Dataset Information

Oligorotaxane Radicals under Orders.

ABSTRACT: A strategy for creating foldameric oligorotaxanes composed of only positively charged components is reported. Threadlike components-namely oligoviologens-in which different numbers of 4,4'-bipyridinium (BIPY(2+)) subunits are linked by p-xylylene bridges, are shown to be capable of being threaded by cyclobis(paraquat-p-phenylene) (CBPQT(4+)) rings following the introduction of radical-pairing interactions under reducing conditions. UV/vis/NIR spectroscopic and electrochemical investigations suggest that the reduced oligopseudorotaxanes fold into highly ordered secondary structures as a result of the formation of BIPY(•+) radical cation pairs. Furthermore, by installing bulky stoppers at each end of the oligopseudorotaxanes by means of Cu-free alkyne-azide cycloadditions, their analogous oligorotaxanes, which retain the same stoichiometries as their progenitors, can be prepared. Solution-state studies of the oligorotaxanes indicate that their mechanically interlocked structures lead to the enforced interactions between the dumbbell and ring components, allowing them to fold (contract) in their reduced states and unfold (expand) in their fully oxidized states as a result of Coulombic repulsions. This electrochemically controlled reversible folding and unfolding process, during which the oligorotaxanes experience length contractions and expansions, is reminiscent of the mechanisms of actuation associated with muscle fibers.

SUBMITTER: Wang Y

PROVIDER: S-EPMC4827492 | biostudies-literature | 2016 Feb

REPOSITORIES: biostudies-literature

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Publications

Oligorotaxane Radicals under Orders.

Wang Yuping Y Frasconi Marco M Liu Wei-Guang WG Sun Junling J Wu Yilei Y Nassar Majed S MS Botros Youssry Y YY Goddard William A WA Wasielewski Michael R MR Stoddart J Fraser JF

ACS central science 20160201 2

A strategy for creating foldameric oligorotaxanes composed of only positively charged components is reported. Threadlike components-namely oligoviologens-in which different numbers of 4,4'-bipyridinium (BIPY(2+)) subunits are linked by p-xylylene bridges, are shown to be capable of being threaded by cyclobis(paraquat-p-phenylene) (CBPQT(4+)) rings following the introduction of radical-pairing interactions under reducing conditions. UV/vis/NIR spectroscopic and electrochemical investigations sugg ...[more]

PMID: 27163033

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Project description:Background/objectivesMany older persons with chronic illness use Physician Orders for Life-Sustaining Treatment (POLST) to document portable medical orders for emergency care. However, some POLSTs contain combinations of orders that do not translate into a cohesive care plan (eg, cardiopulmonary resuscitation [CPR] without intensive care, or intensive care without antibiotics). This study characterizes the prevalence and predictors of POLSTs with conflicting orders.DesignRetrospective cohort study.SettingLarge academic health system.ParticipantsA total of 3,123 POLST users with chronic life-limiting illness who died between 2010 and 2015 (mean age = 69.7 years).MeasurementsIn a retrospective review of all POLSTs in participants' electronic health records, we describe the prevalence of POLSTs with conflicting orders for cardiac arrest and medical interventions, and use clustered logistic regression to evaluate potential predictors of conflicting orders. We also examine the prevalence of conflicts between POLST orders for antibiotics and artificial nutrition with orders for cardiac arrest or medical interventions.ResultsAmong 3,924 complete POLSTs belonging to 3,123 decedents, 209 (5.3%) POLSTs contained orders to "attempt CPR" paired with orders for "limited interventions" or "comfort measures only"; 745/3169 (23.5%) POLSTs paired orders to restrict antibiotics with orders to deliver non-comfort-only care; and, 170/3098 (5.5%) POLSTs paired orders to withhold artificial nutrition with orders to deliver CPR or intensive care. Among POLSTs with orders to avoid intensive care, orders to attempt CPR were more likely to be present in POLSTs completed earlier in the patient's illness course (adjusted odds ratio = 1.27 per twofold increase in days from POLST to death; 95% confidence interval = 1.18-1.36; P < .001).ConclusionAlthough most POLSTs are actionable by clinicians, 5% had conflicting orders for cardiac arrest and medical interventions, and 24% had one or more conflicts between orders for cardiac arrest, medical interventions, antibiotics, and artificial nutrition. These conflicting orders make implementation of POLST challenging for clinicians in acute care settings.

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Oligorotaxane Radicals under Orders.

Publications

Oligorotaxane Radicals under Orders.

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