a sign flip if and only if all four qubits are in the computational state |1〉. We verify high-fidelity performance of this central four-qubit gate using Hofmann bounds on quantum gate fidelity and Monte Carlo fidelity sampling. We also experimentally demonstrate that the quantum logic circuit can generate genuine multipartite entanglement and we certify the entanglement with the use of suitably tailored entanglement witnesses.

Faithful conditional quantum state transfer between weakly coupled qubits.

One of the strengths of quantum information theory is that it can treat quantum states without referring to their particular physical representation. In principle, quantum states can be therefore fully swapped between various quantum systems by their mutual interaction and this quantum state transfer is crucial for many quantum communication and information processing tasks. In practice, however, the achievable interaction time and strength are often limited by decoherence. Here we propose and experimentally demonstrate a procedure for faithful quantum state transfer between two weakly interacting qubits. Our scheme enables a probabilistic yet perfect unidirectional transfer of an arbitrary unknown state of a source qubit onto a target qubit prepared initially in a known state. The transfer is achieved by a combination of a suitable measurement of the source qubit and quantum filtering on the target qubit depending on the outcome of measurement on the source qubit. We experimentally verify feasibility and robustness of the transfer using a linear optical setup with qubits encoded into polarization states of single photons.

Efficient experimental estimation of fidelity of linear optical quantum Toffoli gate.

We propose an efficiently measurable lower bound on quantum process fidelity of N-qubit controlled-Z gates. This bound is determined by average output state fidelities for N partially conjugate product bases. A distinct advantage of our approach is that only fidelities with product states need to be measured while keeping the total number of measurements much smaller than what is necessary for full quantum process tomography. As an application, we use this method to experimentally estimate quantum process fidelity F of a three-qubit linear optical quantum Toffoli gate and we find that F≥0.83. We also demonstrate the entangling capability of the gate by preparing Greenberger-Horne-Zeilinger-type three-qubit entangled states from input product states.

Noiseless loss suppression in quantum optical communication.

We propose a protocol for conditional suppression of losses in direct quantum state transmission over a lossy quantum channel. The method works by noiselessly attenuating the input state prior to transmission through a lossy channel followed by noiseless amplification of the output state. The procedure does not add any noise; hence, it keeps quantum coherence. We experimentally demonstrate it in the subspace spanned by vacuum and single-photon states, and consider its general applicability.

Effect of pulsed radiofrequency therapy on the suprascapular nerve in shoulder pain of various aetiology.

BACKGROUND: Pulsed radiofrequency treatment (PRF) applied to the suprascapular nerve may provide pain relief for patients suffering from shoulder pain as described in three case series. AIMS: The effect of PRF to the suprascapular nerve was retrospectively analysed on 28 patients with shoulder pain lasting longer than 1 month, with a 6-month follow-up. Group A was treated with PRF and local anaesthetics only while group B was treated with PRF, local anaesthetic and steroid. Pain scores were evaluated before and after the procedure and at 1, 3 and 6 months. RESULTS: More than 50% of patients in both groups had significant pain relief after 3 months. No major, but only one minor complication occurred. CONCLUSIONS: Our results suggest that the analgesic effects of PRF last more than 3 months in the majority of patients. The addition of steroid to the PRF treatment appears to have no benefit.

Genetic testing and prevention of hereditary cancer at the MMCI--over 10 years of experience.

Hereditary cancer syndromes are frequently seen in young cancer patients and patients with a positive family history. Genetic testing is important for the identification of high-risk individuals, and for the early introduction of specialized preventive care or prophylactic surgeries. High-risk tumour suppressor genes (BRCA1 and BRCA2) and DNA repair genes (MLH1, MSH2 and MSH6) are responsible for a substantial part of hereditary breast, ovarian and colorectal cancer. Other hereditary cancers are seen less frequently, but genetic testing has increased for many other site-specific cancers and complex syndromes. Genetic centres and molecular genetic laboratories are located mostly within university or regional hospitals. Some genetic centres are private. It is highly recommended (Czech Society for Medical Genetics) that all laboratories are accredited according to ISO 15,189 and that genetic testing of hereditary cancer syndromes is indicated by medical geneticists. The indication criteria and prevention strategies were published in Supplement 22 of Clinical Oncology 2009 (in Czech). Preventive care for high-risk individuals is organized by thirteen Oncology Centres, which provide most of the oncology care in the Czech Republic. Genetic testing and preventive care for high-risk individuals and mutation carriers is covered by health insurance. The molecular genetic laboratory at the MMCI provides molecular genetic testing of BRCA1, BRCA2, CHEK2 for hereditary breast/ovarian cancer, MLH1, MSH2, MSH6 for Lynch syndrome,TP53 for Li-Fraumeni syndrome, CDKN2A for familial malignant melanoma syndrome and CDH1 gene for hereditary diffuse gastric cancer. Other syndromes are tested in specialized laboratories elsewhere.The use of genetic testing is increasing because of more frequent referrals from oncologists and other specialists and the increasing variety of genes tested. However, in some patients the testing is not recommended and other family members are dying because of the late diagnosis of hereditary syndrome. Greater awareness of the importance of genetic testing in oncology is needed.

[Effect of salpingectomy on the results of IVF in women with tubal sterility--prospective study]. / Vliv salpingektomie na výsledky IVF u zen s tubární sterilitou--prospektivní studie.

OBJECTIVE: To compare the IVF results after salpingectomy of hydrosalpinges visible on ultrasound with IVF results in women with tubal infertility but without hydrosalpinx. DESIGN: Prospective study. SETTING: Sanatorium Pronatal, Na Dlouhé mezi 4/12, 147 00, Praha 4. METHODS: 101 women with tubal factor infertility were evaluated. In a prospective study we compared the results of first IVF cycle after salpingectomy of hydrosalpinges visible on ultrasound performed in 51 women (study group) with IVF results of 50 women with tubal infertility (confirmed by HSG and laparoscopy) but without hydrosalpinges and without salpingectomy. RESULTS: The maternal age in both groups (32.4 +/- 3.9 in salpingectomy group and 33.0 +/- 4.1 in control group), maximum estradiol levels (1392.6 +/- 675.8 pg/ml in salpingectomy group vers. 1624.7 +/- 909.7 pg/ml in control group), number of oocytes (11.3 +/- 5.8 after salpingectomy vers. 11.0 +/- 6.1 in controls), number of embryos generated (7.1 +/- 4.6 vers. 7.9 +/- 4.7) and number of embryos transferred were not statistically different. In their first IVF cycle after salpingectomy has been performed 30 women out of 51 became clinically pregnant (58.8%), while in control group a clinical pregnancy could be verified in 16 women (32.0%). Implantation rate in women after salpingectomy was 28.2% vers. 12.3% in control group. Both implantation rate and pregnancy rate were statistically different at 5% level of significance. CONCLUSION: After salpingectomy of hydrosalpinges visible on ultrasound the implantation rate and clinical pregnancy rate are significantly better when compared to IVF patients with tubal infertility without the presence of hydrosalpinges and without salpingectomy. Salpingectomy should be offered to all patients with hydrosalpinges visible on ultrasound. Moreover, this radical approach should be considered even in women with highly damaged tubes but without the presence of hydrosalpinges.

[Does reduction in multifetal pregnancy increase the risk of poor outcome in twin pregnancy?]. / Zhorsuje redukce vícecetné gravidity perinatální výsledky u dvoucetných gravidit?

OBJECTIVE: To compare perinatal results for multi-foetal pregnancies where the reduction was performed with pregnancies where the reduction was not performed. SETTING: Sanatorium Pronatal, Na Dlouhé mezi 4/12, 147 00, Praha 4--Hodkovicky. METHODS: We have analyzed results of pregnancies, after delivery, for women with twin pregnancy which originated in our sanatorium, as a result of treatment with assisted reproduction methods, in the period of time from January 1st 1996 to December 31st 1998. In the group being monitored there were 122 twin pregnancies originated as a result of reduction of triple and more-foetal pregnancies. We evaluated the percentage of miscarriages, length of pregnancies, weight of the newborns and the manner of termination of the delivery. These results were compared with our control group consisting of 180 cases of twin pregnancies which were not a result of reduction. RESULTS: Analysis was performed for those mothers only where complete data were available. At a 5% level of statistical significance, it was not proved that both groups differed in average term of pregnancy or average weight of the twins. Average age of the mothers differed at 5% level of significance (average age values were 30.16 for the group with reduction and 31.73 for the group without reduction). Fisher test on 5% significance level did not ascertain any significant difference in the probability of miscarriage between the group with reduction (5.26%) and the group without reduction (12.84%). At 5% level of statistical significance, no significant difference in probability of perinatal death of the foetus or delivery of a stillborn foetus was ascertained. However, it is necessary to point out a low frequency of these phenomena in our group. The percentage of cesarean sections did not differ significantly in both groups (86.24% in the group monitored vs 87.24% in the group of twins without reduction). CONCLUSION: The analysis of both groups proves that reduction of multi-foetal pregnancies does not worsen perinatal results in comparison to pregnancies where reduction was not performed.

The influence of different types of antibodies on in vitro fertilization results.

PROBLEM: The influence of anti-sperm (ASA), anti-phospholipid (APA), and antizonal (AZA) antibodies on in vitro fertilization (IVF) results and the need for intracytoplasmic sperm injection (ICSI) were assessed. METHOD OF STUDY: Forty-four couples with infertility of immunologic origin were investigated. ASA in serum and ovulatory mucus were studied by a tray agglutination test (TAT) and indirect mixed anti-globulin reaction test (MAR) test, AZA were studied by passive hemagglutination and commercial enzyme-linked immunosorbent assay (ELISA; BioGen, Germany), and APA were tested by ELISAs in immunoglobulin isotypes IgG and IgM. RESULTS: Because of failed or very low fertilization after standard IVF in the previous cycle, ICSI had to be used in five out of 15 cases with ASA (33.3%), in 16 out of 18 couples with AZA (89.4%), and in only one case if APA were present (9%). Clinical pregnancy rate was 60% in cases with ASA, 38.5% with AZA, and 27.3% per embryo transfer (ET) if APA were detected. CONCLUSIONS: Immunologic infertility can be treated by IVF with very good results. The most important group are women with AZA, in whom IVF ICSI without any delay is recommended.

[Monochorionic twins after treatment of sterility using assisted reproduction methods]. / Monochoriální dvojcata po lécbe sterility metodami asistované reprodukce.

OBJECTIVE: The goal of this study has been to determine frequency of occurrence of monochorial twins within the study group consisting of 521 pregnancies conceived through the In Vitro Fertilization (IVF) programme. DESIGN: An observational study. SETTING: Sanatorium Pronatal, Na Dlouhé mezi 4/12, 147 00 Praha 4-Hodkovicky. METHODS: A condition to be included in the study group was that there was a gestation sac detected by ultrasound. The first ultrasound examination was performed transvaginally and was done between the fifth and the sixth week of each pregnancy. A multiple pregnancy has been classified as monochorial in case when gestation sac contains two yolk sacs and two fetuses. RESULTS: Within the whole study group there were 13 monochorial twins which presents 2.5% of all pregnancies. The incidence of monochorionicity among all multiple pregnancies is 6.4%, in IVF cycles without micromanipulation techniques the occurrence of monochorial twins has been 0.9%, following cryoembryotransfer 3.9%, with micromanipulation (ICSI, AH) it reaches 5.7% of all pregnancies. CONCLUSION: Monochorial twins were detected seven time more frequent in comparison within occurrence in ordinary population. The occurrence rises in connection with the number of fetuses in uterus. In comparison with simple IVF cycles we have proved higher occurrence of monochorionicity in connection with micromanipulation techniques and cryoembryotransfer.

[Hormone replacement for pregnancy in functionally agonadal women after transfer of thawed embryos in the in vitro fertilization program--problems of placental incompetence]. / Hormonální substituce tehotenství funkcne agonadálních zen po prenosu rozmrazených embryí v programu IVF--problematika placentární kompetence.

Experience with hormonal substitution of sterile women treated within the IVF programme by means of donated oocytes changed completely views on endocrinological prerequisites of successful implantations and the further development of early pregnancy. While the effect of oestrogens and progesterone on endometrial proliferation and receptivity has been elaborated in great detail in the literature, data on the substitution of early pregnancy and the onset of placental competence are much scarcer. 1. The placenta is during the 15th week of pregnancy already fully competent and hormonal substitution can be probably terminated already sooner. 2. From the shape of the curves (as compared with steroid levels in spontaneous pregnancies) the authors conclude that the used doses (in particular of progesterone were higher than physiological. 3. Pregnancy of women with primary or secondary ovarian failure is an ideal in vivo model for investigation of the receptivity of the endometrium, the problem of implantation and function of the foetoplacental unit. Available data are not uniform and therefore in this very interesting field further investigations are needed.

[Intracytoplasmic injections (ICSI) with epididymal and testicular spermatozoa]. / Intracytoplazmatická injekce (ICSI) s epididymálními a testikulárními spermiemi.

Azoospermia is no longer a clear indication for using donor sperm. Aspiration of epididymal sperm or extraction of testicular sperm offers the same hope of pregnancy as ICSI using ejaculated sperm. Not even the high effectiveness of ICSI should be the reason for less intensive efforts to assess the exact cause of azoospermia, in particular with regard to genetic aspects.

[Intracytoplasmic sperm injection in the treatment of the most severe cases of andrologic sterility]. / Intracytoplazmatická injekce spermie (ICSI) v lécbe nejzávaznejsích prípadu andrologické sterility.

Intracytoplasmic sperm injection (ICSI) is a procedure which dramatically eliminates the necessity to use donor sperm in androgenically conditioned sterility and enables almost all affected couples to achieve pregnancy. The results in this group, till recently untreatable, are at least comparable with results achieved in the standard IVF programme. The standard success of the transport IVF programme was confirmed also in the transport IVF-ICSI programme. The transport of gametes does not influence the achieved results. It seems that for the results of the transport programme the indication and possibly other (gynaecological) factors of sterility are decisive. Intracytoplasmic sperm injection has become due to its effectivity an integral part of our IVF programme.

[Importance of embryo cryopreservation in a program of in vitro fertilization: experience and results of 550 transfers of thawed embryos]. / Význam kryokonzervace embryí v programu in vitro fertilizace (IVF): zkusenosti a výsledky z 550 prenosu rozmrazených embryí.

Results of 550 transfers of cryopreserved and thawed embryos were analyzed. A total number of 47 pregnancies was achieved (8.5% per embryo transfer). Significantly better results were obtained when no selection of embryos before cryopreservation was made (i.e. pronucleate stage embryos and patients with all embryos frozen) compared to the "spare embryos" group-14 pregnancies per 99 transfers (14%) vs. 33 pregnancies per 451 transfers (7%) respectively. Cultivation of thawed embryos before embryo transfer has a beneficial effect on implantation-19 pregnancies per 121 transfers (16%) in the group of cultured embryos vs. 28 pregnancies per 429 transfers (7%) in the group without cultivation. Cryopreservation significantly contributes to the effectivity of IVF and provides further possibilities for conception in addition to those achieved from the fresh cycle.

[Andrologic and non-andrologic indications for intracytoplasmic sperm injection (ICSI)]. / Andrologické a neandrologické indikace intracytoplazmatické injekce spermie (ICSI).

Intracytoplasmic sperm injection (ICSI) is a very valuable method which implies a qualitative contribution to assisted reproduction and andrologically conditioned sterility, in particular. However, as one of the methods of cellular surgery it has its defined indications which must be respected.