Universality and scaling in complex networks from periods of Chinese history.

Critical physical systems with large numbers of molecules can show universal and scaling behaviors. It is of interest to know whether human societies with large numbers of people can show the same behaviors. Here, we use network theory to analyze Chinese history in periods 209 BCE-23 CE and 515-618 CE) related to the Western Han-Xin Dynasty and the late Northern Wei-Sui Dynasty, respectively. Two persons are connected when they appear in the same historical event. We find that the historical networks from two periods separated about 500 years have interesting universal and scaling behaviors, and they are small-world networks; their average cluster coefficients as a function of degree are similar to the network of movie stars. In the historical networks, the persons with larger degrees prefer to connect with persons with a small degree; however, in the network of movie stars, the persons with larger degrees prefer to connect with persons with large degrees. We also find an interesting similar mechanism for the decline or collapse of historical Chinese dynasties. The collapses of the Xin dynasty (9-23 CE) and the Sui dynasty (581-618 CE) were initiated from their arrogant attitude toward neighboring states.

Oligo(ethylene glycol) side chain effect on the physical properties and molecular arrangement of oligothiophene-isoindigo based conjugated polymers.

Oligo(ethylene glycol) (OEG) side chains are widely used in donor-acceptor conjugated polymers (D-A CPs) and enable the polymers to dissolve and be processed in environmentally friendly and cost-effective nonchlorinated solvents, such as water. However, the OEG effect on the physical properties of D-A CPs has not been thoroughly studied and sometimes the results are controversial. In this study, two oligothiophene-isoindigo based conjugated polymers, P3TI and P4TI, are selected as model polymers to investigate the OEG effect. PnTI has octyl side chains on the oligothiophene unit and 2-hexyldecyl side chains on the isoindigo unit. The replacement of an alkyl side chain with OEG not only changes the optical and thermal properties but also the molecular arrangements of the polymers such as π-π d-spacing, crystallinity, and packing orientation. The domination of the crystallization behavior changes from the oligothiophene unit to the isoindigo unit when the bulky alkyl group is replaced by the flexible and linear OEG. The packing changes from edge-on to face-on orientation. The results are intriguing and provide new insights into this class of polymers.

Medication use and fall-risk assessment for falls in an acute care hospital.

AIM: A nested case-control study was carried out to examine relationships of a fall-risk score and the use of single medications and polypharmacy with falls among hospitalized patients aged 50 years and older in Taiwan. METHODS: There were 83 patients who experienced a fall during hospitalization in an acute-care hospital. Matched by age and sex, five control patients for each case were randomly selected from all other inpatients who had not experienced any fall at the time of the index fall. RESULTS: Patients who took tricyclic antidepressants, diuretics, and narcotics were 3.36-, 1.83- and 2.09-fold, respectively, more likely to experience a fall than their counterparts. Conversely, patients who took beta-blockers were 0.34-fold more likely than those who did not take them to experience a fall. Patients taking ≥6 medications were 3.08-fold more likely than those taking fewer medications to experience a fall, whereas those with anxiety were 4.72-fold more likely to experience a fall than those without. A high fall-risk score was not significantly associated with the occurrence of falls. CONCLUSIONS: Among older hospitalized patients, tricyclic antidepressants, diuretics, narcotics, and polypharmacy should be mindfully prescribed and reviewed on a regular basis. A fall-risk scale developed from community-dwelling older people might not accurately predict falls in hospitalized patients. Further research to validate the negative effect of beta-blocker use on falls is required.

Examination of assumptions in using time tradeoff and standard gamble utilities in individuals with spinal cord injury.

OBJECTIVE: To examine how the time tradeoff (TTO) and standard gamble (SG) utilities perform at different lengths of life expectancy and across patient characteristics such as risk attitudes and injury severity in individuals with traumatic spinal cord injury (SCI). DESIGN: Survey. SETTING: Structured telephone interviews of patients after discharge from 4 teaching hospitals. PARTICIPANTS: Subjects (N=270) who had sustained SCI were block-randomized in groups of 4 to receive 1 of 2 questionnaire versions. One version asked about the TTO and SG at 2 life expectancies of 10 and 20 years, and the other at 20 and 30 years. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The TTO and SG were used to elicit preferences for patients with an SCI. RESULTS: Patients with SCI who were younger and had more severe neurologic lesions, had higher intense risk-taking attitudes, and experienced depression had significantly lower TTO and SG scores than their counterparts. A longer life expectancy was also significantly associated with lower TTO scores. As the life expectancy increased, patients who had sustained SCI more recently (≤1 y ago) were more willing to trade off life years for full health (ie, lower TTO scores). SG scores did not significantly vary according to different life expectancies. CONCLUSIONS: Among patients with SCI, there was a nonlinear relation between the TTO and life expectancy that violated the fundamental assumption of risk neutrality toward life years. Accordingly, TTO utilities elicited for different life expectancies should not be compared in quality-of-life assessments or used in cost-utility analyses. In contrast, SG utilities remained stable at different lengths of life expectancy in SCI patients. Moreover, certain patient characteristics such as age, time lapse since the injury, neurologic severity, risk attitudes, and depressive status can account for some TTO and SG variations among patients with SCI.

Health care utilization and health outcomes: a population study of Taiwan.

Facing escalating health care expenditures, the governments of countries with national health insurance programs are trying to control or even to reduce health care utilization. Little research has examined the effects of decreased health care utilization on health outcomes. Applying a natural experiment design to the Taiwan population between 2000 and 2004, which includes the 2003 SARS epidemic when an average 20% decline in health care utilization occurred, this study examines the association between a decline in health care utilization and health outcomes measured by cause-specific mortality rates. We analyse the monthly mortality rates caused by infectious diseases, cancer, diabetes mellitus, nervous system diseases, cerebrovascular diseases, heart and other vascular diseases, respiratory system diseases, digestive system diseases, genitourinary system diseases and accidents. Models control for age, sex, month and year effects. Results show the heterogeneous effect of reduced health care utilization on health outcomes. Patients with diabetes mellitus or cerebrovascular diseases are vulnerable to short-term reductions in health care; compared with the non-SARS period, mortality caused by diabetes mellitus and cerebrovascular diseases significantly increased during the SARS epidemic by 8.4% and 6.2%, respectively. No significant change in mortality rates caused by the other diseases or accidents is found. This study suggests that governments of countries where health care utilization and spending are similar to or inferior to those in Taiwan should carefully evaluate the impact of policies that attempt to reduce health care utilization. Furthermore, when an area encounters an epidemic, governments should be aware of the negative consequences of voluntary restraints on access to health care that accompany decreases in utilization.

Lower limb wrapping prevents hypotension, but not hypothermia or shivering, after the introduction of epidural anesthesia for cesarean delivery.

The decrease of arterial blood pressure and body temperature after epidural or spinal anesthesia is thought to be the result of sympathetic block, which could cause pooling and redistribution of blood into the lower extremities. Studies have demonstrated that leg wrapping with elastic bandages may reduce the incidence of hypotension after spinal anesthesia. We tried to extend these previous observations to epidural anesthesia by testing the hypothesis that leg wrapping with elastic bandages should decrease the incidence of hypotension in patients receiving epidural anesthesia. Moreover, we evaluated the effect of this maneuver as regards hypothermia and shivering. Sixty parturients were randomly allocated to receive either leg wrapping with tight elastic bandages (leg-wrapped group) or not (control group) before anesthesia. Sublingual temperature was observed at five periods: baseline, immediately after epidural anesthesia, abdominal skin disinfection, skin incision, and delivery. Hypotension and shivering during the observation periods were also recorded. The incidence of hypotension was significantly less frequent (P = 0.03) in the leg-wrapped group (23%) compared with the control group (50%). Shivering incidences were similar in both groups (70% versus 70%). Sublingual temperature decreased significantly (P < 0.001) throughout the procedure in each group. However, no differences were found between the two groups at each designated observation, even if compared by the magnitude of temperature decrease. We conclude that although leg wrapping with elastic bandages prevents maternal hypotension after epidural anesthesia, it does not reduce the incidence or magnitude of hypothermia or prevent shivering.