An interval-parameter stochastic robust optimization model for supporting municipal solid waste management under uncertainty

A stochastic robust interval linear programming model (IPRO) was developed for supporting municipal solid waste management under uncertainty. The model improves upon the existing stochastic robust optimization (SRO) and interval linear programming (ILP) methods by allowing evaluations of trade-offs among expected costs, cost variability, and risk of violating relax constraints simultaneously, as well as reflections of complex uncertainties through both interval and stochastic theories. A long-term waste management problem was used to demonstrate the applicability of IPRO model. The results indicated that IPRO normally led to interval solutions, where waste-management alternatives could be generated by adjusting the decision-variable values within their intervals. The model could also help waste managers to identify desired policies that under various environmental, economic, system-feasibility and system-reliability constraints.

Sensitivity calibration procedures in optical-CT scanning of BANG 3 polymer gel dosimeters

The dose response of the BANG 3 polymer gel dosimeter (MGS Research Inc., Madison, CT) was studied using the OCTOPUS laser CT scanner (MGS Research Inc., Madison, CT). Six 17 cm diameter and 12 cm high Barex cylinders, and 18 small glass vials were used to house the gel. The gel phantoms were irradiated with 6 and 10 MV photons, as well as 12 and 16 MeV electrons using a Varian Clinac 2100EX. Three calibration methods were used to obtain the dose response curves: (a) Optical density measurements on the 18 glass vials irradiated with graded doses from 0 to 4 Gy using 6 or 10 MV large field irradiations; (b) optical-CT scanning of Barex cylinders irradiated with graded doses (0.5, 1, 1.5, and 2 Gy) from four adjacent 4 x 4 cm2 photon fields or 6 x 6 cm2 electron fields; and (c) percent depth dose (PDD) comparison of optical-CT scans with ion chamber measurements for 6 x 6 cm2, 12 and 16 MeV electron fields. The dose response of the BANG3 gel was found to be linear and energy independent within the uncertainties of the experimental methods (about 3%). The slopes of the linearly fitted dose response curves (dose sensitivities) from the four field irradiations (0.0752 +/- 3%, 0.0756 +/- 3%, 0.0767 +/- 3%, and 0.0759 +/- 3% cm(-1) Gy(-1)) and the PDD matching methods (0.0768 +/- 3% and 0.0761 +/- 3% cm(-1) Gy(-1)) agree within 2.2%, indicating a good reproducibility of the gel dose response within phantoms of the same geometry. The dose sensitivities from the glass vial approach are different from those of the cylindrical Barex phantoms by more than 30%, owing probably to the difference in temperature inside the two types of phantoms during gel formation and irradiation, and possible oxygen contamination of the glass vial walls. The dose response curve obtained from the PDD matching approach with 16 MeV electron field was used to calibrate the gel phantom irradiated with the 12 MeV, 6 x 6 cm2 electron field. Three-dimensional dose distributions from the gel measurement and the Eclipse planning system (Varian Corporation, Palo Alto, CA) were compared and evaluated using 3% dose difference and 2 mm distance-to-agreement criteria.

Transcription activity is required for p53-dependent tumor suppression

As a transcription factor, the critical tumor suppressor, p53, directly regulates the transcription of hundreds of genes, leading to cell-cycle arrest, apoptosis, cellular senescence and differentiation. Although it has been assumed that p53 transcription activity is critical for tumor suppression, this assumption has been increasingly contested by recent findings of transcription-independent roles of p53 in apoptosis as well as findings that none of the mutant mice lacking important p53 transcription targets are cancer prone. On the basis of previous findings that p53 transcription activity is abolished in p53(QS) (Leu25Trp26 to Gln25Ser26) knock-in mouse cells after DNA damage, to determine the importance of transcription activity of p53 in tumor suppression, we generated knock-in mice that can conditionally express p53(QS) protein in a Cre-dependent manner. By breeding the knock-in mice with Lck-Cre transgenic mice that specifically express Cre in thymocytes, we show that p53-dependent suppression of thymic lymphomas is abolished in thymocytes expressing high levels of p53(QS) protein. In addition, p53(QS) protein is accumulated in some of the thymic tumors. Therefore, p53 transcription activity induced by DNA damage is required for tumor suppression. Together with the findings that the disruption of various p53-dependent functions individually fails to promote cancer, our findings indicate that various transcription-dependent functions of p53 must collaborate to efficiently suppress tumorigenesis.

A laser-Compton scattering prototype experiment at 100 MeV linac of Shanghai Institute of Applied Physics

As a prototype of the Shanghai Laser Electron Gamma Source in the Shanghai Synchrotron Radiation Facility, an x-ray source based on laser-Compton scattering (LCS) has been installed at the terminal of the 100 MeV linac of the Shanghai Institute of Applied Physics. LCS x-rays are generated by interactions between Q-switched Nd:yttrium aluminum garnet laser pulses [with wavelength of 1064 nm and pulse width of 21 ns (full width at half maximum)] and electron bunches [with energy of 108 MeV and pulse width of 0.95 ns (rms)] at an angle of 42 degrees between laser and electron beam. In order to measure the energy spectrum of LCS x-rays, a Si(Li) detector along the electron beam line axis is positioned at 9.8 m away from a LCS chamber. After background subtraction, the LCS x-ray spectrum with the peak energy of 29.1+/-4.4|(stat)+/-2.1|(syst) keV and the peak width (rms) of 7.8+/-2.8|(stat)+/-0.4|(syst) keV is observed. Normally the 100 MeV linac operates with the electron macropulse charge of 1.0 nC/pulse, and the electron and laser collision repetition rate of 20 Hz. Therefore, the total LCS x-ray flux of (5.2+/-2.0) x 10(2) Hz can be achieved.

Endovascular treatment of wide-neck middle cerebral artery aneurysms with stents: a review of 16 cases

BACKGROUND AND PURPOSE

MCA aneurysms are common and often pose technical challenges to interventionalists. Intracranial stents are widely used in treating wide-neck aneurysms in other locations. To evaluate the feasibility, effectiveness, and safety of stent placement in MCA aneurysms, we performed this retrospective study.

MATERIALS AND METHODS

Between October 2003 and May 2009, 16 patients with 16 wide-neck MCA aneurysms were treated with stents at our institution. We retrospectively collected and analyzed the data for these patients, including demographics, morphologic features of the aneurysms, treatment results, and follow-up.

RESULTS

Seventeen stents, including 12 Neuroform, 4 LEO, and 1 Enterprise, were successfully deployed in this series. Of the 13 aneurysms treated with stent-assisted embolization, complete occlusion was achieved in 9 aneurysms; residual neck remained in 1, and residual aneurysm was present in 3. Contrast stasis in the aneurysm sac was observed in the other 3 aneurysms treated with stent alone. Procedure-related complication occurred in 1 patient, leading to no permanent effect. The mRS score at discharge was 0-2 in 14 patients and 3-6 in 2. The angiographic follow-up results of 9 patients (mean, 5.6 months) showed that all aneurysms remained stable or improved; there was no in-stent stenosis, recurrence, or retreatment. The clinical follow-up (mean, 20.1 months) demonstrated no neurologic deterioration or rebleeding.

CONCLUSIONS

Our preliminary experience demonstrates that stent placement for the treatment of selected wide-neck MCA aneurysms is feasible. However, its safety and efficacy should be further evaluated by larger case series and more adequate follow-up.

Azimuthal charged-particle correlations and possible local strong parity violation

Parity-odd domains, corresponding to nontrivial topological solutions of the QCD vacuum, might be created during relativistic heavy-ion collisions. These domains are predicted to lead to charge separation of quarks along the system's orbital momentum axis. We investigate a three-particle azimuthal correlator which is a P even observable, but directly sensitive to the charge separation effect. We report measurements of charged hadrons near center-of-mass rapidity with this observable in Au + Au and Cu + Cu collisions at square root of s(NN) = 200 GeV using the STAR detector. A signal consistent with several expectations from the theory is detected. We discuss possible contributions from other effects that are not related to parity violation.

Four types of potassium currents in motor nerve terminals of snake

The experiments were performed on transversus abdominis muscle of Elaphe dione by subendothelial recording. The results indicate that in snake motor nerve endings there exist four types of K(+) channels, i.e. voltage-dependent fast and slow K(+) channels, Ca(2+)-activated K(+) channel and ATP-sensitive K(+) channel. (i) The typical wave form of snake terminal current was the double-peaked negativity in standard solution. The first peak was attributed to Na(+) influx (I(Na)) in nodes of Ranvier. The second one was blocked by 3,4-aminopyridine (3,4-DAP) or tetraethylammonium (TEA), which corresponded to fast K(+) outward current (I(k.f)) through the fast K(+) channels in terminal part. (ii) After I(K.F) as well as the slow K(+) current (I(K.S)) were blocked by 3, 4-DAP, the TEA-sensitive Ca(2 +)-dependent K(+) current (I(K(Ca))) passing through Ca(2 +)-activated K(+) channel was revealed, whose amplitude depended on [K(+)](o) and [ca(2+) ](o). It was blocked by Ba(2+), Cd(2+) or Co(2+). (iii) I(K.F) and I(K(Ca)) were blocked by TEA, while I(K. S) was retained. It was sensitive to 3,4-DAP, partially blocked by ethanol (200 mmol/L) or beta-bungarotoxin (2 micromol/L), and enhanced by low pH (6.4-6.7). This is the first report that certain current component of motor nerve terminal is sensitive to pH in the range of 6. 4-7. 5. (iv) That diazoxide (200 micromol/L) increased the second negative peak and the effect was eliminated after further addition of glibenclamide (50 micromol/L) was taken as evidence for the presence of ATP-sensitive K(+) current (I(K.ATP)) at snake nerve terminal.

Raman spectroscopic characteristics of microcosmic and photosensitive damage on space structure of liposomes sensitized by hypocrellin and its derivatives

Raman spect-pic characteristics of microcosmic and photosensitive damage on space structure of DP-PC liposomes sensitized by hypocrellin and its derivatives are obvious. The trans conformation decreased and the gauche conformation increased. The longitudinal order-parameter in chains and the lateral order-parameter between chains decreased in different degrees. The lateral packing became loose. Photodamage on the liposomes sensitized by 5-Br-hypocrellin B was stronger than that by hypocrellins A and B.

A, Hegde P, Cronin E, Kane M, Tavakoli B, Xu Y. Near Infrared Imaging Using US Localization To Assess Response to Neoadjuvant Chemotherapy

Background: Pilot data obtained from a novel ultrasound (US)-guided diffusive-wave optical tomography in the near infrared (NIR) spectrum showed that it is feasible to use this technique to monitor vascular changes within breast tumors during neoadjuvant chemotherapy. These changes correlated well to tumor pathologic response. The earlier study was performed at a single hospital with a smaller patient pool and the tumor vascular assessment was made at a period of two treatment cycles. The objectives of this study are: (i) to validate the initial findings with a larger patient pool, and (ii) to assess vascular changes at every treatment cycle and to correlate early vascular changes with the tumor pathological response.Materials and Methods: 13 patients who underwent neoadjuvant treatment were recruited from two hospitals from December 2007 to May 2009 and their tumor vascular content was assessed with a combined imager consisting of a commercially available US system coupled to a NIR imager (NIR/US). Patients were imaged before their treatment, at the end of every treatment cycle and before their definitive surgery. The co-registered US was used to localize the tumor and to guide the NIR imaging reconstruction, and the NIR imager was used to map the tumor vascular distribution which was assessed based on a percentage total hemoglobin (%tHb) concentration normalized to the pre-treatment level. Of the 13 patients, 12 patients had contrast enhanced MRI before treatment and prior to surgery. The NIR results were compared with MRI findings. At treatment completion, pathological assessment revealed three response groups: complete or near-complete responders (A), partial responders (B), and non-responders (C).Results: There were four complete or near-complete responders, five partial responders, and four non-responders. The mean %tHbs of groups of A, B and C at the treatment completion were 38%±7.0%, 57.3%±5.7%, and 91.0%±10.1%, respectively (differences statistically significant, p<0.05). At the end of cycle one, the %tHb of group A showed no noticeable difference than that of partial and non-responder groups, however, the %tHb at the end of cycle two or three of group A was significantly lower than that of partial and non-responder groups. Figure 1 shows an example of a complete responder imaged before the treatment and at the end of cycle two.All complete or near-complete responders showed rapid reduction in %tHb at the end of cycle two or three; while all non-responders showed no change or small change in %tHb throughout the treatment. On average, partial responders showed changes in between. Both NIR/US and MRI were equally effective in distinguishing different response groups in this study.Discussion: Our findings indicate that NIR can be used during neoadjuvant chemotherapy to repeatedly monitor tumor vascular changes. NIR/US may also assess early pathological response during treatment.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5016.

Treatment and outcome of intracranial hemorrhage after carotid artery stenting. A ten year single center experience

SUMMARY

Intracranial hemorrhage following carotid artery stenting (CAS) is a rare but potentially devastating complication. The present study reviewed intracranial hemorrhage cases from patients undergoing CAS in ten years to find the methods to rescue patients from this fatal complication. Patients with postoperative intracranial hemorrhage following CAS were retrospectively selected, and clinical features, treatments and outcomes were studied. Ten patients with intracranial hemorrhage were identified. The mean onset time of hemorrhage was 6.1-/+7.1h. Intracerebral hemorrhage occurred in eight patients and SAH in two patients. The patients were treated by stopping anti-platelet and anticoagulant for at least three days, and surgical drainage of the hematoma/ventricle drainage or conservative treatment. Six patients survived, two had left moderate paralysis, four had a good recovery at four week follow-up, and four patients died. No patients underwent thrombosis in stent after withdrawing of antiplatelet and anticoagulant. Intracranial hemorrhage after CAS occurs usually in a few hours and leads to catastrophic results. Once patients have intracranial hemorrhage, good neurocritical care may help to save them. Stopping antiplatelet and anticoagulant for at least three days may avoid thrombosis in the stenting site.