Beam Energy and Centrality Dependence of Direct-Photon Emission from Ultrarelativistic Heavy-Ion Collisions

The PHENIX collaboration presents first measurements of low-momentum (0.4<p_{T}<3  GeV/c) direct-photon yields from Au+Au collisions at sqrt[s_{NN}]=39 and 62.4 GeV. For both beam energies the direct-photon yields are substantially enhanced with respect to expectations from prompt processes, similar to the yields observed in Au+Au collisions at sqrt[s_{NN}]=200. Analyzing the photon yield as a function of the experimental observable dN_{ch}/dη reveals that the low-momentum (>1  GeV/c) direct-photon yield dN_{γ}^{dir}/dη is a smooth function of dN_{ch}/dη and can be well described as proportional to (dN_{ch}/dη)^{α} with α≈1.25. This scaling behavior holds for a wide range of beam energies at the Relativistic Heavy Ion Collider and the Large Hadron Collider, for centrality selected samples, as well as for different A+A collision systems. At a given beam energy, the scaling also holds for high p_{T} (>5  GeV/c), but when results from different collision energies are compared, an additional sqrt[s_{NN}]-dependent multiplicative factor is needed to describe the integrated-direct-photon yield.

Argon plasma coagulation is an effective treatment for chronic radiation proctitis in gynaecological malignancy: an observational study

AIM

Chronic radiation proctitis (CRP) develops in 5-15% of patients after pelvic radiation therapy, with rectal bleeding being the main symptom. Reports suggest that argon plasma coagulation (APC) can be an effective therapy for CRP following radiotherapy for prostate cancer, but there is less information about how useful it is after radiotherapy for gynaecological malignancy. The aim of this work therefore was to study the efficacy of APC for CRP after radiotherapy for gynaecological malignancy.

METHOD

This was a prospective study of consecutive patients with CRP following radiotherapy for gynaecological malignancy at IPGME&R, SDLD, Kolkata, India; symptoms included rectal bleeding grade (RBG) ≥ 2. APC was performed at monthly intervals to a maximum of four treatment sessions. Severity of disease at baseline was graded (endoscopically) by the total colonoscopic severity score (TCSS) and treatment response was assessed by reduction in RBG from ≥ 2 to ≤ 1 measured at > 6 months after cessation of APC.

RESULTS

Seventy patients [90% with cervical cancer, 10% with endometrial cancer; mean age 51.93 ± 9.15 years; median RBG 3 (range 2-4)] received APC. Seven patients died due to underlying malignancy and seven patients were lost to follow-up. Fifty-six (85.7%) patients responded to therapy after a median of 2 (range 1-4) treatment sessions. Multivariate analysis demonstrated that a lower haemoglobin at the start of treatment predicted failure of therapy (P < 0.05).

CONCLUSION

APC is an effective management option for CRP in female patients with gynaecological malignancy. However, the more anaemic the patient the less likely it is to be successful.

Hydroxyethylamine derivatives as HIV-1 protease inhibitors: a predictive QSAR modelling study based on Monte Carlo optimization

Application of HIV-1 protease inhibitors (as an anti-HIV regimen) may serve as an attractive strategy for anti-HIV drug development. Several investigations suggest that there is a crucial need to develop a novel protease inhibitor with higher potency and reduced toxicity. Monte Carlo optimized QSAR study was performed on 200 hydroxyethylamine derivatives with antiprotease activity. Twenty-one QSAR models with good statistical qualities were developed from three different splits with various combinations of SMILES and GRAPH based descriptors. The best models from different splits were selected on the basis of statistically validated characteristics of the test set and have the following statistical parameters: r² = 0.806, Q² = 0.788 (split 1); r² = 0.842, Q² = 0.826 (split 2); r² = 0.774, Q² = 0.755 (split 3). The structural attributes obtained from the best models were analysed to understand the structural requirements of the selected series for HIV-1 protease inhibitory activity. On the basis of obtained structural attributes, 11 new compounds were designed, out of which five compounds were found to have better activity than the best active compound in the series.

Is it Safe to Use Gadolinium-Based Contrast Agents in Mri?

Gadolinium-based contrast agents have greatly expanded the capability of magnetic resonance imaging and have been used extensively in neuroradiology over the past 30 years. When initially developed they were thought to be relatively harmless; it was later discovered they are associated with nephrogenic systemic fibrosis and should be used with caution in certain patient groups, especially those with renal failure. Lately it has been found that the use of these contrast agents may result in deposition of gadolinium in the brain even in patients with an intact blood-brain barrier. While this has not been shown to be associated with any clinical effects, a precautionary approach has been advised by the regulatory authorities. Here we review the development of the gadolinium contrast agents, their use and the advice related to this new information.

Effect of Curcumin Addition on the Adsorption and Transport of a Cationic Dye across DPPG-POPG Liposomes Probed by Second Harmonic Spectroscopy

The effect of addition of curcumin on the adsorption and transport characteristics of a cationic dye, LDS⁺, across negatively charged bilayers composed of POPG and DPPG lipids were investigated by the interface selective second harmonic (SH) spectroscopic technique. Curcumin induced changes in the SH electric field signal of the LDS⁺ ions (E_2ω (LDS⁺)) were observed to depend critically on the bilayer acyl chain saturation/unsaturation ratio (S/U). Following earlier works, the increase in the E_2ω (LDS⁺) signal is attributed to the release of the Na⁺ counterions present in the head group region of the bilayer by curcumin and the decay of the E_2ω (LDS⁺) signal is attributed to the bilayer intercalated state of curcumin. While the changes observed in the E_2ω (LDS⁺) signal in the presence of POPG liposomes were consistent with our earlier study ( Varshney, G. K. et al. Langmuir , 2016 , 32 , 10415 - 10421 ), they were significantly different for DPPG liposomes, following curcumin addition. While the increase in the E_2ω (LDS⁺) signal in the presence of POPG liposomes, is marginal (∼10-20%) and instantaneous (<1 s) followed by a rapid decay (completed within ∼100 s), in the presence of DPPG liposomes it was observed to increase slowly and at saturation shows a substantial increase (100-200%), following curcumin addition. When liposomes consisting of a mixture of POPG and DPPG lipids are used, curcumin induced kinetic characteristics of the E_2ω (LDS⁺) signal showed a mixture of the individual kinetic characteristics observed for the unsaturated (POPG) and saturated (DPPG) liposomes. The observed kinetic trends of the E_2ω (LDS⁺) signal following curcumin addition are explained on the basis of the relative strength of the Na⁺-POPG and Na⁺-DPPG interaction. Higher ordering of the lipid acyl chain region in DPPG liposome makes the Na⁺-DPPG interaction much stronger than the Na⁺-POPG interaction. Further, it is proposed that, in POPG-DPPG liposomes, individual domains of POPG and DPPG lipids exist at low temperature as suggested by the observed temperature dependent kinetic characteristics of the E_2ω (LDS⁺) signal following curcumin addition. These domains are dependent on the S/U ratio and phase state of the bilayer. The gel phase was observed to be more conducive for individual domain formation. Results presented in this work not only support the notion that biological activity of curcumin is associated with its bilayer altering properties, but more interestingly it provides a qualitative insight about how bilayer phase separation can be achieved by modulating the hydrophobic interactions between the lipid acyl chains.

Family-led rehabilitation after stroke in India (ATTEND): a randomised controlled trial

BACKGROUND

Most people with stroke in India have no access to organised rehabilitation services. The effectiveness of training family members to provide stroke rehabilitation is uncertain. Our primary objective was to determine whether family-led stroke rehabilitation, initiated in hospital and continued at home, would be superior to usual care in a low-resource setting.

METHODS

The Family-led Rehabilitation after Stroke in India (ATTEND) trial was a prospectively randomised open trial with blinded endpoint done across 14 hospitals in India. Patients aged 18 years or older who had had a stroke within the past month, had residual disability and reasonable expectation of survival, and who had an informal family-nominated caregiver were randomly assigned to intervention or usual care by site coordinators using a secure web-based system with minimisation by site and stroke severity. The family members of participants in the intervention group received additional structured rehabilitation training-including information provision, joint goal setting, carer training, and task-specific training-that was started in hospital and continued at home for up to 2 months. The primary outcome was death or dependency at 6 months, defined by scores 3-6 on the modified Rankin scale (range, 0 [no symptoms] to 6 [death]) as assessed by masked observers. Analyses were by intention to treat. This trial is registered with Clinical Trials Registry-India (CTRI/2013/04/003557), Australian New Zealand Clinical Trials Registry (ACTRN12613000078752), and Universal Trial Number (U1111-1138-6707).

FINDINGS

Between Jan 13, 2014, and Feb 12, 2016, 1250 patients were randomly assigned to intervention (n=623) or control (n=627) groups. 33 patients were lost to follow-up (14 intervention, 19 control) and five patients withdrew (two intervention, three control). At 6 months, 285 (47%) of 607 patients in the intervention group and 287 (47%) of 605 controls were dead or dependent (odds ratio 0·98, 95% CI 0·78-1·23, p=0·87). 72 (12%) patients in the intervention group and 86 (14%) in the control group died (p=0·27), and we observed no difference in rehospitalisation (89 [14%]patients in the intervention group vs 82 [13%] in the control group; p=0·56). We also found no difference in total non-fatal events (112 events in 82 [13%] intervention patients vs 110 events in 79 [13%] control patients; p=0·80).

INTERPRETATION

Although task shifting is an attractive solution for health-care sustainability, our results do not support investment in new stroke rehabilitation services that shift tasks to family caregivers, unless new evidence emerges. A future avenue of research should be to investigate the effects of task shifting to health-care assistants or team-based community care.

FUNDING

The National Health and Medical Research Council of Australia.

Expression dynamics of HSP70 during chronic heat stress in Tharparkar cattle

Six male Tharparkar cattle aged 2-3 years were selected for the study. The animals were acclimatized in the psychrometric chamber at thermoneutral zone (TNZ) for 15 days and then exposed to 42 °C temperature up to 23 days followed by 12 days of recovery period. Physiological responses were estimated, and peripheral blood mononuclear cells (PBMCs) were isolated at TNZ on day 1, day 5, and day 12; after 6 h of heat stress exposure on day 16 to day 20, day 25, day 30, day 32, day 34, day 36, and day 38; and a recovery period on day 45 and day 50. The PBMCs were cultured to study the effect of thermal challenge on HSP70 messenger RNA (mRNA) expression pattern at different temperature-time combinations. The mRNA and protein expression of HSP70 in PBMCs along with serum extracellular HSP70 (eHSP70) was increased (P < 0.05) and showed two peaks on day 17 and day 32 (2nd and 17th days of thermal challenge, respectively). The HSP70 mRNA expression was increased (P < 0.05) in a temperature- and time-dependent manner in heat stress challenge treatment as compared to control in cultured PBMCs. HSP70 expression was found to be higher (P < 0.05) after 10 days of heat exposure (corresponds to chronic heat stress) as compared to the first 5 days of heat stress (corresponds to short-term heat stress) and control period at TNZ. The present findings indicate that HSP70 is possibly involved in heat stress adaptive response in Tharparkar cattle and the biphasic expression pattern may be providing a second window of protection during chronic heat stress.

Weak localization and the approach to metal-insulator transition in single crystalline germanium nanowires

We study the low-temperature electronic transport properties of single germanium nanowires (NWs) with diameters down to 45 nm to investigate the weak localization (WL) behavior and approach to metal-insulator transition (MIT) within them. The NWs (single crystalline) we investigate lie on the metallic side of the MIT with an extrapolated zero temperature conductivity [Formula: see text] in the range 23 to 1790 [Formula: see text] cm)^-1 and show a temperature-dependent conductivity which below 30 K can be described by a 3D WL behavior with Thouless length [Formula: see text] and [Formula: see text]. From the observed value of [Formula: see text] and the value of the critical carrier concentration n _c, it is observed that the approach to MIT can be described by the scaling equation [Formula: see text] with [Formula: see text], which is a value expected for an uncompensated system. The investigation establishes a NW size limit for the applicability of 3D scaling theories.

A comparative study on the effect of Curcumin and Chlorin-p6 on the transport of the LDS cation across a negatively charged POPG bilayer: Effect of pH

We report the use of interface selective Second Harmonic generation technique to investigate the transport of the LDS cation across POPG liposomes in the pH range of 4.0 to 8.0 in the presence and absence of two amphiphilic drugs, Curcumin and Chlorin-p₆ (Cp₆). Our results show that bilayer permeability of liposomes is significantly affected by the presence of the drugs and pH of the medium as evidenced by significant changes in the transport kinetics of the LDS. Studies carried out in the pH range 4.0-8.0 show that while Cp₆ significantly enhanced the transport of LDS at pH4.0, the transport of the cation was seen to increase with increasing pH, with maximum effect at pH7.4 for Curcumin. The pH dependent bilayer localization of both the drugs was investigated by conducting steady state FRET studies using DPH labeled lipids as donors. The FRET results and the relative population of the various ionic/nonionic species of the drugs at different pH suggest that distance dependent interaction between the various ionic species of the drugs and polar head groups of the lipid is responsible for the observed pH dependence enhancement of the drug induced membrane permeability. Another interesting observation was that the stability of Curcumin in presence of POPG liposomes was observed to degrade significantly near physiological pH (7.4 and 8.0). Although this degradation did not affect the liposome integrity, interestingly this was observed to enhance the transport of the LDS cation across the bilayer. That the degradation products of Curcumin are equally effective as the drug itself in enhancing the membrane permeability lends additional support to the current opinion that the bioactive degradation products of the drug may have a significant contribution to its observed pharmacological effects.

Metals as chemical tracers to discriminate ecological populations of threatened Franciscana dolphins (Pontoporia blainvillei) from Argentina

Franciscana dolphins are the most impacted small cetacean in the Southwestern Atlantic Ocean, classified as Vulnerable A3d by IUCN. Essential (Fe, Mo, Mn, Cr, Ni, Co) and non-essential (Ag, Pb, Sn) trace elements (TEs) were measured in liver, kidney, and brain samples of by-catch Franciscana dolphins that were living in estuarine (n = 21) and marine (n = 21) habitats (1) to assess whether TEs posed a threat and (2) to evaluate the suitability of TEs for discriminating ecological populations of this species in Argentinean waters. Essential TEs showed little variation in tissues from both groups in agreement with levels reported for other cetaceans and suggesting that these concentrations correspond to normal physiological levels. Non-essential TEs were higher in estuarine juveniles and adults dolphins than in marine specimens. These results suggest anthropogenic sources associated with estuarine area and that Franciscana dolphins are good sentinels of the impact of the environment. The difference in the concentrations of TEs beetwen ecological populations appeared to be related to distinct exposures in both geographical areas, and it is suggested that Ag and Sn concentrations in adults are good chemical tracers of anthropogenic input of TEs. These results provide additional information for improved management and regulatory policy.

Effect of Bilayer Partitioning of Curcumin on the Adsorption and Transport of a Cationic Dye Across POPG Liposomes Probed by Second-Harmonic Spectroscopy

The effect of Curcumin partitioning into the bilayer during the adsorption and transport of a cationic dye, LDS, across a negatively charged POPG bilayer was investigated by the interface-selective second-harmonic (SH) spectroscopic technique. The intensity of SH electric field (E_2ω) arising due to LDS adsorbed on the outer bilayer of the POPG liposome was observed to increase instantaneously (<1 s) following the addition of Curcumin. The fractional increase in the SH electric field (E^f_2ω) and the bilayer transport rates (k_T) of LDS were studied with respect to the pH of the solution and also with the Curcumin content in the lipid bilayer. Results obtained indicate that compared with the anionic form of the drug, its neutral form is more conducive of increasing the E^f_2ω of LDS. With increasing Curcumin content in the lipid bilayer, two distinct regimes could be observed in terms of E^f_2ω and k_T values of LDS. For Curcumin:Lipid (C/L) ratio ≤0.02, the E^f_2ω of LDS increases rapidly, while k_T remains unchanged; and for C/L ratio ≥0.02, the E^f_2ω values remains more or less constant, while there is a significant (∼40 times) increase followed by a modest increase in the k_T values of LDS. The observed results support an earlier two-state binding model of Curcumin with the POPG bilayer. In addition, it is further proposed that at low C/L ratio Curcumin binds to the surface of the bilayer replacing the counterions (Na⁺) bound to the lipid head groups, which changes the bilayer surface charge density, thereby causing more LDS cations to adsorb on the bilayer surface. At high C/L ratio, Curcumin intercalates within the hydrophobic domain of the bilayer, altering its hydrophobicity and inducing enhanced transport of the LDS cation. Results presented in this work provide further insights into how Curcumin alters bilayer properties when it partitions from the aqueous to the bilayer phase.

The role of metallothioneins, selenium and transfer to offspring in mercury detoxification in Franciscana dolphins (Pontoporia blainvillei)

The concentrations of mercury (Hg), selenium (Se) and metallothioneins (MT) were evaluated in fetuses, calves, juveniles and adults of the endangered coastal Franciscana dolphin (Pontoporia blainvillei) from Argentina. Mercury concentrations varied among analyzed tissues (liver, kidney, muscle and brain), with liver showing the higher concentrations in all specimens. An age-dependent accumulation was found in liver, kidney and brain. No significant relationship between Hg and MT concentrations was found for all tissues analyzed. Hepatic Hg molar concentrations were positively correlated with those of Se, indicating a great affinity between these two elements. Furthermore, dark granules of HgSe were observed in Kupffer cells in the liver by electron microscopy, suggesting the role of this macrophage in the detoxification of Hg. A transfer of Hg through placenta was proved. The presence of Hg in brain in all age classes did not show concentrations associated with neurotoxicity.

Natural killer cells contribute to hepatic injury and help in viral persistence during progression of hepatitis B e-antigen-negative chronic hepatitis B virus infection

Hepatitis B e-antigen negative (e(-)) chronic HBV infection (CHI) encompasses a heterogeneous clinical spectrum ranging from inactive carrier (IC) state to e(-) chronic hepatitis B (CHB), cirrhosis and hepatic decompensation. In the backdrop of dysfunctional virus-specific T cells, natural killer (NK) cells are emerging as innate effectors in CHI. We characterized CD3(-) CD56(+) NK cells in clinically well-defined, treatment-naive e(-) patients in IC, e(-)CHB or decompensated liver cirrhosis (LC) phase to appraise their role in disease progression. The NK cell frequencies increased progressively with disease severity (IC 8.2%, e(-)CHB 13.2% and LC 14.4%). Higher proportion of NK cells from LC/e(-)CHB expressed CD69, NKp46, NKp44, TRAIL and perforin, the last two being prominent features of CD56(bright) and CD56(dim) NK subsets, respectively. The frequencies of CD3(-) CD56(+) NK cells together with TRAIL(+) CD56(bright) and Perforin(+) CD56(dim) NK cells correlated positively with serum alanine transaminase levels in e(-)CHB/LC. K562 cell-stimulated NK cells from e(-)CHB/LC exhibited significantly greater degranulation but diminished interferon-γ production than IC. Further, Perforin(+) NK cell frequency inversely correlated with autologous CD4(+) T-cell count in e(-) patients and ligands of NK receptors were over-expressed in CD4(+) T cells from e(-)CHB/LC relative to IC. Co-culture of sorted CD56(dim) NK cells and CD4(+) T cells from e(-)CHB showed enhanced CD4(+) T-cell apoptosis, which was reduced by perforin inhibitor, concanamycin A, suggesting a possible perforin-dependent NK cell-mediated CD4(+) T-cell depletion. Moreover, greater incidence of perforin-expressing NK cells and decline in CD4(+) T cells were noticed intrahepatically in e(-)CHB than IC. Collectively, NK cells contribute to the progression of e(-)CHI by enhanced TRAIL- and perforin-dependent cytolytic activity and by restraining anti-viral immunity through reduced interferon-γ secretion and perforin-mediated CD4(+) T-cell lysis.

Centrality-Dependent Modification of Jet-Production Rates in Deuteron-Gold Collisions at √[s(NN)]=200 GeV

Jet production rates are measured in p+p and d+Au collisions at sqrt[s_{NN}]=200  GeV recorded in 2008 with the PHENIX detector at the Relativistic Heavy Ion Collider. Jets are reconstructed using the R=0.3 anti-k_{t} algorithm from energy deposits in the electromagnetic calorimeter and charged tracks in multiwire proportional chambers, and the jet transverse momentum (p_{T}) spectra are corrected for the detector response. Spectra are reported for jets with 12<p_{T}<50  GeV/c, within a pseudorapidity acceptance of |η|<0.3. The nuclear-modification factor (R_{dAu}) values for 0%-100% d+Au events are found to be consistent with unity, constraining the role of initial state effects on jet production. However, the centrality-selected R_{dAu} values and central-to-peripheral ratios (R_{CP}) show large, p_{T}-dependent deviations from unity, challenging the conventional models that relate hard-process rates and soft-particle production in collisions involving nuclei.

Surfactant induced aggregation behavior of Merocyanine-540 adsorbed on polymer coated positively charged gold nanoparticles

Surfactant induced aggregation behavior of Merocyanine 540 adsorbed on polymer (PDD) coated gold nanoparticles (AuNP) is reported. The absorption band of the dye shifts to higher energy in the presence of free polymer and polymer coated AuNP implying aggregation. Addition of a negatively charged surfactant (SDS) induces multiple bands in the extinction spectrum of the dye adsorbed on nanoparticle surface. The highest (460nm) and lowest (564nm) energy bands of the dye become prominent at 10 and >50μM SDS concentrations respectively (dye: 10μM; AuNP: 100-200pM). Based on earlier results the high energy band is likely to originate from dye aggregates and the low energy band is likely to originate from dye monomers. This is attributed to the interplay between polymer-surfactant and polymer-dye interactions at the AuNP surface. The extinction spectra of dye adsorbed at AuNP surface remain unaffected in the presence of a positively charged (CTAB) or a neutral surfactant (Tx-100), at low surfactant concentrations. However at higher surfactant concentrations (>60μM) dye aggregation takes place which is attributed to dye-surfactant interactions. The fluorescence intensity of the dye quenched significantly but its lifetime increased in the presence of polymer coated AuNP. This is attributed to aggregation and reduction in the photoisomerization rate of the dye adsorbed on AuNP surface.