Published Date 19 August 2016, Vol.98:39–44,doi:10.1016/j.polymer.2016.06.008
Title
Concentration dependent structure of poly(styrene-b-ethylene-alt-propylene) in 1-phenyldodecane
Author
Marcel Ockhoma Tapa
Soo-Hyung Choi,
Department of Chemical Engineering, Hongik University, Seoul 04066, Republic of Korea
Received 14 January 2016. Revised 22 May 2016. Accepted 1 June 2016. Available online 3 June 2016. Highlights
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Structure of block copolymer solution in a nearly neutral solvent is investigated using small-angle X-ray scattering (SAXS).
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The nearly neutral solvent mainly attenuates the incompatibility between the two blocks.
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Slight selective nature of the solvent leads to uneven solvent distribution on the two domains.
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Intensive SAXS analysis reveals quantitative estimate of averaged solvent distribution.
Abstract
The concentration and temperature dependence of the structure formed by poly(styrene-b-ethylene-alt-propylene) (PS-PEP) diblock copolymer in 1-phenyldodecane, a nearly neutral solvent, was studied using small-angle X-ray scattering (SAXS). As the polymer concentration decreases from 100 wt% to 10 wt%, PS-PEP (Mn,PS = 42,000 g/mol, Mn,PEP = 62,000 g/mol, Mw/Mn = 1.04) solutions form lamellae, hexagonally packed cylinders, and disordered structure. The results show that the neutral solvent mainly attenuates the unfavorable interaction between PS and PEP blocks, and thus reduces the domain spacing. The slight selective nature of the solvent, however, leads to uneven solvent distribution on the two domains. In particular, SAXS analysis equipped with the form factor fitting results in quantitative estimate of averaged solvent composition in micro-phase separated domains.
Fatigue and dizziness can be difficult to diagnose and treat.Photo Credit sick woman image by forca from Fotolia.com
Overview
Dizziness and fatigue are two symptoms frequently reported to physicians in primary care practices. In a study conducted by Drs. Kroenke and colleagues and cited in "The Archives of Internal Medicine" in 1990 only 39% of patients reported receiving treatment that brought relief from these symptoms. Sometimes the symptoms have easy solutions but often together and separately these symptoms point to a variety of underlying causes that can prove difficult to diagnose and treat. Both dizziness and fatigue can occur because of a medical problem, lifestyle or a psychological issue.
Characterizing Dizziness and Fatigue
While dizziness has a limited number of concrete and very specific definitions, causes, and treatments, fatigue often results from putting in too many hours at work or physical exertion. However, fatigue can also demonstrate the sign of a more serious condition including, but not limited to, heart disease, diabetes, low thyroid, cancer and depression. Four types of dizziness described by the Mayo Clinic include vertigo or a feeling of spinning, feeling faint, loss of balance or equilibrium and lightheadedness. Each has multiple causes and treatments. Fatigue is defined as physical and/or mental exhaustion that can result from stress, medication, overwork or mental and physical illness or disease.
Medical Issues
Fatigue and dizziness can affect each other as illustrated in the twin syndromes chronic fatigue and fibromyalgia. According to the Centers for Disease Control both of these syndromes have complex causes, often of unknown origin. Obtaining refreshing sleep can be problematic for patients with both of these diseases and lack of sleep causes fatigue, lack of energy and exhaustion. Lack of refreshing sleep can also cause dizziness and dizziness and can lead to fatigue.
Your pharmaceutical cabinet can also be implicated in both fatigue and dizziness. Many medications cite warnings not to drive due to potential symptoms of fatigue and dizziness. Dizziness is also a side-effect of anti-seizure drugs, sedatives and tranquilizers.
A particular heart condition called “heart block”, which a problem with the heart’s rhythm, leads to symptoms of both dizziness and fatigue in patients who have this problem.
Lifestyle Issues
Unlike chronic fatigue and fibromyalgia and other medical problems such as sleep apnea, lack of sleep can be a lifestyle choice and can lead to fatigue and dizziness. According to the National Sleep Foundation several factors can lead to a night of bad sleep including poor sleep hygiene. To improve your sleep hygiene, don't nap during the day, stay away from large meals, caffeine, nicotine and alcohol near bedtime. Get plenty of exercise. To associate your bed with sleep don't watch TV, read or listen to the radio while in bed. Don't bring your problems to bed. Other lifestyle issues that may or may not be choices that can cause fatigue include overwork, living a stressful life and living in a stressful environment.
Psychological Issues
Anxiety and depression both play a role in dizziness and fatigue. Symptoms of anxiety and hyperventilation which often go hand in hand cause lightheadedness, one of the four types of dizziness described earlier. According to the University of Maryland Medical Center, treatment for anxiety can include a combination of medication, cognitive behavioral therapy and exercise. Fatigue can be a symptom of depression. Those who become depressed often sleep too much and fatigue is the result. The Mayo Clinic recommends getting appropriate diagnosis and treatment. Treatment often includes a combination of medication and counseling.
A woman with six-pack abs holds two hand weights.Photo Credit Max5799/iStock/Getty Images
Men and women with six-pack abs adorn fitness magazine covers and star in ads for supplements and gyms. But now, the impressive six-pack isn't enough. Defined muscular middles on the likes of Taye Diggs and Bradley Cooper reveal an elusive eight-pack. This "step up" from a six-pack comes from a combination of diligent exercise, meticulous diet and genetic blessing. Achieving an eight-pack is no easy feat and may not be achievable by everyone, but much of the work begins in the kitchen.
The Eight-Pack Defined
When your body fat is low enough -- usually at least 6 to 9 percent for men or 16 to 19 percent for women -- the muscles of your rectus abdominis may show when you bare your midriff. These are the muscles closest to the surface and appear cut or defined when the layer of fat covering them has mostly disappeared.
Several muscles make up the rectus abdominis region; the eight-pack results when you can see the four pairs that are separated by the linea alba, a strip of connective tissue that draws a line down the center of your core. Three bands of connective tissue between each of the muscle pairs form the cut lines, or valleys, between each of the packs. Developing the valley between the lowest two sets of muscles turns a six-pack into the eight-pack look.
The degree to which you can develop these valleys does depend a lot on genetics. But, without conscientious attention to diet and exercise -- you'll never achieve a washboard belly. Most men will need to reduce their body fat to less than 6 percent and women to less than 16 percent to achieve an eight-pack.
Eating for an Eight-Pack
Protein is a key component in an abs diet. This macronutrient supports your gym efforts to build muscle all over your body. More muscle boosts your metabolism and stimulates greater calorie burn and fat loss. Every meal -- whether it's a snack or sit-down -- should contain a portion of protein such as 4 ounces of lean meat, a scoop of whey, 1/2 to 1 cup of low-fat dairy or 3 ounces of soy.
Sugar, alcohol, processed foods and refined carbohydrates, including white bread and rice, are off the table. Instead, most of your carbohydrates come from vegetables and fruits with the occasional 1/2-cup serving of whole grains at one or two daily meals.
Consuming small meals every two to three hours also supports the goal of achieving an eight-pack because it prevents you from feeling engorged, helps you get in all the calories and protein you need and prevents feelings of deprivation. However, eating mini meals six to eight times per day isn't essential to achieving an eight-pack. Just avoid skipping meals and starving yourself -- which can promote the release of stress hormones that promote storage of fat in your belly -- but don't go out of your way to eat when you're not hungry or your schedule doesn't allow it.
Abs Diet Sample Foods
Include a variety of foods in your eight-pack meal plan to expose your body to a wide array of nutrients. Ideal high-protein foods to include are egg whites, tuna and other white fish, chicken breast and flank steak. Cottage cheese, Greek yogurt and tofu can also support your abs diet. Leafy greens, broccoli, cauliflower, summer squash and sweet potatoes are options for vegetables. Choose 1/2 to 1 cup of quinoa, oats and brown rice as carbohydrate sources daily. Apples, oranges, grapefruit and blueberries make good fruit choices.
An eight-pack doesn't come from a fat-free diet, either. Go for 1/4 cup of walnuts or pumpkin seeds or a 4-ounce serving of salmon daily, for example, to get healthy unsaturated fats that assist with nutrient absorption and provide essential hormone and brain support.
Breakfast might consist of 1/2 cup of dry oats cooked in water served with one-half of a grapefruit and 6 egg whites; lunch might be composed of a large green salad topped with chicken breast and pumpkin seeds; dinner is white fish with a small sweet potato and a cup or two of steamed broccoli. Between meals, have a can of water-packed tuna with celery and mustard; 1 cup of cottage cheese mixed with walnuts and chopped apple; or a whey protein shake made with plain yogurt and blueberries.
Eight-Pack Exercise and Expectations
Without focused abdominal exercise, an eight-pack is only a pipe dream even if you're following all the right dietary provisions. Perform five or six exercises every other day for one to three sets of eight to 12 repetitions to build a strong core musculature. This will help contribute to the muscles and definition that will be revealed with an optimal diet, but it will also provide balanced strength at the core so you're functionally, as well as aesthetically, developed. Traditional crunches while consciously contracting your abdominal muscles, hanging leg raises, plank holds, captain's chair crunches, bicycle maneuvers and decline bench curl-ups are examples of exercises to include.
Keep your sights realistic too. Not everyone is genetically predisposed to sculpting an eight-pack. Some people's abdominal muscles are staggered or angled in a way that doesn't develop into a clear set of "packs." You may diet yourself down to an extremely low body fat level and find that only four of your abdominal muscles are visible.
In structural biology, a protein subunit is a single protein molecule that assembles (or "coassembles") with other protein molecules to form a protein complex. Some naturally occurring proteins have a relatively small number of subunits and therefore described as oligomeric, for example hemoglobin or DNA polymerase. Others may consist from a very large number of subunits and therefore described as multimeric, for example microtubules and other cytoskeletonproteins. The subunits of a multimeric protein may be identical, homologous or totally dissimilar and dedicated to disparate tasks.
Rendering of HLA-A11 showing the α (A*1101 gene product) and β (Beta-2 microglobin)subunits. This receptor has a bound peptide (in the binding pocket) of heterologous origin that also contributes to function.
In some protein assemblies, one subunit may be a "catalytic subunit" that enzymatically catalyzes a reaction, whereas a "regulatory subunit" will facilitate or inhibit the activity. Although telomerase has telomerase reverse transcriptase as a catalytic subunit, regulation is accomplished by factors outside of the protein.[1] An enzyme composed of both regulatory and catalytic subunits when assembled is often referred to as a holoenzyme. For example, class I phosphoinositide 3-kinase is composed of a p110 catalytic subunit and a p85 regulatory subunit.[2] One subunit is made of one polypeptide chain. A polypeptide chain has one gene coding for it – meaning that a protein must have one gene for each unique subunit.
A subunit is often named with a Greek or Roman letter, and the numbers of this type of subunit in a protein is indicated by a subscript. For example, ATP synthase has a type of subunit called α. Three of these are present in the ATP synthase molecule, and is therefore designated α3. Larger groups of subunits can also the specified, like α3β3-hexamer and c-ring.
Subunit Vaccines
A subunit vaccine presents an antigen to the immune system without introducing viral particles, whole or otherwise. One method of production involves isolation of a specific protein from a virus and administering this by itself. A weakness of this technique is that isolated proteins can be denatured and will then become associated with antibodies different from the desired antibodies. A second method of making a subunit vaccine involves putting an antigen's gene from the targeted virus or bacterium into another virus (virus vector), yeast (yeast vector in the case of the hepatitis B vaccine[3] or attenuated bacterium (bacterial vector) to make a recombinant virus or bacteria to serve as the important component of a recombinant vaccine (called a recombinant subunit vaccine). The recombinant vector that is genomically modified will express the antigen. The antigen (one or more subunits of protein) is extracted from the vector.[4] Just like the highly successful subunit vaccines, the recombinant-vector-produced antigen will be of little to no risk to the patient. This is the type of vaccine currently in use for hepatitis B,[5] and it is experimentally popular, being used to try to develop new vaccines for difficult-to-vaccinate-against viruses such as ebolavirus and HIV.[6]
Vi capsular polysaccharide vaccine (ViCPS) is another subunit vaccine (contains the signature polysaccharide linked to the Vi capsular antigen), in this case, against typhoidcaused by the Typhi serotype of Salmonella.[7] It is also called a conjugate vaccine, in which a polysaccharide antigen has been covalently attached to a carrier protein for T-cell-dependent antigen processing (utilizing MHC II).[8]
^Manuela Raffatellu1, Daniela Chessa1, R. Paul Wilson, Richard Dusold, Salvatore Rubino, Andreas J. Bäumler (June 2005). "The Vi Capsular Antigen of Salmonella enterica Serotype Typhi Reduces Toll-Like Receptor-Dependent Interleukin-8 Expression in the Intestinal Mucosa". Infect. Immun.73 (6). pp. 3367–3374. doi:10.1128/IAI.73.6.3367-3374.2005.
^Brenda A. Wilson, Abigail A. Salyers, Dixie D. Whitt, Malcolm E. Winkler. Bacterial Pathogenesis, A Molecular Approach, Third Edition. ASM Press, American Society for Microbiology, 1752 N St. NW, Washington, D.C. 20036-2904, copyrightyear=2011.
Dilip Gore; Reecha Pandit (2011). "In silico Identification of Cell Surface Antigens in Neisseria meningitidis". Biomirror2: 1–5.
