Chloride Ion-Containing Polymeric Ionic Liquids for Application as Electrolytes in Solid-State Batteries

Organic, solid-state batteries require efficient solid electrolytes able to provide stable ion conduction. Here, solid electrolytes based on ionic liquid (IL) polymers with chloride counterions as electrolyte materials for batteries are presented. Acrylic monomers with imidazolium substituents with alkyl side groups that are linked by alkyl spacers to the acrylic group are employed. The IL monomers with chloride counterions are either converted by thermally initiated radical polymerization into linear homopolymers or incorporated into polymer networks by UV-initiated copolymerization utilizing a bifunctional, non-ionic cross-linker. Both procedures successfully yielded the desired materials, which is confirmed by NMR spectroscopy (linear homopolymers) or Raman spectroscopy (IL networks). The ionic conductivities at room temperature are measured by Electrochemical Impedance Spectroscopy. The ionic conductivities of the linear homopolymers are in the range of 10⁻⁴ to 10⁻⁶ S cm⁻¹, while those of the IL networks are about two orders of magnitude lower. They increase to 10⁻⁴ S cm⁻¹ at 70 °C. The electrochemical stability is examined by Linear Sweep Voltammetry and is proven in the voltage range of −2 to +2 V. The results reveal that the materials represent promising electrolytes for potential solid-state battery applications.     

Pleural tuberculosis in Harare, Zimbabwe: the relationship between human immunodeficiency virus, CD4 lymphocyte count, granuloma formation and disseminated disease

objective   To elucidate the relationship between HIV, CD4¹ count and pleural TB. method   In a prospective study, 94 patients presenting at two large Harare hospitals with clinically suspected pleural TB were enrolled over a 10-month period. All underwent standardized evaluation, closed pleural aspiration and biopsy. Patients receiving directly observed anti-TB therapy were followed-up. results   Pleural TB was diagnosed in 90 individuals (median age 33 years; range 18-65; 64 males); the seroprevalence of HIV was 85%. HIV-positive patients were older than HIV-negative individuals (median age 33 vs 23 years, P = 0.013) and had a significantly lower median CD4¹ count (191 vs 1106 × 10⁶/l respectively, P = 0.004). A CD4¹ count of <200 × 10⁶/l was associated with a length of illness >30 days (65% vs 37%; P = 0.05), a positive pleural fluid smear (37% vs 0%; P = 0.0006) and a positive pleural biopsy Ziehl-Neelsen stain (35% vs 7%; P = 0.021). However, a relationship between CD4¹ count and either pleural granuloma formation or radiological evidence of disseminated disease was not observed. conclusion   In sub-Saharan Africa, TB pleural effusions have become associated with older age, a chronic onset, and an increased mycobacterial load. These data emphasize the complex relationship between pleural TB, HIV infection and a low CD4¹ count.     

The inequity of Medicaid reimbursement in the United States

The United States Medicaid programme aims to provide public health insurance to certain categories of the low-income population. Considerable non-uniformity exists within the programme because each of the 50 states, Washington, DC and 5 territories are individually responsible, within broad federal guidelines, for its administration. The non-uniformity shows up in different eligibility requirements, benefits and health care provider reimbursement rates. This paper examines reimbursement rate variations across individual programmes and discusses how these variations affect health care provider participation. Dual market theory suggests, and empirical results conclude that low reimbursement rates cause health care providers to participate less fully in the programme. Variations in access to medical care because of differences in reimbursement rates thereby create severe horizontal and vertical inequities across programmes. To reduce these inequities, the federal government might offer earmarked grants for the mandated purpose of raising reimbursement rates to a uniform percentage of private rates in all programmes.     

Energy intake deficit and physical performance at altitude

BACKGROUND: Physical performance of sea-level (SL) residents acutely exposed to altitude (ALT) is diminished and may improve somewhat with ALT acclimatization. HYPOTHESIS: A large reduction in lean body mass (LBM), due to severe energy intake deficit during the first 21 d of ALT (4300 m) acclimatization, will adversely affect performance. METHODS: At ALT, 10 men received a deficit (DEF) of 1500 kcal x d(-1) below body weight (BW) maintenance requirements and 7 men received adequate (ADQ) kcal x d(-1) to maintain BW. Performance was assessed by: 1) maximal oxygen uptake (VO2max); 2) time to complete 50 cycles of a lift and carry task (L+C); 3) number of one-arm elbow flexions (10% BW at 22 flexions x min(-1); and 4) adductor pollicis (AP) muscle strength and endurance time (repeated 5-s static contractions at 50% of maximal force followed by 5-s rest, to exhaustion). Performance and body composition (using BW and circumference measures) were determined at SL and at ALT on days 2 through 21. RESULTS: At SL, there were no between-group differences (p > 0.05) for any of the performance measures. From SL to day 21 at ALT, BW and LBM declined by 6.6 +/- 3 kg and 4.6 kg, respectively, for the DEF group (both p < 0.01), but did not change (both p > 0.05) for the ADQ group. Performance changes from day 2 or 3 to day 20 or 21 at ALT were as follows (values are means +/- SD): VO2max (ml x min(-1)): DEF = +97 +/- 237, ADQ = +159 +/- 156; L + C (s): DEF = -62 +/- 35*, ADQ = -35 +/- 20* (*p < 0.05; improved from day 3); arm flex (reps): DEF = -2 +/- 7, ADQ = +2 +/- 8; AP endurance (min): DEF = +1.4 +/- 2, ADQ = + 1.9 +/- 2; AP strength (kg): DEF = -0.7 +/- 4, ADQ = -1.2 +/- 2. There were no differences in performance between groups. CONCLUSIONS: A significant BW and LBM loss due to underfeeding during the first 21 d of ALT acclimatization does not impair physical performance at ALT.     

Substrate oxidation is altered in women during exercise upon acute altitude exposure

PURPOSE: The purpose of this study was to determine whether substrate oxidation during submaximal exercise in women is affected by an acute exposure to 4300-m altitude and menstrual cycle phase. METHODS: Eight female lowlanders (mean +/- SD; 33 +/- 3 yr, 58 +/- 6 kg, 163 +/- 8 cm) completed a peak oxygen uptake (VO2peak) and submaximal exercise to exhaustion (EXH) test at 70% of their altitude-specific VO2peak at sea level (SL) and during an acute altitude (AA) exposure to 4300 m in a hypobaric chamber (446 mm Hg) in their early-follicular and midluteal menstrual cycle phase. The respiratory exchange ratio (RER) was calculated from oxygen uptake and carbon dioxide output measurements made during the EXH tests, and used to estimate the percent contribution of fat and carbohydrate to energy metabolism. Blood samples were taken at rest and every 15 min during the EXH tests. Blood samples were evaluated for glucose, lactate, glycerol, free fatty acids, insulin, growth hormone, cortisol, glucagon, epinephrine, norepinephrine, estradiol, and progesterone concentrations. RESULTS: Despite increased (P < 0.05) estradiol and progesterone levels in the midluteal phase, substrate oxidation, energy substrates, and metabolic hormones were not affected by cycle phase at SL or AA. However, free fatty acids and cortisol were increased (P < 0.05) whereas RER was decreased (P < 0.05) during exercise upon AA exposure compared with SL in both cycle phases. CONCLUSIONS: These data suggest that substrate oxidation is altered in women during exercise at AA compared with SL but is not affected by cycle phase. Whether increased fat or protein oxidation accounts for the lower RER values during the AA exposure cannot be determined from this study but warrants further investigation.     

Intraocular pressure and acclimatization to 4300 M altitude

BACKGROUND: Studies were conducted to determine the effect of altitude exposure on intraocular pressure (IOP) and any relationship with the severity of acute mountain sickness (AMS). HYPOTHESES: a) IOP is decreased during exposure to 4300 m altitude; b) there is a positive correlation between IOP and AMS; and c) there is a correlation between changes in urinary catecholamines and IOP. METHODS: IOP (noncontact tonometry) was measured in 11 resting males during acute simulated altitude (446 mmHg, < 2 h, hypobaric chamber), during altitude acclimatization (15 d at 4300 m), and in 6 of the 11 volunteers during re-exposure in the chamber after 8 d at sea level (Study A). In a second study (Study B) of 12 females, IOP (contact tonometry) and 24-h urinary catecholamines were measured during a 50-h chamber exposure (446 mmHg). AMS severity was assessed using the Environmental Symptoms Questionnaire (ESQ-C). RESULTS: IOP decreased 25% after 2 d at altitude and returned toward sea level values by 15 d (Study A). IOP was reduced 13% after 5 h of exposure followed by return toward sea level values (Study B). Significant correlation was found between the sea level IOP and ESQ-C (Study A); significant correlation was found between the reduction in IOP and the ESQ-C and urinary epinephrine concentrations (Study B). CONCLUSIONS: Altitude exposure resulted in a reduction in IOP that occurred within hours and recovered during acclimatization. This reduction may be related to increases in epinephrine concentration. Measurement of IOP before and during altitude exposure may provide an objective method of assessing an individual's response to hypoxic stress.     

Slower fatigue and faster recovery of the adductor pollicis muscle in women matched for strength with men

In previous gender comparisons of muscle performance, men and women rarely have been closely matched, absolute force has not been equalized, and rates of fatigue and early recovery have not been determined. We compared adductor pollicis muscle performance at a similar absolute force development in healthy men and women (both n=9) matched for adductor pollicis maximal voluntary contraction (MVC) force (132 +/- 5 N for women and 136 +/- 4 N for men, mean +/- SE, P > 0.05). Subjects repeated static contractions at a target force of approximately 50% of MVC force of rested muscle (68 +/- 3 N or 51.9 +/- 1.0% MVC for women and 72 +/- 2 N or 53.0 +/- 2.0% MVC for men, P > 0.05) for 5 s followed by 5 s rest until exhaustion, i. e. inability to maintain the target force for 5 s. MVC force was measured following each minute of exercise, at exhaustion, and after each minute for 3 min of passive recovery. For women compared with men: MVC force fell less after 1 min of exercise (to 93 +/- 1% vs. 80 +/- 3% of MVC force of rested muscle, respectively, P < 0.05); MVC force (N min-1) fell approximately 2-fold slower (P < 0.05); and endurance time to exhaustion was nearly two times longer (14.7 +/- 1. 6 min vs. 7.9 +/- 0.7 min, P < 0.05). After declining to a similar level of MVC force of rested muscle at exhaustion (56 +/- 1% for women and 56 +/- 3% for men), MVC force rose faster in women than in men (to 71 +/- 2% vs. 65 +/- 3% of MVC force of rested muscle, respectively; P < 0.05) during the first minute of recovery. The findings are consistent with the hypothesis that slower adductor pollicis muscle fatigue in women is linked with differences between men and women both in impairment of force generating capacity, per se, and in rates of recovery between contractions.