TASK DEFINITION: Given a passage, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.
PROBLEM: Bone and antler collagen δ(13) C and δ(15) N values are often assumed to be equivalent when measured in palaeodietary, palaeoclimate and palaeocological studies. Although compositionally similar, bone grows slowly and is remodelled whereas antler growth is rapid and remodelling does not occur. These different patterns of growth could result in isotopic difference within antler and between the two tissue types. Here we test whether red deer (Cervus elaphus) bone and antler δ(13) C and δ(15) N values are equivalent, and whether intra-antler isotopic values are uniform.', 'Bone and antler were isotopically analysed from six stags that lived in a temperate maritime climate on the Isle of Rum, Scotland. Multiple antlers from different years were sampled per individual, together with a single bone sample per individual. Up to 12 samples were taken along the length of each antler (total of 25 antlers, 259 samples) so that a chronological record of the isotopic composition during antler growth could be obtained. Collagen was extracted and its δ(13) C and δ(15) N values were measured by continuous-flow isotope ratio mass spectrometry.', 'Intra-antler collagen isotope signatures vary, and show that not all antlers from an individual or a growth year are equivalent in carbon and nitrogen isotopic ratios. δ(15) N values typically increase with distance along antler length, but no overall trend is observed in δ(13) C values. An isotopic offset is visible between bone and antler, with bone δ(13) C and δ(15) N values being higher in most cases.

SOLUTION: Are red deer bone and antler collagen isotopically equivalent in carbon and nitrogen?

PROBLEM: It is known that enhancement of sympathetic nerve activity based on a decrease in parasympathetic nerve activity is associated with fatigue induced by mental tasks lasting more than 30 min. However, to measure autonomic nerve function and assess fatigue levels in both clinical and industrial settings, shorter experimental durations and more sensitive measurement methods are needed. The aim of the present study was to establish an improved method for inducing fatigue and evaluating the association between it and autonomic nerve activity.', 'Twenty-eight healthy female college students participated in the study. We used a kana pick-out test (KPT) as a brief verbal cognitive task and recorded electrocardiography (ECG) to measure autonomic nerve activity. The experimental design consisted of a 16-min period of ECG: A pre-task resting state with eyes open for 3 min and eyes closed for 3 min, the 4-min KPT, and a post-task resting state with eyes open for 3 min and eyes closed for 3 min.', 'Baseline fatigue sensation, measured by a visual analogue scale before the experiment, was associated with the decrease in parasympathetic sinus modulation, as indicated the by ratio of low-frequency component power (LF) to high-frequency component power (HF), during the KPT. The LF/HF ratio during the post-KPT rest with eyes open tended to be greater than the ratio during the KPT and correlated with fatigue sensation. Fatigue sensation was correlated negatively with log-transformed HF, which is an index of parasympathetic sinus modulation, during the post-KPT rest with eyes open.

SOLUTION: Does fatigue correlate with the decrease in parasympathetic sinus modulation induced by a cognitive challenge?

PROBLEM: To investigate the prognostic value of weight loss before diagnosis in patients with advanced stage non-small cell lung cancer (NSCLC) treated with first-line chemotherapy.', 'A total of 81 NSCLC patients with stages IIIB/IV were included in this retrospective cross-sectional study. Study variables were weight loss in the last 3 months before diagnosis, patient demographic, clinical and laboratory characteristics and histological features of the tumor before administering first-line chemotherapy. Then, the patients were stratified into 4 groups based on their weight loss before being diagnosed with NSCLC.', 'The patients were predominantly male (68%), with a smoking history (62%), 5 to 10 kg weight loss in the last 3 months (31%), and had metastatic disease (64%) and adenocarcinoma (40%) at the time of diagnosis. On the other hand, most of the patients with 5 to 10 kg weight loss in the last 3 months before diagnosis had squamous cell carcinoma (44%), stage IV disease (56%), and the first disease progression was in the brain (64%). Pre-diagnosis weight loss had a negative impact on progression-free survival (PFS), independent from weight loss during first-line chemotherapy, but no such effect was noticed on overall survival (OS).

SOLUTION:
Is weight loss at the time of diagnosis associated with prognosis in patients with advanced-stage non-small cell lung cancer?