Comparative LCA of multi-product processes with non-common products: a systematic approach applied to chlorine electrolysis technologies

Purpose

Multi-product processes are one source of multi-functionality causing widely discussed methodological problems within life cycle assessment. A multi-functionality problem exists for comparative life cycle assessment (LCA) of multi-product processes with non-common products. This work develops a systematic workflow for fixing the multi-functionality problem caused by the non-common products. A novel technology for chlor-alkali electrolysis is analyzed and compared to the industrial standard technology to illustrate the approach and to benchmark the new technology's environmental impact.

Methods

A matrix-based workflow for comparative LCA of multi-product systems is presented. Products are distinguished in main products and by-products based on the reason of process operation. We argue that only main products form the reference flows of the compared multi-product systems. Fixing the multi-functionality problem follows directly from the chosen reference flows. The framework suggests system expansion to fix the multi-functionality problem if non-common main products exist. Non-common by-products still cause a multi-functionality problem. These by-products are systematically identified and the multi-functionality problem is fixed with avoided burden and allocation. A case study applies the workflow for comparing environmental impacts of the standard chlorine electrolysis to a novel process using oxygen-depolarized cathodes. Three scenarios are derived and evaluated. The assessed impact categories are cumulative energy demand, global warming potential, acidification potential, photochemical ozone creation potential, eutrophication potential, and human toxicity potential.

Results and discussion

The proposed workflow minimizes the methodological choices. The multi-functionality problem is systematically fixed based on the distinction between the main products and by-products. Inconsistent solutions are prevented by rigorous identification of unequal by-products within the compared systems. Selecting avoided burden processes or allocation factors is the remaining ambiguous choice common to the standard methods. The case study demonstrates the applicability of the workflow to comparative LCA of multi-product systems. The case study results show lower environmental impacts for the novel electrolysis technology in all practically relevant scenarios and impact categories.

Conclusions

The framework for comparative LCA of multi-product systems with non-common products adds systematic clarity to the general ISO standards. The approach reduces the subjective choices of LCA practitioners to the identification of reason of process operation. This reason is defined if the site-specific economic conditions are known. The matrix-based formulation allows identification of inconsistencies caused by multi-functionality. For the novel electrolysis technology, the results indicate significant potential for environmental impact reduction.     

Involvement of hydrogen sulfide and homocysteine transsulfuration pathway in the progression of kidney fibrosis after ureteral obstruction

Hydrogen sulfide (H₂S) produced by cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE) in the transsulfuration pathway of homocysteine plays a number of pathophysiological roles. Hyperhomocysteinemia is involved in kidney fibrosis. However, the role of H₂S in kidney fibrosis remains to be defined. Here, we investigated the role of H₂S and its acting mechanism in unilateral ureteral obstruction (UO)-induced kidney fibrosis in mice. UO decreased expressions of CBS and CSE in the kidney with decrease of H₂S concentration. Treatment with sodium hydrogen sulfide (NaHS, a H₂S producer) during UO reduced UO-induced oxidative stress with preservations of catalase, copper-zinc superoxide dismutase (CuZnSOD), and manganese superoxide dismutase (MnSOD) expression, and glutathione level. In addition, NaHS mitigated decreases of CBS and CSE expressions, and H₂S concentration in the kidney. NaHS treatment attenuated UO-induced increases in levels of TGF-β1, activated Smad3, and activated NF-κB. This study provided the first evidence of involvement of the transsulfuration pathway and H₂S in UO-induced kidney fibrosis, suggesting that H₂S and its transsulfuration pathway may be a potential target for development of therapeutics for fibrosis-related diseases.     

Sequence polymorphisms in ribosomal RNA genes and variations in chromosomal loci of Oenothera odorata and O. laciniata

Numerous studies on Oenothera species have been investigated for the physiological and ecological characteristics. However, no such an information based on molecular cytogenetic has yet been introduced, in turn, is very essential for identifying sequence polymorphisms of rRNA genes with their loci on mitotic phases for further biological researches. In this study, sequence variations of rRNA genes in Oenothera odorata and O. laciniata were examined to identify informative factors as unique or repeat sequences in intra- and inter-specific variations. Intra-specific variation revealed that the sequences of the rRNA genes including the spacer regions were highly conserved revealing only a few variations. From the inter-specific variation, spacer regions of species were completely different as (1) non-homologous sequences in NTS and (2) different type repeat sequences in ITS 1, 2 and 5.8S rRNA, whereas the remaining coding regions were highly conserved. FISH was carried out on mitotic phases using the 5S rDNA of the analyzed sequences. From the interphase and metaphase chromosomes of the examined species, two loci of 5S rDNA in O. odorata and four loci in O. laciniata were confirmed on the telomeric region of the short arm. Due to the small size and unclear centromere of the chromosomes, karyotype could not be completed. However, we confirmed that the chromosomes are organized by meta- and acrocentric chromosomes and the chromosomes with identified loci were assumed to be paired by the location of loci at the telomeric region on the short arm with relative lengths.     

The community structures of the coniferous and deciduous dead wood‐dwelling arthropods in Korea

We examined the structure of the arthropod community among deciduous and coniferous dead woods along the process of wood decay. We collected dead wood‐dwelling arthropods from April 2010 to October 2011 by using a vacuum aspirator and an electric chain saw in three areas (Mt. Woonak, Mt. Wolchul, Mt. Jingang) in Korea. We identified them to species levels and classified them into functional groups. We collected 8792 arthropods (5 classes, 20 orders, 58 families, and 93 species). The species richness and abundance of arthropods increased with the progress of decay in dead woods. The evenness index seemed to be shown at a lower value at late decay stage than at early‐ and mid‐decay stages. The diversity index (H′) in conifers was lower than that in deciduous dead woods at the early decay stage but this situation was reversed at the late decay stage. Arthropod communities of functional groups, except the xylophagous insects, did not differ in the variables, but the proportion of xylophagous insects increased as the decay stages progressed. The abundance of arthropods and xylophagous was statistically significantly different. The patterns generated by non‐metric multidimensional scaling in the overall arthropod community composition revealed that the species composition between study areas were significantly different. We confirmed that dead woods play very important roles as arthropods' habitats. Thus, we suggest that the role of dead woods should be emphasized in the management of forest ecosystems.     

Development and Validation of a Smartphone Addiction Scale (SAS)

Objective

The aim of this study was to develop a self-diagnostic scale that could distinguish smartphone addicts based on the Korean self-diagnostic program for Internet addiction (K-scale) and the smartphone''s own features. In addition, the reliability and validity of the smartphone addiction scale (SAS) was demonstrated.

Methods

A total of 197 participants were selected from Nov. 2011 to Jan. 2012 to accomplish a set of questionnaires, including SAS, K-scale, modified Kimberly Young Internet addiction test (Y-scale), visual analogue scale (VAS), and substance dependence and abuse diagnosis of DSM-IV. There were 64 males and 133 females, with ages ranging from 18 to 53 years (M = 26.06; SD = 5.96). Factor analysis, internal-consistency test, t-test, ANOVA, and correlation analysis were conducted to verify the reliability and validity of SAS.

Results

Based on the factor analysis results, the subscale “disturbance of reality testing” was removed, and six factors were left. The internal consistency and concurrent validity of SAS were verified (Cronbach''s alpha = 0.967). SAS and its subscales were significantly correlated with K-scale and Y-scale. The VAS of each factor also showed a significant correlation with each subscale. In addition, differences were found in the job (p<0.05), education (p<0.05), and self-reported smartphone addiction scores (p<0.001) in SAS.

Conclusions

This study developed the first scale of the smartphone addiction aspect of the diagnostic manual. This scale was proven to be relatively reliable and valid.     

Light Transmission and Preference of Eye Patches for Occlusion Treatment

Purpose

To investigate light transmission and preference for six eye patches for occlusion therapy.

Methods

Six patches were examined, including; Ortopad Fun Pack, Ortopad Flesh, Kawamoto A-1, Kawamoto A-2, 3M Opticlude, and Everade Eye Guard. The size and the presence of a light blocking pad of patches were investigated. The amount of light transmitted through the patches was evaluated, using a digital light meter and a model eye, in three different environments; indoors with fluorescent light, outdoors on a sunny day, and strong light from illuminator. After patching the normal eye, the flash visual evoked potential (VEP) was measured. Thirty patients with amblyopia or horizontal strabismus, who received occlusion therapy as initial treatment, were included. After using all six patches, patients completed a 7-item questionnaire regarding the patch preference for size, color and shape, adhesive power, pain with removal, skin irritation after removing patch, parent’s preference and overall opinion.

Results

All patches had a light-blocking pad, except the 3M Nexcare. Ortopad had the strongest light blocking power in the three environments, and the 3M Nexcare had the weakest power. In flash VEP, Ortopad and Kawamoto patches showed flat, but 3M Nexcare and Everade Eye Guard showed normal response. There were significant preferential differences among the patches in all the items of the questionnaire (P<0.05). In comparison between the patches respectively, 3M Nexcare received the lowest satisfaction in pain when removing a patch and skin irritation after removing a patch. Kawamoto A-2 received the lowest score in the overall satisfaction.

Conclusions

We found differences in the light-blocking power and in the preference of the various patches for the occlusion treatment. This is a pilot study regarding only characteristics and preferences of patches. Further clinical studies regarding the relationship between characteristics or preferences of patches and outcomes of occlusion treatment are needed.     

Prediction of drugs having opposite effects on disease genes in a directed network

Background

Developing novel uses of approved drugs, called drug repositioning, can reduce costs and times in traditional drug development. Network-based approaches have presented promising results in this field. However, even though various types of interactions such as activation or inhibition exist in drug-target interactions and molecular pathways, most of previous network-based studies disregarded this information.

Methods

We developed a novel computational method, Prediction of Drugs having Opposite effects on Disease genes (PDOD), for identifying drugs having opposite effects on altered states of disease genes. PDOD utilized drug-drug target interactions with ‘effect type’, an integrated directed molecular network with ‘effect type’ and ‘effect direction’, and disease genes with regulated states in disease patients. With this information, we proposed a scoring function to discover drugs likely to restore altered states of disease genes using the path from a drug to a disease through the drug-drug target interactions, shortest paths from drug targets to disease genes in molecular pathways, and disease gene-disease associations.

Results

We collected drug-drug target interactions, molecular pathways, and disease genes with their regulated states in the diseases. PDOD is applied to 898 drugs with known drug-drug target interactions and nine diseases. We compared performance of PDOD for predicting known therapeutic drug-disease associations with the previous methods. PDOD outperformed other previous approaches which do not exploit directional information in molecular network. In addition, we provide a simple web service that researchers can submit genes of interest with their altered states and will obtain drugs seeming to have opposite effects on altered states of input genes at http://gto.kaist.ac.kr/pdod/index.php/main.

Conclusions

Our results showed that ‘effect type’ and ‘effect direction’ information in the network based approaches can be utilized to identify drugs having opposite effects on diseases. Our study can offer a novel insight into the field of network-based drug repositioning.

     

A New Equation to Estimate Muscle Mass from Creatinine and Cystatin C

Background

With evaluation for physical performance, measuring muscle mass is an important step in detecting sarcopenia. However, there are no methods to estimate muscle mass from blood sampling.

Methods

To develop a new equation to estimate total-body muscle mass with serum creatinine and cystatin C level, we designed a cross-sectional study with separate derivation and validation cohorts. Total body muscle mass and fat mass were measured using dual-energy x-ray absorptiometry (DXA) in 214 adults aged 25 to 84 years who underwent physical checkups from 2010 to 2013 in a single tertiary hospital. Serum creatinine and cystatin C levels were also examined.

Results

Serum creatinine was correlated with muscle mass (P < .001), and serum cystatin C was correlated with body fat mass (P < .001) after adjusting glomerular filtration rate (GFR). After eliminating GFR, an equation to estimate total-body muscle mass was generated and coefficients were calculated in the derivation cohort. There was an agreement between muscle mass calculated by the novel equation and measured by DXA in both the derivation and validation cohort (P < .001, adjusted R² = 0.829, β = 0.95, P < .001, adjusted R² = 0.856, β = 1.03, respectively).

Conclusion

The new equation based on serum creatinine and cystatin C levels can be used to estimate total-body muscle mass.     

Prolonged Cerebral Circulation Time Is the Best Parameter for Predicting Vasospasm during Initial CT Perfusion in Subarachnoid Hemorrhagic Patients

Purpose

We sought to imitate angiographic cerebral circulation time (CCT) and create a similar index from baseline CT perfusion (CTP) to better predict vasospasm in patients with subarachnoid hemorrhage (SAH).

Methods

Forty-one SAH patients with available DSA and CTP were retrospectively included. The vasospasm group was comprised of patients with deterioration in conscious functioning and newly developed luminal narrowing; remaining cases were classified as the control group. The angiography CCT (XA-CCT) was defined as the difference in TTP (time to peak) between the selected arterial ROIs and the superior sagittal sinus (SSS). Four arterial ROIs were selected to generate four corresponding XA-CCTs: the right and left anterior cerebral arteries (XA-CCT_RA2 and XA-CCT_LA2) and right- and left-middle cerebral arteries (XA-CCT_RM2 and XA-CCT_LM2). The CCTs from CTP (CT-CCT) were defined as the differences in TTP from the corresponding arterial ROIs and the SSS. Correlations of the different CCTs were calculated and diagnostic accuracy in predicting vasospasm was evaluated.

Results

Intra-class correlations ranged from 0.96 to 0.98. The correlations of XA-CCT_RA2, XA-CCT_RM2, XA-CCT_LA2, and XA-CCT_LM2 with the corresponding CT-CCTs were 0.64, 0.65, 0.53, and 0.68, respectively. All CCTs were significantly prolonged in the vasospasm group (5.8–6.4 s) except for XA-CCT_LA2. CT-CCT_A2 of 5.62 was the optimal cut-off value for detecting vasospasm with a sensitivity of 84.2% and specificity 82.4%

Conclusion

CT-CCTs can be used to interpret cerebral flow without deconvolution algorithms, and outperform both MTT and TTP in predicting vasospasm risk. This finding may help facilitate management of patients with SAH.