Negative / Null Result ReportOpen accessComputer Science
C. Abel, N. J. Ayres, G. Ban et al. · 2017 · arXiv
We report on a search for ultra-low-mass axion-like dark matter by analysing the ratio of the spin-precession frequencies of stored ultracold neutrons and $^{199}$Hg atoms for an axion-induced oscillating electric dipole moment of the neutron and an axion-wind spin-precession effect. No signal consistent with dark matter is observed for the axion mass range $10^{-24}~\textrm{eV} \le m_a \le 10^{-17}~\textrm{eV}$. Our null result sets the first laboratory constraints on the coupling of axion dark matter to gluons, which improve on astrophysical limits by up to 3 orders of magnitude, and also im
Negative / Null Result ReportOpen accessEconomics, Econometrics and Finance
Ruiwu Liu · 2021 · arXiv
Acemoglu and Johnson (2007) put forward the unprecedented view that health improvement has no significant effect on income growth. To arrive at this conclusion, they constructed predicted mortality as an instrumental variable based on the WHO international disease interventions to analyse this problem. I replicate the process of their research and eliminate some biases in their estimate. In addition, and more importantly, we argue that the construction of their instrumental variable contains a violation of the exclusion restriction of their instrumental variable. This negative correlation betw
Negative / Null Result Report
Cui L, Harrison L, Liu J · 2022 · Preprint
Many studies have failed to replicate the disfluency effect (i.e. disfluent font better than fluent font) on Cognitive Reflection Test (CRT) performance shown in Alter et al. (2007). Those studies manipulated perceptual disfluency using…
View details →DOI: 10.31234/osf.io/qdxw3 Negative / Null Result Report
Katsuhiko Naruse, Itsuko Okada, Masahiko Ogawa et al. · 2020 · International Journal of Gynecology & Obstetrics
Intra‐anal swabbing for GBS in pregnant women did not improve the detection rate compared to perianal swabbing, but increased the detection of ESBL‐producing E.coli .
View details →DOI: 10.1002/ijgo.13238 Negative / Null Result ReportOpen accessPhysics
Ulrich Kolb, Isabelle Baraffe · 1999 · arXiv
Using improved, up-to-date stellar input physics tested against observations of low-mass stars and brown dwarfs we calculate the secular evolution of low-mass donor cataclysmic variables (CVs), including those which form with a brown dwarf donor. Our models confirm the mismatch between the calculated minimum period (Pmin ~ 70 min) and the observed short-period cut-off (~ 80 min) in the CV period histogram. We find that tidal and rotational corrections applied to the one-dimensional stellar structure equations have no significant effect on the period minimum. Theoretical period distributions sy
Negative / Null Result ReportOpen accessComputer Science
Varun Kotte · 2026 · arXiv
Prompt-only, single-step LLM query rewriting, where a rewrite is generated from the query alone without retrieval feedback, is commonly used in production RAG pipelines, but its effect on dense retrieval is poorly understood. We present a systematic empirical study across three BEIR benchmarks, two dense retrievers, and multiple training configurations, and find strongly domain-dependent behavior: rewriting degrades nDCG@10 by 9.0 percent on FiQA, improves it by 5.1 percent on TREC-COVID, and has no significant effect on SciFact. We identify a consistent mechanism: degradations co-occur with r
Negative / Null Result ReportOpen accessBiology (General)
Qiaoli Wang, Wenpei Wang, Yonghui Wang et al. · 2024 · Journal of Fungi
Manganese is one of the trace elements necessary for organisms to maintain normal biological activities and is also a cofactor for manganese superoxide dismutase (Mn-SOD) and manganese peroxidase (MnP). In order to find a simple and effective method to rejuvenate the degenerated V. volvacea strains, we explored the effect of the exogenous addition of MnSO 4 on the antioxidant vigour and productivity of degenerated strains of V. volvacea . The results showed that the exogenous MnSO 4 had no significant effect on the non-degenerated strain T0, but it could effectively increase the mycelial growt
View details →DOI: 10.3390/jof10120825 Negative / Null Result ReportOpen accessPlant culture
J. Harb, A. A. Saquet, R. Bisharat et al. · 2012 · Journal of Applied Botany and Food Quality
Biochemical and quality changes of sweet cherries cv. Regina were assessed over three consecutive years after storage in different modified atmosphere packaging (MAP) liners, with or without hydrocooling, compared to regular atmosphere (RA) storage. All plastic liners used in the experiment resulted in CO2-enrichment and O2-reduction inside packages, with the following impact on fruit quality after five weeks of storage: improved retention of fruit firmness and red color of skin, no significant effect on acidity and total soluble solids, and minimal loss of fruit weight. Fruit decay was absent
Negative / Null Result ReportOpen accessElementary particle physics
John K. Webb, Chung-Chi Lee, Dinko Milaković · 2022 · Universe
Recent advances in spectroscopic instrumentation and calibration methods dramatically improve the quality of quasar spectra. Supercomputer calculations show that, at high spectral resolution, procedures used in some previous analyses of spacetime variations of fundamental constants are likely to generate spurious measurements, biased systematically towards a null result. Developments in analysis methods are also summarised and a prescription given for the analysis of new and forthcoming data.
View details →DOI: 10.3390/universe8050266 Negative / Null Result ReportOpen accessMedicine
Abraham D. Flaxman, Riley Hazard, Ian Riley et al. · 2020 · BMC Medicine
Abstract We recently published in BMC Medicine an evaluation of the comparative diagnostic performance of InSilicoVA, a software to map the underlying causes of death from verbal autopsy interviews. The developers of this software claim to have failed to replicate our results and appear to have also failed to locate our replication archive for this work. In this Correspondence, we provide feedback on how this might have been done more usefully and offer some suggestions to improve future attempts at reproducible research. We also offer an alternative interpretation of the results presented by
View details →DOI: 10.1186/s12916-020-01517-w Negative / Null Result ReportOpen accessNeurosciences. Biological psychiatry. Neuropsychiatry
Maximiliano A. Hawkes, Mauricio F. Farez, Ismael L. Calandri et al. · Arquivos de Neuro-Psiquiatria
ABSTRACT Lack of stroke awareness and slow activation of emergency medical services (EMS) are frequently reported reasons for delayed arrival to the hospital. We evaluated these variables in our population. Methods Review of hospital records and structured telephone interviews of 100 consecutive stroke patients. Forward stepwise logistic regression was used for the statistical analysis. Results Seventy patients (75%) arrived at the hospital 4.5 hours after stroke symptoms onset. The use of EMS did not improve arrival times. Most patients who recognized their symptoms did not use EMS (p < 0.02)
View details →DOI: 10.1590/0004-282x20160142 Negative / Null Result ReportOpen accessMedicine
K. Tani, T. Iwanaga, K. Sonoda et al. · 2001 · Journal of Veterinary Medical Science
Fifty-six hamsters with demodicosis were treated with daily oral administration of ivermectin (0.3 mg/kg). Thirty-three cases (58.9%) were cured and 6 cases (10.7%) had improved clinically but needed to continue treatment. Of 5 cases…
View details →DOI: 10.1292/jvms.63.1245 Methods Dead-EndOpen accessMicrobiology
Fadi Fadil, Claudia Samol, Raffaela S. Berger et al. · 2022 · Metabolites
Metabolic fingerprinting by mass spectrometry aims at the comprehensive, semiquantitative analysis of metabolites. Isotope dilution, if successfully implemented, may provide a more reliable, relative quantification. Therefore, the 13 C labeled yeast extract of the IROA TruQuant kit was added as an internal standard (IS) to human urine samples measured in full-scan mode on a high-performance liquid chromatography-time-of-flight mass spectrometer (HPLC–TOFMS) system. The isotope ratio approach enabled the analysis of 112 metabolites. The correlation with reference data did not improve significan
View details →DOI: 10.3390/metabo12080741 Negative / Null Result ReportOpen accessMedicine (General)
MM. Tahmasbi, F. Farahmand , AA. Amis · 1999 · Acta Medica Iranica
The resistant* of pateSa against lateral displacement (Le. the stability), was studied tinder a range of conditions in vitro, at a range of knee flexion angles. Muscle forces were applied in physiological directions along the separate quadriceps muscles. Normal muscle actions with constant tension showed constant patellar stability up to sixty degrees knee flexion, and then a significant increase at ninety degrees. A pathological knee was simulated by relaxing vastus medians, and ■ lateral stability then dropped by 47%. Isolated rttlnaeular release in the pathological knee did not improv
Negative / Null Result ReportOpen accessPsychology
Stephanie M Sherman, Timothy P Buckley, Elsa Baena et al. · 2016 · Frontiers in Psychology
Many college students struggle to perform well on exams in the early morning. Although students drink caffeinated beverages to feel more awake, it is unclear whether these actually improve performance. After consuming coffee (caffeinated or decaffeinated), college-age adults completed implicit and explicit memory tasks in the early morning and late afternoon (Experiment 1). During the morning, participants ingesting caffeine demonstrated a striking improvement in explicit memory, but not implicit memory. Caffeine did not alter memory performance in the afternoon. In Experiment 2, participants
View details →DOI: 10.3389/fpsyg.2016.01764 Negative / Null Result ReportOpen accessMicrobiology
Amanda Louise White, Gregory Jaye Bix · 2023 · Biomolecules
Therapeutic angiogenesis has long been considered a viable treatment for vasculature disruptions, including cerebral vasculature diseases. One widely-discussed treatment method to increase angiogenesis is vascular endothelial growth factor (VEGF) A. In animal models, treatment with VEGFA proved beneficial, resulting in increased angiogenesis, increased neuronal density, and improved outcome. However, VEGFA administration in clinical trials has thus far failed to replicate the promising results seen in animal models. The lack of beneficial effects in humans and the difficulty in medicinal trans
View details →DOI: 10.3390/biom13040702 Negative / Null Result ReportOpen accessInternal medicine
Dae-Yeon Kim, Hee-Soon Park, Dong-Jae Han et al. · 2013 · Kidney Research and Clinical Practice
Renal failure caused by scrub typhus is known to be reversible. In most cases, renal function is almost fully restored after appropriate antibiotic treatment. A 71-year-old man was diagnosed with scrub typhus complicated by renal failure. A renal biopsy revealed histopathologic findings consistent with acute tubulointerstitial nephritis. Renal function did not improve 18 months after discharge and the patient required continuous hemodialysis. Although severe renal failure requiring dialysis is a rare complication of scrub typhus, we describe a case of scrub typhus requiring maintenance hemodia
View details →DOI: 10.1016/j.krcp.2013.09.003 Negative / Null Result ReportOpen accessNeoplasms. Tumors. Oncology. Including cancer and carcinogens
Michele Bottosso, Gaia Griguolo, Severine Guiu et al. · 2025 · npj Breast Cancer
Abstract Brain metastases (BMs) are a common complication of advanced breast cancer (BC), and their management has significantly evolved. We evaluated the clinical impact of these changes dividing patients diagnosed with BCBMs at three Institutions according to year of BMs diagnosis: 2000-2007 (group A), 2008-2014 (group B) and 2015-2022 (group C). Stereotactic radiotherapy increased (p < 0.001), and WBRT decreased (p = 0.010) over time. Among HER2+ BC patients, more received anti-HER2 therapy after BM diagnosis in recent years (p < 0.011). Overall survival (OS) did not improve in the entire c
View details →DOI: 10.1038/s41523-025-00735-w Negative / Null Result ReportOpen accessOphthalmology
Jemal Zeberga Shifa, Alemayehu Mekonnen Gezmu, Gezahen Negusse Ayane et al. · 2019 · The Pan-American Journal of Ophthalmology
A 22-year-old female patient was diagnosed to have HIV and treated by highly active antiretroviral therapy (HAART) since 2012 had developed a reduction of vision in both eyes secondary to cataract. The cataract was extracted from both eyes with no immediate postoperative complication. During follow-up, it was recognized that she had had bilateral Stage 3 macular hole in both eyes. The visual acuity in both eyes was 6/60 which did not improve with application of pinhole. Pars plana vitrectomy was done and sealed the macular hole in the left eye. The visual acuity remained the same in both eyes
View details →DOI: 10.4103/pajo.pajo_15_19 Negative / Null Result ReportOpen accessDiseases of the musculoskeletal system
Alexander C. Lehn, Cullen O'Gorman, Sarah Olson et al. · 2017 · Tremor and Other Hyperkinetic Movements
Background: Orthostatic tremor (OT) was first described in 1977. It is characterized by rapid tremor of 13–18 Hz and can be recorded in the lower limbs and trunk muscles. OT remains difficult to treat, although some success has been reported with deep brain stimulation (DBS). Case Report: We report a 68-year-old male with OT who did not improve significantly after bilateral thalamic stimulation. Discussion: Although some patients were described who improved after DBS surgery, more information is needed about the effect of these treatment modalities on OT, ideally i
View details →DOI: 10.7916/d8280jhr Negative / Null Result ReportOpen accessScience
NATALIA C. SILVA, KAREN M. LEÃO, JOÃO T. PÁDUA et al. · 2021 · Anais da Academia Brasileira de Ciências
Abstract To evaluate the addition of antioxidants in extenders on post-thaw bovine semen quality and in vitro embryo production efficiency. Six semen samples were collected from five Holstein bulls. In the experiment I, the samples were diluted with AndroMed® and Bovimix® and added antioxidants glutathione (1.5 and 2.5 mM) and melatonin (0.5 and 1.0 mM). In the experiment II, the best treatments obtained in experiment I were used for in vitro fecundation. Glutathione did not improve sperm viability. Melatonin had a negative effect on semen characteristics. Andromed® showed better results in sp
View details →DOI: 10.1590/0001-3765202120191229 Negative / Null Result ReportOpen accessMedicine
M.Ghasemi, Z. Hajheidari, M. Golpour · 2007 · Journal of Mazandaran University of Medical Sciences
AbstractPemphigus Erythematosus specially its localized form is a rare autoimmune blistering disease combining features of Pemphigus Foliaceus and Lupus Erythematosus. We reported a 60 years old woman with skin lesion which presented Erythemato squamo plaque with oozing in the right cheek. The chief compliant was burning and pruritus. Skin biopsy was obtained and discoid Lupus Erythemato was reported. She was prescribed with topical steroid but did not improve. All of the lab tests such as Anti DNA, ESR, RF, CRP, CH50, C3, C4, ANA were normal. The biopsy repeated and Pemphigus Erythematosus wa
Negative / Null Result ReportOpen accessDiseases of the blood and blood-forming organs
Daniel A. Ermann, Victoria A. Vardell, Lindsey Fitzgerald et al. · 2026 · eJHaem
ABSTRACT Introduction B‐cell prolymphocytic leukemia (B‐PLL) is a rare, aggressive leukemic B‐cell malignancy historically associated with poor outcomes and recently reclassified in the WHO Fifth Edition but retained as a distinct entity in the ICC. Methods We analyzed 950 patients labeled as B‐PLL in the National Cancer Database (2004–2019), identified using ICD‐O‐3 morphology code 9833/3. Results Median age was 72 years, and 72% received systemic therapy at diagnosis. Median overall survival (OS) was poor (2.8 years) and did not improve over time. Patients initially managed with active surve
View details →DOI: 10.1002/jha2.70299 Negative / Null Result ReportOpen accessMedicine
Xavier Jannot, Alpha Oumar Diallo, Judicaelle Didierjean et al. · 2025 · European Journal of Case Reports in Internal Medicine
We report the case of a 75-year-old woman admitted to the emergency department for confusion, gait disturbances and mutism associated with an inflammatory syndrome occurring 3 weeks after acute carbon monoxide intoxication. The main hypothesis upon arrival was infectious meningoencephalitis, and the patient was put on acyclovir and antibiotics in meningeal doses. After a short stay in intensive care, the patient’s condition did not improve, and the revaluation of her case history and imaging studies led to the diagnosis of post-interval syndrome secondary to carbon monoxide intoxication after
View details →DOI: 10.12890/2025_005235 Null DatasetOpen accessMaterials of engineering and construction. Mechanics of materials
· 2009 · eXPRESS Polymer Letters
The thermal and reaction to fire characteristics of a flame retardant unsaturated polyester (UP) ternary system are presented here. Thermal gravimetric analysis showed an improved thermal stability between 200–600°C with the addition of ammonium polyphosphate (APP) and aluminium trihydroxide (ATH) formulation. Cone calorimetry tests indicated that ATH is more efficient than calcium carbonate at delaying the ignition time, lowering the carbon monoxide yield and lowering the peak heat release (PHRR). However the addition of APP and ATH to the formulation failed to demonstrate any significant syn
View details →DOI: 10.3144/expresspolymlett.2009.92 Failed Experiment ReportOpen accessMedical physics. Medical radiology. Nuclear medicine
Ma Li, Men Yu, Feng Lingling et al. · 2019 · Radiology and Oncology
The mainstay therapy for locally advanced non-small cell lung cancer is concurrent chemoradiotherapy. Loco-regional recurrence constitutes the predominant failure patterns. Previous studies confirmed the relationship between increased biological equivalent doses and improved overall survival. However, the large randomized phase III study, RTOG 0617, failed to demonstrate the benefit of dose-escalation to 74 Gy compared with 60 Gy by simply increasing fraction numbers.
View details →DOI: 10.2478/raon-2019-0006 Negative / Null Result ReportOpen accessSpecial aspects of education
Ning Zhang, Fan Ouyang · 2023 · International Journal of Educational Technology in Higher Education
Abstract Collaborative knowledge construction (CKC) involved students’ sharing of information, improvement of ideas, and construction of collective knowledge. In this process, knowledge extraction and analysis can provide valuable insights into students’ knowledge capacities, depths, and levels in order to improve the CKC quality. However, existing studies tended to extract and analyze knowledge from a single perspective (e.g., the number of certain knowledge types and knowledge structures), which failed to demonstrate the complexity and dynamics of knowledge construction and advancement. To f
View details →DOI: 10.1186/s41239-023-00414-5 Negative / Null Result ReportOpen accessChemistry
Yu Jia, Cao Yu, Song Hang et al. · 2012 · Journal of the Serbian Chemical Society
Ab initio Hartree-Fock (HF) method and Density Functional Theory (DFT) were used to calculate the optical rotation of 26 chiral compounds. The effects of theory and basis sets used for calculation, solvents influence on the geometry and values of calculated optical rotation were all discussed. The polarizable continuum model, included in the calculation, did not improve the accuracy effectively, but it was superior to γs. Optical rotation of five or sixmembered of cyclic compound has been calculated and 17 pyrrolidine or piperidine derivatives which were calculated by HF and DFT methods gave a
View details →DOI: 10.2298/jsc110905207y Negative / Null Result ReportMedicine
Janz C, Timpka J, Storch A et al. · 2026 · Journal of Parkinson's disease
BackgroundThe Parkinson's Disease (PD) Home Diary (HD) is a common clinical outcome measure, but studies show only fair agreement between clinical observer and patient assessments, with no significant improvement after patient…
View details →DOI: 10.1177/1877718x261461073 Negative / Null Result ReportOpen accessMedicine
Liu S, Chen B, Zhu Y et al. · 2025 · The oncologist
Background Previous results of our trial demonstrated that the addition of induction chemotherapy (IC) prior to definitive chemoradiotherapy (CRT) failed to significantly improve the response rate or 3-year survival in patients with…
View details →DOI: 10.1093/oncolo/oyae295 