Proteomic Characterization of Plasma in Lemierre's Syndrome

BACKGROUND

 The underlying mechanisms of thrombosis in Lemierre's syndrome and other septic thrombophlebitis are incompletely understood. Therefore, in this case control study we aimed to generate hypotheses on its pathogenesis by studying the plasma proteome in patients with these conditions.

METHODS

 All patients with Lemierre's syndrome in the Skåne Region, Sweden, were enrolled prospectively during 2017 to 2021 as cases. Age-matched patients with other severe infections were enrolled as controls. Patient plasma samples were analyzed using label-free data-independent acquisition liquid chromatography tandem mass spectrometry. Differentially expressed proteins in Lemierre's syndrome versus other severe infections were highlighted. Functions of differentially expressed proteins were defined based on a literature search focused on previous associations with thrombosis.

RESULTS

 Eight patients with Lemierre's syndrome and 15 with other severe infections were compared. Here, 20/449 identified proteins were differentially expressed between the groups. Of these, 14/20 had functions previously associated with thrombosis. Twelve of 14 had a suggested prothrombotic effect in Lemierre's syndrome, whereas 2/14 had a suggested antithrombotic effect.

CONCLUSION

 Proteins involved in several thrombogenic pathways were differentially expressed in Lemierre's syndrome compared to other severe infections. Among identified proteins, several were associated with endothelial damage, platelet activation, and degranulation, and warrant further targeted studies.

Symptoms predictive of Fusobacterium necrophorum pharyngotonsillitis - an observational study of cases presenting to hospitals in Southern Sweden

OBJECTIVES

Fusobacterium necrophorum is a common cause of pharyngotonsillitis. However, no guidelines exist on when to diagnose or treat it. We aimed to investigate associations between clinical criteria and F. necrophorum-positivity in pharyngotonsillitis and assess the predictive potential of a simple scoring system.

METHODS

Pharyngotonsillitis patients who were tested for F. necrophorum (PCR) and presented to hospitals in the Skåne Region, Sweden, between 2013-2020 were eligible. Data were retrieved from electronic chart reviews and registries. By logistic regression we investigated associations between F. necrophorum-positivity and pre-specified criteria: age 13-30 years, symptom duration ≤ 3 days, absence of viral symptoms (e.g. cough, coryza), fever, tonsillar swelling/exudate, lymphadenopathy and CRP ≥ 50 mg/L. In secondary analyses, associated variables were weighted by strength of association into a score and its predictive accuracy of F. necrophorum was assessed.

RESULTS

Among 561 cases included, 184 (33%) had F. necrophorum, which was associated with the following criteria: age 13-30, symptom duration ≤ 3 days, absence of viral symptoms, tonsillar swelling/exudate and CRP ≥ 50 mg/L. Age 13-30 had the strongest association (OR5.7 95%CI 3.7-8.8). After weighting, these five variables had a sensitivity and specificity of 68% and 71% respectively to predict F. necrophorum-positivity at the proposed cut-off.

CONCLUSION

Our results suggest that F. necrophorum cases presenting to hospitals might be better distinguished from other pharyngotonsillitis cases by a simple scoring system presented, with age 13-30 being the strongest predictor for F. necrophorum. Prospective studies, involving primary care settings, are needed to evaluate generalisability of findings beyond cases presenting to hospitals.

Low usefulness of reporting tonsillar PCR Ct-values in pharyngeal infections with Fusobacterium necrophorum

Tonsillar Fusobacterium necrophorum PCR Ct-values were higher in participants with asymptomatic tonsillar carriage than patients with pharyngeal infections. However, Ct-values were not associated with severity of disease or predictive of development of complications and hence lacked clinical usefulness. The reporting of F. necrophorum Ct-values in clinical samples is not recommended.

Infectivity of exhaled SARS-CoV-2 aerosols is sufficient to transmit covid-19 within minutes

Exhaled SARS-CoV-2-containing aerosols contributed significantly to the rapid and vast spread of covid-19. However, quantitative experimental data on the infectivity of such aerosols is missing. Here, we quantified emission rates of infectious viruses in exhaled aerosol from individuals within their first days after symptom onset from covid-19. Six aerosol samples from three individuals were culturable, of which five were successfully quantified using TCID50. The source strength of the three individuals was highest during singing, when they exhaled 4, 36, or 127 TCID50/s, respectively. Calculations with an indoor air transmission model showed that if an infected individual with this emission rate entered a room, a susceptible person would inhale an infectious dose within 6 to 37 min in a room with normal ventilation. Thus, our data show that exhaled aerosols from a single person can transmit covid-19 to others within minutes at normal indoor conditions.

Observation of high-energy neutrinos from the Galactic plane

The origin of high-energy cosmic rays, atomic nuclei that continuously impact Earth's atmosphere, is unknown. Because of deflection by interstellar magnetic fields, cosmic rays produced within the Milky Way arrive at Earth from random directions. However, cosmic rays interact with matter near their sources and during propagation, which produces high-energy neutrinos. We searched for neutrino emission using machine learning techniques applied to 10 years of data from the IceCube Neutrino Observatory. By comparing diffuse emission models to a background-only hypothesis, we identified neutrino emission from the Galactic plane at the 4.5σ level of significance. The signal is consistent with diffuse emission of neutrinos from the Milky Way but could also arise from a population of unresolved point sources.

Size distribution of exhaled aerosol particles containing SARS-CoV-2 RNA

BACKGROUND

SARS-CoV-2 in exhaled aerosols is considered an important contributor to the spread of COVID-19. However, characterizing the size distribution of virus-containing aerosol particles has been challenging as high concentrations of SARS-CoV-2 in exhaled air is mainly present close to symptom onset. We present a case study of a person with COVID-19 who was able to participate in extensive measurements of exhaled aerosols already on the day of symptom onset and then for the following three days.

METHODS

Aerosol collection was performed using an eight-stage impactor while the subject was breathing, talking and singing, for 30 min each, once every day. In addition, nasopharyngeal samples, saliva samples, room air samples and information on symptom manifestations were collected every day. Samples were analyzed by RT-qPCR for detection of SARS-CoV-2 RNA.

RESULTS

SARS-CoV-2 RNA was detected in seven of the eight particle size fractions, from 0.34 to >8.1 µm, with the highest concentrations found in 0.94-2.8 µm particles. The concentration of SARS-CoV-2 RNA was highest on the day of symptom onset, and declined for each day thereafter.

CONCLUSION

Our data showed that 90% of the exhaled SARS-CoV-2 RNA was found in aerosol particles <4.5 µm, indicating the importance of small particles for the transmission of COVID-19 close to symptom onset. These results are important for our understanding of airborne transmission, for developing accurate models and for selecting appropriate mitigation strategies.

Evidence for neutrino emission from the nearby active galaxy NGC 1068

A supermassive black hole, obscured by cosmic dust, powers the nearby active galaxy NGC 1068. Neutrinos, which rarely interact with matter, could provide information on the galaxy’s active core. We searched for neutrino emission from astrophysical objects using data recorded with the IceCube neutrino detector between 2011 and 2020. The positions of 110 known gamma-ray sources were individually searched for neutrino detections above atmospheric and cosmic backgrounds. We found that NGC 1068 has an excess of 79 − 20 + 22 neutrinos at tera–electron volt energies, with a global significance of 4.2σ, which we interpret as associated with the active galaxy. The flux of high-energy neutrinos that we measured from NGC 1068 is more than an order of magnitude higher than the upper limit on emissions of tera–electron volt gamma rays from this source.

Associations Between Findings of Fusobacterium necrophorum or β-Hemolytic Streptococci and Complications in Pharyngotonsillitis-A Registry-Based Study in Southern Sweden

BACKGROUND

Most pharyngotonsillitis guidelines focus on the identification of group A streptococci (GAS), guided by clinical scores determining whom to test with a rapid antigen detection test. Nevertheless, many patients testing negative with this test are evaluated for group C/G streptococci (GCS/GGS) and Fusobacterium necrophorum, yet their importance remains debated. Our primary aim was to evaluate associations between complications and findings of F. necrophorum, GAS, or GCS/GGS in pharyngotonsillitis.

METHODS

This was a retrospective, registry-based study of pharyngotonsillitis cases tested for F. necrophorum (polymerase chain reaction) and β-hemolytic streptococci (culture) in the Skåne Region, Sweden, in 2013-2020. Patients with prior complications or antibiotics (within 30 days) were excluded. Data were retrieved from registries and electronic charts. Logistic regression analyses were performed with a dichotomous composite outcome of complications as primary outcome, based on International Classification of Diseases, Tenth Revision, codes. Cases with negative results (polymerase chain reaction and culture) were set as reference category. Complications within 30 days were defined as peritonsillar or pharyngeal abscess, otitis, sinusitis, sepsis or septic complications, recurrence of pharyngotonsillitis (after 15-30 days) or hospitalization.

RESULTS

Of 3700 registered cases, 28% had F. necrophorum, 13% had GCS/GGS, 10% had GAS, and 54% had negative results. The 30-day complication rates were high (20%). F. necrophorum (odds ratio, 1.8; 95% confidence interval, 1.5-2.1) and GAS (1.9; 1.5-2.5) were positively associated with complications, whereas GCS/GGS were negatively associated (0.7; 0.4-0.98).

CONCLUSIONS

Our results indicate that F. necrophorum is a relevant pathogen in pharyngotonsillitis, whereas the relevance of testing for GCS/GGS is questioned. However, which patient to test and treat for F. necrophorum remains to be defined.

Surface and Optoelectronic Properties of Ultrathin Trigonal Selenium: A Density Functional Theory Study with van der Waals Correction

Selenium is an important earth-abundant and nontoxic semiconductor with numerous applications across semiconductor industries. Selenium has drawn attention from scientific communities for photovoltaics and imaging devices. Its usage as a photosensitive material largely involves the synthesis of the amorphous phase (a-Se) via various experimental techniques. However, the ground state crystalline phase of this material, the trigonal selenium (t-Se), a layered van der Waals solid, has not been extensively studied for its optimum electronic and optical properties. In this work, we present systematic studies based on density functional theory (DFT) for ultrathin (101̅0) surface slabs of t-Se. We report the surface energy as well as work function and electronic and optical properties as a function of number of layers for (101̅0) surface slabs to access its suitability for applications as a photosensitive material and compare these calculations to historical data.

Low Prevalence of Mild Alpha-1-Antitrypsin Deficiency in Hospitalized COVID-19-Patients

Introduction

Alpha-1-antitrypsin (AAT) has been shown to inhibit SARS-CoV-2 cell entry and suggested as a therapeutic agent for COVID-19. Furthermore, epidemiological association of high prevalence of Alpha-1-antitrypsin deficiency (AATD) and regional severity of COVID-19-impact has been hypothesized. In our study setting, the estimated prevalence rates of mild (PI*MZ, PI*SS or PI*MS) and moderate-to-severe AATD (PI*ZZ or PI*SZ) are high, 9% and 0.2%, respectively. Our primary aim was to examine the prevalence rate of AATD among hospitalized COVID-19-patients.

Methods

In this prospective observational study, enrollment occurred from December 2020 to January 2021 in two COVID-19-units at Skåne University Hospital, Lund, Sweden. Case definition was a patient hospitalized due to COVID-19. Patients were screened for AATD with PI-typing and if results were inconclusive, PCR for the S- and Z-genes were performed. Patients were categorized as severe or moderate COVID-19 and 30-day-mortality data were collected. The primary outcome was prevalence rate of AATD. The secondary outcome investigated association between presence of mild AATD and severe COVID-19.

Results

We enrolled 61 patients with COVID-19. Two patients out of 61 (3%) had mild AATD (PI*MZ) and none had moderate-to-severe AATD. 30/61 (49%) had severe COVID-19. Both patients with mild AATD developed severe COVID-19. Yet, presence of AATD was not significantly associated with severe COVID-19 (p=0.24).

Conclusion

Mild AATD (PI*MS or PI*MZ) was rare in a small cohort of hospitalized patients with COVID-19 in a study setting with a high background prevalence of AATD.

SARS-CoV-2 in exhaled aerosol particles from covid-19 cases and its association to household transmission

Background

Coronavirus disease 2019 (COVID-19) transmission via exhaled aerosol particles has been considered an important route for the spread of infection, especially during super-spreading events involving loud talking or singing. However, no study has previously linked measurements of viral aerosol emissions to transmission rates.

Methods

During February–March 2021, COVID-19 cases that were close to symptom onset were visited with a mobile laboratory for collection of exhaled aerosol particles during breathing, talking, and singing, respectively, and of nasopharyngeal and saliva samples. Aerosol samples were collected using a BioSpot-VIVAS and a NIOSH bc-251 2-stage cyclone, and all samples were analyzed by RT-qPCR for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA detection. We compared transmission rates between households with aerosol-positive and aerosol-negative index cases.

Results

SARS-CoV-2 RNA was detected in at least 1 aerosol sample from 19 of 38 (50%) included cases. The odds ratio (OR) of finding positive aerosol samples decreased with each day from symptom onset (OR 0.55, 95 confidence interval [CI] .30–1.0, P = .049). The highest number of positive aerosol samples were from singing, 16 (42%), followed by talking, 11 (30%), and the least from breathing, 3 (8%). Index cases were identified for 13 households with 31 exposed contacts. Higher transmission rates were observed in households with aerosol-positive index cases, 10/16 infected (63%), compared to households with aerosol-negative index cases, 4/15 infected (27%) (χ² test, P = .045).

Conclusions

COVID-19 cases were more likely to exhale SARS-CoV-2-containing aerosol particles close to symptom onset and during singing or talking as compared to breathing. This study supports that individuals with SARS-CoV-2 in exhaled aerosols are more likely to transmit COVID-19.

Short blood culture time-to-positivity in Fusobacterium necrophorum bacteremia is associated with Lemierre's syndrome

The usefulness of blood culture time-to-positivity (TTP) in the diagnosis of endovascular infections has previously been shown. Here, we investigated TTP in 41 patients with F. necrophorum bacteraemia and found an association between short TTP and Lemierre's syndrome (p = 0.026).

Geographical differences in tonsillar carriage rates of Fusobacterium necrophorum - A cross-sectional study in Sweden and Zambia

While Fusobacterium necrophorum historically has been considered normal tonsillar flora, recent studies from Europe and the US have suggested that carriage occur transiently in adolescence and young adulthood. However, no studies originating from Africa exist. In this cross-sectional study of tonsillar carriage of F. necrophorum, we aimed to investigate geographical differences in tonsillar carriage rates of F. necrophorum in healthy participants aged 15-25 years in Sweden and Zambia and further investigate the age distribution of tonsillar carriage in Zambia. Specimens were obtained by tonsillar swabs and analyzed with real-time PCR for F. necrophorum. In participants aged 15-25 years, tonsillar carriage was more common in Sweden 21/100 (21%) than in Zambia 6/192 (3%), p < 0.001. In Zambian participants aged above 25 years tonsillar carriage was rare 1/76 (1%). In conclusion, the high rate of tonsillar carriage in participants aged 15-25 years in Sweden has implications on the interpretation of tonsillar findings in patients with pharyngotonsillitis. Interestingly, a geographical difference was found with tonsillar carriage rarely identified in Zambia.

Jugular Vein Thrombosis and Anticoagulation Therapy in Lemierre's Syndrome-A Post Hoc Observational and Population-Based Study of 82 Patients

Background

Lemierre’s syndrome is typically caused by Fusobacterium necrophorum where an oropharyngeal infection is followed by septic internal jugular vein thrombophlebitis with subsequent septic embolization. Yet, the pathogenesis of septic thrombophlebitis, differences dependent on the presence of jugular vein thrombosis, and the role of anticoagulant therapy are insufficiently understood.

Methods

Patients with invasive infection with F. necrophorum and Lemierre’s syndrome who had been investigated for jugular vein thrombosis were included from a previous population-based observational study in Sweden. Medical records were reviewed and compared in patients with and without jugular vein thrombosis. Then, patients with jugular vein thrombosis were compared by exposure to therapeutic, prophylactic, or no anticoagulation. Outcomes examined were thrombosis progression, early or late peripheral septic complications, chronic major sequelae, 30-day mortality, and major bleeding.

Results

Fifty-one of 82 (62%) radiologically investigated patients with Lemierre’s syndrome had jugular vein thrombosis. Patients with jugular vein thrombosis had lower platelet levels (median, 76 vs 112 ×10⁹/L; P = .04) on presentation and more days to defervesence (12 vs 7 days; P = .03) yet similar rates of major sequelae and 30-day mortality. No significant differences in outcomes were seen between patients with jugular vein thrombosis exposed to therapeutic, prophylactic, or no anticoagulation therapy, yet study outcomes were rare.

Conclusions

Patients with Lemierre’s syndrome with jugular vein thrombosis were more severely affected, yet had similar prognosis. Most patients with jugular vein thrombosis recovered well without therapeutic anticoagulation therapy, though adverse events were similarly rare in anticoagulated patients. The observational design and rarity of study outcomes require cautious interpretation.

Fluorescent bicolour sensor for low-background neutrinoless double β decay experiments

Observation of the neutrinoless double β decay is the only practical way to establish that neutrinos are their own antiparticles¹. Because of the small masses of neutrinos, the lifetime of neutrinoless double β decay is expected to be at least ten orders of magnitude greater than the typical lifetimes of natural radioactive chains, which can mimic the experimental signature of neutrinoless double β decay². The most robust identification of neutrinoless double β decay requires the definition of a signature signal-such as the observation of the daughter atom in the decay-that cannot be generated by radioactive backgrounds, as well as excellent energy resolution. In particular, the neutrinoless double β decay of ¹³⁶Xe could be established by detecting the daughter atom, ¹³⁶Ba²⁺, in its doubly ionized state^3-8. Here we demonstrate an important step towards a 'barium-tagging' experiment, which identifies double β decay through the detection of a single Ba²⁺ ion. We propose a fluorescent bicolour indicator as the core of a sensor that can detect single Ba²⁺ ions in a high-pressure xenon gas detector. In a sensor made of a monolayer of such indicators, the Ba²⁺ dication would be captured by one of the molecules and generate a Ba²⁺-coordinated species with distinct photophysical properties. The presence of such a single Ba²⁺-coordinated indicator would be revealed by its response to repeated interrogation with a laser system, enabling the development of a sensor able to detect single Ba²⁺ ions in high-pressure xenon gas detectors for barium-tagging experiments.

Aortitis caused by Abiotrophia defectiva: Description of two cases

Abiotrophia defectiva is a well-known endocarditis pathogen, however it has never been described as a cause of primary aortitis. Here we describe the first published case of thoracic aortitis and an unusual case of aortic graft infection due to A. defectiva, which were both managed conservatively.

Wavelength-shifting properties of luminescence nanoparticles for high energy particle detection and specific physics process observation

Ultraviolet (UV) photon detection is becoming increasingly important in the quest to understand the fundamental building blocks of our universe. Basic properties of neutrinos and Dark Matter are currently being explored through interactions with noble elements. In response to interactions with fundamental particles, these elements emit scintillation photons in the UV range. However, most available detectors have poor response in the UV so it is typically necessary to shift UV to a wavelength, matching the sensitivity of the viable detectors. We report on development of UV-enhanced photosensors using wavelength-shifting properties of nanoparticles. Several nanoparticle coatings were tested for absorption of UV light with subsequent emission in the visible wavelength for high energy particle detection. ZnS:Mn,Eu, ZnS:Mn, CuCy (Copper Cysteamine) and CdTe nanoparticles all exhibited enhanced detection for wavelengths in the range 200-320 nm in several different tests, while ZnS:Ag and CdS nanoparticle showed little or no enhancement in that range. In addition, various LaF3:Ce nanoparticle concentrations in approximately constant thickness of 2,5-diphenyloxazole (PPO)/polystyrene bases were also tested to optimize the nanoparticle concentration for the best outcome. Our studies indicated that ZnS:Mn,Eu, ZnS:Mn, Cu-Cy, CdTe and LaF3:Ce nanoparticles show potential for light detection from fundamental particle interactions.

[Not Available]

Good outcomes when emergency physicians diagnosed deep vein thrombosis Deep vein thrombosis of the lower limb is best diagnosed with ultrasound. Internationally, several studies have shown promising and often equal results when emergency physicians have been compared with radiologists in diagnosing thrombosis. Our results confirm these findings in a non-academic hospital and for the first time in a Swedish setting. Our findings form the basis for a multi-centre study on new diagnostic routines in patients with suspected proximal deep vein thrombosis in the emergency department, potentially resulting in faster and more resource-effective management.

Remotely-sensed, nocturnal, dew point correlates with malaria transmission in Southern Province, Zambia: a time-series study

BACKGROUND

Plasmodium falciparum transmission has decreased significantly in Zambia in the last decade. The malaria transmission is influenced by environmental variables. Incorporation of environmental variables in models of malaria transmission likely improves model fit and predicts probable trends in malaria disease. This work is based on the hypothesis that remotely-sensed environmental factors, including nocturnal dew point, are associated with malaria transmission and sustain foci of transmission during the low transmission season in the Southern Province of Zambia.

METHODS

Thirty-eight rural health centres in Southern Province, Zambia were divided into three zones based on transmission patterns. Correlations between weekly malaria cases and remotely-sensed nocturnal dew point, nocturnal land surface temperature as well as vegetation indices and rainfall were evaluated in time-series analyses from 2012 week 19 to 2013 week 36. Zonal as well as clinic-based, multivariate, autoregressive, integrated, moving average (ARIMAX) models implementing environmental variables were developed to model transmission in 2011 week 19 to 2012 week 18 and forecast transmission in 2013 week 37 to week 41.

RESULTS

During the dry, low transmission season significantly higher vegetation indices, nocturnal land surface temperature and nocturnal dew point were associated with the areas of higher transmission. Environmental variables improved ARIMAX models. Dew point and normalized differentiated vegetation index were significant predictors and improved all zonal transmission models. In the high-transmission zone, this was also seen for land surface temperature. Clinic models were improved by adding dew point and land surface temperature as well as normalized differentiated vegetation index. The mean average error of prediction for ARIMAX models ranged from 0.7 to 33.5%. Forecasts of malaria incidence were valid for three out of five rural health centres; however, with poor results at the zonal level.

CONCLUSIONS

In this study, the fit of ARIMAX models improves when environmental variables are included. There is a significant association of remotely-sensed nocturnal dew point with malaria transmission. Interestingly, dew point might be one of the factors sustaining malaria transmission in areas of general aridity during the dry season.

Battling Malaria in Rural Zambia with Modern Technology: A Qualitative Study on the Value of Cell Phones, Geographical Information Systems, Asymptomatic Carriers and Rapid Diagnostic Tests to Identify, Treat and Control Malaria

During the last decade much progress has been made in reducing malaria transmission in Macha, Southern Province, Zambia. Introduction of artemisinin combination therapies as well as mass screenings of asymptomatic carriers is believed to have contributed the most. When an endemic malaria situation is moving towards a non-endemic situation the resident population loses acquired immunity and therefore active case detection and efficient surveillance is crucial to prevent epidemic outbreaks. Our purpose was to evaluate the impact of cell phone surveillance and geographical information systems on malaria control in Macha. Furthermore, it evaluates what screening and treatment of asymptomatic carriers and implementation of rapid diagnostic tests in rural health care has led to. Ten in-depth semi-structured interviews, field observations and data collection were performed at the Macha Research Trust and at surrounding rural health centers. This qualitative method was inspired by rapid assessment procedure. The cell phone surveillance has been easily integrated in health care, and its integration with Geographical Information Systems has provided the ability to follow malaria transmission on a weekly basis. In addition, active case detection of asymptomatic carriers has been fruitful, which is reflected in it soon being applied nationwide. Furthermore, rapid diagnostic tests have provided rural health centers with reliable malaria diagnostics, thereby decreasing excessive malaria treatments and selection for drug resistance. This report reflects the importance of asymptomatic carriers in targeting malaria elimination, as well as development of effective surveillance systems when transmission decreases. Such an approach would be cost-efficient in the long run through positive effects in reduced child mortality and relief in health care.

Competitors as collaborators

Driven by a shared mission, former rivals are forming unlikely partnerships to meet community needs.

Merger's closed. What's next? Use this eight-step checklist to make sure the merger achieves its promise

Use this checklist to ensure that the newly merged organization thrives.

Detective quantum efficiency dependence on x-ray energy weighting in mammography

An evaluation of the dependence of detective quantum efficiency (DQE) on the incident energy spectrum has been made for mammography. The DQE dependence on the energy spectrum has been evaluated for energy-integrating detectors, photon-counting detectors, and detectors that measure the energy of each photon. To isolate the effect of the x-ray energy spectrum the detector has been assumed to be ideal, i.e., all noise sources are assumed to be zero except for quantum fluctuations. The result shows that the improvement in DQE, if the energy-integrating detector is compared to a single-photon counting detector, is of the order of 10%. Comparing the energy-integrating detector and the detector measuring the energy for each photon the improvement is around 30% using a molybdenum anode spectrum typical in mammography. It is shown that the optimal weight factors to combine the data in the case the energy is measured are very well approximated if the weight factors are proportional to E(-3). Another conclusion is that in calculating the DQE, a detector should be compared to one that uses ideal energy weighting for each photon since this provides the best signal-to-noise ratio. This has generally been neglected in the literature.