Search for Light Dark Matter with NA64 at CERN.

Thermal dark matter models with particle χ masses below the electroweak scale can provide an explanation for the observed relic dark matter density. This would imply the existence of a new feeble interaction between the dark and ordinary matter. We report on a new search for the sub-GeV χ production through the interaction mediated by a new vector boson, called the dark photon A^{'}, in collisions of 100 GeV electrons with the active target of the NA64 experiment at the CERN SPS. With 9.37×10^{11} electrons on target collected during 2016-2022 runs NA64 probes for the first time the well-motivated region of parameter space of benchmark thermal scalar and fermionic dark matter models. No evidence for dark matter production has been found. This allows us to set the most sensitive limits on the A^{'} couplings to photons for masses m_{A^{'}}≲0.35 GeV, and to exclude scalar and Majorana dark matter with the χ-A^{'} coupling α_{D}≤0.1 for masses 0.001≲m_{χ}≲0.1 GeV and 3m_{χ}≤m_{A^{'}}.

Association of Fat Mass with SARC-F in Older Patients Undergoing Haemodialysis.

BACKGROUND/OBJECTIVES: An increase in fat mass is accompanied by a loss of muscle mass and function in chronic kidney disease. However, no studies in haemodialysis (HD) patients have investigated the relationship between fat mass and sarcopenia. The primary aim of this study is to assess the prevalence of sarcopenia, while the secondary aim is to verify the association between the fat mass percentage and SARC-F and SARC-F combined with calf circumference (SARC-F+CC) in elderly HD patients. SUBJECTS/METHODS: A cross-sectional study enrolled 96 HD older patients (male, n = 66). SARC-F ≥4 is used to define the muscle function loss, whereas SARC-F ≥6 or SARC-F ≥11 (with the calf circumference added) are the thresholds to diagnose sarcopenia. The fat mass percentage is obtained using bioelectrical impedance analysis. RESULTS: We found that 37.5% had a risk of muscle function loss due to SARC-F ≥4, 21.8% risk of sarcopenia using the SARC-F ≥6, and when using CC, the prevalence of risk of sarcopenia increased to 41.6% according to SARC-F+CC ≥11. In addition, there was an association between adiposity and sarcopenia for SARC-F ≥6 (OR: 1.25, p= 0.028) and SARC-F+CC ≥11 (OR: 1.25, p= 0.0003), but not with muscle function loss (SARC-F ≥4). CONCLUSION: In conclusion, we found that 37.5% of HD patients had a risk of muscle function loss and 21-41% presented sarcopenia, depending on the cut-off point used. In addition, higher adiposity was associated with an increased likelihood of having sarcopenia by 25%.

Fatigue Is Not Associated with Phase Angle in Hemodialysis Patients.

PURPOSE: The aim of this study was to investigate the association between fatigue and phase angle (PA) in patients with chronic kidney disease (CKD) on hemodialysis (HD). METHODS: A cross-sectional study with older patients than 18 years diagnosed with CKD undergoing HD. From 160 (58.36±15.05 years) patients, (n=96; 60%) are men. Body mass and height were assessed using a portable scale and stadiometer, followed by body mass index (BMI) calculus. The bioimpedance electrical analysis was performed using the Bodystat QuadScan 4000. The sample size was dichotomized in two groups, using the median of our sample, either normal when PA ≥5.4º, or low when the PA <5.4º. The Chalder fatigue questionnaire was used the assess the fatigue. The multiple regression was applied to assess the association between fatigue questionnaire and PA. RESULTS: Were considered normal PA≥5.4º (n=78, 48.8%) and low PA<5.4º (n=82, 51.2%). The patients of the PA<5.4º group are older compared to the PA≥5.4º group (63.1±15.1 vs. 53.3±13.4 years, p<0.001). There was no association between PA and fatigue score in the crude model (OR: 1.02, 95%CI: 0.96-1.08, p=0.47) and after confounding variables (OR: 1.03, CI: 0.95-1.12, p=0.43). CONCLUSIONS: In HD patients, we found that patients with lower PA values are older. In addition, we did not find association between fatigue and PA.

25OH Vitamin D Is No Associated with Muscle Function Loss in Adults and Elderly Patients Undergoing Hemodialysis.

OBJECTIVES: In patients with chronic kidney disease, sarcopenia is associated with dialysis treatment, accelerated protein catabolism, and high energy demand. Thus, this study aimed to assess the association between 25-OH vitamin D concentrations and muscle function in patients undergoing hemodialysis. DESIGN: A cross-sectional study. SETTING: Performed in a hemodialysis clinic. PARTICIPANTS: 79 adult and elderly patients undergoing hemodialysis. MEASUREMENTS: The sample was divided according to the SARC-F definition, being 55 patients allocated in the SARC-F <4 group and 24 in the SARC-F ≥4 group. Normal 25-OH vitamin D concentrations was considered when ≥30 ng/dL. RESULTS: Vitamin D concentrations and number of patients with low or normal muscle function did not differ between the groups. There was no correlation between SARC-F and 25-OH vitamin D levels (r: -0.09, p=0.42). CONCLUSIONS: 25-OH vitamin D has no association with muscle function loss in adults and elderly patients undergoing hemodialysis.

Air pollution-induced tanning of human skin.

BACKGROUND: Melanism is more frequent in animals living in polluted areas on urban-industrial sites. Given that an increasing number of people are exposed to elevated air pollution levels, it is possible that environmental pollutants affect melanogenesis in human skin. Epidemiological studies have shown that exposure to traffic-related air pollutants such as diesel exhaust particles (DEP) is associated with more clinical signs of hyperpigmentation. However, mechanistic evidence linking DEP exposure to pigmentation has been elusive. OBJECTIVES: To develop an ex␣vivo skin model to allow for repetitive topical application of relevant ambient DEP, and to provide proof of concept in humans. METHODS: We measured skin pigmentation, melanin and pigmentation-associated gene expression, and evaluated oxidative stress. RESULTS: Repetitive exposure of ex␣vivo skin to DEP at nontoxic concentrations increased skin pigmentation. This increase was visible to the naked eye, time dependent, and associated with an increase in melanin content and the transcription of genes involved in de novo melanin synthesis. Similarly, in healthy participants (n = 76), repetitive topical application of DEP at nontoxic concentrations increased skin pigmentation. DEP-induced pigmentation was mediated by an oxidative stress response. After the application of DEP, epidermal antioxidants were depleted, lipid peroxidation and oxidative DNA damage were enhanced, and in a vehicle-controlled, double-blind clinical study DEP-induced pigmentation was prevented by the topical application of an antioxidant mixture. CONCLUSIONS: Similar to solar radiation, air pollutants cause skin tanning. As eumelanin is an antioxidant, it is proposed that this response serves to protect human skin against air pollution-induced oxidative stress.

SARC-F Is Better Correlated with Muscle Function Indicators than Muscle Mass in Older Hemodialysis Patients.

BACKGROUND: Sarcopenia can be characterized by European Consensus for Sarcopenia (EWGSOP2) criteria, but it methods are not easily accessible. Likewise, the Strength, Assistance with walking, Rise from a Chair, Climb stairs and Falls (SARC-F) has been proposed. OBJECTIVE: The aim of this study was i) to evaluate the prevalence for risk sarcopenia and ii) to correlate the SARC-F with components of the EWGSOP2 consensus in hemodialysis (HD) patients. MEASUREMENTS: This cross-sectional study enrolled ninety-five (male n= 59; 62%) HD older patients. Sarcopenia risk was assessed using the SARC-F, which ≥4 score indicates sarcopenia risk. Sarcopenia was confirmed through of the EWGSOP2 consensus, including the handgrip strength (HGS <27kg for men and <16kg for women) using the dynamometer, muscle mass through appendicular muscle mass (ASMI/m2 <7.0 kg/m2 for men and 5.5 kg/m2 for women) using the bioimpedance electrical, and physical performance through of gait speed (GS <0.8 m/s). RESULTS: From 95 patients, n=21(22%) presented sarcopenia risk. SARC-F ≥4 group are older (64.9±13.9 vs. 56.9±14.6 y, p= 0.028), presented lower ASMI (7.4±1.2 vs. 8.3±1.8 kg/m2, p=0.033), HGS (20.5±5.7 vs. 27.2±10.2 kg, p=0.005), and GS (0.5±0.1 vs. 0.7±0.1 m/s, p=0.001) than SARC-F<4 group. SARC-F score was negatively correlated with EWGSOP2 components: ASMI x SARC-F (r=-0.27, p=0.007), HGS x SARC-F (r=-0.35, p=0.0005), and GS x SARC-F (r=-0.47, p<0.0001). Although, no difference of number of patients with low or normal ASMI values was found, 62% and 95% of SARC-F≥4 group patients presented low HGS and gait speed, respectively. CONCLUSIONS: In older HD patients, 22% presented sarcopenia risk. In addition, SARC-F is better correlated with muscle function indicators (HGS and gait speed) than muscle mass.

Metasurface-bounded open cavities supporting virtual absorption: free-space energy accumulation in lossless systems.

We investigate an anomalous scattering phenomenon exhibited by a lossless system based on metasurfaces. Electromagnetic energy is neither reflected nor transmitted but stored within the system to be available again at a different time. We analytically derive the proper excitation conditions and verify the response of the system through a proper set of full-wave simulations, demonstrating the key role of the metasurface in enabling such a zero-scattering condition. The practical feasibility and the opportunities offered by the proposed metasurface-based system may open the door to the design of virtual absorbers with dynamic properties in energy absorbing, storing, and releasing.

Ultrafast Quantum Interference in the Charge Migration of Tryptophan.

Extreme-ultraviolet-induced charge migration in biorelevant molecules is a fundamental step in the complex path leading to photodamage. In this work we propose a simple interpretation of the charge migration recently observed in an attosecond pump-probe experiment on the amino acid tryptophan. We find that the decay of the prominent low-frequency spectral structure with increasing pump-probe delay is due to a quantum beating between two geometrically distinct, almost degenerate charge oscillations. Quantum beating is ubiquitous in these systems, and at least on the few-to-tens of femtosecond time scales, it may dominate over decoherence the line intensities of time-resolved spectra. We also address the experimentally observed phase shift in the charge oscillations of two different amino acids, tryptophan and phenylalanine. Our results indicate that a beyond mean-field treatment of the electron dynamics is necessary to reproduce the correct behavior.

Analysis of risk factors and postoperative predictors for recurrent lumbar disc herniation.

BACKGROUND: This study identified risk factors and postoperative indicators for recurrent lumbar disc herniations (rLDH) following microdiscectomy. METHODS: We retrospectively reviewed the 1-year recurrence rate for LDH in 209 consecutive patients undergoing microdiscectomy (2013-2018). RESULTS: Utilizing a multivariate analysis, higher body mass index (BMI) and postsurgery Oswestry disability index (ODI) were significantly associated with an increased risk of rLDH. CONCLUSION: Elevated postsurgery ODI and higher BMI were significantly associated with increased risk of rLDH.

First-Principles Nonequilibrium Green's Function Approach to Ultrafast Charge Migration in Glycine.

We investigate the photoinduced ultrafast charge migration phenomenon in the glycine molecule using a recently proposed nonequilibrium Green's functions (NEGF) approach. We first consider the dynamics resulting from the sudden removal of an electron in the valence shells, finding a satisfactory agreement with available data. Then we explicitly simulate the laser-induced photoionization process and study the evolution of the system after the pulse. We disentangle polarization and correlation effects in the electron dynamics and assign the main frequencies to specific elements of the reduced one-particle density matrix. We show that electronic correlations renormalize the bare frequencies, redistribute the spectral weights, and give rise to new spectral features.

Many-body perturbation theory calculations using the yambo code.

yambo is an open source project aimed at studying excited state properties of condensed matter systems from first principles using many-body methods. As input, yambo requires ground state electronic structure data as computed by density functional theory codes such as Quantum ESPRESSO and Abinit. yambo's capabilities include the calculation of linear response quantities (both independent-particle and including electron-hole interactions), quasi-particle corrections based on the GW formalism, optical absorption, and other spectroscopic quantities. Here we describe recent developments ranging from the inclusion of important but oft-neglected physical effects such as electron-phonon interactions to the implementation of a real-time propagation scheme for simulating linear and non-linear optical properties. Improvements to numerical algorithms and the user interface are outlined. Particular emphasis is given to the new and efficient parallel structure that makes it possible to exploit modern high performance computing architectures. Finally, we demonstrate the possibility to automate workflows by interfacing with the yambopy and AiiDA software tools.

Dosimetric and chemical characteristics of Fricke gels based on PVA matrices cross-linked with glutaraldehyde.

Fricke gel radiochemical sensors based on various matrices have been studied for decades as 3D dosimeters for radiotherapy. Despite their many appealing features, progressive aging and blurring of the signal have prevented the widespread use of these dosimeters, so far. We have addressed these shortcomings and hereby present our development of a Fricke gel based on a chemically cross-linked PVA matrix. We investigated the influence of several parameters of the polymeric matrix on sensitivity, diffusion coefficient and spontaneous oxidation of the proposed gel dosimeter. Based on these findings, we optimized the gel compositions. Our new gel formulation combines transparency, high sensitivity and simple production method, typical of gels based on natural polymers, with low diffusion coefficient and slow spontaneous oxidation typical of PVA gels made by freezing-thawing.

Ultrafast Charge Migration in XUV Photoexcited Phenylalanine: A First-Principles Study Based on Real-Time Nonequilibrium Green's Functions.

The early-stage density oscillations of the electronic charge in molecules irradiated by an attosecond XUV pulse takes place on femto- or subfemtosecond time scales. This ultrafast charge migration process is a central topic in attoscience because it dictates the relaxation pathways of the molecular structure. A predictive quantum theory of ultrafast charge migration should incorporate the atomistic details of the molecule, electronic correlations, and the multitude of ionization channels activated by the broad-bandwidth XUV pulse. We propose a first-principles nonequilibrium Green's function method fulfilling all three requirements and apply it to a recent experiment on the photoexcited phenylalanine amino acid. Our results show that dynamical correlations are necessary for a quantitative overall agreement with the experimental data. In particular, we are able to capture the transient oscillations at frequencies 0.15 and 0.30 PHz in the hole density of the amine group as well as their suppression and the concomitant development of a new oscillation at frequency 0.25 PHz after ∼14 fs.

The development of episodic future thinking in middle childhood.

The ability to imagine future events (episodic future thinking-EFT) emerges in preschoolers and further improves during middle childhood and adolescence. In the present study, we focused on the possible cognitive factors that affect EFT and its development. We assessed the ability to mentally project forward in time of a large cohort of 135 6- to 11-year-old children through a task with minimal narrative demands (the Picture Book Trip task adapted from Atance and Meltzoff in Cogn Dev 20(3):341-361. doi:10.1016/j.cogdev.2005.05.001, 2005) in order to avoid potential linguistic effects on children's performance. The results showed that this task can be used to assess the development of EFT at least until the age of 8. Furthermore, EFT scores correlated with measures of phonological short-term and verbal working memory. These results support the possibility that cognitive factors such as working memory play a key role in EFT.

Deep spinal infection in instrumented spinal surgery: diagnostic factors and therapy.

AIM: Postoperative surgical site infections (SSI) are complication of spinal surgery. These complications may lead to a poor outcome with neurological deficits, spinal deformity and chronic pain. The purpose of this study is to explore the statistical value of diagnostic parameters and the proper therapy. METHOD: We retrospectively reviewed 550 patients who underwent spinal instrumentation at our department from January 2011 to December 2015. The SSI was present in 16 patients out of 550 operated. Diagnostic criteria of SSI were the positivity of the surgical wound swab or blood culture, the clinical findings, positivity of laboratory tests and radiological elements. All patients had peri-operative antibiotic prophylaxis. Diagnostic laboratory findings were compared with a homogeneous control group of 16 patients and analyzed by univariate statistical analysis with Chi-square test for the discrete variables. P<0,05 was considered statistically significant. RESULTS: Matching the SSI patients with a group of control, fever was not statistically significant for diagnosis as number of leukocytes, neutrophils and lymphocytes. On the contrary values of ESR and CRP were statistically significant with p <0, 01. The hardware was removed only in 3 patients (18%) out of 16 SSI patients. CONCLUSION: In this study the statistically significant parameters to diagnose SSI are ESR and CRP values. The leucocytes count, number of lymphocytes and presence of fever integrates the data of ESR and CRP with no statistical significance. Most patients with SSI reach clinical healing with favorable outcome by means of target antibiotic therapy without hardware removal.

Correlation between individual inflammation genetic profile and platelet rich plasma efficacy in hair follicle regeneration: a pilot study reveals prognostic value of IL-1a polymorphism.

OBJECTIVE: Hair loss generates severe psychosocial implications. To date, exploring the prognostic factors of possible clinical benefit of autologous blood concentrate platelet rich plasma (PRP) was failed. The aim of our pilot study was to explore the correlation between the individual inflammation genetic profile and PRP efficacy in the treatment of hair follicle regeneration. PATIENTS AND METHODS: 41 volunteers (25 men, 16 women) took part in this retrospective study. All the patients were scheduled for 4 sessions of PRP application with intervals of 40-60 days. All the patients were checked up at 6 weekly intervals for 6 months and, then, at the end of the first year. A panel of 5 polymorphisms on 4 genes (IL-1a, IL-1b, IL-6, and IL-10) implicated in the individual genetic inflammation profile were performed. RESULTS: A significant increase rate in hair density was noticed after the third month of treatment in 32/41 (78%) of the subjects. We found an interesting association between the pro-inflammatory cytokine IL-1α polymorphism C>A (rs17561) and responders to PRP treatment. The cases carrying C/C genotype (coding for Ser114) were 21 (66%) in responders and only 2 (22%) in non-responders (p<0.05). In addition, about IL-1a, the frequency of G/G genotype in responder patients was over two times lower in responder (31%) than in non-responder patients (78%). CONCLUSIONS: Our pilot study demonstrated a correlation between the individual genetic inflammatory profile and the efficacy of the PRP treatment in males. On the contrary, in females, it showed a negative correlation. IL-1a could be used as a prognostic value for PRP efficacy. Also, these results provide preliminary evidence that may encourage the design of controlled clinical trials to properly test this modus operandi on a large number of subjects.

Risk factors of surgical site infections in instrumented spine surgery.

BACKGROUND: The incidence of wound infections associated with instrumented spine surgery ranges from 2 to 20%. These complications may lead to poor outcomes. Knowing the risk factors associated with surgical site infections (SSI) after utilizing spinal implants is essential to avoid these complications, including hardware removal. METHODS: We reviewed retrospectively 550 patients who underwent spinal fusion surgery from 2011 to 2015; 16 developed SSI after spinal instrumentation. The diagnosis of SSI was established based on positive wound swab or blood cultures, and various clinical, laboratory, and radiological findings. Additional preoperative and intraoperative risk factors were analyzed. RESULTS: The incidence of SSI after spinal instrumentation surgery was 2.9%. Obesity was a statistically significant parameter (P = 0.013) that contributed to SSI along with the alcoholism and/or drug abuse (P = 0.034); use of a Foley catheter nearly reached significance levels. CONCLUSIONS: There is an increased risk of SSI in patients who are obese or use drugs and/or alcohol. Clear preoperative identification of these risk factors prior to implanting spinal instrumentation should help prevent SSI in the future.

Comparing the performance of three panels rules of blood smear review criteria on an Italian multicenter evaluation.

BACKGROUND: The aims of this study were to compare the diagnostic accuracy of blood smear review criteria, by means of three different panel rules, those proposed by: the International Consensus Group for Hematology [41-ICGH rules], the Italian Survey [IS rules] and the Working Group on Hematology-SIBioC (WGH) consensus rules (WGH rules). METHODS: This study is based on 2707 peripheral blood (PB) samples referred for routine hematological testing to the WGH-associated laboratories displaced all over the Italian territory. The PB samples were processed on seven different hematology analyzers (HAs): Advia 2120i, XE-2100, BC-6800, ABX Pentra, XN-1000, Cell-DYN Sapphire, and DxH800, respectively. All the results provided by the HAs were analyzed through the application of three different blood smear review criteria: that is, the 41-ICGH, IS, and WGH rules. Finally, data were compared with those obtained by optical microscopy (OM), as the current gold standard. RESULTS: The overall the agreement OM classification with ICGH, IS, and WGH panel rules is 0.83, 0.83, and 0.85, respectively. The false negatives are 2.1%, 3.0%, and 2.9%, while false positives are 15.1%, 13.7%, and 11.7%, respectively. All the seven HAs showed variable interinstrument performance, as three different criteria for OM review were adopted on each of them from time to time. CONCLUSION: These results presented show that the customization of validation rules is necessary for enhancing the quality of hematological testing and optimizing workflow.

Performance evaluation of the automated nucleated red blood cell count of five commercial hematological analyzers.

INTRODUCTION: Recent automated hematology analyzers (HAs) can identify and report nucleated red blood cells (NRBC) count as a separate population out of white blood cells (WBC). The aim of this study was to investigate the analytical performances of NRBC enumeration on five top of the range HAs. METHODS: We evaluated the within-run and between-day precision, limit of blank (LoB), limit of detection (LoD), and limit of quantitation (LoQ) of XE-2100 and XN-module (Sysmex), ADVIA 2120i (Siemens), BC-6800 (Mindray), and UniCel DxH 800 (Beckman Coulter). Automated NRBC counts were also compared with optical microscopy (OM). RESULTS: The limits of detection for NRBC of the BC-6800, XN-module, XE-2100, UniCel DxH 800, and ADVIA 2120i are 0.035×109 /L, 0.019×109 /L, 0.067×109 /L, 0.038×109 /L, and 0.167×109 /L, respectively. Our data indicated excellent performance in terms of precision. The agreement with OM was excellent for BC-6800, XN-module, and XE-2100 (Bias 0.023, 0.019, and 0.033×109 /L, respectively). ADVIA 2120i displayed a significant constant error and UniCel DxH 800 both proportional and small constant error. CONCLUSION: Regards to NRBC counting, the performances shown by BC-6800, XN-module, and XE-2100 are excellent also a low count, ADVIA 2120i and UniCel DxH 800 need to be improved.