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2.
Phys Rev Lett ; 127(26): 269902, 2021 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-35029505

RESUMO

Retraction of DOI: 10.1103/PhysRevLett.102.197002.

3.
Phys Rev Lett ; 126(1): 015703, 2021 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-33480771

RESUMO

We present results from the SPring-8 Angstrom Compact free electron LAser facility, where we used a high intensity (∼10^{20} W/cm^{2}) x-ray pump x-ray probe scheme to observe changes in the ionic structure of silicon induced by x-ray heating of the electrons. By avoiding Laue spots in the scattering signal from a single crystalline sample, we observe a rapid rise in diffuse scattering and a transition to a disordered, liquidlike state with a structure significantly different from liquid silicon. The disordering occurs within 100 fs of irradiation, a timescale that agrees well with first principles simulations, and is faster than that predicted by purely inertial behavior, suggesting that both the phase change and disordered state reached are dominated by Coulomb forces. This method is capable of observing liquid scattering without masking signal from the ambient solid, allowing the liquid structure to be measured throughout and beyond the phase change.

4.
5.
J Synchrotron Radiat ; 24(Pt 1): 196-204, 2017 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-28009559

RESUMO

Direct metrology of coherent short-wavelength beamlines is important for obtaining operational beam characteristics at the experimental site. However, since beam-time limitation imposes fast metrology procedures, a multi-parametric metrology from as low as a single shot is desirable. Here a two-dimensional (2D) procedure based on high-resolution Fresnel diffraction analysis is discussed and applied, which allowed an efficient and detailed beamline characterization at the SACLA XFEL. So far, the potential of Fresnel diffraction for beamline metrology has not been fully exploited because its high-frequency fringes could be only partly resolved with ordinary pixel-limited detectors. Using the high-spatial-frequency imaging capability of an irradiated LiF crystal, 2D information of the coherence degree, beam divergence and beam quality factor M2 were retrieved from simple diffraction patterns. The developed beam metrology was validated with a laboratory reference laser, and then successfully applied at a beamline facility, in agreement with the source specifications.

6.
Eur J Gynaecol Oncol ; 38(1): 150-152, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29767887

RESUMO

Retroperitoneal leiomyosarcoma is a relatively rare and aggressive tumor. Because of its rarity, it is difficult to arrive at a definite diagnosis preoperatively and to design an effective strategy. Here the authors report a case of peritoneal leiomyosarcoma in which diagnosis was difficult because the clinical course resembled that of ovarian cancer. A 77-year-old woman diagnosed with ovarian cancer underwent laparotomy. The excised tumor contained a necrotic polypoid mass that histologically displayed the features of leiomyosarcoma. The patient received adjuvant chemotherapy with a combination of gemcitabine and docetaxel but died two months after surgery owing to the aggressive behavior of the tumor. Because the preoperative diagnosis in this case was ovarian cancer, arriving at a treatment strategy assuming peritoneal leiomyosarcoma was difficult. If complete surgical resection of tumor is not performed, as in the present case, the prognosis can be extremely poor.


Assuntos
Leiomiossarcoma/diagnóstico , Neoplasias Ovarianas/diagnóstico , Neoplasias Retroperitoneais/diagnóstico , Idoso , Feminino , Humanos , Leiomiossarcoma/cirurgia , Neoplasias Ovarianas/cirurgia , Neoplasias Retroperitoneais/cirurgia
7.
Pharmazie ; 72(5): 296-299, 2017 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-29441876

RESUMO

We implemented an antimicrobial stewardship (AS) program whereby pharmacists sought appropriate use of antimicrobial agents in January 2012. At that time, we targeted anti-methicillin-resistant Staphylococcus aureus (MRSA) agents and carbapenems; however, in January 2014, we added tazobactam/piperacillin (TAZ/PIPC). We evaluated outcomes using multilateral analyses. The average one-day dosage of carbapenems increased; however, the duration of administration and number of recipient patients decreased significantly (P < 0.01). Moreover, the percentage of patients receiving meropenem (MEPM), for whom the time above minimal inhibitory concentration (MIC) was 40% or higher increased (P < 0.01). In contrast, patient utilization of TAZ/PIPC increased significantly after targeting of carbapenems as specific antibacterial agents. However, after TAZ/PIPC was targeted as a specific antibacterial agent, the number of TAZ/PIPC administrations decreased significantly (P < 0.01). The duration of hospitalization and mortality rate in patients receiving specific antibacterial agents significantly decreased after implementation of the AS program (P < 0.01). In conclusion, pharmacist's interventions to provide AS and patient follow-up reduced improper use and promoted proper administration of antibacterial agents. Furthermore, AS was effective in improving patient prognoses and suppressing drug-resistant strains, as well as promoting effective treatment.


Assuntos
Antibacterianos/administração & dosagem , Gestão de Antimicrobianos/organização & administração , Hospitalização/estatística & dados numéricos , Farmacêuticos/organização & administração , Carbapenêmicos/administração & dosagem , Mortalidade Hospitalar , Humanos , Tempo de Internação/estatística & dados numéricos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Ácido Penicilânico/administração & dosagem , Ácido Penicilânico/análogos & derivados , Assistência Farmacêutica/organização & administração , Piperacilina/administração & dosagem , Combinação Piperacilina e Tazobactam , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia
8.
Public Health ; 139: 13-21, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27450441

RESUMO

OBJECTIVES: Hepatitis C virus (HCV) infection is endemic in the Democratic Republic of the Congo (DRC), where the prevalence of HCV antibodies (anti-HCV) is reported to range from 0.2% to 13.7%. However, the reported prevalence rates have been inconsistent. Therefore, a meta-analysis of observational studies was conducted to provide updates on the prevalence of HCV infection in the DRC. STUDY DESIGN: Systematic review and meta-analysis. METHODS: Medline, EMBASE and Google Scholar were searched for publications reporting on HCV infection in the DRC up to autumn 2015. In addition, a manual search was undertaken to detect relevant papers. Studies performed in groups at low risk of HCV (blood donors and pregnant women) were used for the meta-analysis. The random effects model was used to estimate the pooled prevalence of anti-HCV. RESULTS: Sixteen studies with 13,799 participants (aged 6 months-71 years) met the inclusion criteria. The studies were performed in blood donors, pregnant women, military personnel, individuals with human immunodeficiency virus, children, commercial sex workers, Congolese patients living in Canada, patients with sickle cell disease and hospitalized patients. The reviewed studies revealed the presence of anti-HCV in almost all studied age groups and did not differ between sexes. The pooled prevalence of anti-HCV was 2.9% [95% confidence interval 1.5-4.3%]. Subgroup analyses revealed that the prevalence rates of anti-HCV in blood donors and pregnant women were 2.7% (95% confidence interval: 1.1-4.4%) and 3.3% (1.4-5.1%), respectively. CONCLUSIONS: HCV infection remains an issue of public concern in the DRC, demonstrating a need for adequate hepatitis control programmes. Efforts must be made to virtually eliminate transfusion-transmitted HCV throughout the country.


Assuntos
Doenças Endêmicas , Hepatite C/epidemiologia , República Democrática do Congo/epidemiologia , Anticorpos Anti-Hepatite C/sangue , Humanos , Prevalência
9.
Pharmazie ; 71(6): 349-51, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27455556

RESUMO

Neutropenia may develop as an adverse event in patients with multiple myeloma receiving lenalidomide (LEN) plus dexamethasone (DEX) therapy. In the present study, we examined the risk factors associated with grade 3/4 neutropenia during the first cycle of LEN plus DEX therapy. We observed that hemoglobin level (≤ 8.5 g/dl) was a significant risk factor for grade 3/4 neutropenia during the first cycle of therapy (odds ratio: 19.40; 95% confidence interval: 2.68-141.00; p < 0.01). thus, our findings suggest that determining the hemoglobin level could be useful in the risk management for neutropenia in patients receiving LEN plus DEX therapy.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Mieloma Múltiplo/complicações , Neutropenia/induzido quimicamente , Neutropenia/epidemiologia , Idoso , Idoso de 80 Anos ou mais , Antineoplásicos/administração & dosagem , Antineoplásicos Hormonais/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Dexametasona/administração & dosagem , Feminino , Hemoglobinas/metabolismo , Humanos , Lenalidomida , Masculino , Pessoa de Meia-Idade , Mieloma Múltiplo/tratamento farmacológico , Fatores de Risco , Talidomida/administração & dosagem , Talidomida/análogos & derivados
10.
Pharmazie ; 71(2): 109-12, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27004376

RESUMO

Inappropriate antimicrobial treatment could adversely affect the recovery of patients with aspiration pneumonia. We attempted to identify inappropriate antibacterial treatment and to determine the standard use of anti-methicillin-resistant Staphylococcus aureus (MRSA) drugs in aspiration pneumonia patients with MRSA-positive in sputum. Aspiration pneumonia patients with MRSA-positive sputum treated between January 2013 and May 2013 were included in this study to determine the risk factors for death during hospitalization. The relationship between anti-MRSA medicine use and death during hospitalization was also investigated. More than 107 MRSA colony-forming units in sputum culture, creatinine clearance of less than 30 mL/min, and quinolone use were found to be risk factors for death during hospitalization. The death rate during hospitalization was significantly lower in cases a Geckler classification of 4 or 5 when anti-MRSA treatment was initiated soon after the culture was obtained. Therefore, we concluded that the use of quinolones as antibacterial treatment in aspiration pneumonia patients with MRSA-positive sputum should be avoided and that anti-MRSA treatment should be started in cases with good quality sputum cultures.


Assuntos
Antibacterianos/uso terapêutico , Staphylococcus aureus Resistente à Meticilina , Pneumonia Aspirativa/tratamento farmacológico , Pneumonia Aspirativa/microbiologia , Escarro/microbiologia , Infecções Estafilocócicas/tratamento farmacológico , Mortalidade Hospitalar , Humanos , Pneumonia Aspirativa/mortalidade , Quinolonas/uso terapêutico , Fatores de Risco , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/mortalidade
11.
Pharmazie ; 71(8): 484-488, 2016 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-29442037

RESUMO

This study was retrospectively carried out to compare the efficacy of echinocandins such as micafungin (MCFG) and caspofungin (CPFG) in the treatment of antibiotic-unresponsive febrile patients with hematologic malignancies. A total of 163 patients received either MCFG or CPFG. We evaluated the efficacy of echinocandin against fever decline in all patients. Fever decline, defined as a body temperature of less than 37.5 °C sustained for more than 48 h without scheduled antipyretic medication. Efficacy assessments showed that the incidence of fever decline was not significantly different between the MCFG and CPFG groups (P=0.599). The median number of days from the start of echinocandin administration to fever decline was 5 in both the MCFG and CPFG groups. Multivariate analysis showed that the use of anti-MRSA drugs (HR, 0.64; 95%CI, 0.45-0.90; P=0.011) and a change from echinocandins to voriconazole or liposomal-amphotericin B (HR, 0.50; 95%CI, 0.30-0.74; P<0.001) are significant risk factors for sustained fever. A significant difference (P=0.002) in incidence of fever decline was however associated with differences in the timing of anti-MRSA drug administration. The median number of days from the start of echinocandin administration to fever decline was 5 when administration of the anti-MRSA drug occurred "simultaneously or prior to echinocandin start" and 11 in the "next day or later of echinocandin start" group. In other words, starting anti-MRSA drug treatment after echinocandin treatment is a risk factor. In conclusion, MCFG and CPFG have similar efficacy as empirical antifungal agents in the treatment of antibioticunresponsive febrile patients with hematopoietic malignancies.


Assuntos
Antifúngicos/uso terapêutico , Equinocandinas/uso terapêutico , Febre/tratamento farmacológico , Febre/etiologia , Neoplasias Hematológicas/complicações , Lipopeptídeos/uso terapêutico , Micoses/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Caspofungina , Farmacorresistência Fúngica , Feminino , Humanos , Masculino , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Micafungina , Pessoa de Meia-Idade , Micoses/complicações , Estudos Retrospectivos , Fatores de Risco , Infecções Estafilocócicas/tratamento farmacológico , Adulto Jovem
12.
Br J Cancer ; 106(9): 1535-42, 2012 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-22531720

RESUMO

BACKGROUND: PI3K/Akt (PKB) pathway has been shown in several cell types to be activated by ligands to cell surface integrins, leading to the metastasis of tumour cells. The signalling pathways involved in the metastatic spread of human scirrhous gastric carcinoma cells have not been defined. METHODS: The role of the PI3K/Akt pathway in an extensive peritoneal-seeding cell line, OCUM-2MD3 and a parental cell line, OCUM-2M, was investigated by assessing in vitro adhesion and spreading assay, and in vivo peritoneal metastatic model. We also examined the correlation of PI3K/Akt pathway with integrin signals by immunoprecipitations, using cells by transfection with mutant p85 (Δp85). RESULTS: Adhesiveness and spreading of OCUM-2MD3 cells on collagen type IV was significantly decreased by PI3K inhibitors and expression of mutant p85, but not by inhibitors of protein kinase C (PKC) or extracellular signal-regulated kinase (ERK). Immunoprecipitation studies indicated that the PI3K/Akt pathway was associated with integrin signalling through Src and vinculin. In an in vivo experimental metastasis model, p85 inhibition reduced peritoneal metastasis of OCUM-2MD3 cells. CONCLUSION: PI3K/Akt signalling may be required for integrin-dependent attachment and spreading of scirrhous gastric carcinoma cells, and would be translated into generating better strategies to optimise their use in cancer clinical trials.


Assuntos
Adenocarcinoma Esquirroso/patologia , Adesão Celular , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Neoplasias Peritoneais/secundário , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Neoplasias Gástricas/patologia , Adenocarcinoma Esquirroso/metabolismo , Animais , Western Blotting , Comunicação Celular , Proliferação de Células , MAP Quinases Reguladas por Sinal Extracelular/antagonistas & inibidores , Feminino , Humanos , Imunoprecipitação , Integrinas/metabolismo , Camundongos , Camundongos Nus , Neoplasias Peritoneais/metabolismo , Inibidores de Fosfoinositídeo-3 Quinase , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Transdução de Sinais , Neoplasias Gástricas/metabolismo , Células Tumorais Cultivadas
13.
Phys Rev Lett ; 108(17): 175005, 2012 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-22680876

RESUMO

Short pulse laser interactions at intensities of 2×10(21) W cm(-2) with ultrahigh contrast (10(-15)) on submicrometer silicon nitride foils were studied experimentally by using linear and circular polarizations at normal incidence. It was observed that, as the target decreases in thickness, electron heating by the laser begins to occur for circular polarization leading to target normal sheath acceleration of contaminant ions, while at thicker targets no acceleration or electron heating is observed. For linear polarization, all targets showed exponential energy spreads with similar electron temperatures. Particle-in-cell simulations demonstrate that the heating is due to the rapid deformation of the target that occurs early in the interaction. These experiments demonstrate that finite spot size effects can severely restrict the regime suitable for radiation pressure acceleration.

14.
J Sports Med Phys Fitness ; 52(2): 212-20, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22525659

RESUMO

AIM: The aim of this study was to assess the effects of long-term physical exercise on peripheral nerve using both nerve conduction study (NCS) and ultrasonography (US). METHODS: The authors measured nerve conduction study and ultrasonography in 15 male (mean, 20±1.5 years) handball players and 13 male (mean, 21.3±1.9 years) control subjects. Cross-sectional area of the median nerve was evaluated using ultrasonography at the carpal tunnel and 6 cm proximal to the wrist, and the ulnar nerve at 6 cm proximal to the wrist crease, 2 cm proximal to the medial epicondyle, the epicondyle, and 2 cm distal to epicondyle. RESULTS: US shows significantly increased cross-sectional area of both median and ulnar nerve in the players compared with that in the controls, and the latency times in both nerves were significantly delayed in the players compared with that in the controls. Cross-sectional area of the median nerve showed a significant correlation with latency (r=0.330, P<0.01). CONCLUSION: This study suggests that the players have a tendency toward having both median and ulnar motor nerve damage in the wrist or elbow region although they are asymptomatic.


Assuntos
Exercício Físico/fisiologia , Nervo Mediano/diagnóstico por imagem , Nervo Mediano/fisiologia , Condução Nervosa , Nervo Ulnar/diagnóstico por imagem , Nervo Ulnar/fisiologia , Adolescente , Adulto , Humanos , Masculino , Esportes/fisiologia , Fatores de Tempo , Ultrassonografia , Adulto Jovem
15.
Br J Cancer ; 105(11): 1750-8, 2011 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-22015554

RESUMO

BACKGROUND: The intake of dietary fatty acids is highly correlated with the risk of various cancers. Linoleic acid (LA) is the most abundant polyunsaturated fat in the western diet, but the mechanism(s) by fatty acids such as LA modulate cancer cells is unclear. In this study, we examined the role of LA in various steps in gastric cancer progression. METHODS: The difference in gene expression between LA-treated and untreated OCUM-2MD3 gastric carcinoma cells was examined by mRNA differential display. The involvement of candidate genes was examined by oligo- and plasmid-mediated RNA interference. Biological functions of several of these genes were examined using in vitro assays for invasion, angiogenesis, apoptosis, cell viability, and matrix digestion. Angiogenesis in vivo was measured by CD-31 immunohistochemistry and microvessel density scoring. RESULTS: LA enhanced the plasminogen activator inhibitor 1 (PAI-1) mRNA and protein expression, which are controlled by PAI-1 mRNA-binding protein. LA-stimulated invasion depended on PAI-1. LA also enhanced angiogenesis by suppression of angiostatin, also through PAI-1. LA did not alter cell growth in culture, but increased dietary LA-enhanced tumour growth in an animal model. CONCLUSION: Our findings suggest that dietary LA impacts multiple steps in cancer invasion and angiogenesis, and that reducing LA in the diet may help slow cancer progression.


Assuntos
Angiostatinas/antagonistas & inibidores , Angiostatinas/metabolismo , Ácido Linoleico/farmacologia , Inibidor 1 de Ativador de Plasminogênio/metabolismo , Neoplasias Gástricas/irrigação sanguínea , Angiostatinas/sangue , Angiostatinas/genética , Animais , Apoptose/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Progressão da Doença , Feminino , Perfilação da Expressão Gênica/métodos , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Camundongos , Camundongos Nus , Análise em Microsséries/métodos , Invasividade Neoplásica/genética , Invasividade Neoplásica/patologia , Neovascularização Patológica/induzido quimicamente , Neovascularização Patológica/genética , Neovascularização Patológica/metabolismo , Inibidor 1 de Ativador de Plasminogênio/sangue , Inibidor 1 de Ativador de Plasminogênio/genética , Interferência de RNA , RNA Mensageiro/genética , Proteínas de Ligação a RNA/sangue , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Neoplasias Gástricas/genética , Neoplasias Gástricas/metabolismo , Células Tumorais Cultivadas
16.
Br J Cancer ; 105(3): 393-402, 2011 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-21750550

RESUMO

BACKGROUND: Although the anti-tumour effect of cyclooxygenase-2 (Cox-2) inhibitors in invasive bladder cancer has been confirmed, its mechanisms of action are unclear. Recently, the concept of an epithelial-to-mesenchymal transition (EMT) promoting carcinoma progression has been suggested, and a key feature of the EMT is the downregulation of E-cadherin. In this study, we investigated the effect of Cox-2 inhibitors on reversal EMT and tumour growth inhibition in bladder cancer cells. METHODS: We used three Cox-2 inhibitors, etodolac, celecoxib and NS-398 and three human bladder cancer cell lines, T24, 5637 and KK47, in this study. T24 xenograft tumour mouse model was used in the in vivo study. RESULTS: Within the clinical drug concentrations, only etodolac showed the in vitro growth inhibition in T24 not in the other cell lines. Etodolac reduced SNAIL mRNA and vimentin cell surface expression, and induced E-cadherin mRNA and E-cadherin cell surface expression, in T24. Etodolac also most strongly inhibited the cell migration of T24 in vitro and showed the highest tumour growth inhibition in T24 tumour in vivo. CONCLUSION: Etodolac at clinical doses exhibited induced in vitro and in vivo anti-tumour effects and reversal effect of EMT in T24. These results suggest that etodolac is a good candidate for an anti-tumour or chemopreventive reagent for high-grade bladder cancer.


Assuntos
Inibidores de Ciclo-Oxigenase 2/farmacologia , Transição Epitelial-Mesenquimal , Etodolac/farmacologia , Animais , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Caderinas/metabolismo , Desdiferenciação Celular , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , Camundongos , Camundongos Nus , Neoplasias da Bexiga Urinária , Vimentina/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
17.
Phys Rev Lett ; 107(2): 025501, 2011 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-21797616

RESUMO

Europium hydride EuH(x), when exposed to high-pressure H2, has been found to exhibit the following structural and valence changes: Pnma(x = 2, divalent) → P63/mmc(x = 2, 7.2-8.7 GPa) → I4/m(x > 2, 8.7-9.7 GPa) → I4/mmm(x > 2, 9.7 GPa-,trivalent). With a trivalent character and a distorted cubic fcc structure, the I4/mmm structure is the ß phase commonly observed for other rare-earth metal hydrides. Our study clearly demonstrates that EuH(x) is no longer an irregular member of the rare-earth metal hydrides.

18.
Phys Rev Lett ; 106(10): 105001, 2011 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-21469796

RESUMO

Experiments using an electron beam produced by laser-wakefield acceleration have shown that varying the overall beam-plasma interaction length results in current filamentation at lengths that exceed the laser depletion length in the plasma. Three-dimensional simulations show this to be a combination of hosing, beam erosion, and filamentation of the decelerated beam. This work suggests the ability to perform scaled experiments of astrophysical instabilities. Additionally, understanding the processes involved with electron beam propagation is essential to the development of wakefield accelerator applications.

19.
Phys Rev Lett ; 107(6): 065003, 2011 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-21902332

RESUMO

By using temporal pulse shaping of high-contrast, short pulse laser interactions with solid density targets at intensities of 2 × 10(21) W cm(-2) at a 45° incident angle, we show that it is possible to reproducibly generate quasimonoenergetic proton and ion energy spectra. The presence of a short pulse prepulse 33 ps prior to the main pulse produced proton spectra with an energy spread between 25% and 60% (ΔE/E) with energy of several MeV, with light ions becoming quasimonoenergetic for 50 nm targets. When the prepulse was removed, the energy spectra was broad. Numerical simulations suggest that expansion of the rear-side contaminant layer allowed for density conditions that prevented the protons from being screened from the sheath field, thus providing a low energy cutoff in the observed spectra normal to the target surface.

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