Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

Q: Context: Most solid human tumors exist in an acidic microenvironment, due in part to inefficient vasculature and a higher intrinsic rate of glycolysis. This leads to a tumor-selective pH gradient, which can be exploited therapeutically with antitumor agents such as the camptothecins (CPTs). Previous work in this laboratory has shown that camptothecin activity is enhanced 40- to 60-fold in monolayer cell culture by reducing the extracellular pH to 6.8. Three-dimensional histoculture has been shown to be a technique that allows human tumor tissue to grow in an in vivo-like way with maintenance of tissue histology and function and drug sensitivity for long periods of time.', 'In the current study, we utilized these features of histoculture to study new analogues of camptothecin that have superior pharmacological properties.', 'We evaluated six CPT analogues in histocultures of human brain, neuroblastoma, breast, colon, and prostate tumors. Fragments were exposed to 10,11-methylenedioxy-CPT (MDC), 7-chloromethyl-MDC, SN-38, topotecan (TPT), 9-amino-CPT, 10-amino-CPT, paclitaxel, 5-fluorouracil, 4-hydroperoxycyclophosphamide and doxorubicin, and antitumor activity was assessed. For in vivo tumor outgrowth studies, fragments were treated in parallel, implanted into nude mice, and monitored for development of tumors. RESULTS. Against 15 of 16 tumor xenografts and all primary tumor samples tested, all compounds were cytotoxic at pH 7.4 (IC(50) range 13-921 microM). MDC, SN-38, TPT, and 9-amino-CPT achieved an average 5-fold increase in activity (range 3-14) at pH 6.8, while 7-chloromethyl-MDC was enhanced 8-fold (range 6-14). The most potentiated analogue was 10-amino-CPT at 27-fold (range 17-49). In contrast, the other agents were active against one or more tumor types but were not enhanced by acidic pH. Importantly, the toxicity of MDC in histoculture of D54 glioma xenografts strongly correlated with the outgrowth of treated fragments subsequently implanted in vivo.
Answer: Evaluation of anticancer drug activity in native-state histoculture supports the concept that pH modulation may be an important approach to improve the selectivity and antitumor effectiveness of camptothecin-based chemotherapy.

A: Is the activity of camptothecin analogues enhanced in histocultures of human tumors and human tumor xenografts by modulation of extracellular pH?
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Q: Context: Contralateral groin exploration in children with unilateral inguinal hernia is still controversial, particularly in infants. The patency rate of processus vaginalis is highest in infants but there are few data on the subsequent risk of contralateral hernia development in infants. In this retrospective study, we aimed to find out the incidence of contralateral inguinal hernia following unilateral inguinal herniotomy in infants aged less than one year.', 'All infants who underwent a unilateral Inguinal herniotomy between January 1990 and December 1998 were studied retrospectively. Infants with bilateral hernia (n = 7) were excluded from the study.', 'One hundred and one infants (93 boys and 8 girls) were studied. Median age at operation was 23 (range 2-52) weeks. The herniotomy was right-sided in 75% of the infants. Follow-up ranged from three and a half years to 11 years. A contralateral hernia developed in nine infants (9.0%). One of the initial hernias was incarcerated. Median time from operation to occurrence of contralateral hernia was 18 (range 2-60) months. None of the contralateral hernia was incarcerated. Age, sex, incarceration and side of initial hernia did not influence the development of contralateral hernia.
Answer: The low incidence and benign nature of contralateral hernia development in infants undergoing a unilateral inguinal herniotomy does not justify routine contralateral groin exploration.

A: Is contralateral groin exploration justified in infants with a unilateral inguinal hernia?
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Q: Context: The study compared two channel-reduction approaches in order to investigate the effects of systematic motor imagery (MI) neurofeedback practice in an everyday environment using a very user-friendly EEG system consisting of individualized caps and highly portable hardware.', 'Sixteen BCI novices were trained over four consecutive days to imagine left and right hand movements while receiving feedback. The most informative bipolar channels for use on the subsequent days were identified on the first day for each individual based on a high-density online MI recording.', 'Online classification accuracy on the first day was 85.1% on average (range: 64.7-97.7%). Offline an individually-selected bipolar channel pair based on common spatial patterns significantly outperformed a pair informed by independent component analysis and a standard 10-20 pair. From day 2 to day 4 online MI accuracy increased significantly (day 2: 69.1%; day 4: 73.3%), which was mostly caused by a reduction in ipsilateral event-related desynchronization of sensorimotor rhythms.
Answer: The present study demonstrates that systematic MI practice in an everyday environment with a user-friendly EEG system results in MI learning effects.

A:
Does wireless EEG with individualized channel layout enable efficient motor imagery training?
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