Cellulose nanofibers (CNFs) in the recycling of nickel and cadmium battery metals using electrodeposition.

Cellulose nanofibers (CNFs) were employed in the aqueous electrodeposition of nickel and cadmium for battery metal recycling. The electrowinning of mixed Ni-Cd metal ion recycling solutions demonstrated that cadmium with a purity of over 99% could be selectively extracted while leaving the nickel in the solution. Two types of CNFs were evaluated: negatively charged CNFs (a-CNF) obtained through acid hydrolysis (-75 µeq. g-1) and positively charged CNFs (q-CNF) functionalized with quaternary ammonium groups (+85 µeq. g-1). The inclusion of CNFs in the Ni-Cd electrolytes induced growth of cm-sized dendrites in conditions where dendrites were otherwise not observed, or increased the degree of dendritic growth when it was already present to a lesser extent. The augmented dendritic growth correlated with an increase in deposition yields of up to 30%. Additionally, it facilitated the formation of easily detachable dendritic structures, enabling more efficient processing on a large scale and enhancing the recovery of the toxic cadmium metal. Regardless of the charged nature of the CNFs, both negatively and positively charged CNFs led to a significant formation of protruding cadmium dendrites. When deposited separately, dendritic growth and increased deposition yields remained consistent for the cadmium metal. However, dendrites were not observed during the deposition of nickel; instead, uniformly deposited layers were formed, albeit at lower yields (20%), when positively charged CNFs were present. This paper explores the potential of utilizing cellulose and its derivatives as the world's largest biomass resource to enhance battery metal recycling processes.

Experimental review: chemical reduction of graphene oxide (GO) to reduced graphene oxide (rGO) by aqueous chemistry.

The electrical conductivity of reduced graphene oxide (rGO) obtained from graphene oxide (GO) using sodium borohydride (NaBH4) as a reducing agent has been investigated as a function of time (2 min to 24 h) and temperature (20 °C to 80 °C). Using a 300 mM aqueous NaBH4 solution at 80 °C, reduction of GO occurred to a large extent during the first 10 min, which yielded a conductivity increase of 5 orders of magnitude to 10 S m-1. During the residual 1400 min of reaction, the reduction rate decreased significantly, eventually resulting in a rGO conductivity of 1500 S m-1. High resolution XPS measurements showed that C/O increased from 2.2 for the GO to 6.9 for the rGO at the longest reaction times, due to the elimination of oxygen. The steep increase in conductivity recorded during the first 8-12 min of reaction was mainly due to the reduction of C-O (e.g., hydroxyl and epoxy) groups, suggesting the preferential attack of the reducing agent on C-O rather than C[double bond, length as m-dash]O groups. In addition, the specular variation of the percentage content of C-O bond functionalities with the sum of Csp2 and Csp3 indicated that the reduction of epoxy or hydroxyl groups had a greater impact on the restoration of the conductive nature of the graphite structure in rGO. These findings were reflected in the dramatic change in the structural stability of the rGO nanofoams produced by freeze-drying. The reduction protocol in this study allowed to achieve the highest conductivity values reported so far for the aqueous reduction of graphene oxide mediated by sodium borohydride. The 4-probe sheet resistivity approach used to measure the electrical conductivity is also, for the first time, presented in detail for filtrate sheet assemblies' of stacked GO/rGO sheets.

A comparative study of two protocols for treadmill walking exercise testing in ambulating subjects with incomplete spinal cord injury.

STUDY DESIGN: This is a comparative study of two exercise testing protocols. OBJECTIVES: The objective of this study was to compare maximal oxygen uptake (VO2 max) and achieved criteria for maximal exercise testing between the Sunnaas Protocol-a newly designed treadmill exercise test protocol-and the Modified Bruce Protocol in persons with incomplete spinal cord injury (SCI). SETTING: This study was conducted in Sunnaas Rehabilitation Hospital, Norway. METHODS: Twenty persons (19 men) with incomplete SCI (AIS D) capable of ambulating without assistive devices performed two treadmill walking exercise tests (Sunnaas Protocol and Modified Bruce Protocol) until exhaustion 1-3 days apart. The key differences between the protocols are the smaller increments in speed and shorter duration on each workload in the Sunnaas Protocol. Cardiovascular responses were measured continuously throughout both tests. RESULTS: The subjects exhibited statistically significantly higher VO2 max when using the Sunnaas Protocol (37.1±9.9 vs 35.4±9.8 ml kg-1 min-1, P=0.01), with a mean between-test difference of 1.8 ml kg-1 min-1 (95% confidence interval: 0.49-3.16). There was no significant difference in mean maximal heart rate (HR max). Nineteen (95%) subjects achieved at least three of the four criteria for maximal oxygen uptake using the Sunnaas Protocol. Thirteen (65%) subjects achieved at least three of the criteria using a Modified Bruce protocol. CONCLUSIONS: The small differences in both VO2 max and achieved criteria in favor of the Sunnaas Protocol suggest that it could be a useful alternative treadmill exercise test protocol for ambulating persons with incomplete SCI.

Energetic and cardiovascular responses to treadmill walking and stationary cycling in subjects with incomplete spinal cord injury.

STUDY DESIGN: Randomized controlled trail. OBJECTIVES: To investigate if people with incomplete spinal cord injury (SCI) can perform high-intensity weight-bearing exercise by comparing cardiovascular responses at maximal workloads during stationary cycling and treadmill walking, and to explore mechanical efficiencies at sub-maximal workloads. SETTING: Sunnaas Rehabilitation Hospital, Nesoddtangen, Norway. METHODS: Fifteen people with incomplete SCI and 15 healthy control subjects performed sub-maximal and maximal exercise tests of both stationary cycling and uphill treadmill walking on separate days. Oxygen uptake (VO(2); l min(-1) and ml kg(-1) min(-1)), carbon dioxide production (VCO(2); l min(-1)), respiratory exchange ratio (RER) and heart rate (HR) were continuously measured throughout the tests. RESULTS: The SCI group showed no significant differences in peak VO(2) (2.42±0.68 l min(-1) versus 2.58±0.76 l min(-1), P=0.19) or other cardiovascular responses at maximal workloads for stationary cycling as compared with uphill treadmill walking, except for higher RER during the cycle test. The control subjects exhibited a significantly higher peak VO(2) during the treadmill test as compared with the cycle test (P=0.007). Both groups had lower mechanical efficiency when walking as compared with cycling, but the mean difference between cycling and walking was not significantly different between the groups during sub-maximal workloads (P >0.24). CONCLUSION: Subjects with incomplete SCI were able to perform high-intensity weight-bearing exercise and exhibited similar mechanical efficiencies at sub-maximal workloads as healthy controls. Uphill walking might be a good alternative to weight-bearing exercise for increasing the physical capacity of people with incomplete SCI.

Gas-assisted electron-beam-induced nanopatterning of high-quality Si-based insulator.

An oxygen-assisted electron-beam-induced deposition (EBID) process, in which an oxygen flow and the vapor phase of the precursor, tetraethyl orthosilicate (TEOS), are both mixed and delivered through a single needle, is described. The optical properties of the SiO(2+δ) (- 0.04 ≤ δ ≤ +0.28) are comparable to fused silica. The electrical resistivity of both single-needle and double-needle SiO(2+δ) are comparable (greater than 7 GΩ cm) and a measured breakdown field is greater than 400 V µm(-1). Compared to the double-needle process the advantage of the single-needle technique is the ease of alignment and the proximity to the deposition location, which facilitates fabrication of complex 3D structures for nanophotonics, photovoltaics, micro- and nano-electronics applications.

Making flexible magnetic aerogels and stiff magnetic nanopaper using cellulose nanofibrils as templates.

Nanostructured biological materials inspire the creation of materials with tunable mechanical properties. Strong cellulose nanofibrils derived from bacteria or wood can form ductile or tough networks that are suitable as functional materials. Here, we show that freeze-dried bacterial cellulose nanofibril aerogels can be used as templates for making lightweight porous magnetic aerogels, which can be compacted into a stiff magnetic nanopaper. The 20-70-nm-thick cellulose nanofibrils act as templates for the non-agglomerated growth of ferromagnetic cobalt ferrite nanoparticles (diameter, 40-120 nm). Unlike solvent-swollen gels and ferrogels, our magnetic aerogel is dry, lightweight, porous (98%), flexible, and can be actuated by a small household magnet. Moreover, it can absorb water and release it upon compression. Owing to their flexibility, high porosity and surface area, these aerogels are expected to be useful in microfluidics devices and as electronic actuators.

Low-frequency low-field magnetic susceptibility of ferritin and hemosiderin.

Low-frequency low-field magnetic susceptibility measurements were made on four samples of mammalian tissue iron oxide deposits. The samples comprised: (1) horse spleen ferritin; (2) dugong liver hemosiderin; (3) thalassemic human spleen ferritin; and (4) crude thalassemic human spleen hemosiderin. These samples were chosen because Mössbauer spectroscopic measurements on the samples indicated that they exemplified the variation in magnetic and mineral structure found in mammalian tissue iron oxide deposits. The AC-magnetic susceptometry yielded information on the magnetization kinetics of the four samples indicating samples 1, 2, and 3 to be superparamagnetic with values of around 10(11) s(-1) for the pre-exponential frequency factor in the Néel-Arrhenius equation and values for characteristic magnetic anisotropy energy barriers in the range 250-400 K. Sample 4 was indicated to be paramagnetic at all temperatures above 1.3 K. The AC-magnetic susceptometry data also indicated a larger magnetic anisotropy energy distribution in the dugong liver sample compared with samples 1 and 3 in agreement with previous Mössbauer spectroscopic data on these samples. At temperatures below 200 K, samples 1-3 exhibited Curie-Weiss law behavior, indicating weak particle-particle interactions tending to favor antiparallel alignment of the particle magnetic moments. These interactions were strongest for the dugong liver hemosiderin, possibly reflecting the smaller separation between mineral particles in this sample. This is the first magnetic susceptometry study of hemosiderin iron deposits and demonstrates that the AC-magnetic susceptometry technique is a fast and informative method of studying such tissue iron oxide deposits.

[Sick leave II for backache--municipality of Kristiansand. A one-year follow up with and without an outpatient program]. / Sykmelding II på grunn av ryggsmerter--Kristiansand kommune. Ett års oppfølging med og uten tre ukers dagpasientprogram.

186 patients from Kristiansand who had been certified as sick for more than eight weeks because of low back pain were recruited consecutively and studied over a period of one year. 91 of these patients participated for three weeks in an out-patient programme involving physical activity and theoretical education. The control group (95 patients) consisted of 65 patients recruited before the treatment group and 30 recruited after the treatment group. The duration of certified sick leave was reported by the national Insurance Office of Kristiansand. The subjective ratings of low back pain, function and quality of life were stated by all subjects at the time of inclusion in the study and again after six and 12 months. The treatment group also stated their subjective assessment after the three weeks of intervention. The results show a significant improvement of low back pain, function and quality of life in the treatment group only, both following the intervention and after one year. 15% of the treatment group were still certified as unfit for work after one year, as against 23% of the one and 26% of the other control group. These differences were not, however, statistically significant.

Removing a retained placenta by oxytocin--a controlled study.

No increase in maternal plasma oxytocin concentration was detected after administration of 100 IU oxytocin into the umbilical veins of seven women immediately after delivery. The delivery of the placenta was accelerated after umbilical vein injection of 100 IU oxytocin in a placebo-controlled study of 40 women: 12 minutes (4 to 40) in the oxytocin group versus 40 minutes (29 to 40) in the placebo group (median and interquartile ranges), p less than 0.05.

Long-term and withdrawal effects of two different oestrogen-progestogen combinations on lipid and lipoprotein profiles in post-menopausal women.

Serum lipids and lipoproteins were studied in 86 healthy post-menopausal women at 3-monthly intervals throughout 2 yr of treatment with cyclic oestradiol valerate plus cyproterone acetate (E2V + CPA), continuous 17 beta-oestradiol plus norethisterone acetate (E2 + NETA), or placebo. Withdrawal effects were also investigated. Serum oestrogen levels were similar following the 2 hormone regimens. Serum total and low-density-lipoprotein (LDL) cholesterol were significantly reduced by 5-8% during cyclic E2V + CPA therapy and by 15-20% during continuous E2 + NETA treatment. The concentrations remained significantly reduced throughout the 2 yr of treatment. Virtually no changes were observed in the placebo group. High-density-lipoprotein (HDL) cholesterol concentrations were significantly reduced in relation to pretreatment values during the first year of continuous E2 + NETA therapy, but were not significantly different from the levels in the cyclic E2V + CPA or the placebo groups. Serum triglyceride levels remained almost constant in all the groups. Withdrawal of hormone therapy resulted in steep increases in total and LDL-cholesterol, the levels returning to pretreatment values. A similar increase in HDL-cholesterol was observed in the E2 + NETA group, following withdrawal. Vaginal bleeding episodes were experienced by all the women receiving the E2V + CPA regimen and they occurred regularly in 63% of the women. Fifty-two (52) percent of the women receiving E2 + NETA did not bleed at all. The results of the present study suggest that the continuous addition of NETA may enhance the oestrogen-induced changes in total and LDL-cholesterol, whereas only minor changes in the oestrogen-induced effects on these variables are produced by the cyclic addition of CPA. However, in the case of HDL-cholesterol, the antagonistic effect of CPA seems to be moderate in comparison with that of NETA.

Climacteric symptoms after oral and percutaneous hormone replacement therapy.

One hundred and ten (110) healthy early post-menopausal women with mild subjective vasomotor symptoms (mean Kupperman index score 11) participated in a long-term, double-blind, placebo-controlled therapeutic trial. The effects of 2 hormone regimens were evaluated. Group I received percutaneous oestrogen therapy for 2 yr, opposed by oral micronized progesterone (200 mg) during the second year, while Group II received oral 17 beta-oestradiol valerate together with cyproterone acetate (CPA). The serum oestrogen concentrations differed markedly in the 2 treatment groups. In Group I the serum/oestrone/oestradiol ratio was 1 (comparable to the pre-menopausal value), but in group II the ratio was greater than 5. Despite the difference in the serum oestradiol and oestrone concentrations, the mean symptom scores were rapidly and similarly reduced in both treatment groups (P less than 0.001). They remained low throughout the study and were not significantly different from pre-menopausal values.

The long-term effect of oral and percutaneous estradiol on plasma renin substrate and blood pressure.

The long-term effect of percutaneous and oral estrogen replacement therapy on blood pressure, plasma renin substrate, and serum estrogens was examined in a 2 year placebo-controlled study with 110 early postmenopausal women. The women were allocated to four treatment groups: (1) oral cyclical combination of 2 mg estradiol valerate and cyproterone acetate, (2) oral placebo, (3) percutaneous 17 beta-estradiol, supplemented by 200 mg oral progesterone during the second year, or (4) percutaneous placebo cream. Systolic and diastolic blood pressure remained unchanged in both hormone treatment groups, whereas the diastolic blood pressure tended to increase in both placebo groups. Plasma renin substrate increased during oral treatment with estradiol, but remained unchanged with percutaneous estradiol. No correlation was found between blood pressure and plasma renin substrate. During percutaneous administration of estradiol, the serum concentrations of estrone and estradiol continued to rise after 3 months and reached a plateau at 6 months of therapy. Serum estrone but not estradiol showed the same pattern during oral estradiol therapy. No further changes in any of the measured variables were observed in the women treated with percutaneous estradiol after addition of cyclical oral progesterone. We conclude that both oral and percutaneous treatment with estradiol may provide protection against the age-related increase in diastolic blood pressure observed in early postmenopausal women, and that the metabolic steady state is not attained until after 3 months of estradiol therapy.

Continuous oestrogen-progestogen treatment and serum lipoproteins in postmenopausal women.

Serum lipids and lipoproteins were examined in 44 healthy postmenopausal women every 3 months during 1 year of treatment with either continuous oestrogen-norethisterone acetate or placebo. Total serum cholesterol and LDL-cholesterol levels were reduced by approximately 15% and 20% (P less than 0.001), respectively in the hormone group but were unchanged in the placebo group. Serum triglycerides levels remained constant in both groups. HDL-cholesterol levels were significantly reduced by approximately 10% in the hormone group but significant reductions of 5-10% also occurred in the placebo group so that differences between the two groups were only significant after 3 months of treatment. Vaginal bleedings were experienced during the first 3 months by eight of the 21 women receiving hormones, but in only one woman after 9 months of therapy. The addition of norethisterone acetate to postmenopausal oestrogen therapy in clinically relevant doses had no adverse effects on lipoproteins as previously reported, even though administered continuously. Moreover, the low frequency of bleeding with continuous oestrogen-progestogen therapy would make this an appropriate alternative in postmenopausal replacement therapy.

The effect of percutaneous estradiol and natural progesterone on postmenopausal bone loss.

The effect of percutaneous estradiol alone and combined with natural progesterone on postmenopausal bone loss was studied. A total of 57 women who had experienced a natural menopause 6 months to 3 years previously entered the study. After an initial examination the women were allocated in a blinded pattern to treatment with 3 mg of percutaneous estradiol or placebo. The code was broken after 1 year of treatment, and the women receiving estradiol continued with a cyclic addition of progesterone, whereas those receiving placebo continued with placebo. The women were examined every 3 months during the 2 years of treatment. Measurement of the bone mineral content in the forearms (single photon absorptiometry) and the spine and total skeleton (dual photon absorptiometry) showed a significant decrease of 5% to 7% in the placebo group during the 2 years of treatment, whereas it remained constant in all bone compartments in the estradiol group. Addition of progesterone did not influence the results. Biochemical estimates of calcium metabolism changed toward a premenopausal level in the estradiol group but remained unchanged in the placebo group. We conclude that percutaneous estradiol is effective as preventive therapy of postmenopausal bone loss and that addition of progesterone does not influence bone or calcium metabolism.

Long-term effects of percutaneous estrogens and oral progesterone on serum lipoproteins in postmenopausal women.

Serum lipids and lipoproteins were examined in a group of 45 healthy postmenopausal women who were treated for 2 years with either 3 mg of percutaneous estradiol (n = 20) or placebo (n = 25). Percutaneous estradiol was given alone during the first year of treatment and in combination with oral micronized progesterone (200 mg) for 12 days of each cycle during the second year. The women were examined every 3 months throughout the 2 years. Percutaneous estrogen therapy significantly reduced total serum cholesterol and low-density lipoprotein cholesterol, whereas no significant differences were observed in serum triglycerides and high-density lipoprotein cholesterol. Addition of oral progesterone during the second year of treatment did not produce any significant alterations in serum total cholesterol or low-density lipoprotein cholesterol, both of which remained significantly reduced. Serum triglycerides remained virtually unchanged, whereas a slight but significant increase (p less than 0.05) was observed in high-density lipoprotein cholesterol levels at the end of the study period. We conclude that percutaneous estrogen administration produces changes in total serum cholesterol and low-density lipoprotein cholesterol levels similar to those observed after oral estrogen administration. However, the magnitude and time course of the response seem to be modulated by the route of administration. Addition of oral micronized progesterone does not influence the beneficial estrogenic actions on serum lipids and lipoproteins and seems to be a proper "progestogen" in percutaneous estrogen therapy.